Publications of Brian Hare
%%
@article{fds369844,
Author = {Salomons, H and Smith, KCM and Callahan-Beckel, M and Callahan, M and Levy, K and Kennedy, BS and Bray, EE and Gnanadesikan, GE and Horschler,
DJ and Gruen, M and Tan, J and White, P and vonHoldt, BM and MacLean, EL and Hare, B},
Title = {Response to Hansen Wheat et al.: Additional analysis further
supports the early emergence of cooperative communication in
dogs compared to wolves raised with more human
exposure.},
Journal = {Learning & behavior},
Volume = {51},
Number = {2},
Pages = {131-134},
Year = {2023},
Month = {June},
Abstract = {Here, we address Hansen Wheat et al.'s commentary in this
journal in response to Salomons et al. Current Biology,
31(14), 3137-3144.E11, (2021). We conduct additional
analyses in response to Hansen Wheat et al.'s two main
questions. First, we examine the claim that it was the move
to a human home environment which enabled the dog puppies to
outperform the wolf puppies in gesture comprehension tasks.
We show that the youngest dog puppies who had not yet been
individually placed in raisers' homes were still highly
skilled, and outperformed similar-aged wolf puppies who had
higher levels of human interaction. Second, we address the
claim that willingness to approach a stranger can explain
the difference between dog and wolf pups' ability to succeed
in gesture comprehension tasks. We explain the various
controls in the original study that render this explanation
insufficient, and demonstrate via model comparison that the
covariance of species and temperament also make this parsing
impossible. Overall, our additional analyses and
considerations support the domestication hypothesis as laid
out by Salomons et al. Current Biology, 31(14),
3137-3144.E11, (2021).},
Doi = {10.3758/s13420-023-00576-2},
Key = {fds369844}
}
@article{fds363720,
Author = {Zhou, W and Hare, B},
Title = {The Early Expression of Blatant Dehumanization in Children
and Its Association with Outgroup Negativity.},
Journal = {Human nature (Hawthorne, N.Y.)},
Volume = {33},
Number = {2},
Pages = {196-214},
Year = {2022},
Month = {June},
Abstract = {Dehumanization is observed in adults across cultures and is
thought to motivate human violence. The age of its first
expression remains largely untested. This research
demonstrates that diverse representations of humanness,
including a novel one, readily elicit blatant dehumanization
in adults (N = 482) and children (aged 5-12;
N = 150). Dehumanizing responses in both age groups are
associated with support for outgroup inferiority. Similar to
the link previously observed in adults, dehumanization by
children is associated with a willingness to punish outgroup
transgressors. These findings suggest that exposure to
cultural norms throughout adolescence and adulthood are not
required for the development of outgroup
dehumanization.},
Doi = {10.1007/s12110-022-09427-x},
Key = {fds363720}
}
@article{fds359024,
Author = {Rimbach, R and Amireh, A and Allen, A and Hare, B and Guarino, E and Kaufman, C and Salomons, H and Pontzer, H},
Title = {Total energy expenditure of bottlenose dolphins (Tursiops
truncatus) of different ages.},
Journal = {The Journal of experimental biology},
Year = {2021},
Month = {July},
Abstract = {Marine mammals are thought to have an energetically
expensive lifestyle because endothermy is costly in marine
environments. However, measurements of total energy
expenditure (TEE; kcal/day) are available only for a limited
number of marine mammals, because large body size and
inaccessible habitats make TEE measurements expensive and
difficult for many taxa. We measured TEE in 10 adult common
bottlenose dolphins (Tursiops truncatus) living in natural
seawater lagoons at two facilities (Dolphin Research Center
and Dolphin Quest) using the doubly labeled water method. We
assessed the relative effects of body mass, age, and
physical activity on TEE. We also examined whether TEE of
bottlenose dolphins, and more generally marine mammals,
differs from that expected for their body mass compared to
other eutherian mammals, using phylogenetic least squares
(PGLS) regressions. There were no differences in body mass
or TEE (unadjusted TEE and TEE adjusted for fat free mass
(FFM)) between dolphins from both facilities. Our results
show that Adjusted TEE decreased and fat mass (FM) increased
with age. Different measures of activity were not related to
age, body fat or Adjusted TEE. Both PGLS and the
non-phylogenetic linear regression indicate that marine
mammals have an elevated TEE compared to terrestrial
mammals. However, bottlenose dolphins expended 17.1% less
energy than other marine mammals of similar body mass. The
two oldest dolphins (>40 years) showed a lower TEE, similar
to the decline in TEE seen in older humans. To our
knowledge, this is the first study to show an age-related
metabolic decline in a large non-human mammal.},
Doi = {10.1242/jeb.242218},
Key = {fds359024}
}
@article{fds358337,
Author = {Salomons, H and Smith, KCM and Callahan-Beckel, M and Callahan, M and Levy, K and Kennedy, BS and Bray, EE and Gnanadesikan, GE and Horschler,
DJ and Gruen, M and Tan, J and White, P and vonHoldt, BM and MacLean, EL and Hare, B},
Title = {Cooperative Communication with Humans Evolved to Emerge
Early in Domestic Dogs.},
Journal = {Current biology : CB},
Volume = {31},
Number = {14},
Pages = {3137-3144.e11},
Year = {2021},
Month = {July},
Abstract = {Although we know that dogs evolved from wolves, it remains
unclear how domestication affected dog cognition. One
hypothesis suggests dog domestication altered social
maturation by a process of selecting for an attraction to
humans.<sup>1-3</sup> Under this account, dogs became more
flexible in using inherited skills to cooperatively
communicate with a new social partner that was previously
feared and expressed these unusual social skills early in
development.<sup>4-6</sup> Here, we comparedog (n = 44) and
wolf (n = 37) puppies, 5-18 weeks old, on a battery of
temperament and cognition tasks. We find that dog puppies
are more attracted to humans, read human gestures more
skillfully, and make more eye contact with humans than wolf
puppies. The two species are similarly attracted to familiar
objects and perform similarly on non-social measures of
memory and inhibitory control. These results are consistent
with the idea that domestication enhanced the
cooperative-communicative abilities of dogs as selection for
attraction to humans altered social maturation.},
Doi = {10.1016/j.cub.2021.06.051},
Key = {fds358337}
}
@article{fds356121,
Author = {Pontzer, H and Brown, MH and Wood, BM and Raichlen, DA and Mabulla, AZP and Harris, JA and Dunsworth, H and Hare, B and Walker, K and Luke, A and Dugas, LR and Schoeller, D and Plange-Rhule, J and Bovet, P and Forrester, TE and Thompson, ME and Shumaker, RW and Rothman, JM and Vogel, E and Sulistyo, F and Alavi, S and Prasetyo, D and Urlacher, SS and Ross, SR},
Title = {Evolution of water conservation in humans.},
Journal = {Current biology : CB},
Volume = {31},
Number = {8},
Pages = {1804-1810.e5},
Year = {2021},
Month = {April},
Abstract = {To sustain life, humans and other terrestrial animals must
maintain a tight balance of water gain and water loss each
day.<sup>1-3</sup> However, the evolution of human water
balance physiology is poorly understood due to the absence
of comparative measures from other hominoids. While humans
drink daily to maintain water balance, rainforest-living
great apes typically obtain adequate water from their food
and can go days or weeks without drinking<sup>4-6</sup>.
Here, we compare isotope-depletion measures of water
turnover (L/d) in zoo- and rainforest-sanctuary-housed apes
(chimpanzees, bonobos, gorillas, and orangutans) with 5
diverse human populations, including a hunter-gatherer
community in a semi-arid savannah. Across the entire sample,
water turnover was strongly related to total energy
expenditure (TEE, kcal/d), physical activity, climate
(ambient temperature and humidity), and fat free mass. In
analyses controlling for those factors, water turnover was
30% to 50% lower in humans than in other apes despite
humans' greater sweating capacity. Water turnover in zoo and
sanctuary apes was similar to estimated turnover in wild
populations, as was the ratio of water intake to dietary
energy intake (∼2.8 mL/kcal). However, zoo and sanctuary
apes ingested a greater ratio of water to dry matter of
food, which might contribute to digestive problems in
captivity. Compared to apes, humans appear to target a lower
ratio of water/energy intake (∼1.5 mL/kcal). Water stress
due to changes in climate, diet, and behavior apparently led
to previously unknown water conservation adaptations in
hominin physiology.},
Doi = {10.1016/j.cub.2021.02.045},
Key = {fds356121}
}
@article{fds353051,
Author = {Bray, EE and Gruen, ME and Gnanadesikan, GE and Horschler, DJ and Levy,
KM and Kennedy, BS and Hare, BA and MacLean, EL},
Title = {Dog cognitive development: a longitudinal study across the
first 2 years of life.},
Journal = {Animal cognition},
Volume = {24},
Number = {2},
Pages = {311-328},
Year = {2021},
Month = {March},
Abstract = {While our understanding of adult dog cognition has grown
considerably over the past 20 years, relatively little is
known about the ontogeny of dog cognition. To assess the
development and longitudinal stability of cognitive traits
in dogs, we administered a battery of tasks to 160 candidate
assistance dogs at 2 timepoints. The tasks were designed to
measure diverse aspects of cognition, ranging from executive
function (e.g., inhibitory control, reversal learning,
memory) to sensory discrimination (e.g., vision, audition,
olfaction) to social interaction with humans. Subjects first
participated as 8-10-week-old puppies, and then were
retested on the same tasks at ~ 21 months of age. With few
exceptions, task performance improved with age, with the
largest effects observed for measures of executive function
and social gaze. Results also indicated that individual
differences were both early emerging and enduring; for
example, social attention to humans, use of human
communicative signals, independent persistence at a problem,
odor discrimination, and inhibitory control all exhibited
moderate levels of rank-order stability between the two
timepoints. Using multiple regression, we found that young
adult performance on many cognitive tasks could be predicted
from a set of cognitive measures collected in early
development. Our findings contribute to knowledge about
changes in dog cognition across early development as well as
the origins and developmental stability of individual
differences.},
Doi = {10.1007/s10071-020-01443-7},
Key = {fds353051}
}
@article{fds355599,
Author = {Hare, B and Ferrans, M},
Title = {Is cognition the secret to working dog success?},
Journal = {Animal cognition},
Volume = {24},
Number = {2},
Pages = {231-237},
Year = {2021},
Month = {March},
Abstract = {Dogs' special relationship with humans not only makes them
ubiquitous in our lives, but working dogs specifically
perform essential functions for us such as sniffing out
bombs and pulling wheelchairs for the disabled. To enhance
the performance of working dogs, it is essential to
understand the cognitive skills that underlie and lead to
their success. This review details recent work in the field
of canine cognition, including how dogs have evolved
socio-cognitive skills that mimic or, in some cases, rival
even our closest primate relatives. We review how these
findings have laid the foundation for new studies that hope
to help enhance working dog programs. This includes work
that has begun to reveal the development and stability of
the most important traits for service work. Discoveries like
these suggest the possibility of translating what we have
learned to improve breeding, selection, and training for
these jobs. The latest research we review here shows promise
in contributing to the production of better dogs and,
consequently, more help for people.},
Doi = {10.1007/s10071-021-01491-7},
Key = {fds355599}
}
@article{fds353832,
Author = {Bowie, A and Walker, K and Bunnell, G and Morel, D and Minesi, F and Belais, R and Hare, B},
Title = {Assessing conservation attitudes and behaviors of Congolese
children neighboring the world's first bonobo (Pan paniscus)
release site.},
Journal = {American journal of primatology},
Volume = {83},
Number = {1},
Pages = {e23217},
Year = {2021},
Month = {January},
Abstract = {Poaching and habitat destruction in the Congo Basin threaten
African great apes including the bonobo (Pan paniscus),
chimpanzees (Pan troglodytes), and gorillas (Gorilla spp.)
with extinction. One way to combat extinction is to
reintroduce rescued and rehabilitated apes and repopulate
native habitats. Reintroduction programs are only successful
if they are supported by local populations. Ekolo ya Bonobo,
located in Equateur province of the Democratic Republic of
Congo (DRC), is the world's only reintroduction site for
rehabilitated bonobos. Here we assess whether children, of
the Ilonga-Pôo, living adjacent to Ekolo ya Bonobo
demonstrate more pro-ape conservation attitudes than
children living in, Kinshasa, the capital city. We examined
children's attitudes toward great apes because children are
typically the focus of conservation education programs. We
used the Great Ape Attitude Questionnaire to test the
Contact Hypothesis, which posits that proximity to great ape
habitat influences pro-conservation attitudes toward great
apes. Ilonga-Pôo children who live in closer contact with
wild bonobos felt greater responsibility to protect great
apes compared to those in Kinshasa who live outside the
natural habitat of great apes. These results suggest that
among participants in the DRC, spatial proximity to a
species fosters a greater sense of responsibility to protect
and conserve. These results have implications for the
successful implementation of great ape reintroduction
programs in the Congo Basin. The data analyzed in this study
were collected in 2010 and therefore provide a baseline for
longitudinal study of this reintroduction
site.},
Doi = {10.1002/ajp.23217},
Key = {fds353832}
}
@article{fds353050,
Author = {Gnanadesikan, GE and Hare, B and Snyder-Mackler, N and Call, J and Kaminski, J and Miklósi, Á and MacLean, EL},
Title = {Breed Differences in Dog Cognition Associated with
Brain-Expressed Genes and Neurological Functions.},
Journal = {Integrative and comparative biology},
Volume = {60},
Number = {4},
Pages = {976-990},
Year = {2020},
Month = {October},
Abstract = {Given their remarkable phenotypic diversity, dogs present a
unique opportunity for investigating the genetic bases of
cognitive and behavioral traits. Our previous work
demonstrated that genetic relatedness among breeds accounts
for a substantial portion of variation in dog cognition.
Here, we investigated the genetic architecture of breed
differences in cognition, seeking to identify genes that
contribute to variation in cognitive phenotypes. To do so,
we combined cognitive data from the citizen science project
Dognition.com with published breed-average genetic
polymorphism data, resulting in a dataset of 1654
individuals with cognitive phenotypes representing 49
breeds. We conducted a breed-average genome-wide association
study to identify specific polymorphisms associated with
breed differences in inhibitory control, communication,
memory, and physical reasoning. We found five single
nucleotide polymorphisms (SNPs) that reached genome-wide
significance after Bonferroni correction, located in EML1,
OR52E2, HS3ST5, a U6 spliceosomal RNA, and a long noncoding
RNA. When we combined results across multiple SNPs within
the same gene, we identified 188 genes implicated in breed
differences in cognition. This gene set included more genes
than expected by chance that were (1) differentially
expressed in brain tissue and (2) involved in nervous system
functions including peripheral nervous system development,
Wnt signaling, presynapse assembly, and synaptic vesicle
exocytosis. These results advance our understanding of the
genetic underpinnings of complex cognitive phenotypes and
identify specific genetic variants for further
research.},
Doi = {10.1093/icb/icaa112},
Key = {fds353050}
}
@article{fds350126,
Author = {Gnanadesikan, GE and Hare, B and Snyder-Mackler, N and MacLean,
EL},
Title = {Estimating the heritability of cognitive traits across dog
breeds reveals highly heritable inhibitory control and
communication factors.},
Journal = {Animal cognition},
Volume = {23},
Number = {5},
Pages = {953-964},
Year = {2020},
Month = {September},
Abstract = {Trait heritability is necessary for evolution by both
natural and artificial selection, yet we know little about
the heritability of cognitive traits. Domestic dogs are a
valuable study system for questions regarding the evolution
of phenotypic diversity due to their extraordinary
intraspecific variation. While previous studies have
investigated morphological and behavioral variation across
dog breeds, few studies have systematically assessed breed
differences in cognition. We integrated data from
Dognition.com-a citizen science project on dog
cognition-with breed-averaged genetic data from published
sources to estimate the among-breed heritability of
cognitive traits using mixed models. The resulting dataset
included 11 cognitive measures for 1508 adult dogs across 36
breeds. A factor analysis yielded four factors interpreted
as reflecting inhibitory control, communication, memory, and
physical reasoning. Narrow-sense among-breed heritability
estimates-reflecting the proportion of cognitive variance
attributable to additive genetic variation-revealed that
scores on the inhibitory control and communication factors
were highly heritable (inhibitory control:
h<sup>2</sup> = 0.70; communication:
h<sup>2</sup> = 0.39), while memory and physical
reasoning were less heritable (memory: h<sup>2</sup> = 0.17;
physical reasoning: h<sup>2</sup> = 0.21). Although the
heritability of inhibitory control is partially explained by
body weight, controlling for breed-average weight still
yields a high heritability estimate (h<sup>2</sup> = 0.50),
while other factors are minimally affected. Our results
indicate that cognitive phenotypes in dogs covary with breed
relatedness and suggest that cognitive traits have strong
potential to undergo selection. The highest heritabilities
were observed for inhibitory control and communication, both
of which are hypothesized to have been altered by
domestication.},
Doi = {10.1007/s10071-020-01400-4},
Key = {fds350126}
}
@article{fds350795,
Author = {Bray, EE and Gruen, ME and Gnanadesikan, GE and Horschler, DJ and Levy,
KM and Kennedy, BS and Hare, BA and MacLean, EL},
Title = {Cognitive characteristics of 8- to 10-week-old assistance
dog puppies},
Journal = {Animal Behaviour},
Volume = {166},
Pages = {193-206},
Year = {2020},
Month = {August},
Abstract = {To characterize the early ontogeny of dog cognition, we
tested 168 domestic dog, Canis familiaris, puppies (97
females, 71 males; mean age = 9.2 weeks) in a novel test
battery based on previous tasks developed and employed with
adolescent and adult dogs. Our sample consisted of Labrador
retrievers, golden retrievers and Labrador × golden
retriever crosses from 65 different litters at Canine
Companions for Independence, an organization that breeds,
trains and places assistance dogs for people with
disabilities. Puppies participated in a 3-day cognitive
battery that consisted of 14 tasks measuring different
cognitive abilities and temperament traits such as executive
function (e.g. inhibitory control, reversal learning,
working memory), use of social cues, sensory discriminations
and reactivity to and recovery from novel situations. At
8–10 weeks of age, and despite minimal experience with
humans, puppies reliably used a variety of
cooperative-communicative gestures from humans. Puppies
accurately remembered the location of hidden food for delays
of up to 20 s, and succeeded in a variety of visual,
olfactory and auditory discrimination problems. They also
showed some skill at executive function tasks requiring
inhibitory control and reversal learning, although they
scored lower on these tasks than is typical in adulthood.
Taken together, our results confirm the early emergence of
sensitivity to human communication in dogs and contextualize
these skills within a broad array of other cognitive
abilities measured at the same stage of ontogeny.},
Doi = {10.1016/j.anbehav.2020.05.019},
Key = {fds350795}
}
@article{fds349657,
Author = {Watowich, MM and MacLean, EL and Hare, B and Call, J and Kaminski, J and Miklósi, Á and Snyder-Mackler, N},
Title = {Age influences domestic dog cognitive performance
independent of average breed lifespan.},
Journal = {Animal cognition},
Volume = {23},
Number = {4},
Pages = {795-805},
Year = {2020},
Month = {July},
Abstract = {Across mammals, increased body size is positively associated
with lifespan. However, within species, this relationship is
inverted. This is well illustrated in dogs (Canis
familiaris), where larger dogs exhibit accelerated life
trajectories: growing faster and dying younger than smaller
dogs. Similarly, some age-associated traits (e.g., growth
rate and physiological pace of aging) exhibit accelerated
trajectories in larger breeds. Yet, it is unknown whether
cognitive performance also demonstrates an accelerated life
course trajectory in larger dogs. Here, we measured
cognitive development and aging in a cross-sectional study
of over 4000 dogs from 66 breeds using nine memory and
decision-making tasks performed by citizen scientists as
part of the Dognition project. Specifically, we tested
whether cognitive traits follow a compressed (accelerated)
trajectory in larger dogs, or the same trajectory for all
breeds, which would result in limited cognitive decline in
larger breeds. We found that all breeds, regardless of size
or lifespan, tended to follow the same quadratic trajectory
of cognitive aging-with a period of cognitive development in
early life and decline in later life. Taken together, our
results suggest that cognitive performance follows similar
age-related trajectories across dog breeds, despite
remarkable variation in developmental rates and
lifespan.},
Doi = {10.1007/s10071-020-01385-0},
Key = {fds349657}
}
@article{fds348897,
Author = {Gruen, ME and White, P and Hare, B},
Title = {Do dog breeds differ in pain sensitivity? Veterinarians and
the public believe they do.},
Journal = {PloS one},
Volume = {15},
Number = {3},
Pages = {e0230315},
Year = {2020},
Month = {January},
Abstract = {Humans do not respond to the pain of all humans equally;
physical appearance and associated group identity affect how
people respond to the pain of others. Here we ask if a
similar differential response occurs when humans evaluate
different individuals of another species. Beliefs about pain
in pet dogs (Canis familiaris) provide a powerful test,
since dogs vary so much in size, shape, and color, and are
often associated with behavioral stereotypes. Using an
on-line survey, we asked both the general public and
veterinarians to rate pain sensitivity in 28 different dog
breeds, identified only by their pictures. We found that
both the general public and veterinarians rated smaller dogs
(i.e. based on height and weight) as being more sensitive to
pain; the general public respondents rated breeds associated
with breed specific legislation as having lower pain
sensitivity. While there is currently no known physiological
basis for such breed-level differences, over 90% of
respondents from both groups indicated belief in differences
in pain sensitivity among dog breeds. We discuss how these
results inform theories of human social discrimination and
suggest that the perception of breed-level differences in
pain sensitivity may affect the recognition and management
of painful conditions in dogs.},
Doi = {10.1371/journal.pone.0230315},
Key = {fds348897}
}
@article{fds349331,
Author = {Brooks, J and Kays, R and Hare, B},
Title = {Coyotes living near cities are bolder: Implications for dog
evolution and human-wildlife conflict},
Journal = {Behaviour},
Volume = {157},
Number = {3-4},
Pages = {289-313},
Year = {2020},
Month = {January},
Abstract = {How animal populations adapt to human modified landscapes is
central to understanding modern behavioural evolution and
improving wildlife management. Coyotes (Canis latrans) have
adapted to human activities and thrive in both rural and
urban areas. Bolder coyotes showing reduced fear of humans
and their artefacts may have an advantage in urban
environments. We analysed the reactions of 636 coyotes to
novel human artefacts (camera traps) at 575 sites across the
state of North Carolina. Likelihood of a coyote approaching
the camera increased with human housing density suggesting
that urban coyotes are experiencing selection for boldness
and becoming more attracted to human artefacts. This has
implications for both human-wildlife conflict and theories
of dog domestication. We also note physical traits in
coyotes that could be the result of domestication-related
selection pressures, or dog hybridization.},
Doi = {10.1163/1568539X-bja10002},
Key = {fds349331}
}
@misc{fds361337,
Author = {Woods, V and Hare, B},
Title = {Uncanny valley of the apes},
Pages = {104-120},
Booktitle = {Why We Love and Exploit Animals: Bridging Insights from
Academia and Advocacy},
Year = {2019},
Month = {December},
ISBN = {9780815396642},
Abstract = {Humans have a complex emotional relationship with the other
members of our great apes family. Great apes are appealing
because of the close resemblances we share, but these
resemblances can cause feelings of aversion and disgust. We
propose that these feelings may stem from the uncanny valley
- the point at which someone or something becomes almost,
but not quite human. We argue that the uncanny valley has
made great apes an effective tool for a particular type of
dehumanization, known as simianization. Simianization has
been especially prolonged and pervasive towards black
people, dating from the transatlantic slave trade and
continuing today. In the reverse direction, the humanness of
great apes has made them a source of fascination, but has
not saved them from extensive population decline and may
have facilitated their exploitation. Preliminary research
into decreasing the human-animal divide shows promise for
mitigating the negative impact of simianization of people
and for improving attitudes towards, and the welfare of,
great apes.},
Key = {fds361337}
}
@article{fds340823,
Author = {Horschler, DJ and Hare, B and Call, J and Kaminski, J and Miklósi, Á and MacLean, EL},
Title = {Absolute brain size predicts dog breed differences in
executive function.},
Journal = {Animal cognition},
Volume = {22},
Number = {2},
Pages = {187-198},
Year = {2019},
Month = {March},
Abstract = {Large-scale phylogenetic studies of animal cognition have
revealed robust links between absolute brain volume and
species differences in executive function. However, past
comparative samples have been composed largely of primates,
which are characterized by evolutionarily derived neural
scaling rules. Therefore, it is currently unknown whether
positive associations between brain volume and executive
function reflect a broad-scale evolutionary phenomenon, or
alternatively, a unique consequence of primate brain
evolution. Domestic dogs provide a powerful opportunity for
investigating this question due to their close genetic
relatedness, but vast intraspecific variation. Using citizen
science data on more than 7000 purebred dogs from 74 breeds,
and controlling for genetic relatedness between breeds, we
identify strong relationships between estimated absolute
brain weight and breed differences in cognition.
Specifically, larger-brained breeds performed significantly
better on measures of short-term memory and self-control.
However, the relationships between estimated brain weight
and other cognitive measures varied widely, supporting
domain-specific accounts of cognitive evolution. Our results
suggest that evolutionary increases in brain size are
positively associated with taxonomic differences in
executive function, even in the absence of primate-like
neuroanatomy. These findings also suggest that variation
between dog breeds may present a powerful model for
investigating correlated changes in neuroanatomy and
cognition among closely related taxa.},
Doi = {10.1007/s10071-018-01234-1},
Key = {fds340823}
}
@misc{fds366381,
Author = {Yamamoto, S and Tokuyama, N and Clay, Z and Hare,
B},
Title = {Chimpanzee and bonobo},
Pages = {324-334},
Booktitle = {Encyclopedia of Animal Behavior},
Year = {2019},
Month = {January},
ISBN = {9780128132517},
Abstract = {Chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) are
both our evolutionary closest living relatives. Human and
Pan lineages diverged around 7 million years ago, and the
chimpanzee and the bonobo branched 1-2 million years ago.
Accordingly, the two species have a lot of similarities in
their appearance, behavior, and societies; however, research
highlights some striking differences between these close
sister species. There are a number of traits in which
bonobos and chimpanzees are more similar to humans than they
are each other have been recognized recently. This
comparison provides an extremely powerful test of ideas
about human uniqueness. Given that both species are equally
related to us, balanced insights are needed from both
chimpanzees and bonobos in order to understand the selective
pressures which may have shaped the human mind. Here we
concisely review their evolution, society, and cognition,
and suggest its implication for the evolutionary processes
by which cognitive traits evolve in apes.},
Doi = {10.1016/B978-0-12-809633-8.90716-7},
Key = {fds366381}
}
@article{fds366382,
Author = {Barron, AB and Hare, B},
Title = {Prosociality and a Sociosexual Hypothesis for the Evolution
of Same-Sex Attraction in Humans.},
Journal = {Frontiers in psychology},
Volume = {10},
Pages = {2955},
Year = {2019},
Month = {January},
Abstract = {Human same-sex sexual attraction (SSSA) has long been
considered to be an evolutionary puzzle. The trait is
clearly biological: it is widespread and has a strong
additive genetic basis, but how SSSA has evolved remains a
subject of debate. Of itself, homosexual sexual behavior
will not yield offspring, and consequently individuals
expressing strong SSSA that are mostly or exclusively
homosexual are presumed to have lower fitness and
reproductive success. How then did the trait evolve, and how
is it maintained in populations? Here we develop a novel
argument for the evolution of SSSA that focuses on the
likely adaptive social consequences of SSSA. We argue that
same sex sexual attraction evolved as just one of a suite of
traits responding to strong selection for ease of social
integration or prosocial behavior. A strong driver of recent
human behavioral evolution has been selection for reduced
reactive aggression, increased social affiliation, social
communication, and ease of social integration. In many
prosocial mammals sex has adopted new social functions in
contexts of social bonding, social reinforcement,
appeasement, and play. We argue that for humans the social
functions and benefits of sex apply to same-sex sexual
behavior as well as heterosexual behavior. As a consequence
we propose a degree of SSSA, was selected for in recent
human evolution for its non-conceptive social benefits. We
discuss how this hypothesis provides a better explanation
for human sexual attractions and behavior than theories that
invoke sexual inversion or single-locus genetic
models.},
Doi = {10.3389/fpsyg.2019.02955},
Key = {fds366382}
}
@misc{fds372661,
Author = {Yamamoto, S and Tokuyama, N and Clay, Z and Hare,
B},
Title = {Chimpanzee and Bonobo},
Volume = {1},
Pages = {V1-324-V1-334},
Booktitle = {Encyclopedia of Animal Behavior, Second Edition: Volume
1-5},
Year = {2019},
Month = {January},
ISBN = {9780128132517},
Abstract = {Chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) are
both our evolutionary closest living relatives. Human and
Pan lineages diverged around 7 million years ago, and the
chimpanzee and the bonobo branched 1–2 million years ago.
Accordingly, the two species have a lot of similarities in
their appearance, behavior, and societies; however, research
highlights some striking differences between these close
sister species. There are a number of traits in which
bonobos and chimpanzees are more similar to humans than they
are each other have been recognized recently. This
comparison provides an extremely powerful test of ideas
about human uniqueness. Given that both species are equally
related to us, balanced insights are needed from both
chimpanzees and bonobos in order to understand the selective
pressures which may have shaped the human mind. Here we
concisely review their evolution, society, and cognition,
and suggest its implication for the evolutionary processes
by which cognitive traits evolve in apes.},
Doi = {10.1016/B978-0-12-809633-8.90716-7},
Key = {fds372661}
}
@article{fds335476,
Author = {Lucca, K and MacLean, EL and Hare, B},
Title = {The development and flexibility of gaze alternations in
bonobos and chimpanzees.},
Journal = {Developmental science},
Volume = {21},
Number = {4},
Pages = {e12598},
Year = {2018},
Month = {July},
Abstract = {Infants' early gaze alternations are one of their first
steps towards a sophisticated understanding of the social
world. This ability, to gaze alternate between an object of
interest and another individual also attending to that
object, has been considered foundational to the development
of many complex social-cognitive abilities, such as theory
of mind and language. However, to understand the evolution
of these abilities, it is important to identify whether and
how gaze alternations are used and develop in our closest
living relatives, bonobos (Pan paniscus) and chimpanzees
(Pan troglodytes). Here, we evaluated the development of
gaze alternations in a large, developmental sample of
bonobos (N = 17) and chimpanzees (N = 35). To assess the
flexibility of ape gaze alternations, we tested whether they
produced gaze alternations when requesting food from a human
who was either visually attentive or visually inattentive.
Similarly to human infants, both bonobos and chimpanzees
produced gaze alternations, and did so more frequently when
a human communicative partner was visually attentive.
However, unlike humans, who gaze alternate frequently from
early in development, chimpanzees did not begin to gaze
alternate frequently until adulthood. Bonobos produced very
few gaze alternations, regardless of age. Thus, it may be
the early emergence of gaze alternations, as opposed gaze
alternations themselves, that is derived in the human
lineage. The distinctively early emergence of gaze
alternations in humans may be a critical underpinning for
the development of complex human social-cognitive
abilities.},
Doi = {10.1111/desc.12598},
Key = {fds335476}
}
@article{fds331591,
Author = {Hare, B},
Title = {Domestication experiments reveal developmental link between
friendliness and cognition},
Journal = {Journal of Bioeconomics},
Volume = {20},
Number = {1},
Pages = {159-163},
Publisher = {Springer Nature},
Year = {2018},
Month = {April},
Abstract = {The goal of economics is to understand human preferences.
Most research focuses on adult humans and does not take an
evolutionary approach. In biology experimental evolution has
been able to shift the preferences of animals. As an
example, artificial selection for friendly behavior toward
humans results in a syndrome of changes that strongly
resembles differences between wild and domestic animals.
These domestication experiments have revealed precise
genetic and neurobiological systems that are altered by the
selection and linked through expanded windows of
development. Similar evolutionary experiments selecting for
a range of social, risk or discounting preferences could
push economics toward consilience with biology. Prospects
for a unified theory of economic behavior would be
drastically improved.},
Doi = {10.1007/s10818-017-9264-9},
Key = {fds331591}
}
@article{fds331590,
Author = {Krupenye, C and Hare, B},
Title = {Bonobos Prefer Individuals that Hinder Others over Those
that Help.},
Journal = {Current biology : CB},
Volume = {28},
Number = {2},
Pages = {280-286.e5},
Year = {2018},
Month = {January},
Abstract = {Humans closely monitor others' cooperative relationships [1,
2]. Children and adults willingly incur costs to reward
helpers and punish non-helpers-even as bystanders [3-5].
Already by 3 months, infants favor individuals that they
observe helping others [6-8]. This early-emerging prosocial
preference may be a derived motivation that accounts
for many human forms of cooperation that occur beyond
dyadic interactions and are not exhibited by other animals
[9, 10]. As the most socially tolerant nonhuman ape [11-17]
(but see [18]), bonobos (Pan paniscus) provide a powerful
phylogenetic test of whether this trait is derived in
humans. Bonobos are more tolerant than chimpanzees, can
flexibly obtain food through cooperation, and voluntarily
share food in captivity and the wild, even with strangers
[11-17] (but see [18]). Their neural architecture exhibits a
suite of characteristics associated with greater sensitivity
to others [19, 20], and their sociality is hypothesized to
have evolved due to selection against male aggression
[21-23]. Here we show in four experiments that bonobos
discriminated agents based on third-party interactions.
However, they did not exhibit the human preference for
helpers. Instead, they reliably favored a hinderer that
obstructed another agent's goal (experiments 1-3). In a
final study (experiment 4), bonobos also chose a dominant
individual over a subordinate. Bonobos' interest in
hinderers may reflect attraction to dominant individuals
[24]. A preference for helpers over hinderers may therefore
be derived in humans, supporting the hypothesis that
prosocial preferences played a central role in the evolution
of human development and cooperation.},
Doi = {10.1016/j.cub.2017.11.061},
Key = {fds331590}
}
@article{fds339286,
Author = {MacLean, EL and Hare, B},
Title = {Enhanced Selection of Assistance and Explosive Detection
Dogs Using Cognitive Measures.},
Journal = {Frontiers in veterinary science},
Volume = {5},
Pages = {236},
Year = {2018},
Month = {January},
Abstract = {Working dogs play a variety of important roles, ranging from
assisting individuals with disabilities, to explosive and
medical detection work. Despite widespread demand, only a
subset of dogs bred and trained for these roles ultimately
succeed, creating a need for objective measures that can
predict working dog aptitude. Most previous research has
focused on temperamental characteristics of successful dogs.
However, working dogs also face diverse cognitive challenges
both in training, and throughout their working lives. We
conducted a series of studies investigating the
relationships between individual differences in dog
cognition, and success as an assistance or detection dog.
Assistance dogs (<i>N</i> = 164) and detection dogs
(<i>N</i> = 222) were tested in the Dog Cognition Test
Battery, a 25-item instrument probing diverse aspects of dog
cognition. Through exploratory analyses we identified a
subset of tasks associated with success in each training
program, and developed shorter test batteries including only
these measures. We then used predictive modeling in a
prospective study with an independent sample of assistance
dogs (<i>N</i> = 180), and conducted a replication study
with an independent sample of detection dogs (<i>N</i> =
90). In assistance dogs, models using data on individual
differences in cognition predicted higher probabilities of
success for dogs that ultimately succeeded in the program,
than for those who did not. For the subset of dogs with
predicted probabilities of success in the 4th quartile
(highest predicted probability of success), model
predictions were 86% accurate, on average. In both the
exploratory and prospective studies, successful dogs were
more likely to engage in eye contact with a human
experimenter when faced with an unsolvable task, or when a
joint social activity was disrupted. In detection dogs, we
replicated our exploratory findings that the most successful
dogs scored higher on measures of sensitivity to human
communicative intentions, and two measures of short term
memory. These findings suggest that that (1) individual
differences in cognition contribute to variance in working
dog success, and (2) that objective measures of dog
cognition can be used to improve the processes through which
working dogs are evaluated and selected.},
Doi = {10.3389/fvets.2018.00236},
Key = {fds339286}
}
@misc{fds335477,
Author = {Hare, B and Yamamoto, S},
Title = {Minding the bonobo mind},
Pages = {1-14},
Booktitle = {Bonobos: Unique in Mind, Brain, and Behavior},
Publisher = {Oxford University Press},
Year = {2018},
Month = {January},
ISBN = {9780198728511},
Abstract = {In this chapter we introduce the central role the bonobo
plays in testing evolutionary hypotheses regarding ape minds
(including our own). The importance of bonobos has become
apparent only recently with sustained fieldwork at multiple
sites in the Congo Basin as well as the first direct
quantitative comparisons between bonobos, chimpanzees and
humans. This recent work has revealed a number of traits in
which bonobos and chimpanzees are more similar to humans
than they are to each other. This means that bonobos are
crucial to determining the evolutionary processes by which
cognitive traits evolved in our own lineage. Based on the
evidence within, it becomes clear that one can no longer
know chimpanzees or humans without also knowing bonobos. We
argue this makes investing in bonobo research and improved
protection for bonobos in captivity and the wild an even
higher priority.},
Doi = {10.1093/oso/9780198728511.003.0001},
Key = {fds335477}
}
@misc{fds335478,
Author = {Krupenye, C and MacLean, EL and Hare, B},
Title = {Does the bonobo have a (chimpanzee-like) theory of
mind?},
Pages = {81-94},
Booktitle = {Bonobos: Unique in Mind, Brain, and Behavior},
Publisher = {Oxford University Press},
Year = {2018},
Month = {January},
ISBN = {9780198728511},
Abstract = {Theory of mind-the ability to reason about the thoughts and
emotions of others-is central to what makes us human.
Chimpanzees too appear to understand some psychological
states. While less is known about bonobos, several lines of
evidence suggest that the social-cognitive abilities of the
two sister taxa may differ in key respects. This chapter
outlines a framework to guide future research on bonobo
social cognition based on the predictions of two potentially
complementary hypotheses. The self-domestication hypothesis
suggests that selection against aggression and for
prosociality in bonobos may have impacted the ontogeny of
their social-cognitive skills relative to chimpanzees. The
empathizing-systemizing hypothesis links degree of prenatal
brain masculinization, a potential result of
self-domestication, to adult cognition. Specifically,
relative feminization may yield more flexible theory of mind
skills in bonobos than chimpanzees. Finally, directions for
future study, including development of new paradigms that
maximize ecological validity for bonobos, are
discussed.},
Doi = {10.1093/oso/9780198728511.003.0006},
Key = {fds335478}
}
@misc{fds335479,
Author = {Tan, J and Hare, B},
Title = {Prosociality among non-kin in bonobos and chimpanzees
compared},
Pages = {140-154},
Booktitle = {Bonobos: Unique in Mind, Brain, and Behavior},
Publisher = {Oxford University Press},
Year = {2018},
Month = {January},
ISBN = {9780198728511},
Abstract = {Models of the origin of human prosociality towards non-kin
have been primarily developed from chimpanzee studies.
Substantially less effort has been made to consider the
prosociality of bonobos. Like chimpanzees, bonobos cooperate
with non-kin extensively but, unlike chimpanzees,
immigrating members are central to bonobo cooperation. In
experiments bonobos are tolerant during encounters with
strangers and during co-feeding. They help strangers without
immediate tangible reward, and forfeit monopolizable food to
facilitate a physical interaction with them. Such
prosociality seems proactive as it is not elicited by
solicitation. Bonobos also seem to prefer sharing food over
non-food objects, while chimpanzees reliably transfer
non-food objects rather than food. These findings highlight
the possibility that human sharing with strangers might have
also evolved as a mutualistic endeavour to initiate a
long-term partnership. Future models of human prosociality
will need to incorporate findings from both Pan
species.},
Doi = {10.1093/oso/9780198728511.003.0010},
Key = {fds335479}
}
@book{fds335480,
Author = {Hare, B and Yamamoto, S},
Title = {Bonobos: Unique in mind, brain, and behavior},
Pages = {1-290},
Publisher = {Oxford University Press},
Year = {2018},
Month = {January},
ISBN = {9780198728511},
Abstract = {During the past decade there has been an explosion of
scientific interest in the bonobo (Pan paniscus). This
research has revealed exactly how unique bonobos are in
their minds, brains and behavior. This book makes clear the
central role that bonobos play as we test hypotheses
relating to the processes by which evolution shapes ape
cognition (including our own species). The book’s
introduction describes the recent interest into bonobo
cognition while briefly reviewing the history of research
with bonobos. To place this new work in its evolutionary
contexts, researchers from the two most active bonobo field
sites start the book by reporting on recent discoveries
regarding the social behavior of bonobos. The following
three sections explore social cognition and behavior of
bonobos from viewpoints of development, communication, and
cooperation. Then the fifth section considers the cognitive
abilities deployed by bonobos as they forage for and process
food. The sixth section focuses on large scale comparison of
bonobos to both chimpanzees and humans in their cognitive
abilities and brain anatomy. Finally, the last two sections
include chapters exploring the past and future of the
bonobos, providing novel perspectives on how to promote the
survival of this highly endangered species. These chapters
are contributed by experts representing diverse disciplines
and take together study bonobos living in a range of
settings. They present overwhelming evidence for bonobo
uniqueness and the new understanding this creates will
contribute to a bright future for bonobos living in
captivity and the wild.},
Doi = {10.1093/oso/9780198728511.001.0001},
Key = {fds335480}
}
@misc{fds335481,
Author = {Faust, LJ and André, C and Belais, R and Minesi, F and Pereboom, Z and Rodriguez, K and Hare, B},
Title = {Bonobo population dynamics: Past patterns and future
predictions for the Lola ya Bonobo population using
demographic modelling},
Pages = {266-274},
Booktitle = {Bonobos: Unique in Mind, Brain, and Behavior},
Publisher = {Oxford University Press},
Year = {2018},
Month = {January},
ISBN = {9780198728511},
Abstract = {Wildlife sanctuaries rescue, rehabilitate, reintroduce and
provide life-long care for orphaned and injured animals.
Understanding a sanctuary’s population dynamics—patterns
in arrival, mortality and projected changes in population
size—allows careful planning for future needs. Building on
previous work on the population dynamics of chimpanzees (Pan
troglodytes) in sanctuaries of the Pan African Sanctuary
Alliance (PASA; Faust et al. 2011), this chapter extends
analyses to the only PASA bonobo sanctuary. Its authors
analysed historic demographic patterns and projected future
population dynamics using an individual-based demographic
model. The population has been growing at 6.7 per cent per
year, driven by arrivals of new individuals (mean = 5.5
arrivals per year). Several model scenarios projecting
varying arrival rates, releases and breeding scenarios
clarify potential future growth trajectories for the
sanctuary. This research illustrates how data on historic
dynamics can be modelled to inform future sanctuary capacity
and management needs.},
Doi = {10.1093/oso/9780198728511.003.0018},
Key = {fds335481}
}
@misc{fds335482,
Author = {Walker, K and Hare, B},
Title = {Bonobo baby dominance: Did female defense of offspring lead
to reduced male aggression?},
Pages = {49-64},
Booktitle = {Bonobos: Unique in Mind, Brain, and Behavior},
Publisher = {Oxford University Press},
Year = {2018},
Month = {January},
ISBN = {9780198728511},
Abstract = {The dominance style of bonobos presents an evolutionary
puzzle. Bonobos are not male dominant but female bonobos do
not show traits typical of female-dominant species. This
chapter proposes the offspring dominance hypothesis (ODH) as
a potential solution. ODH suggests the social system of
bonobos evolved as a defence against infanticide and is not
due to pressure to monopolize resources. Females that
prevented aggression towards offspring and preferred mating
with less aggressive males were most successful. Supporting
ODH, during observations at Lola ya Bonobo Sanctuary it was
found that: 1) adult male bonobos are rarely aggressive
towards offspring with mothers, 2) some mother-reared
juvenile bonobos attain rank higher than adult males and 3)
mother-reared offspring often socially interact with adult
males without their mothers nearby. These preliminary
findings provide initial support that the bonobo social
system evolved due to fitness advantages of effectively
protecting offspring against consequences of male
aggression.},
Doi = {10.1093/oso/9780198728511.003.0004},
Key = {fds335482}
}
@misc{fds335483,
Author = {Hare, B and Woods, V},
Title = {Cognitive comparisons of genus Pan support bonobo
self-domestication},
Pages = {214-232},
Booktitle = {Bonobos: Unique in Mind, Brain, and Behavior},
Publisher = {Oxford University Press},
Year = {2018},
Month = {January},
ISBN = {9780198728511},
Abstract = {The self-domestication hypothesis (SDH) suggests bonobo
psychology evolved due to selection against aggression and
in favour of prosociality. This hypothesis was formulated
based on similarities between bonobos and domesticated
animals. This chapter reviews the first generation of
quantitative research that supports the predictions of the
SDH. Similar to domestic animals, bonobos are prosocial
towards strangers, are more flexible with cooperative
problems, are more responsive to social cues and show
expanded windows of development compared to their closest
relatives, chimpanzees. A preliminary comparison of bonobo
and chimpanzee infants suggests that when hearing a
stranger, bonobos have a xenophilic response while
chimpanzees have a xenophobic response. The chapter explores
why the research with bonobos has implications for theories
of both human and animal cognitive evolution, and why
bonobos will be central in studying evolutionary processes
that lead to cognitive change.},
Doi = {10.1093/oso/9780198728511.003.0015},
Key = {fds335483}
}
@article{fds329757,
Author = {Tan, J and Ariely, D and Hare, B},
Title = {Bonobos respond prosocially toward members of other
groups.},
Journal = {Scientific reports},
Volume = {7},
Number = {1},
Pages = {14733},
Year = {2017},
Month = {November},
Abstract = {Modern humans live in an "exploded" network with unusually
large circles of trust that form due to prosociality toward
unfamiliar people (i.e. xenophilia). In a set of experiments
we demonstrate that semi-free ranging bonobos (Pan paniscus)
- both juveniles and young adults - also show spontaneous
responses consistent with xenophilia. Bonobos voluntarily
aided an unfamiliar, non-group member in obtaining food even
when he/she did not make overt requests for help. Bonobos
also showed evidence for involuntary, contagious yawning in
response to videos of yawning conspecifics who were complete
strangers. These experiments reveal that xenophilia in
bonobos can be unselfish, proactive and automatic. They
support the first impression hypothesis that suggests
xenophilia can evolve through individual selection in social
species whenever the benefits of building new bonds outweigh
the costs. Xenophilia likely evolved in bonobos as the risk
of intergroup aggression dissipated and the benefits of
bonding between immigrating members increased. Our findings
also mean the human potential for xenophilia is either
evolutionarily shared or convergent with bonobos and not
unique to our species as previously proposed.},
Doi = {10.1038/s41598-017-15320-w},
Key = {fds329757}
}
@article{fds324356,
Author = {MacLean, EL and Herrmann, E and Suchindran, S and Hare,
B},
Title = {Individual differences in cooperative communicative skills
are more similar between dogs and humans than
chimpanzees},
Journal = {Animal Behaviour},
Volume = {126},
Pages = {41-51},
Publisher = {Elsevier BV},
Year = {2017},
Month = {April},
Abstract = {By 2.5 years of age humans are more skilful than other apes
on a set of social, but not nonsocial, cognitive tasks.
Individual differences in human infants, but not
chimpanzees, Pan troglodytes, are also explained by
correlated variance in these cooperative communicative
skills. Relative to nonhuman apes, domestic dogs, Canis
familiaris, perform more like human infants in cooperative
communicative tasks, but it is unknown whether dog and human
cognition share a similar underlying structure. We tested
552 dogs in a large-scale test battery modelled after
similar work with humans and nonhuman apes. Unlike
chimpanzees, but similarly to humans, individual differences
in dogs were explained by correlated variance in skills for
solving cooperative communicative problems. Direct
comparisons of data from all three species revealed similar
patterns of individual differences in cooperative
communication between human infants (N = 105) and domestic
dogs (N = 430), which were not observed in chimpanzees
(N = 106). Future research will be needed to examine
whether the observed similarities are a result of similar
psychological mechanisms and evolutionary processes in the
dog and human lineages.},
Doi = {10.1016/j.anbehav.2017.01.005},
Key = {fds324356}
}
@article{fds323646,
Author = {Hare, B},
Title = {Survival of the Friendliest: Homo sapiens Evolved via
Selection for Prosociality.},
Journal = {Annual review of psychology},
Volume = {68},
Pages = {155-186},
Year = {2017},
Month = {January},
Abstract = {The challenge of studying human cognitive evolution is
identifying unique features of our intelligence while
explaining the processes by which they arose. Comparisons
with nonhuman apes point to our early-emerging
cooperative-communicative abilities as crucial to the
evolution of all forms of human cultural cognition,
including language. The human self-domestication hypothesis
proposes that these early-emerging social skills evolved
when natural selection favored increased in-group
prosociality over aggression in late human evolution. As a
by-product of this selection, humans are predicted to show
traits of the domestication syndrome observed in other
domestic animals. In reviewing comparative, developmental,
neurobiological, and paleoanthropological research,
compelling evidence emerges for the predicted relationship
between unique human mentalizing abilities, tolerance, and
the domestication syndrome in humans. This synthesis
includes a review of the first a priori test of the
self-domestication hypothesis as well as predictions for
future tests.},
Doi = {10.1146/annurev-psych-010416-044201},
Key = {fds323646}
}
@article{fds322443,
Author = {Reddy, RB and Krupenye, C and MacLean, EL and Hare,
B},
Title = {No evidence for contagious yawning in lemurs.},
Journal = {Animal cognition},
Volume = {19},
Number = {5},
Pages = {889-898},
Year = {2016},
Month = {September},
Abstract = {Among some haplorhine primates, including humans, relaxed
yawns spread contagiously. Such contagious yawning has been
linked to social bonds and empathy in some species. However,
no studies have investigated contagious yawning in
strepsirhines. We conducted an experimental study of
contagious yawning in strepsirhines, testing ring-tailed and
ruffed lemurs (n = 24) in a paradigm similar to one that
has induced contagious yawning in haplorhines. First, in a
control experiment, we investigated whether lemurs responded
to projected video content in general (experiment 1). We
showed them two videos to which we expected differential
responses: one featured a terrestrial predator and the other
a caretaker holding food. Next, to test for yawn contagion,
we showed individual lemurs life-size video projections of
groupmates and conspecific strangers yawning, and control
footage of the same individuals at rest (experiment 2).
Then, to examine whether a group context might enhance or
allow for contagion, we exposed subjects to the same videos
in a group setting (experiment 3). Lemurs produced alarm
vocalizations and moved upward while viewing the predator,
but not the caretaker, demonstrating that they do perceive
video content meaningfully. However, lemurs did not yawn in
response to yawning stimuli when tested alone, or with their
groupmates. This study provides preliminary evidence that
lemurs do not respond to yawning stimuli similarly to
haplorhines, and suggests that this behavior may have
evolved or become more exaggerated in haplorhines after the
two major primate lineages split.},
Doi = {10.1007/s10071-016-0986-1},
Key = {fds322443}
}
@article{fds322444,
Author = {Pontzer, H and Brown, MH and Raichlen, DA and Dunsworth, H and Hare, B and Walker, K and Luke, A and Dugas, LR and Durazo-Arvizu, R and Schoeller,
D and Plange-Rhule, J and Bovet, P and Forrester, TE and Lambert, EV and Thompson, ME and Shumaker, RW and Ross, SR},
Title = {Metabolic acceleration and the evolution of human brain size
and life history.},
Journal = {Nature},
Volume = {533},
Number = {7603},
Pages = {390-392},
Year = {2016},
Month = {May},
Abstract = {Humans are distinguished from the other living apes in
having larger brains and an unusual life history that
combines high reproductive output with slow childhood growth
and exceptional longevity. This suite of derived traits
suggests major changes in energy expenditure and allocation
in the human lineage, but direct measures of human and ape
metabolism are needed to compare evolved energy strategies
among hominoids. Here we used doubly labelled water
measurements of total energy expenditure (TEE; kcal day(-1))
in humans, chimpanzees, bonobos, gorillas and orangutans to
test the hypothesis that the human lineage has experienced
an acceleration in metabolic rate, providing energy for
larger brains and faster reproduction without sacrificing
maintenance and longevity. In multivariate regressions
including body size and physical activity, human TEE
exceeded that of chimpanzees and bonobos, gorillas and
orangutans by approximately 400, 635 and 820 kcal day(-1),
respectively, readily accommodating the cost of humans'
greater brain size and reproductive output. Much of the
increase in TEE is attributable to humans' greater basal
metabolic rate (kcal day(-1)), indicating increased organ
metabolic activity. Humans also had the greatest body fat
percentage. An increased metabolic rate, along with changes
in energy allocation, was crucial in the evolution of human
brain size and life history.},
Doi = {10.1038/nature17654},
Key = {fds322444}
}
@article{fds332975,
Author = {Rosati, AG and Hare, B},
Title = {Reward currency modulates human risk preferences},
Journal = {Evolution and Human Behavior},
Volume = {37},
Number = {2},
Pages = {159-168},
Publisher = {Elsevier BV},
Year = {2016},
Month = {March},
Abstract = {Monetary and biological rewards differ in many ways. Yet
studies of human decision-making typically involve money,
whereas nonhuman studies involve food. We therefore examined
how context shifts human risk preferences to illuminate the
evolution of decision-making. First, we assessed peoples'
risk preferences across food, prizes, and money in a task
where individuals received real rewards and learned about
payoffs through experience. We found that people were
relatively more risk-seeking for both food and prizes
compared to money-indicating that people may treat abstract
reward markers differently from concrete rewards. Second, we
compared human risk preferences for food with that of our
closest phylogenetic relatives, chimpanzees (Pan
troglodytes) and bonobos (Pan paniscus), in order to
illuminate the evolutionary origins of human decision-making
strategies. In fact, human and chimpanzees were both
relatively more risk-seeking compared to bonobos. Finally,
we investigated why people respond differently to money
versus concrete rewards when making decisions. We found that
people were more risk-prone when making decisions about
money that was constrained as a store of value, compared to
money that could be freely exchanged. This shows that people
are sensitive to money's usefulness as a store of value that
can be used to acquire other types of rewards. Our results
indicate that humans exhibit different preferences when
making risky decisions about money versus food, an important
consideration for comparative research. Furthermore,
different psychological processes may underpin decisions
about abstract rewards compared to concrete
rewards.},
Doi = {10.1016/j.evolhumbehav.2015.10.003},
Key = {fds332975}
}
@article{fds322445,
Author = {Krupenye, C and Rosati, AG and Hare, B},
Title = {What's in a frame? Response to Kanngiesser & Woike
(2016).},
Journal = {Biology letters},
Volume = {12},
Number = {1},
Pages = {20150959},
Year = {2016},
Month = {January},
Doi = {10.1098/rsbl.2015.0959},
Key = {fds322445}
}
@article{fds240356,
Author = {Stewart, L and MacLean, EL and Ivy, D and Woods, V and Cohen, E and Rodriguez, K and McIntyre, M and Mukherjee, S and Call, J and Kaminski,
J and Miklósi, Á and Wrangham, RW and Hare, B},
Title = {Citizen Science as a New Tool in Dog Cognition
Research},
Journal = {PLoS ONE},
Volume = {10},
Number = {9},
Pages = {e0135176},
Publisher = {Public Library of Science},
Year = {2015},
Month = {September},
url = {http://hdl.handle.net/10161/10647 Duke open access
repository},
Abstract = {<p>Family dogs and dog owners offer a potentially powerful
way to conduct citizen science to answer questions about
animal behavior that are difficult to answer with more
conventional approaches. Here we evaluate the quality of the
first data on dog cognition collected by citizen scientists
using the <italic>Dognition</italic>.<italic>com</italic>
website. We conducted analyses to understand if data
generated by over 500 citizen scientists replicates
internally and in comparison to previously published
findings. Half of participants participated for free while
the other half paid for access. The website provided each
participant a temperament questionnaire and instructions on
how to conduct a series of ten cognitive tests.
Participation required internet access, a dog and some
common household items. Participants could record their
responses on any PC, tablet or smartphone from anywhere in
the world and data were retained on servers. Results from
citizen scientists and their dogs replicated a number of
previously described phenomena from conventional lab-based
research. There was little evidence that citizen scientists
manipulated their results. To illustrate the potential uses
of relatively large samples of citizen science data, we then
used factor analysis to examine individual differences
across the cognitive tasks. The data were best explained by
multiple factors in support of the hypothesis that
nonhumans, including dogs, can evolve multiple cognitive
domains that vary independently. This analysis suggests that
in the future, citizen scientists will generate useful
datasets that test hypotheses and answer questions as a
complement to conventional laboratory techniques used to
study dog psychology.</p>},
Doi = {10.1371/journal.pone.0135176},
Key = {fds240356}
}
@article{fds240357,
Author = {Bray, E and MacLean, E and Hare, B},
Title = {Increasing arousal enhances inhibitory control in calm but
not excitable dogs},
Journal = {Animal Cognition},
Volume = {18},
Number = {6},
Pages = {1-13},
Publisher = {Springer Berlin Heidelberg},
Year = {2015},
Month = {July},
ISSN = {1435-9448},
url = {http://hdl.handle.net/10161/10608 Duke open access
repository},
Abstract = {The emotional-reactivity hypothesis proposes that
problem-solving abilities can be constrained by temperament,
within and across species. One way to test this hypothesis
is with the predictions of the Yerkes-Dodson law. The law
posits that arousal level, a component of temperament,
affects problem solving in an inverted U-shaped
relationship: Optimal performance is reached at intermediate
levels of arousal and impeded by high and low levels. Thus,
a powerful test of the emotional-reactivity hypothesis is to
compare cognitive performance in dog populations that have
been bred and trained based in part on their arousal levels.
We therefore compared a group of pet dogs to a group of
assistance dogs bred and trained for low arousal (N = 106)
on a task of inhibitory control involving a detour response.
Consistent with the Yerkes-Dodson law, assistance dogs,
which began the test with lower levels of baseline arousal,
showed improvements when arousal was artificially increased.
In contrast, pet dogs, which began the test with higher
levels of baseline arousal, were negatively affected when
their arousal was increased. Furthermore, the dogs' baseline
levels of arousal, as measured in their rate of tail
wagging, differed by population in the expected directions.
Low-arousal assistance dogs showed the most inhibition in a
detour task when humans eagerly encouraged them, while more
highly aroused pet dogs performed worst on the same task
with strong encouragement. Our findings support the
hypothesis that selection on temperament can have important
implications for cognitive performance.},
Doi = {10.1007/s10071-015-0901-1},
Key = {fds240357}
}
@article{fds240360,
Author = {Reddy, RB and MacLean, EL and Sandel, AA and Hare,
B},
Title = {Social inhibitory control in five lemur species.},
Journal = {Primates; journal of primatology},
Volume = {56},
Number = {3},
Pages = {241-252},
Year = {2015},
Month = {July},
ISSN = {0032-8332},
Abstract = {We tested five lemur species-ring-tailed lemurs, ruffed
lemurs, mongoose lemurs, black lemurs, and Coquerel's
sifakas-(N = 52) in an experiment that evaluated skills
for inhibitory control in a social context. First, two human
experimenters presented identical food rewards; the
"generous" experimenter allowed the subject to eat from her
hand, whereas the "competitive" experimenter always withheld
the reward. Lemurs quickly learned to approach the generous
experimenter and avoid the competitive one. In the
inhibition test phase, we endowed the competitive
experimenter with a more valuable food reward but the
competitive experimenter continued to withhold food from the
subject. Thus, lemurs were required to inhibit approaching
the more desirable reward in favor of the lesser but
obtainable reward presented by the generous experimenter. In
test trials, lemurs' tendency to approach the competitive
experimenter increased from the reputation phase,
demonstrating sensitivity to the experimental manipulation.
However, subjects approached the larger reward less
frequently in test trials compared with pretest
food-preference trials, evidencing some capacity for
inhibitory control in this context. Despite differences in
sociality and ecology, the five lemur species did not differ
in this ability. Although the study did not uncover species
differences, this experimental task may provide a useful
measure of social inhibition in broader comparative
studies.},
Doi = {10.1007/s10329-015-0467-1},
Key = {fds240360}
}
@article{fds240359,
Author = {MacLean, EL and Hare, B},
Title = {Evolution. Dogs hijack the human bonding
pathway.},
Journal = {Science (New York, N.Y.)},
Volume = {348},
Number = {6232},
Pages = {280-281},
Year = {2015},
Month = {April},
ISSN = {0036-8075},
Doi = {10.1126/science.aab1200},
Key = {fds240359}
}
@article{fds240361,
Author = {MacLean, EL and Hare, B},
Title = {Bonobos and chimpanzees exploit helpful but not prohibitive
gestures},
Journal = {Behaviour},
Volume = {152},
Number = {3-4},
Pages = {493-520},
Publisher = {BRILL},
Year = {2015},
Month = {February},
ISSN = {0005-7959},
Abstract = {Previous research has shown that chimpanzees exploit the
behavior of humans and conspecifics more readily in a
competitive than a cooperative context. However, it is
unknown whether bonobos, who outperform chimpanzees in some
cooperative tasks, also show greater cognitive flexibility
in competitive contexts. Here we tested the
cooperative-competitive hypothesis further by comparing
bonobos and chimpanzees in a series of tasks where a human
gesture indicated the correct (cooperative) or incorrect
(competitive) choice. A human either pointed cooperatively
to the object a subject should choose, or competitively to
the object subjects should avoid choosing. In contrast to
previous research, subjects were most skilled at choosing
the correct location when the communicator was cooperative
and there were no major differences between bonobos and
chimpanzees. Analysis of gaze direction revealed that in
some cases subjects visually followed the direction of the
experimenter's gesture despite choosing incorrectly,
dissociating gesture following from gesture comprehension.
This supports the hypothesis that, unlike human children,
nonhuman apes respond to the direction of social gestures
more readily than they understand the communicative
intentions underlying them.We evaluate these findings in
regard to previous studies comparing the cooperative and
communicative skills of bonobos and chimpanzees.},
Doi = {10.1163/1568539X-00003203},
Key = {fds240361}
}
@article{fds240362,
Author = {Schroepfer-Walker, K and Wobber, V and Hare, B},
Title = {Experimental evidence that grooming and play are social
currency in bonobos and chimpanzees},
Journal = {Behaviour},
Volume = {152},
Number = {3-4},
Pages = {545-562},
Publisher = {BRILL},
Year = {2015},
Month = {February},
ISSN = {0005-7959},
Abstract = {While natural observations show apes use grooming and play
as social currency, no experimental manipulations have been
carried out to measure the effects of these behaviours on
relationship formation in apes. While previous experiments
have demonstrated apes quickly learn the identity of
individuals who will provide food in a variety of
cooperative and non-cooperative situations, no experiment
has ever examined how grooming and play might shape the
preferences of apes for different individuals. We gave a
group bonobos (N = 25) and chimpanzees (N = 30) a choice
between an unfamiliar human who had recently groomed or
played with them and one who had not. Both species showed a
preference for the unfamiliar human that had interacted with
them over the one who did not. The effect was largely driven
by the males of both species while interacting with females
showed little effect on their preferences for unfamiliar
humans. Subjects showed this preference even though they
only had social interactions with one of the unfamiliar
humans for a few minutes before each trial and their choices
were not rewarded with food differentially. Our results
support the long held idea that grooming and play act as a
form of social currency in great apes (and likely many other
species) that can rapidly shape social relationships,
particularly between unfamiliar individuals.},
Doi = {10.1163/1568539X-00003258},
Key = {fds240362}
}
@article{fds240363,
Author = {Tan, J and Kwetuenda, S and Hare, B},
Title = {Preference or paradigm? Bonobos show no evidence of
other-regard in the standard prosocial choice
task},
Journal = {Behaviour},
Volume = {152},
Number = {3-4},
Pages = {521-544},
Publisher = {BRILL},
Year = {2015},
Month = {February},
ISSN = {0005-7959},
Abstract = {Bonobos are the only ape species, other than humans, that
have demonstrated prosocial behaviors toward groupmates and
strangers. However, bonobos have not been tested in the most
frequently used test of prosociality in animals. The current
study tested the other-regarding preferences of bonobos in
two experiments using the prosocial choice task. In the
first experiment subjects preferred a food option that would
benefit both themselves and another bonobo. This preference
was likely the result of a location bias developed in the
pretest since they showed the same preference in the
non-social control condition within test sessions. A second
experiment was designed to help subjects overcome this bias
that might interfere with their social choices. Bonobos
again did not prefer to choose the prosocial option.
However, results suggest constraints of this paradigm in
revealing social preferences. In discussing our results we
consider why bonobos show robust prosocial preferences in
other paradigms but not here. While others have suggested
that such contradictory results might suggest interesting
motivational or cognitive differences between humans and
non-humans, we propose that the current 'standard' paradigm
has failed validation due to three methodological
constraints. Across the dozens of studies completed few have
demonstrated that non-human subjects understand the causal
properties of the apparatus, non-social biases quickly
develop in inadequately counterbalanced pretests that
typically explain subjects' choices in the test, and even
human children found this choice task too cognitively
demanding to consistently show prosocial preferences. We
suggest it is time to consider switching to a variety of
more powerful and valid measures.},
Doi = {10.1163/1568539X-00003230},
Key = {fds240363}
}
@article{fds240364,
Author = {Hare, B and Yamamoto, S},
Title = {Moving bonobos off the scientifically endangered
list},
Journal = {Behaviour},
Volume = {152},
Number = {3-4},
Pages = {247-258},
Publisher = {BRILL},
Year = {2015},
Month = {February},
ISSN = {0005-7959},
Abstract = {This Special Issue of Behaviour includes twelve novel
empirical papers focusing on the behaviour and cognition of
both captive and wild bonobos (Pan paniscus). As our species
less known closest relative, the bonobo has gone from being
little studied to increasingly popular as a species of focus
over the past decade. We suggest that bonobos are ready to
come off the scientific endangered list as a result. This
Special Issue is exhibit A in showing that a renaissance in
bonobo research is well underway. In this Editorial we
review a number of traits in which bonobos and chimpanzees
are more similar to humans than they are each other.We show
how this means that bonobos provide an extremely powerful
test of ideas about human uniqueness as well as being
crucial to determining the evolutionary processes by which
cognitive traits evolve in apes. This introduction places
the twelve empirical contributions within the Special Issue
in the larger evolutionary context to which they contribute.
Overall this Special Issue demonstrates how anyone
interested in understanding humans or chimpanzees must also
know bonobos.},
Doi = {10.1163/1568539X-00003263},
Key = {fds240364}
}
@article{fds240365,
Author = {Krupenye, C and Rosati, AG and Hare, B},
Title = {Bonobos and chimpanzees exhibit human-like framing
effects.},
Journal = {Biology letters},
Volume = {11},
Number = {2},
Pages = {20140527},
Year = {2015},
Month = {February},
ISSN = {1744-9561},
Abstract = {Humans exhibit framing effects when making choices,
appraising decisions involving losses differently from those
involving gains. To directly test for the evolutionary
origin of this bias, we examined decision-making in humans'
closest living relatives: bonobos (Pan paniscus) and
chimpanzees (Pan troglodytes). We presented the largest
sample of non-humans to date (n = 40) with a simple task
requiring minimal experience. Apes made choices between a
'framed' option that provided preferred food, and an
alternative option that provided a constant amount of
intermediately preferred food. In the gain condition, apes
experienced a positive 'gain' event in which the framed
option was initially presented as one piece of food but
sometimes was augmented to two. In the loss condition, apes
experienced a negative 'loss' event in which they initially
saw two pieces but sometimes received only one. Both
conditions provided equal pay-offs, but apes chose the
framed option more often in the positive 'gain' frame.
Moreover, male apes were more susceptible to framing than
were females. These results suggest that some human economic
biases are shared through common descent with other apes and
highlight the importance of comparative work in
understanding the origins of individual differences in human
choice.},
Doi = {10.1098/rsbl.2014.0527},
Key = {fds240365}
}
@article{fds240367,
Author = {MacLean, EL and Krupenye, C and Hare, B},
Title = {Dogs (Canis familiaris) account for body orientation but not
visual barriers when responding to pointing
gestures.},
Journal = {Journal of comparative psychology (Washington, D.C. :
1983)},
Volume = {128},
Number = {3},
Pages = {285-297},
Year = {2014},
Month = {August},
ISSN = {0735-7036},
Abstract = {In a series of four experiments we investigated whether dogs
use information about a human's visual perspective when
responding to pointing gestures. While there is evidence
that dogs may know what humans can and cannot see, and that
they flexibly use human communicative gestures, it is
unknown if they can integrate these two skills. In
Experiment 1 we first determined that dogs were capable of
using basic information about a human's body orientation
(indicative of her visual perspective) in a point following
context. Subjects were familiarized with experimenters who
either faced the dog and accurately indicated the location
of hidden food, or faced away from the dog and (falsely)
indicated the unbaited container. In test trials these cues
were pitted against one another and dogs tended to follow
the gesture from the individual who faced them while
pointing. In Experiments 2-4 the experimenter pointed
ambiguously toward two possible locations where food could
be hidden. On test trials a visual barrier occluded the
pointer's view of one container, while dogs could always see
both containers. We predicted that if dogs could take the
pointer's visual perspective they should search in the only
container visible to the pointer. This hypothesis was
supported only in Experiment 2. We conclude that while dogs
are skilled both at following human gestures, and exploiting
information about others' visual perspectives, they may not
integrate these skills in the manner characteristic of human
children.},
Doi = {10.1037/a0035742},
Key = {fds240367}
}
@article{fds240373,
Author = {Rosati, AG and Rodriguez, K and Hare, B},
Title = {The ecology of spatial memory in four lemur
species.},
Journal = {Animal cognition},
Volume = {17},
Number = {4},
Pages = {947-961},
Year = {2014},
Month = {July},
ISSN = {1435-9448},
Abstract = {Evolutionary theories suggest that ecology is a major factor
shaping cognition in primates. However, there have been few
systematic tests of spatial memory abilities involving
multiple primate species. Here, we examine spatial memory
skills in four strepsirrhine primates that vary in level of
frugivory: ruffed lemurs (Varecia sp.), ring-tailed lemurs
(Lemur catta), mongoose lemurs (Eulemur mongoz), and
Coquerel's sifakas (Propithecus coquereli). We compare these
species across three studies targeting different aspects of
spatial memory: recall after a long-delay, learning
mechanisms supporting memory and recall of multiple
locations in a complex environment. We find that ruffed
lemurs, the most frugivorous species, consistently showed
more robust spatial memory than the other species across
tasks-especially in comparison with sifakas, the most
folivorous species. We discuss these results in terms of the
importance of considering both ecological and social factors
as complementary explanations for the evolution of primate
cognitive skills.},
Doi = {10.1007/s10071-014-0727-2},
Key = {fds240373}
}
@article{fds240371,
Author = {MacLean, EL and Hare, B and Nunn, CL and Addessi, E and Amici, F and Anderson, RC and Aureli, F and Baker, JM and Bania, AE and Barnard, AM and Boogert, NJ and Brannon, EM and Bray, EE and Bray, J and Brent, LJN and Burkart, JM and Call, J and Cantlon, JF and Cheke, LG and Clayton, NS and Delgado, MM and DiVincenti, LJ and Fujita, K and Herrmann, E and Hiramatsu, C and Jacobs, LF and Jordan, KE and Laude, JR and Leimgruber,
KL and Messer, EJE and Moura, ACDA and Ostojić, L and Picard, A and Platt,
ML and Plotnik, JM and Range, F and Reader, SM and Reddy, RB and Sandel,
AA and Santos, LR and Schumann, K and Seed, AM and Sewall, KB and Shaw, RC and Slocombe, KE and Su, Y and Takimoto, A and Tan, J and Tao, R and van
Schaik, CP and Virányi, Z and Visalberghi, E and Wade, JC and Watanabe,
A and Widness, J and Young, JK and Zentall, TR and Zhao,
Y},
Title = {The evolution of self-control.},
Journal = {Proc Natl Acad Sci U S A},
Volume = {111},
Number = {20},
Pages = {E2140-E2148},
Year = {2014},
Month = {May},
ISSN = {0027-8424},
Abstract = {Cognition presents evolutionary research with one of its
greatest challenges. Cognitive evolution has been explained
at the proximate level by shifts in absolute and relative
brain volume and at the ultimate level by differences in
social and dietary complexity. However, no study has
integrated the experimental and phylogenetic approach at the
scale required to rigorously test these explanations.
Instead, previous research has largely relied on various
measures of brain size as proxies for cognitive abilities.
We experimentally evaluated these major evolutionary
explanations by quantitatively comparing the cognitive
performance of 567 individuals representing 36 species on
two problem-solving tasks measuring self-control.
Phylogenetic analysis revealed that absolute brain volume
best predicted performance across species and accounted for
considerably more variance than brain volume controlling for
body mass. This result corroborates recent advances in
evolutionary neurobiology and illustrates the cognitive
consequences of cortical reorganization through increases in
brain volume. Within primates, dietary breadth but not
social group size was a strong predictor of species
differences in self-control. Our results implicate robust
evolutionary relationships between dietary breadth, absolute
brain volume, and self-control. These findings provide a
significant first step toward quantifying the primate
cognitive phenome and explaining the process of cognitive
evolution.},
Doi = {10.1073/pnas.1323533111},
Key = {fds240371}
}
@article{fds240377,
Author = {Bray, J and Krupenye, C and Hare, B},
Title = {Ring-tailed lemurs (Lemur catta) exploit information about
what others can see but not what they can
hear.},
Journal = {Animal cognition},
Volume = {17},
Number = {3},
Pages = {735-744},
Year = {2014},
Month = {May},
url = {http://www.ncbi.nlm.nih.gov/pubmed/24218121},
Abstract = {Studies suggest that haplorhine primates are sensitive to
what others can see and hear. Using two experimental
designs, we tested the hypothesis that ring-tailed lemurs (N
= 16) are also sensitive to the visual and auditory
perception of others. In the first task, we used a go/no-go
design that required lemurs to exploit only auditory
information. In the second task, we used a forced-choice
design where lemurs competed against a human who would
prevent them from obtaining food if their approaches were
detected. Subjects were given the choice of obtaining food
silently or noisily when the competitor's back was turned.
They were also given the choice to obtain food when the
competitor could either see them or not. Here, we replicate
the findings of previous studies indicating that ring-tailed
lemurs are sensitive to whether they can be seen; however,
we found no evidence that subjects are sensitive to whether
others can hear them. Our findings suggest that ring-tailed
lemurs converge with haplorhine primates only in their
sensitivity to the visual information of others. The results
emphasize the importance of investigating social cognition
across sensory domains in order to elucidate the cognitive
mechanisms that underlie apparently complex social behavior.
These findings also suggest that the social dynamics of
haplorhine groups impose greater cognitive demands than
lemur groups, despite similarities in total group
size.},
Doi = {10.1007/s10071-013-0705-0},
Key = {fds240377}
}
@article{fds240380,
Author = {Wobber, V and Herrmann, E and Hare, B and Wrangham, R and Tomasello,
M},
Title = {Differences in the early cognitive development of children
and great apes.},
Journal = {Developmental psychobiology},
Volume = {56},
Number = {3},
Pages = {547-573},
Year = {2014},
Month = {April},
ISSN = {0012-1630},
Abstract = {There is very little research comparing great ape and human
cognition developmentally. In the current studies we
compared a cross-sectional sample of 2- to 4-year-old human
children (n=48) with a large sample of chimpanzees and
bonobos in the same age range (n=42, hereafter: apes) on a
broad array of cognitive tasks. We then followed a group of
juvenile apes (n=44) longitudinally over 3 years to track
their cognitive development in greater detail. In skills of
physical cognition (space, causality, quantities), children
and apes performed comparably at 2 years of age, but by 4
years of age children were more advanced (whereas apes
stayed at their 2-year-old performance levels). In skills of
social cognition (communication, social learning, theory of
mind), children out-performed apes already at 2 years, and
increased this difference even more by 4 years. Patterns of
development differed more between children and apes in the
social domain than the physical domain, with support for
these patterns present in both the cross-sectional and
longitudinal ape data sets. These results indicate key
differences in the pattern and pace of cognitive development
between humans and other apes, particularly in the early
emergence of specific social cognitive capacities in
humans.},
Doi = {10.1002/dev.21125},
Key = {fds240380}
}
@article{fds240368,
Author = {Cieri, RL and Churchill, SE and Franciscus, RG and Tan, J and Hare,
B},
Title = {Craniofacial feminization, social tolerance, and the origins
of behavioral modernity},
Journal = {Current Anthropology},
Volume = {55},
Number = {4},
Pages = {419-443},
Publisher = {University of Chicago Press},
Year = {2014},
Month = {January},
ISSN = {0011-3204},
Abstract = {The past 200,000 years of human cultural evolution have
witnessed the persistent establishment of behaviors
involving innovation, planning depth, and abstract and
symbolic thought, or what has been called "behavioral
modernity." Demographic models based on increased human
population density from the late Pleistocene onward have
been increasingly invoked to understand the emergence of
behavioral modernity. However, high levels of social
tolerance, as seen among living humans, are a necessary
prerequisite to life at higher population densities and to
the kinds of cooperative cultural behaviors essential to
these demographic models. Here we provide data on
craniofacial feminization (reduction in average brow ridge
projection and shortening of the upper facial skeleton) in
Homo sapiens from the Middle Pleistocene to recent times. We
argue that temporal changes in human craniofacial morphology
reflect reductions in average androgen reactivity (lower
levels of adult circulating testosterone or reduced androgen
receptor densities), which in turn reflect the evolution of
enhanced social tolerance since the Middle Pleistocene. ©
2014 by The Wenner-Gren Foundation for Anthropological
Research. All rights reserved.},
Doi = {10.1086/677209},
Key = {fds240368}
}
@article{fds240372,
Author = {Pontzer, H and Raichlen, DA and Gordon, AD and Schroepfer-Walker, KK and Hare, B and O'Neill, MC and Muldoon, KM and Dunsworth, HM and Wood, BM and Isler, K and Burkart, J and Irwin, M and Shumaker, RW and Lonsdorf, EV and Ross, SR},
Title = {Primate energy expenditure and life history.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {111},
Number = {4},
Pages = {1433-1437},
Year = {2014},
Month = {January},
ISSN = {0027-8424},
Abstract = {Humans and other primates are distinct among placental
mammals in having exceptionally slow rates of growth,
reproduction, and aging. Primates' slow life history
schedules are generally thought to reflect an evolved
strategy of allocating energy away from growth and
reproduction and toward somatic investment, particularly to
the development and maintenance of large brains. Here we
examine an alternative explanation: that primates' slow life
histories reflect low total energy expenditure (TEE)
(kilocalories per day) relative to other placental mammals.
We compared doubly labeled water measurements of TEE among
17 primate species with similar measures for other placental
mammals. We found that primates use remarkably little energy
each day, expending on average only 50% of the energy
expected for a placental mammal of similar mass. Such large
differences in TEE are not easily explained by differences
in physical activity, and instead appear to reflect systemic
metabolic adaptation for low energy expenditures in
primates. Indeed, comparisons of wild and captive primate
populations indicate similar levels of energy expenditure.
Broad interspecific comparisons of growth, reproduction, and
maximum life span indicate that primates' slow metabolic
rates contribute to their characteristically slow life
histories.},
Doi = {10.1073/pnas.1316940111},
Key = {fds240372}
}
@misc{fds330815,
Author = {Hare, B},
Title = {Is human free will prisoner to primate, ape, and hominin
preferences and biases?},
Pages = {361-366},
Booktitle = {Moral Psychology, Volume 4: Free Will And Moral
Responsibility},
Year = {2014},
Month = {January},
ISBN = {9780262525473},
Key = {fds330815}
}
@article{fds240378,
Author = {MacLean, E and Hare, B},
Title = {Spontaneous triadic engagement in bonobos (Pan paniscus) and
chimpanzees (Pan troglodytes).},
Journal = {Journal of comparative psychology (Washington, D.C. :
1983)},
Volume = {127},
Number = {3},
Pages = {245-255},
Year = {2013},
Month = {August},
ISSN = {0735-7036},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000323579000003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Humans are believed to have evolved a unique motivation to
participate in joint activities that first develops during
infancy and supports the development of shared
intentionality. We conducted five experiments with bonobos
(Pan paniscus) and chimpanzees (Pan troglodytes) (Total n =
119) to assess their motivation to spontaneously participate
in joint activities with a conspecific or a human. We found
that even the youngest subjects preferred to interact
together with a human and a toy rather than engaging in an
identical game alone. In addition, we found that subjects
could spontaneously interact with a human in a turn-taking
game involving passing a ball back and forth and used
behaviors to elicit additional interaction when the game was
disrupted. However, when paired with a conspecific, subjects
preferred to interact with an object individually rather
than together. Our results indicate that nonhuman apes are
motivated to engage in triadic activities if they occur
spontaneously with humans and require a minimum amount of
coordination. These findings leave open the question of
whether these activities are coordinated through shared
intentions.},
Doi = {10.1037/a0030935},
Key = {fds240378}
}
@article{fds240383,
Author = {Wobber, V and Hare, B and Lipson, S and Wrangham, R and Ellison,
P},
Title = {Different ontogenetic patterns of testosterone production
reflect divergent male reproductive strategies in
chimpanzees and bonobos.},
Journal = {Physiology & behavior},
Volume = {116-117},
Pages = {44-53},
Year = {2013},
Month = {May},
ISSN = {0031-9384},
Abstract = {Male reproductive effort is often strongly related to levels
of the steroid hormone testosterone. However, little
research has examined whether levels of testosterone
throughout development might be tied to individual or
species differences in the reproductive strategies pursued
by adult males. Here, we tested the hypothesis that
inter-specific differences in male reproductive strategy are
associated with differences in the pattern of testosterone
production throughout early life and puberty. We compared
testosterone levels from infancy to adulthood in two closely
related species where levels of mating competition and
male-male aggression differ significantly, bonobos (Pan
paniscus) and chimpanzees (Pan troglodytes). We predicted
that the reduction in male mating competition found in
bonobos would be accompanied by a lesser developmental
increase in testosterone production. We performed
radioimmunoassay of salivary testosterone levels in a
mixed-longitudinal sample of both species, collected from
individuals living in semi free-ranging populations. This
allowed us to examine the effects of development in a more
naturalistic setting than possible in a zoo or laboratory.
We found that among chimpanzees, testosterone levels
declined slightly from infancy to juvenility, then remained
low until increasing markedly during adolescence (with
pubertal increases most pronounced among males). In
contrast, there was little change in testosterone production
with age in bonobos of either sex, with levels of
testosterone consistent throughout infancy, juvenility, and
the transition to adulthood. Our data are therefore
consistent with the hypothesis that the ontogenetic pattern
of testosterone production can be subject to rapid
evolutionary change, shifting in association with species
differences in male reproductive strategy.},
Doi = {10.1016/j.physbeh.2013.03.003},
Key = {fds240383}
}
@article{fds240386,
Author = {Herrmann, E and Keupp, S and Hare, B and Vaish, A and Tomasello,
M},
Title = {Direct and indirect reputation formation in nonhuman great
apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, Pongo
pygmaeus) and human children (Homo sapiens).},
Journal = {Journal of comparative psychology (Washington, D.C. :
1983)},
Volume = {127},
Number = {1},
Pages = {63-75},
Year = {2013},
Month = {February},
ISSN = {0735-7036},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000315340300010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Humans make decisions about when and with whom to cooperate
based on their reputations. People either learn about others
by direct interaction or by observing third-party
interactions or gossip. An important question is whether
other animal species, especially our closest living
relatives, the nonhuman great apes, also form reputations of
others. In Study 1, chimpanzees, bonobos, orangutans, and
2.5-year-old human children experienced a nice experimenter
who tried to give food/toys to the subject and a mean
experimenter who interrupted the food/toy giving. In studies
2 and 3, nonhuman great apes and human children could only
passively observe a similar interaction, in which a nice
experimenter and a mean experimenter interacted with a third
party. Orangutans and 2.5-year-old human children preferred
to approach the nice experimenter rather than the mean one
after having directly experienced their respective
behaviors. Orangutans, chimpanzees, and 2.5-year-old human
children also took into account experimenter actions toward
third parties in forming reputations. These studies show
that the human ability to form direct and indirect
reputation judgment is already present in young children and
shared with at least some of the other great
apes.},
Doi = {10.1037/a0028929},
Key = {fds240386}
}
@article{fds240379,
Author = {Maclean, EL and Sandel, AA and Bray, J and Oldenkamp, RE and Reddy, RB and Hare, BA},
Title = {Group Size Predicts Social but Not Nonsocial Cognition in
Lemurs.},
Journal = {PloS one},
Volume = {8},
Number = {6},
Pages = {e66359},
Booktitle = {PLoS One},
Year = {2013},
Month = {January},
ISSN = {1932-6203},
Abstract = {The social intelligence hypothesis suggests that living in
large social networks was the primary selective pressure for
the evolution of complex cognition in primates. This
hypothesis is supported by comparative studies demonstrating
a positive relationship between social group size and
relative brain size across primates. However, the
relationship between brain size and cognition remains
equivocal. Moreover, there have been no experimental studies
directly testing the association between group size and
cognition across primates. We tested the social intelligence
hypothesis by comparing 6 primate species (total N = 96)
characterized by different group sizes on two cognitive
tasks. Here, we show that a species' typical social group
size predicts performance on cognitive measures of social
cognition, but not a nonsocial measure of inhibitory
control. We also show that a species' mean brain size (in
absolute or relative terms) does not predict performance on
either task in these species. These data provide evidence
for a relationship between group size and social cognition
in primates, and reveal the potential for cognitive
evolution without concomitant changes in brain size.
Furthermore our results underscore the need for more
empirical studies of animal cognition, which have the power
to reveal species differences in cognition not detectable by
proxy variables, such as brain size.},
Doi = {10.1371/journal.pone.0066359},
Key = {fds240379}
}
@article{fds240384,
Author = {Rosati, AG and Hare, B},
Title = {Chimpanzees and bonobos exhibit emotional responses to
decision outcomes.},
Journal = {PloS one},
Volume = {8},
Number = {5},
Pages = {e63058},
Year = {2013},
Month = {January},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23734175},
Abstract = {The interface between cognition, emotion, and motivation is
thought to be of central importance in understanding complex
cognitive functions such as decision-making and executive
control in humans. Although nonhuman apes have complex
repertoires of emotional expression, little is known about
the role of affective processes in ape decision-making. To
illuminate the evolutionary origins of human-like patterns
of choice, we investigated decision-making in humans'
closest phylogenetic relatives, chimpanzees (Pan
troglodytes) and bonobos (Pan paniscus). In two studies, we
examined these species' temporal and risk preferences, and
assessed whether apes show emotional and motivational
responses in decision-making contexts. We find that (1)
chimpanzees are more patient and more risk-prone than are
bonobos, (2) both species exhibit affective and motivational
responses following the outcomes of their decisions, and (3)
some emotional and motivational responses map onto
species-level and individual-differences in decision-making.
These results indicate that apes do exhibit emotional
responses to decision-making, like humans. We explore the
hypothesis that affective and motivational biases may
underlie the psychological mechanisms supporting value-based
preferences in these species.},
Doi = {10.1371/journal.pone.0063058},
Key = {fds240384}
}
@article{fds240387,
Author = {Hare, B},
Title = {Animal behavior. For $60, a peek inside your dog's
mind.},
Journal = {Science (New York, N.Y.)},
Volume = {339},
Number = {6117},
Pages = {260-261},
Year = {2013},
Month = {January},
ISSN = {0036-8075},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000313622000013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Doi = {10.1126/science.339.6117.260},
Key = {fds240387}
}
@article{fds240388,
Author = {Tan, J and Hare, B},
Title = {Bonobos share with strangers.},
Journal = {PloS one},
Volume = {8},
Number = {1},
Pages = {e51922},
Year = {2013},
Month = {January},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23300956},
Abstract = {Humans are thought to possess a unique proclivity to share
with others--including strangers. This puzzling phenomenon
has led many to suggest that sharing with strangers
originates from human-unique language, social norms, warfare
and/or cooperative breeding. However, bonobos, our closest
living relative, are highly tolerant and, in the wild, are
capable of having affiliative interactions with strangers.
In four experiments, we therefore examined whether bonobos
will voluntarily donate food to strangers. We show that
bonobos will forego their own food for the benefit of
interacting with a stranger. Their prosociality is in part
driven by unselfish motivation, because bonobos will even
help strangers acquire out-of-reach food when no desirable
social interaction is possible. However, this prosociality
has its limitations because bonobos will not donate food in
their possession when a social interaction is not possible.
These results indicate that other-regarding preferences
toward strangers are not uniquely human. Moreover, language,
social norms, warfare and cooperative breeding are
unnecessary for the evolution of xenophilic sharing.
Instead, we propose that prosociality toward strangers
initially evolves due to selection for social tolerance,
allowing the expansion of individual social networks. Human
social norms and language may subsequently extend this
ape-like social preference to the most costly
contexts.},
Doi = {10.1371/journal.pone.0051922},
Key = {fds240388}
}
@misc{fds219184,
Author = {A. Melis and F. Warneken and B. Hare},
Title = {Collaboration and helping in chimpanzees.},
Pages = {166-183},
Booktitle = {The Chimpanzee Mind},
Year = {2013},
Key = {fds219184}
}
@article{fds219188,
Author = {E. Herrmann and B. Hare and J. Cisseski and M. Tomasello},
Title = {The origins of human temperament: children avoid novelty
more than other apes.},
Journal = {Developmental Science},
Volume = {14},
Pages = {1393-1405},
Year = {2013},
Key = {fds219188}
}
@article{fds219196,
Author = {E. Herrmann and S. Keupp and B. Hare and A. Vaish and M.
Tomasello},
Title = {Direct and indirect reputation formation in great apes and
human children.},
Journal = {Journal of Comparative Psychology},
Volume = {127},
Pages = {63-75},
Year = {2013},
Key = {fds219196}
}
@article{fds219197,
Author = {E. Maclean and B. Hare},
Title = {Spontaneous triadic play in bonobos and chimpanzees.},
Journal = {Journal of Comparative Psychology},
Year = {2013},
Key = {fds219197}
}
@article{fds219201,
Author = {A. Rosati and V. Wobber and F. Warneken and A. Melis and E. Herrmann and J.
Kaminski, J. Tan and C. Krupenye and K. Schroepfer and B.
Hare},
Title = {Assessing the psychological health of cpative and wild apes:
a response to Ferdowsian et al. in press},
Journal = {Journal of Comparative Psychology},
Year = {2013},
Key = {fds219201}
}
@misc{fds219205,
Author = {V. Wobber and B. Hare},
Title = {The evolution of human socio-cognitive development.},
Booktitle = {The Development of Social Cognition},
Year = {2013},
Key = {fds219205}
}
@article{fds219990,
Author = {T. Wobber and E. Herrmann and B. Hare and R. Wrangham and M.
Tomasello},
Title = {The evolution of cognitive development in Pan and
Homo.},
Booktitle = {Developmental Psychobiology},
Year = {2013},
Key = {fds219990}
}
@book{fds219139,
Author = {B. Hare and V. Woods},
Title = {The Genius of Dogs},
Publisher = {Dutton: Penguin Group},
Year = {2013},
Key = {fds219139}
}
@article{fds240385,
Author = {Bray, EE and MacLean, EL and Hare, BA},
Title = {Context specificity of inhibitory control in
dogs},
Journal = {Animal Cognition},
Volume = {17},
Number = {1},
Pages = {1-17},
Booktitle = {Animal Cognition},
Publisher = {Springer Nature},
Year = {2013},
ISSN = {1435-9448},
Abstract = {Across three experiments, we explored whether a dog's
capacity for inhibitory control is stable or variable across
decision-making contexts. In the social task, dogs were
first exposed to the reputations of a stingy experimenter
that never shared food and a generous experimenter who
always shared food. In subsequent test trials, dogs were
required to avoid approaching the stingy experimenter when
this individual offered (but withheld) a higher-value reward
than the generous experimenter did. In the A-not-B task,
dogs were required to inhibit searching for food in a
previously rewarded location after witnessing the food being
moved from this location to a novel hiding place. In the
cylinder task, dogs were required to resist approaching
visible food directly (because it was behind a transparent
barrier), in favor of a detour reaching response. Overall,
dogs exhibited inhibitory control in all three tasks.
However, individual scores were not correlated between
tasks, suggesting that context has a large effect on dogs'
behavior. This result mirrors studies of humans, which have
highlighted intra-individual variation in inhibitory control
as a function of the decision-making context. Lastly, we
observed a correlation between a subject's age and
performance on the cylinder task, corroborating previous
observations of age-related decline in dogs' executive
function.},
Doi = {10.1007/s10071-013-0633-z},
Key = {fds240385}
}
@article{fds240444,
Author = {Nunn, CL and Hare, B},
Title = {Pathogen flow: what we need to know.},
Journal = {American journal of primatology},
Volume = {74},
Number = {12},
Pages = {1084-1087},
Year = {2012},
Month = {December},
ISSN = {0275-2565},
Doi = {10.1002/ajp.22070},
Key = {fds240444}
}
@article{fds240443,
Author = {Rosati, AG and Hare, B},
Title = {Chimpanzees and bonobos exhibit divergent spatial memory
development.},
Journal = {Developmental science},
Volume = {15},
Number = {6},
Pages = {840-853},
Year = {2012},
Month = {November},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23106738},
Abstract = {Spatial cognition and memory are critical cognitive skills
underlying foraging behaviors for all primates. While the
emergence of these skills has been the focus of much
research on human children, little is known about
ontogenetic patterns shaping spatial cognition in other
species. Comparative developmental studies of nonhuman apes
can illuminate which aspects of human spatial development
are shared with other primates, versus which aspects are
unique to our lineage. Here we present three studies
examining spatial memory development in our closest living
relatives, chimpanzees (Pan troglodytes) and bonobos (P.
paniscus). We first compared memory in a naturalistic
foraging task where apes had to recall the location of
resources hidden in a large outdoor enclosure with a variety
of landmarks (Studies 1 and 2). We then compared older apes
using a matched memory choice paradigm (Study 3). We found
that chimpanzees exhibited more accurate spatial memory than
bonobos across contexts, supporting predictions from these
species' different feeding ecologies. Furthermore,
chimpanzees - but not bonobos - showed developmental
improvements in spatial memory, indicating that bonobos
exhibit cognitive paedomorphism (delays in developmental
timing) in their spatial abilities relative to chimpanzees.
Together, these results indicate that the development of
spatial memory may differ even between closely related
species. Moreover, changes in the spatial domain can emerge
during nonhuman ape ontogeny, much like some changes seen in
human children.},
Doi = {10.1111/j.1467-7687.2012.01182.x},
Key = {fds240443}
}
@article{fds240442,
Author = {Rosati, AG and Hare, B},
Title = {Decision making across social contexts: Competition
increases preferences for risk in chimpanzees and
bonobos},
Journal = {Animal Behaviour},
Volume = {84},
Number = {4},
Pages = {869-879},
Publisher = {Elsevier BV},
Year = {2012},
Month = {October},
ISSN = {0003-3472},
url = {http://hdl.handle.net/10161/6945 Duke open access
repository},
Abstract = {Context can have a powerful influence on decision-making
strategies in humans. In particular, people sometimes shift
their economic preferences depending on the broader social
context, such as the presence of potential competitors or
mating partners. Despite the important role of competition
in primate conspecific interactions, as well as evidence
that competitive social contexts impact primates' social
cognitive skills, there has been little study of how social
context influences the strategies that nonhumans show when
making decisions about the value of resources. Here we
investigate the impact of social context on preferences for
risk (variability in payoffs) in our two closest
phylogenetic relatives, chimpanzees, Pan troglodytes, and
bonobos, Pan paniscus. In a first study, we examine the
impact of competition on patterns of risky choice. In a
second study, we examine whether a positive play context
affects risky choices. We find that (1) apes are more likely
to choose the risky option when making decisions in a
competitive context; and (2) the play context did not
influence their risk preferences. Overall these results
suggest that some types of social contexts can shift
patterns of decision making in nonhuman apes, much like in
humans. Comparative studies of chimpanzees and bonobos can
therefore help illuminate the evolutionary processes shaping
human economic behaviour. © 2012 The Association for the
Study of Animal Behaviour.},
Doi = {10.1016/j.anbehav.2012.07.010},
Key = {fds240442}
}
@misc{fds240381,
Author = {Rosati, Alexandra G. and Santos, Laurie R. and Hare,
B},
Title = {Primate Neuroethology},
Pages = {117-143},
Booktitle = {Primate Neuroethology},
Publisher = {Oxford University Press, USA},
Editor = {Platt, ML and Ghazanfar, AA},
Year = {2012},
Month = {August},
ISBN = {9780199929245},
url = {http://hdl.handle.net/10161/7465 Duke open access
repository},
Abstract = {This edited volume is the first of its kind to bridge the
epistemological gap between primate ethologists and primate
neurobiologists.},
Key = {fds240381}
}
@article{fds240441,
Author = {Hare, B and Wobber, V and Wrangham, R},
Title = {The self-domestication hypothesis: Evolution of bonobo
psychology is due to selection against aggression},
Journal = {Animal Behaviour},
Volume = {83},
Number = {3},
Pages = {573-585},
Publisher = {Elsevier BV},
Year = {2012},
Month = {March},
ISSN = {0003-3472},
Abstract = {Experiments indicate that selection against aggression in
mammals can have multiple effects on their morphology,
physiology, behaviour and psychology, and that these results
resemble a syndrome of changes observed in domestic animals.
We hypothesize that selection against aggression in some
wild species can operate in a similar way. Here we consider
the bonobo, Pan paniscus, as a candidate for having
experienced this 'self-domestication' process. We first
detail the changes typically seen in domesticated species
including shifts in development. We then show that bonobos
show less severe forms of aggression than chimpanzees, Pan
troglodytes, and suggest that this difference evolved
because of relaxed feeding competition. We next review
evidence that phenotypic differences in morphology and
behaviour between bonobos and chimpanzees are analogous to
differences between domesticates and their wild ancestors.
We then synthesize the first set of a priori experimental
tests of the self-domestication hypothesis comparing the
psychology of bonobos and chimpanzees. Again, bonobo traits
echo those of domesticates, including juvenilized patterns
of development. We conclude that the self-domestication
hypothesis provides a plausible account of the origin of
numerous differences between bonobos and chimpanzees, and
note that many of these appear to have arisen as incidental
by-products rather than adaptations. These results raise the
possibility that self-domestication has been a widespread
process in mammalian evolution, and suggest the need for
research into the regulatory genes responsible for shifts in
developmental trajectories in species that have undergone
selection against aggression. © 2011 The Association for
the Study of Animal Behaviour.},
Doi = {10.1016/j.anbehav.2011.12.007},
Key = {fds240441}
}
@article{fds240446,
Author = {MacLean, EL and Matthews, LJ and Hare, BA and Nunn, CL and Anderson, RC and Aureli, F and Brannon, EM and Call, J and Drea, CM and Emery, NJ and Haun,
DBM and Herrmann, E and Jacobs, LF and Platt, ML and Rosati, AG and Sandel,
AA and Schroepfer, KK and Seed, AM and Tan, J and van Schaik, CP and Wobber, V},
Title = {How does cognition evolve? Phylogenetic comparative
psychology.},
Journal = {Anim Cogn},
Volume = {15},
Number = {2},
Pages = {223-238},
Year = {2012},
Month = {March},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21927850},
Abstract = {Now more than ever animal studies have the potential to test
hypotheses regarding how cognition evolves. Comparative
psychologists have developed new techniques to probe the
cognitive mechanisms underlying animal behavior, and they
have become increasingly skillful at adapting methodologies
to test multiple species. Meanwhile, evolutionary biologists
have generated quantitative approaches to investigate the
phylogenetic distribution and function of phenotypic traits,
including cognition. In particular, phylogenetic methods can
quantitatively (1) test whether specific cognitive abilities
are correlated with life history (e.g., lifespan),
morphology (e.g., brain size), or socio-ecological variables
(e.g., social system), (2) measure how strongly phylogenetic
relatedness predicts the distribution of cognitive skills
across species, and (3) estimate the ancestral state of a
given cognitive trait using measures of cognitive
performance from extant species. Phylogenetic methods can
also be used to guide the selection of species comparisons
that offer the strongest tests of a priori predictions of
cognitive evolutionary hypotheses (i.e., phylogenetic
targeting). Here, we explain how an integration of
comparative psychology and evolutionary biology will answer
a host of questions regarding the phylogenetic distribution
and history of cognitive traits, as well as the evolutionary
processes that drove their evolution.},
Doi = {10.1007/s10071-011-0448-8},
Key = {fds240446}
}
@article{fds240440,
Author = {MacLean, EL and Hare, B},
Title = {Bonobos and chimpanzees infer the target of another's
attention},
Journal = {Animal Behaviour},
Volume = {83},
Number = {2},
Pages = {345-353},
Publisher = {Elsevier BV},
Year = {2012},
Month = {February},
ISSN = {0003-3472},
Abstract = {We examined the ability of bonobos, Pan paniscus (N= 39),
and chimpanzees, Pan troglodytes (N= 74), to infer the
target of an experimenter's visual attention in a series of
three experiments. In each experiment subjects were first
introduced to a novel object while an experimenter's (E1)
visual access to this object was manipulated by (1) having
E1 orient towards or away from the object, (2) positioning a
visual occluder that did or did not block E1's view of the
object, or (3) substituting a different experimenter for E1
during the introduction phase of the trial. After subjects
were introduced to the objects in one of these ways, E1
vocalized excitedly while gazing ambiguously towards the
previously introduced target object and a second location on
the same visual plane. In each experiment we measured
whether subjects looked at the object or the alternative
target of the E1's gaze. We predicted that if subjects
recognized when E1 was previously familiar with the object,
they would search for an alternative target of his attention
more frequently in these trials. In all three contexts,
chimpanzees, and in one context, bonobos, behaved
consistently with this prediction. These results are not
easily explained by learning or behaviour-reading hypotheses
because responses were never rewarded, few trials were
conducted per subject, and the experimenter's behaviour was
the same across experimental conditions at the moment
subjects were required to respond. Therefore, similar to
human infants, subjects most likely remembered what the
experimenter had or had not seen in the past, allowing them
to infer the target of his attention in the present. © 2011
The Association for the Study of Animal Behaviour.},
Doi = {10.1016/j.anbehav.2011.10.026},
Key = {fds240440}
}
@article{fds219191,
Author = {E. MacLean and B. Hare},
Title = {Bonobos and chimpanzees infer the target of an actor's
attention.},
Journal = {Animal Behavior},
Volume = {83},
Pages = {345-353},
Year = {2012},
Key = {fds219191}
}
@article{fds219192,
Author = {B. Hare and T. Wobber and R. Wrangham},
Title = {The self-domestication hypothesis: bonobo psychology evolved
due to selection against male aggression.},
Journal = {Animal Behavior},
Volume = {83},
Pages = {573-585},
Year = {2012},
Key = {fds219192}
}
@article{fds219193,
Author = {A. Rosati and B. Hare},
Title = {Decision-making across social contexts: competition
increases risk-prone choices in chimpanzees and
bonobos.},
Journal = {Animal Behavior},
Volume = {84},
Pages = {869-879},
Year = {2012},
Key = {fds219193}
}
@article{fds240439,
Author = {Herrmann, E and Hare, B and Cissewski, J and Tomasello,
M},
Title = {A comparison of temperament in nonhuman apes and human
infants.},
Journal = {Developmental science},
Volume = {14},
Number = {6},
Pages = {1393-1405},
Year = {2011},
Month = {November},
ISSN = {1363-755X},
Abstract = {The adaptive behavior of primates, including humans, is
often mediated by temperament. Human behavior likely differs
from that of other primates in part due to temperament. In
the current study we compared the reaction of bonobos,
chimpanzees, orangutans, and 2.5-year-old human infants to
novel objects and people - as a measure of their
shyness-boldness, a key temperamental trait. Human children
at the age of 2.5 years avoided novelty of all kinds far
more than the other ape species. This response was most
similar to that seen in bonobos and least like that of
chimpanzees and orangutans. This comparison represents a
first step in characterizing the temperamental profiles of
species in the hominoid clade, and these findings are
consistent with the hypothesis that human temperament has
evolved since our lineage diverged from the other apes in
ways that likely have broad effects on behavior. These
findings also provide new insights into how species
differences in ecology may shape differences in
temperament.},
Doi = {10.1111/j.1467-7687.2011.01082.x},
Key = {fds240439}
}
@article{fds240436,
Author = {Hare, B},
Title = {From hominoid to hominid mind: What changed and
why?},
Journal = {Annual Review of Anthropology},
Volume = {40},
Number = {1},
Pages = {293-309},
Publisher = {ANNUAL REVIEWS},
Year = {2011},
Month = {October},
ISSN = {0084-6570},
Abstract = {The living great apes, and in particular members of the
genus Pan, help test hypotheses regarding the cognitive
skills of our extinct common ancestor. Research with
chimpanzees suggests that we share some but not all of our
abilities to model another's perspective in social
interactions. Large-scale comparisons among human infants,
bonobos, chimpanzees, and orangutans on both social and
physical problem-solving tasks demonstrate that human
infants are unique for their early emerging social cognitive
skills, which facilitate participation in cultural
interactions. Comparisons between bonobos and chimpanzees
also reveal cognitive differences that are likely due to
developmental shifts. These comparative studies suggest that
our species' capabilities to assess the psychological states
of others are built on those abilities that were present in
our last common ape ancestor and were derived, in part,
owing to shifts in cognitive ontogeny that likely account
for species differences among other apes as well. © 2011 by
Annual Reviews. All rights reserved.},
Doi = {10.1146/annurev-anthro-081309-145726},
Key = {fds240436}
}
@article{fds240438,
Author = {Sandel, AA and MacLean, EL and Hare, B},
Title = {Evidence from four lemur species that ringtailed lemur
social cognition converges with that of haplorhine
primates},
Journal = {Animal Behaviour},
Volume = {81},
Number = {5},
Pages = {925-931},
Publisher = {Elsevier BV},
Year = {2011},
Month = {May},
ISSN = {0003-3472},
Abstract = {Many haplorhine primates flexibly exploit social cues when
competing for food. Whether strepsirrhine primates possess
similar abilities is unknown. To explore the phylogenetic
origins of such skills among primates, we tested ringtailed
lemurs, Lemur catta, for their ability to exploit social
cues while competing for food. We found that in two contexts
ringtailed lemurs spontaneously approached food out of their
competitor's view. To assess whether these skills are
related to the relatively complex social structure seen in
ringtailed lemurs or shared more broadly across a range of
strepsirrhines, we then compared ringtailed lemurs to three
lemur species with less complex societies in the same food
competition task (N=50 lemurs). Although all species
skilfully avoided food proximate to a competitor in a
pretest, only ringtailed lemurs performed above chance in
the food competition task that required subjects to avoid
food that an experimenter was facing in favour of one that
he was not facing. We also compared all four species in a
noncompetitive gaze-following task. Ringtailed lemurs were
again the only species that looked up more frequently when
an experimenter gazed into space than when an experimenter
gazed forward (although at relatively low frequencies).
These results are consistent with the hypothesis that
ringtailed lemurs have undergone convergent social-cognitive
evolution with haplorhines, possibly as an adaptation for
living in the largest and most complex social groups among
strepsirrhines. Results are discussed in terms of lemur
cognitive evolution as well as the social intelligence
hypothesis. © 2011 The Association for the Study of Animal
Behaviour.},
Doi = {10.1016/j.anbehav.2011.01.020},
Key = {fds240438}
}
@article{fds240448,
Author = {B. Hare and Woods, V and Hare, B},
Title = {Bonobo but not chimpanzee infants use socio-sexual contact
with peers.},
Journal = {Primates; journal of primatology},
Volume = {52},
Number = {2},
Pages = {111-116},
Year = {2011},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21127940},
Abstract = {Bonobos have been observed to use socio-sexual behavior at
higher frequency than chimpanzees. Little is known about the
developmental influences that shape this behavior in
bonobos. We compared the social sexual behavior of wild-born
bonobo (n = 8) and chimpanzee (n = 16) infants in an
experimental feeding test. Subjects of both species were
orphans of the bushmeat trade living at sanctuaries in peer
groups. During the experiment, chimpanzee infants never had
socio-sexual interactions with one another. In contrast,
bonobo infants had socio-sexual interactions significantly
more than the chimpanzee infants and more often when food
was presented. During these socio-sexual interactions,
bonobo infants did not show a preference for heterosexual
partners or genital-genital positioning that is reproductive
in adults (e.g. a dorso-ventral posture). These findings
suggest that the socio-sexual behavior previously observed
in various captive and wild bonobos is species-typical.
Wild-born bonobos originating from a large geographical
range develop this behavior long before puberty and without
the need for adults initiating such behavior or acting as
models for observational learning. Meanwhile, chimpanzee
infants of the same age with similar rearing history show no
signs of the same socio-sexual behavior. Results are
interpreted regarding hypotheses for the evolution of bonobo
psychology.},
Doi = {10.1007/s10329-010-0229-z},
Key = {fds240448}
}
@article{fds240437,
Author = {Rosati, AG and Hare, B},
Title = {Chimpanzees and bonobos distinguish between risk and
ambiguity.},
Journal = {Biology letters},
Volume = {7},
Number = {1},
Pages = {15-18},
Year = {2011},
Month = {February},
ISSN = {1744-9561},
url = {http://hdl.handle.net/10161/6948 Duke open access
repository},
Abstract = {Although recent research has investigated animal
decision-making under risk, little is known about how
animals choose under conditions of ambiguity when they lack
information about the available alternatives. Many models of
choice behaviour assume that ambiguity does not impact
decision-makers, but studies of humans suggest that people
tend to be more averse to choosing ambiguous options than
risky options with known probabilities. To illuminate the
evolutionary roots of human economic behaviour, we examined
whether our closest living relatives, chimpanzees (Pan
troglodytes) and bonobos (Pan paniscus), share this bias
against ambiguity. Apes chose between a certain option that
reliably provided an intermediately preferred food type, and
a variable option that could vary in the probability that it
provided a highly preferred food type. To examine the impact
of ambiguity on ape decision-making, we interspersed trials
in which chimpanzees and bonobos had no knowledge about the
probabilities. Both species avoided the ambiguous option
compared with their choices for a risky option, indicating
that ambiguity aversion is shared by humans, bonobos and
chimpanzees.},
Doi = {10.1098/rsbl.2010.0927},
Key = {fds240437}
}
@article{fds240433,
Author = {Wobber, V and Hare, B},
Title = {Psychological health of orphan bonobos and chimpanzees in
African sanctuaries.},
Journal = {PloS one},
Volume = {6},
Number = {6},
Pages = {e17147},
Year = {2011},
Month = {January},
ISSN = {1932-6203},
Abstract = {<h4>Background</h4>Facilities across Africa care for apes
orphaned by the trade for "bushmeat." These facilities,
called sanctuaries, provide housing for apes such as bonobos
(Pan paniscus) and chimpanzees (Pan troglodytes) who have
been illegally taken from the wild and sold as pets.
Although these circumstances are undoubtedly stressful for
the apes, most individuals arrive at the sanctuaries as
infants and are subsequently provided with rich physical and
social environments that can facilitate the expression of
species-typical behaviors.<h4>Methods and findings</h4>We
tested whether bonobo and chimpanzee orphans living in
sanctuaries show any behavioral, physiological, or cognitive
abnormalities relative to other individuals in captivity as
a result of the early-life stress they experience. Orphans
showed lower levels of aberrant behaviors, similar levels of
average cortisol, and highly similar performances on a broad
battery of cognitive tests in comparisons with individuals
of the same species who were either living at a zoo or were
reared by their mothers at the sanctuaries.<h4>Conclusion</h4>Taken
together, these results support the rehabilitation strategy
used by sanctuaries in the Pan-African Sanctuary Alliance
(PASA) and suggest that the orphans we examined did not show
long-term signs of stress as a result of their capture. Our
findings also show that sanctuary apes are as
psychologically healthy as apes in other captive settings
and thus represent a valuable resource for non-invasive
research.},
Doi = {10.1371/journal.pone.0017147},
Key = {fds240433}
}
@article{fds240445,
Author = {Schroepfer, KK and Rosati, AG and Chartrand, T and Hare,
B},
Title = {Use of "entertainment" chimpanzees in commercials distorts
public perception regarding their conservation
status.},
Journal = {PloS one},
Volume = {6},
Number = {10},
Pages = {e26048},
Year = {2011},
Month = {January},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22022503},
Abstract = {Chimpanzees (Pan troglodytes) are often used in movies,
commercials and print advertisements with the intention of
eliciting a humorous response from audiences. The portrayal
of chimpanzees in unnatural, human-like situations may have
a negative effect on the public's understanding of their
endangered status in the wild while making them appear as
suitable pets. Alternatively, media content that elicits a
positive emotional response toward chimpanzees may increase
the public's commitment to chimpanzee conservation. To test
these competing hypotheses, participants (n = 165)
watched a series of commercials in an experiment framed as a
marketing study. Imbedded within the same series of
commercials was one of three chimpanzee videos. Participants
either watched 1) a chimpanzee conservation commercial, 2)
commercials containing "entertainment" chimpanzees or 3)
control footage of the natural behavior of wild chimpanzees.
Results from a post-viewing questionnaire reveal that
participants who watched the conservation message understood
that chimpanzees were endangered and unsuitable as pets at
higher levels than those viewing the control footage.
Meanwhile participants watching commercials with
entertainment chimpanzees showed a decrease in understanding
relative to those watching the control footage. In addition,
when participants were given the opportunity to donate part
of their earnings from the experiment to a conservation
charity, donations were least frequent in the group watching
commercials with entertainment chimpanzees. Control
questions show that participants did not detect the purpose
of the study. These results firmly support the hypothesis
that use of entertainment chimpanzees in the popular media
negatively distorts the public's perception and hinders
chimpanzee conservation efforts.},
Doi = {10.1371/journal.pone.0026048},
Key = {fds240445}
}
@misc{fds219187,
Author = {B. Hare and J. Tan},
Title = {What cooperative abilities did we inherit as an
ape?},
Booktitle = {The Primate Mind},
Year = {2011},
Key = {fds219187}
}
@article{fds202130,
Author = {B. Hare and A. Sandel and E. Maclean and B. Hare},
Title = {Convergent evolution in the social cognitive abilities of
lemurs. Animal Behaviour. 81, 925-931},
Year = {2011},
Key = {fds202130}
}
@article{fds202131,
Author = {B. Hare and T. Wobber and B. Hare},
Title = {Psychological health of orphan bonobos and chimpanzees in
African sanctuaries. PLoS One, 6, e17147},
Year = {2011},
Key = {fds202131}
}
@article{fds240429,
Author = {Herrmann, E and Hare, B and Call, J and Tomasello,
M},
Title = {Differences in the cognitive skills of bonobos and
chimpanzees.},
Journal = {PloS one},
Volume = {5},
Number = {8},
Pages = {e12438},
Year = {2010},
Month = {August},
ISSN = {1932-6203},
url = {http://hdl.handle.net/10161/4567 Duke open access
repository},
Abstract = {While bonobos and chimpanzees are both genetically and
behaviorally very similar, they also differ in significant
ways. Bonobos are more cautious and socially tolerant while
chimpanzees are more dependent on extractive foraging, which
requires tools. The similarities suggest the two species
should be cognitively similar while the behavioral
differences predict where the two species should differ
cognitively. We compared both species on a wide range of
cognitive problems testing their understanding of the
physical and social world. Bonobos were more skilled at
solving tasks related to theory of mind or an understanding
of social causality, while chimpanzees were more skilled at
tasks requiring the use of tools and an understanding of
physical causality. These species differences support the
role of ecological and socio-ecological pressures in shaping
cognitive skills over relatively short periods of
evolutionary time.},
Doi = {10.1371/journal.pone.0012438},
Key = {fds240429}
}
@article{fds240435,
Author = {Wobber, V and Hare, B and Maboto, J and Lipson, S and Wrangham, R and Ellison, PT},
Title = {Differential changes in steroid hormones before competition
in bonobos and chimpanzees.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {107},
Number = {28},
Pages = {12457-12462},
Year = {2010},
Month = {July},
ISSN = {0027-8424},
Abstract = {A large body of research has demonstrated that variation in
competitive behavior across species and individuals is
linked to variation in physiology. In particular, rapid
changes in testosterone and cortisol during competition
differ according to an individual's or species'
psychological and behavioral responses to competition. This
suggests that among pairs of species in which there are
behavioral differences in competition, there should also be
differences in the endocrine shifts surrounding competition.
We tested this hypothesis by presenting humans' closest
living relatives, chimpanzees (Pan troglodytes) and bonobos
(Pan paniscus), with a dyadic food competition and measuring
their salivary testosterone and cortisol levels. Given that
chimpanzees and bonobos differ markedly in their
food-sharing behavior, we predicted that they would differ
in their rapid endocrine shifts. We found that in both
species, males showed an anticipatory decrease (relative to
baseline) in steroids when placed with a partner in a
situation in which the two individuals shared food, and an
anticipatory increase when placed with a partner in a
situation in which the dominant individual obtained more
food. The species differed, however, in terms of which
hormone was affected; in bonobo males the shifts occurred in
cortisol, whereas in chimpanzee males the shifts occurred in
testosterone. Thus, in anticipation of an identical
competition, bonobo and chimpanzee males showed differential
endocrine shifts, perhaps due to differences in perception
of the situation, that is, viewing the event either as a
stressor or a dominance contest. In turn, common selection
pressures in human evolution may have acted on the
psychology and the endocrinology of our competitive
behavior.},
Doi = {10.1073/pnas.1007411107},
Key = {fds240435}
}
@misc{fds240382,
Author = {Rosati, A G and Hare, B},
Title = {Social Cognition: From Behavior-Reading to
Mind-Reading},
Pages = {263-270},
Booktitle = {Encyclopedia of Behavioral Neuroscience},
Publisher = {Elsevier Science},
Editor = {Koob, George F. and Le Moal and Michel},
Year = {2010},
Month = {May},
ISBN = {9780080453965},
url = {http://hdl.handle.net/10161/7464 Duke open access
repository},
Abstract = {Primates must navigate complex social landscapes in their
daily lives: gathering information from and about others,
competing with others for rewards like food and mates, and
cooperating to obtain rewards as well. Although many species
may exhibit similar behaviors in naturalistic contexts, the
cognitive bases of the sophisticated behaviors that many
primates exhibit can vary widely across species. In this
article, we examine the psychology underlying primate social
behavior in three situations: gaze-following, competing for
food, and instrumental cooperation. In each of these
domains, various primate gaze-follow, compete, and cooperate
with great success - but experiments have revealed that the
ways they do so can be quite diverse. These examples provide
a framework for investigating social cognition from an
evolutionary perspective that addresses why such different
social-cognitive skills evolved across species.},
Doi = {10.1016/B978-0-08-045396-5.00112-3},
Key = {fds240382}
}
@article{fds240432,
Author = {Vlamings, PHJM and Hare, B and Call, J},
Title = {Reaching around barriers: the performance of the great apes
and 3-5-year-old children.},
Journal = {Animal cognition},
Volume = {13},
Number = {2},
Pages = {273-285},
Year = {2010},
Month = {March},
ISSN = {1435-9448},
Abstract = {Inhibitory control has been suggested as a key predictive
measure of problem-solving skills in human and nonhuman
animals. However, there has yet to be a direct comparison of
the inhibitory skills of the nonhuman apes and their
development in human children. We compared the inhibitory
skills of all great ape species, including 3-5-year-old
children in a detour-reaching task, which required subjects
to avoid reaching directly for food and instead use an
indirect reaching method to successfully obtain the food. We
tested 22 chimpanzees, 18 bonobos, 18 orangutans, 6 gorillas
and 42 children. Our sample included chimpanzees, bonobos
and orangutans housed in zoos (N = 27) and others housed in
sanctuaries in their native habitats (N = 37). Overall,
orangutans were the most skilful apes, including human
children. As expected older children outperformed younger
children. Sanctuary chimpanzees and bonobos outperformed
their zoo counterparts whereas there was no difference
between the two orangutan samples. Most zoo chimpanzees and
bonobos failed to solve the original task, but improved
their performance with additional training, although the
training method determined to a considerable extent the
level of success that the apes achieved in a transfer phase.
In general, the performance of the older children was far
from perfect and comparable to some of the nonhuman apes
tested.},
Doi = {10.1007/s10071-009-0265-5},
Key = {fds240432}
}
@article{fds240434,
Author = {Hare, B and Kwetuenda, S},
Title = {Bonobos voluntarily share their own food with
others.},
Journal = {Current biology : CB},
Volume = {20},
Number = {5},
Pages = {R230-R231},
Year = {2010},
Month = {March},
ISSN = {0960-9822},
Abstract = {Comparisons between chimpanzees and humans have led to the
hypothesis that only humans voluntarily share their own food
with others. However, it is hard to draw conclusions because
the food-sharing preferences of our more tolerant relative,
the bonobo (Pan paniscus), have never been studied
experimentally. We gave unrelated bonobos the choice of
either monopolizing food or actively sharing: we found that
bonobos preferred to release a recipient from an adjacent
room and feed together instead of eating all the food alone.
Thus, food sharing in bonobos does not depend on kinship or
harassment and suggests our own species' propensity for
voluntary food sharing is not unique among the
apes.},
Doi = {10.1016/j.cub.2009.12.038},
Key = {fds240434}
}
@misc{fds240366,
Author = {Rosati, AG and Santos, LR and Hare, B},
Title = {Primate Social Cognition: Thirty Years After Premack and
Woodruff},
Pages = {117-143},
Booktitle = {Primate Neuroethology},
Publisher = {Oxford University Press},
Year = {2010},
Month = {February},
ISBN = {9780195326598},
Abstract = {This chapter addresses two aspects of primate social
cognition-understanding of intentional, goal-directed
action, and understanding perceptions, knowledge, and
beliefs-focusing on the newest comparative research since
the last major reviews were written on the topic over a
decade ago. It first reviews evidence suggesting that
diverse species of primates understand the actions of others
in terms of goals and intentions, and furthermore can reason
about some, but probably not all, kinds of psychological
states. It then examines the hypothesis that primates show
their most complex social skills in competitive contexts,
and suggests that inquiry into other aspects of primate
social life, such as cooperative interactions, may prove to
be the next important step for experimental inquiries into
primate social-cognitive skills. Finally, the chapter
examines primate social cognition in a broader evolutionary
context that may provide a better understanding of both
primate and human cognitive skills.},
Doi = {10.1093/acprof:oso/9780195326598.003.0007},
Key = {fds240366}
}
@article{fds240431,
Author = {Wobber, V and Wrangham, R and Hare, B},
Title = {Bonobos exhibit delayed development of social behavior and
cognition relative to chimpanzees.},
Journal = {Current biology : CB},
Volume = {20},
Number = {3},
Pages = {226-230},
Year = {2010},
Month = {February},
ISSN = {0960-9822},
Abstract = {Phenotypic changes between species can occur when evolution
shapes development. Here, we tested whether differences in
the social behavior and cognition of bonobos and chimpanzees
derive from shifts in their ontogeny, looking at behaviors
pertaining to feeding competition in particular. We found
that as chimpanzees (n = 30) reached adulthood, they became
increasingly intolerant of sharing food, whereas adult
bonobos (n = 24) maintained high, juvenile levels of
food-related tolerance. We also investigated the ontogeny of
inhibition during tasks that simulated feeding competition.
In two different tests, we found that bonobos (n = 30)
exhibited developmental delays relative to chimpanzees (n =
29) in the acquisition of social inhibition, with these
differences resulting in less skill among adult bonobos. The
results suggest that these social and cognitive differences
between two closely related species result from evolutionary
changes in brain development.},
Doi = {10.1016/j.cub.2009.11.070},
Key = {fds240431}
}
@article{fds240428,
Author = {Herrmann, E and Hernández-Lloreda, MV and Call, J and Hare, B and Tomasello, M},
Title = {The structure of individual differences in the cognitive
abilities of children and chimpanzees.},
Journal = {Psychological science},
Volume = {21},
Number = {1},
Pages = {102-110},
Year = {2010},
Month = {January},
ISSN = {0956-7976},
Abstract = {Most studies of animal cognition focus on group performance
and neglect individual differences and the correlational
structure of cognitive abilities. Moreover, no previous
studies have compared the correlational structure of
cognitive abilities in nonhuman animals and humans. We
compared the structure of individual differences of 106
chimpanzees and 105 two-year-old human children using 15
cognitive tasks that posed problems about the physical or
social world. We found a similar factor of spatial cognition
for the two species. But whereas the chimpanzees had only a
single factor in addition to spatial cognition, the children
had two distinct additional factors: one for physical
cognition and one for social cognition. These findings, in
combination with previous research, support the proposal
that humans share many cognitive skills with nonhuman apes,
especially for dealing with the physical world, but in
addition have evolved some specialized skills of social
cognition.},
Doi = {10.1177/0956797609356511},
Key = {fds240428}
}
@misc{fds375266,
Author = {Rosati, AG and Hare, B},
Title = {Social Cognition: From Behavior-Reading to
Mind-Reading},
Volume = {3},
Pages = {V3-263-V3-268},
Booktitle = {Encyclopedia of Behavioral Neuroscience, Three-Volume Set,
1-3},
Year = {2010},
Month = {January},
ISBN = {9780080914558},
Abstract = {Primates must navigate complex social landscapes in their
daily lives: gathering information from and about others,
competing with others for rewards like food and mates, and
cooperating to obtain rewards as well. Although many species
may exhibit similar behaviors in naturalistic contexts, the
cognitive bases of the sophisticated behaviors that many
primates exhibit can vary widely across species. In this
article, we examine the psychology underlying primate social
behavior in three situations: gaze-following, competing for
food, and instrumental cooperation. In each of these
domains, various primate gaze-follow, compete, and cooperate
with great success – but experiments have revealed that
the ways they do so can be quite diverse. These examples
provide a framework for investigating social cognition from
an evolutionary perspective that addresses why such
different social-cognitive skills evolved across
species.},
Doi = {10.1016/B978-0-08-045396-5.00112-3},
Key = {fds375266}
}
@article{fds219173,
Author = {B. Hare and B. Rosati and A. Breaur and J. Kaminski and J. Call and M.
Tomasello},
Title = {Dogs are more skilled than wolves with human social cues: a
response to Udell et al (2008) and Wynne et
al.},
Journal = {Animal Behavior},
Volume = {79},
Pages = {e1-e6},
Year = {2010},
Key = {fds219173}
}
@article{fds219179,
Author = {V. Wobber and R. Wrangham and B. Hare},
Title = {Application of the heterochrony framework to the study of
behavior and cognition.},
Journal = {Communicative and Integrative Biology},
Volume = {3},
Pages = {1-2},
Year = {2010},
Key = {fds219179}
}
@misc{fds219182,
Author = {V. Woods and B. Hare},
Title = {African sanctuaries as a new resource for non-invasive
research on great apes.},
Booktitle = {Encyclopedia of Applied Animal Behavior and
Welfare},
Year = {2010},
Key = {fds219182}
}
@misc{fds219183,
Author = {A. Rosati and B. Hare},
Title = {From social behavior to social cognition in
primates.},
Booktitle = {Encyclopedia of Behavioral Neuroscience},
Year = {2010},
Key = {fds219183}
}
@article{fds219185,
Author = {A. Rosati and B. Hare},
Title = {Chimpanzee and bonobos distinguish between risk and
ambiguity.},
Journal = {Proceedings of Royal Society: Biology Letters.},
Volume = {7},
Pages = {15-18},
Year = {2010},
Key = {fds219185}
}
@article{fds240430,
Author = {Hare, B and Rosati, AG and Kaminski, J and Braeuer, J and Call, J and Tomasello, M},
Title = {The domestication hypothesis for dogs' skills with human
communication: A response to Udell et al. (2008) and Wynne
et al. (2008)},
Journal = {Animal Behaviour},
Volume = {79},
Number = {2},
Pages = {e1-e6},
Publisher = {Elsevier BV},
Year = {2010},
ISSN = {0003-3472},
url = {http://hdl.handle.net/10161/6631 Duke open access
repository},
Doi = {10.1016/j.anbehav.2009.06.031},
Key = {fds240430}
}
@article{fds240427,
Author = {Melis, AP and Hare, B and Tomasello, M},
Title = {Chimpanzees coordinate in a negotiation game},
Journal = {Evolution and Human Behavior},
Volume = {30},
Number = {6},
Pages = {381-392},
Publisher = {Elsevier BV},
Year = {2009},
Month = {November},
ISSN = {1090-5138},
Abstract = {A crucially important aspect of human cooperation is the
ability to negotiate to cooperative outcomes when interests
over resources conflict. Although chimpanzees and other
social species may negotiate conflicting interests regarding
travel direction or activity timing, very little is known
about their ability to negotiate conflicting preferences
over food. In the current study, we presented pairs of
chimpanzees with a choice between two cooperative tasks-one
with equal payoffs (e.g., 5-5) and one with unequal payoffs
(higher and lower than in the equal option, e.g., 10-1).
This created a conflict of interests between partners with
failure to work together on the same cooperative task
resulting in no payoff for either partner. The chimpanzee
pairs cooperated successfully in as many as 78-94% of the
trials across experiments. Even though dominant chimpanzees
preferred the unequal option (as they would obtain the
largest payoff), subordinate chimpanzees were able to get
their way (the equal option) in 22-56% of trials across
conditions. Various analyses showed that subjects were both
strategic and also cognizant of the strategies used by their
partners. These results demonstrate that one of our two
closest primate relatives, the chimpanzee, can settle
conflicts of interest over resources in mutually satisfying
ways-even without the social norms of equity, planned
strategies of reciprocity, and the complex communication
characteristic of human negotiation. © 2009 Elsevier Inc.
All rights reserved.},
Doi = {10.1016/j.evolhumbehav.2009.05.003},
Key = {fds240427}
}
@article{fds240423,
Author = {Wobber, V and Hare, B and Koler-Matznick, J and Wrangham, R and Tomasello, M},
Title = {Breed differences in domestic dogs' (Canis familiaris)
comprehension of human communicative signals},
Journal = {Interaction Studies},
Volume = {10},
Number = {2},
Pages = {206-224},
Publisher = {John Benjamins Publishing Company},
Editor = {Matsuzawa, T},
Year = {2009},
Month = {September},
ISSN = {1572-0373},
Abstract = {Recent research suggests that some human-like social skills
evolved in dogs (Canis familiaris) during domestication as
an incidental by-product of selection for "tame" forms of
behavior. It is still possible, however, that the social
skills of certain dog breeds came under direct selection
that led to further increases in social problem solving
ability. To test this hypothesis, different breeds of
domestic dogs were compared for their ability to use various
human communicative behaviors to find hidden food. We found
that even primitive breeds with little human contact were
able to use communicative cues. Further, "working" dogs
(shepherds and huskies: thought to be bred intentionally to
respond to human cooperative communicative signals) were
more skilled at using gestural cues than were non-working
breeds (basenji and toy poodles: not thought to have been
bred for their cooperative-communicative ability). This
difference in performance existed regardless of whether the
working breeds were more or less genetically wolf-like.
These results suggest that subsequent to initial
domesticating selection giving rise to cue-following skills,
additional selection on communicative abilities in certain
breeds has produced substantive differences in those breeds'
abilities to follow cues. © John Benjamins Publishing
Company.},
Doi = {10.1075/is.10.2.06wob},
Key = {fds240423}
}
@article{fds240426,
Author = {Wobber, V and Hare, B},
Title = {Testing the social dog hypothesis: are dogs also more
skilled than chimpanzees in non-communicative social
tasks?},
Journal = {Behavioural processes},
Volume = {81},
Number = {3},
Pages = {423-428},
Year = {2009},
Month = {July},
ISSN = {0376-6357},
Abstract = {Relative to non-human primates, domestic dogs possess a
number of social skills that seem exceptional-particularly
in solving problems involving cooperation and communication
with humans. However, the degree to which dogs' unusual
skills are contextually specialized is still unclear. Here,
we presented dogs with a social problem that did not require
them to use cooperative-communicative cues and compared
their performance to that of chimpanzees to assess the
extent of dogs' capabilities relative to those of non-human
primates. We tested the abilities of dogs and chimpanzees to
inhibit previously learned responses by using a social and a
non-social version of a reversal learning task. In contrast
to previous findings in cooperative-communicative social
tasks, dogs were not more skilled on the social task than
the non-social task, while chimpanzees were significantly
better in the social paradigm. Chimpanzees were able to
inhibit their prior learning better and more quickly in the
social paradigm than they were in the non-social paradigm,
while dogs took more time to inhibit what they had learned
in both versions of the task. These results suggest that the
dogs' sophisticated social skills in using human social cues
may be relatively specialized as a result of
domestication.},
Doi = {10.1016/j.beproc.2009.04.003},
Key = {fds240426}
}
@article{fds240425,
Author = {McIntyre, MH and Herrmann, E and Wobber, V and Halbwax, M and Mohamba,
C and de Sousa, N and Atencia, R and Cox, D and Hare,
B},
Title = {Bonobos have a more human-like second-to-fourth finger
length ratio (2D:4D) than chimpanzees: a hypothesized
indication of lower prenatal androgens.},
Journal = {Journal of human evolution},
Volume = {56},
Number = {4},
Pages = {361-365},
Year = {2009},
Month = {April},
ISSN = {0047-2484},
Abstract = {The ratio of the second-to-fourth finger lengths (2D:4D) has
been proposed as an indicator of prenatal sex
differentiation. However, 2D:4D has not been studied in the
closest living human relatives, chimpanzees (Pan
troglodytes) and bonobos (Pan paniscus). We report the
results from 79 chimpanzees and 39 bonobos of both sexes,
including infants, juveniles, and adults. We observed the
expected sex difference in 2D:4D, and substantially higher,
more human-like, 2D:4D in bonobos than chimpanzees. Previous
research indicates that sex differences in 2D:4D result from
differences in prenatal sex hormone levels. We hypothesize
that the species difference in 2D:4D between bonobos and
chimpanzees suggests a possible role for early exposure to
sex hormones in the development of behavioral differences
between the two species.},
Doi = {10.1016/j.jhevol.2008.12.004},
Key = {fds240425}
}
@article{fds240424,
Author = {Rosati, AG and Hare, B},
Title = {Looking past the model species: diversity in gaze-following
skills across primates.},
Journal = {Current opinion in neurobiology},
Volume = {19},
Number = {1},
Pages = {45-51},
Year = {2009},
Month = {February},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19394214},
Abstract = {Primates must navigate complex social landscapes in their
daily lives: gathering information from and about others,
competing with others for food and mates, and cooperating to
obtain rewards as well. Gaze-following often provides
important clues as to what others see, know, or will do;
using information about social attention is thus crucial for
primates to be competent social actors. However, the
cognitive bases of the gaze-following behaviors that
primates exhibit appear to vary widely across species. The
ultimate challenge of such analyses will therefore be to
understand why such different cognitive mechanisms have
evolved across species.},
Doi = {10.1016/j.conb.2009.03.002},
Key = {fds240424}
}
@misc{fds219140,
Author = {B. Hare},
Title = {What is the effect of affect on bonobo and chimpanzee
problem solving?},
Pages = {89-102},
Booktitle = {The Neurobiology of the Unwelt: how living beings perceive
the world.},
Year = {2009},
Key = {fds219140}
}
@article{fds219142,
Author = {A. Rosati and B. Hare},
Title = {Beyond the model species: diversity in gaze following skills
across primates.},
Journal = {Current Opinion in Neurobiology},
Volume = {19},
Pages = {45-51},
Year = {2009},
Key = {fds219142}
}
@misc{fds219143,
Author = {B. Hare and V. Woods},
Title = {Out of our minds: how did Homo sapiens come down from the
trees, and why did no one follow?},
Pages = {170-184},
Booktitle = {Innovative Science},
Year = {2009},
Key = {fds219143}
}
@article{fds240421,
Author = {Wobber, V and Hare, B and Wrangham, R},
Title = {Great apes prefer cooked food.},
Journal = {Journal of human evolution},
Volume = {55},
Number = {2},
Pages = {340-348},
Year = {2008},
Month = {August},
ISSN = {0047-2484},
Abstract = {The cooking hypothesis proposes that a diet of cooked food
was responsible for diverse morphological and behavioral
changes in human evolution. However, it does not predict
whether a preference for cooked food evolved before or after
the control of fire. This question is important because the
greater the preference shown by a raw-food-eating hominid
for the properties present in cooked food, the more easily
cooking should have been adopted following the control of
fire. Here we use great apes to model food preferences by
Paleolithic hominids. We conducted preference tests with
various plant and animal foods to determine whether great
apes prefer food items raw or cooked. We found that several
populations of captive apes tended to prefer their food
cooked, though with important exceptions. These results
suggest that Paleolithic hominids would likewise have
spontaneously preferred cooked food to raw, exapting a
pre-existing preference for high-quality, easily chewed
foods onto these cooked items. The results, therefore,
challenge the hypothesis that the control of fire preceded
cooking by a significant period.},
Doi = {10.1016/j.jhevol.2008.03.003},
Key = {fds240421}
}
@article{fds240419,
Author = {Heilbronner, SR and Rosati, AG and Stevens, JR and Hare, B and Hauser,
MD},
Title = {A fruit in the hand or two in the bush? Divergent risk
preferences in chimpanzees and bonobos.},
Journal = {Biology letters},
Volume = {4},
Number = {3},
Pages = {246-249},
Year = {2008},
Month = {June},
ISSN = {1744-9561},
url = {http://hdl.handle.net/10161/7404 Duke open access
repository},
Abstract = {Human and non-human animals tend to avoid risky prospects.
If such patterns of economic choice are adaptive, risk
preferences should reflect the typical decision-making
environments faced by organisms. However, this approach has
not been widely used to examine the risk sensitivity in
closely related species with different ecologies. Here, we
experimentally examined risk-sensitive behaviour in
chimpanzees (Pan troglodytes) and bonobos (Pan paniscus),
closely related species whose distinct ecologies are thought
to be the major selective force shaping their unique
behavioural repertoires. Because chimpanzees exploit riskier
food sources in the wild, we predicted that they would
exhibit greater tolerance for risk in choices about food.
Results confirmed this prediction: chimpanzees significantly
preferred the risky option, whereas bonobos preferred the
fixed option. These results provide a relatively rare
example of risk-prone behaviour in the context of gains and
show how ecological pressures can sculpt economic decision
making.},
Doi = {10.1098/rsbl.2008.0081},
Key = {fds240419}
}
@article{fds240420,
Author = {Ross, SR and Lukas, KE and Lonsdorf, EV and Stoinski, TS and Hare, B and Shumaker, R and Goodall, J},
Title = {Science priorities. Inappropriate use and portrayal of
chimpanzees.},
Journal = {Science (New York, N.Y.)},
Volume = {319},
Number = {5869},
Pages = {1487},
Year = {2008},
Month = {March},
ISSN = {0036-8075},
Abstract = {Depictions of chimpanzees as caricatures can lead people to
think these animals are not endangered and is a problem for
conservation and welfare efforts.},
Doi = {10.1126/science.1154490},
Key = {fds240420}
}
@article{fds240418,
Author = {Herrmann, E and Call, J and Hernández-Lloreda, MV and Hare, B and Tomasello, M},
Title = {Response [3]},
Journal = {Science},
Volume = {319},
Number = {5863},
Pages = {569},
Year = {2008},
Month = {February},
ISSN = {0036-8075},
Key = {fds240418}
}
@article{fds240422,
Author = {Melis, AP and Hare, B and Tomasello, M},
Title = {Do chimpanzees reciprocate received favours?},
Journal = {Animal Behaviour},
Volume = {76},
Number = {3},
Pages = {951-962},
Publisher = {Elsevier BV},
Year = {2008},
Month = {January},
ISSN = {0003-3472},
Abstract = {Reciprocal interactions observed in animals may persist
because individuals keep careful account of services
exchanged with each group member. To test whether
chimpanzees, Pan troglodytes, possess the cognitive skills
required for this type of contingency-based reciprocity, we
gave chimpanzees the choice of cooperating with a
conspecific who had helped them previously or one who had
not helped them in two different experimental tasks. In the
first experiment, one of the partners preferentially
recruited the subjects to cooperate in a mutualistic task,
while the other potential partner never chose to cooperate
with the subject, but rather chose a different partner. In
the second experiment, one of the partners altruistically
helped the subjects to reach food, while the other partner
never helped the subject, but rather took the food himself.
In both experiments there was some evidence that the
chimpanzees increased the amount they cooperated with or
helped the partner who had been more helpful towards them
compared to their baseline behaviour towards the same
individual (or in a control condition). However, in both
experiments this effect was relatively weak and subjects did
not preferentially favour the individual who had favoured
them over the one who had not in either experiment. Although
taken together, these experiments provide some support for
the hypothesis that chimpanzees are capable of contingent
reciprocity, they also suggest that models of immediate
reciprocation and detailed accounts of recent exchanges
(e.g. Tit for Tat) may not play a large role in guiding the
social decisions of chimpanzees. © 2008 The Association for
the Study of Animal Behaviour.},
Doi = {10.1016/j.anbehav.2008.05.014},
Key = {fds240422}
}
@article{fds240417,
Author = {Rosati, AG and Stevens, JR and Hare, B and Hauser,
MD},
Title = {The evolutionary origins of human patience: temporal
preferences in chimpanzees, bonobos, and human
adults.},
Journal = {Current biology : CB},
Volume = {17},
Number = {19},
Pages = {1663-1668},
Year = {2007},
Month = {October},
ISSN = {0960-9822},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17900899},
Abstract = {To make adaptive choices, individuals must sometimes exhibit
patience, forgoing immediate benefits to acquire more
valuable future rewards [1-3]. Although humans account for
future consequences when making temporal decisions [4], many
animal species wait only a few seconds for delayed benefits
[5-10]. Current research thus suggests a phylogenetic gap
between patient humans and impulsive, present-oriented
animals [9, 11], a distinction with implications for our
understanding of economic decision making [12] and the
origins of human cooperation [13]. On the basis of a series
of experimental results, we reject this conclusion. First,
bonobos (Pan paniscus) and chimpanzees (Pan troglodytes)
exhibit a degree of patience not seen in other animals
tested thus far. Second, humans are less willing to wait for
food rewards than are chimpanzees. Third, humans are more
willing to wait for monetary rewards than for food, and show
the highest degree of patience only in response to decisions
about money involving low opportunity costs. These findings
suggest that core components of the capacity for
future-oriented decisions evolved before the human lineage
diverged from apes. Moreover, the different levels of
patience that humans exhibit might be driven by fundamental
differences in the mechanisms representing biological versus
abstract rewards.},
Doi = {10.1016/j.cub.2007.08.033},
Key = {fds240417}
}
@article{fds240415,
Author = {Herrmann, E and Call, J and Hernàndez-Lloreda, MV and Hare, B and Tomasello, M},
Title = {Humans have evolved specialized skills of social cognition:
the cultural intelligence hypothesis.},
Journal = {Science (New York, N.Y.)},
Volume = {317},
Number = {5843},
Pages = {1360-1366},
Year = {2007},
Month = {September},
ISSN = {0036-8075},
Abstract = {Humans have many cognitive skills not possessed by their
nearest primate relatives. The cultural intelligence
hypothesis argues that this is mainly due to a
species-specific set of social-cognitive skills, emerging
early in ontogeny, for participating and exchanging
knowledge in cultural groups. We tested this hypothesis by
giving a comprehensive battery of cognitive tests to large
numbers of two of humans' closest primate relatives,
chimpanzees and orangutans, as well as to 2.5-year-old human
children before literacy and schooling. Supporting the
cultural intelligence hypothesis and contradicting the
hypothesis that humans simply have more "general
intelligence," we found that the children and chimpanzees
had very similar cognitive skills for dealing with the
physical world but that the children had more sophisticated
cognitive skills than either of the ape species for dealing
with the social world.},
Doi = {10.1126/science.1146282},
Key = {fds240415}
}
@article{fds240416,
Author = {Warneken, F and Hare, B and Melis, AP and Hanus, D and Tomasello,
M},
Title = {Spontaneous altruism by chimpanzees and young
children.},
Journal = {PLoS biology},
Volume = {5},
Number = {7},
Pages = {e184},
Year = {2007},
Month = {July},
ISSN = {1545-7885},
Abstract = {People often act on behalf of others. They do so without
immediate personal gain, at cost to themselves, and even
toward unfamiliar individuals. Many researchers have claimed
that such altruism emanates from a species-unique psychology
not found in humans' closest living evolutionary relatives,
such as the chimpanzee. In favor of this view, the few
experimental studies on altruism in chimpanzees have
produced mostly negative results. In contrast, we report
experimental evidence that chimpanzees perform basic forms
of helping in the absence of rewards spontaneously and
repeatedly toward humans and conspecifics. In two
comparative studies, semi-free ranging chimpanzees helped an
unfamiliar human to the same degree as did human infants,
irrespective of being rewarded (experiment 1) or whether the
helping was costly (experiment 2). In a third study,
chimpanzees helped an unrelated conspecific gain access to
food in a novel situation that required subjects to use a
newly acquired skill on behalf of another individual. These
results indicate that chimpanzees share crucial aspects of
altruism with humans, suggesting that the roots of human
altruism may go deeper than previous experimental evidence
suggested.},
Doi = {10.1371/journal.pbio.0050184},
Key = {fds240416}
}
@article{fds240414,
Author = {Burnham, TC and Hare, B},
Title = {Engineering human cooperation : DDDDDoes involuntary neural
activation increase public goods contributions?},
Journal = {Human Nature},
Volume = {18},
Number = {2},
Pages = {88-108},
Publisher = {Springer Nature},
Year = {2007},
Month = {June},
ISSN = {1045-6767},
Abstract = {In a laboratory experiment, we use a public goods game to
examine the hypothesis that human subjects use an
involuntary eye-detector mechanism for evaluating the level
of privacy. Half of our subjects are "watched" by images of
a robot presented on their computer screen. The robot-named
Kismet and invented at MIT-is constructed from objects that
are obviously not human with the exception of its eyes. In
our experiment, Kismet produces a significant difference in
behavior that is not consistent with existing economic
models of preferences, either self- or other-regarding.
Subjects who are "watched" by Kismet contribute 29% more to
the public good than do subjects in the same setting without
Kismet. © 2007 Springer Science & Business Media,
LLC.},
Doi = {10.1007/s12110-007-9012-2},
Key = {fds240414}
}
@article{fds240411,
Author = {Hare, B and Melis, AP and Woods, V and Hastings, S and Wrangham,
R},
Title = {Tolerance allows bonobos to outperform chimpanzees on a
cooperative task.},
Journal = {Current biology : CB},
Volume = {17},
Number = {7},
Pages = {619-623},
Year = {2007},
Month = {April},
ISSN = {0960-9822},
Abstract = {To understand constraints on the evolution of cooperation,
we compared the ability of bonobos and chimpanzees to
cooperatively solve a food-retrieval problem. We addressed
two hypotheses. The "emotional-reactivity hypothesis"
predicts that bonobos will cooperate more successfully
because tolerance levels are higher in bonobos. This
prediction is inspired by studies of domesticated animals;
such studies suggest that selection on emotional reactivity
can influence the ability to solve social problems [1, 2].
In contrast, the "hunting hypothesis" predicts that
chimpanzees will cooperate more successfully because only
chimpanzees have been reported to cooperatively hunt in the
wild [3-5]. We indexed emotional reactivity by measuring
social tolerance while the animals were cofeeding and found
that bonobos were more tolerant of cofeeding than
chimpanzees. In addition, during cofeeding tests only
bonobos exhibited socio-sexual behavior, and they played
more. When presented with a task of retrieving food that was
difficult to monopolize, bonobos and chimpanzees were
equally cooperative. However, when the food reward was
highly monopolizable, bonobos were more successful than
chimpanzees at cooperating to retrieve it. These results
support the emotional-reactivity hypothesis. Selection on
temperament may in part explain the variance in cooperative
ability across species, including hominoids.},
Doi = {10.1016/j.cub.2007.02.040},
Key = {fds240411}
}
@article{fds240412,
Author = {Hare, B},
Title = {From nonhuman to human mind: What changed and
why?},
Journal = {Current Directions in Psychological Science},
Volume = {16},
Number = {2},
Pages = {60-64},
Publisher = {SAGE Publications},
Year = {2007},
Month = {April},
ISSN = {0963-7214},
Abstract = {Two questions regarding the human mind challenge
evolutionary theory: (a) What features of human psychology
have changed since humans' lineage split from that of the
other apes such as chimpanzees and bonobos? And (b) what was
the process by which such derived psychological features
evolved (e.g., what were the selection pressures)? I review
some of the latest research on chimpanzee and canine
psychology that allows inferences to be made regarding these
questions. Copyright © 2007 Association for Psychological
Science.},
Doi = {10.1111/j.1467-8721.2007.00476.x},
Key = {fds240412}
}
@article{fds240410,
Author = {Tomasello, M and Hare, B and Lehmann, H and Call,
J},
Title = {Reliance on head versus eyes in the gaze following of great
apes and human infants: the cooperative eye
hypothesis.},
Journal = {Journal of human evolution},
Volume = {52},
Number = {3},
Pages = {314-320},
Year = {2007},
Month = {March},
ISSN = {0047-2484},
Abstract = {As compared with other primates, humans have especially
visible eyes (e.g., white sclera). One hypothesis is that
this feature of human eyes evolved to make it easier for
conspecifics to follow an individual's gaze direction in
close-range joint attentional and communicative
interactions, which would seem to imply especially
cooperative (mututalistic) conspecifics. In the current
study, we tested one aspect of this cooperative eye
hypothesis by comparing the gaze following behavior of great
apes to that of human infants. A human experimenter "looked"
to the ceiling either with his eyes only, head only (eyes
closed), both head and eyes, or neither. Great apes followed
gaze to the ceiling based mainly on the human's head
direction (although eye direction played some role as well).
In contrast, human infants relied almost exclusively on eye
direction in these same situations. These results
demonstrate that humans are especially reliant on eyes in
gaze following situations, and thus, suggest that eyes
evolved a new social function in human evolution, most
likely to support cooperative (mututalistic) social
interactions.},
Doi = {10.1016/j.jhevol.2006.10.001},
Key = {fds240410}
}
@article{fds240413,
Author = {Warneken, F and Hare, B and Melis, AP and Hanus, D and Tomasello,
M},
Title = {Spontaneous altruism by chimpanzees and young
children},
Journal = {PLoS Biology},
Volume = {5},
Number = {7},
Pages = {1414-1420},
Year = {2007},
ISSN = {1544-9173},
Abstract = {People often act on behalf of others. They do so without
immediate personal gain, at cost to themselves, and even
toward unfamiliar individuals. Many researchers have claimed
that such altruism emanates from a species-unique psychology
not found in humans' closest living evolutionary relatives,
such as the chimpanzee. In favor of this view, the few
experimental studies on altruism in chimpanzees have
produced mostly negative results. In contrast, we report
experimental evidence that chimpanzees perform basic forms
of helping in the absence of rewards spontaneously and
repeatedly toward humans and conspecifics. In two
comparative studies, semi-free ranging chimpanzees helped an
unfamiliar human to the same degree as did human infants,
irrespective of being rewarded (experiment 1) or whether the
helping was costly (experiment 2). In a third study,
chimpanzees helped an unrelated conspecific gain access to
food in a novel situation that required subjects to use a
newly acquired skill on behalf of another individual. These
results indicate that chimpanzees share crucial aspects of
altruism with humans, suggesting that the roots of human
altruism may go deeper than previous experimental evidence
suggested. © 2007 Warneken et al.},
Doi = {10.1371/journal.pbio.0050184},
Key = {fds240413}
}
@article{fds240407,
Author = {Hare, B and Call, J and Tomasello, M},
Title = {Chimpanzees deceive a human competitor by
hiding.},
Journal = {Cognition},
Volume = {101},
Number = {3},
Pages = {495-514},
Year = {2006},
Month = {October},
ISSN = {0010-0277},
Abstract = {There is little experimental evidence that any non-human
species is capable of purposefully attempting to manipulate
the psychological states of others deceptively (e.g.,
manipulating what another sees). We show here that
chimpanzees, one of humans' two closest primate relatives,
sometimes attempt to actively conceal things from others.
Specifically, when competing with a human in three novel
tests, eight chimpanzees, from their first trials, chose to
approach a contested food item via a route hidden from the
human's view (sometimes using a circuitous path to do so).
These findings not only corroborate previous work showing
that chimpanzees know what others can and cannot see, but
also suggest that when competing for food chimpanzees are
skillful at manipulating, to their own advantage, whether
others can or cannot see them.},
Doi = {10.1016/j.cognition.2005.01.011},
Key = {fds240407}
}
@article{fds240409,
Author = {Melis, AP and Hare, B and Tomasello, M},
Title = {Engineering cooperation in chimpanzees: tolerance
constraints on cooperation},
Journal = {Animal Behaviour},
Volume = {72},
Number = {2},
Pages = {275-286},
Publisher = {Elsevier BV},
Year = {2006},
Month = {August},
ISSN = {0003-3472},
Abstract = {The cooperative abilities of captive chimpanzees, Pan
troglodytes, in experiments do not match the sophistication
that might be predicted based on their naturally occurring
cooperative behaviours. This discrepancy might partly be
because in previous experiments potential chimpanzee
cooperators were partnered without regard to their social
relationship. We investigated the ability of chimpanzee
dyads to solve a physical task cooperatively in relation to
their interindividual tolerance levels. Pairs that were most
capable of sharing food outside the test were also able to
cooperate spontaneously (by simultaneously pulling two
ropes) to obtain food. In contrast, pairs that were less
inclined to share food outside of the test were unlikely to
cooperate. Furthermore, previously successful subjects
stopped cooperating when paired with a less tolerant
partner, even when the food rewards were presented in a
dispersed and divisible form to reduce competition between
subjects. These results show that although chimpanzees are
capable of spontaneous cooperation in a novel instrumental
task, tolerance acts as a constraint on their ability to
solve such cooperative problems. This finding highlights the
importance of controlling such social constraints in future
experiments on chimpanzee cooperation, and suggests that the
evolution of human-like cooperative skills might have been
preceded by the evolution of a more egalitarian social
system and a more human-like temperament. © 2006 The
Association for the Study of Animal Behaviour.},
Doi = {10.1016/j.anbehav.2005.09.018},
Key = {fds240409}
}
@article{fds240447,
Author = {Jensen, K and Hare, B and Call, J and Tomasello, M},
Title = {What's in it for me? Self-regard precludes altruism and
spite in chimpanzees.},
Journal = {Proceedings. Biological sciences},
Volume = {273},
Number = {1589},
Pages = {1013-1021},
Year = {2006},
Month = {April},
ISSN = {0962-8452},
Abstract = {Sensitivity to fairness may influence whether individuals
choose to engage in acts that are mutually beneficial,
selfish, altruistic, or spiteful. In a series of three
experiments, chimpanzees (Pan troglodytes) could pull a rope
to access out-of-reach food while concomitantly pulling
another piece of food further away. In the first study, they
could make a choice that solely benefited themselves
(selfishness), or both themselves and another chimpanzee
(mutualism). In the next two experiments, they could choose
between providing food solely for another chimpanzee
(altruism), or for neither while preventing the other
chimpanzee from receiving a benefit (spite). The main result
across all studies was that chimpanzees made their choices
based solely on personal gain, with no regard for the
outcomes of a conspecific. These results raise questions
about the origins of human cooperative behaviour.},
Doi = {10.1098/rspb.2005.3417},
Key = {fds240447}
}
@article{fds240406,
Author = {Melis, AP and Hare, B and Tomasello, M},
Title = {Chimpanzees recruit the best collaborators.},
Journal = {Science (New York, N.Y.)},
Volume = {311},
Number = {5765},
Pages = {1297-1300},
Year = {2006},
Month = {March},
ISSN = {0036-8075},
Abstract = {Humans collaborate with non-kin in special ways, but the
evolutionary foundations of these collaborative skills
remain unclear. We presented chimpanzees with collaboration
problems in which they had to decide when to recruit a
partner and which potential partner to recruit. In an
initial study, individuals recruited a collaborator only
when solving the problem required collaboration. In a second
study, individuals recruited the more effective of two
partners on the basis of their experience with each of them
on a previous day. Therefore, recognizing when collaboration
is necessary and determining who is the best collaborative
partner are skills shared by both chimpanzees and humans, so
such skills may have been present in their common ancestor
before humans evolved their own complex forms of
collaboration.},
Doi = {10.1126/science.1123007},
Key = {fds240406}
}
@article{fds240405,
Author = {Miklósi, A and Topál, J},
Title = {Is there a simple recipe for how to make
friends?},
Journal = {Trends in cognitive sciences},
Volume = {9},
Number = {10},
Pages = {463-464},
Year = {2005},
Month = {October},
Doi = {10.1016/j.tics.2005.08.009},
Key = {fds240405}
}
@article{fds240403,
Author = {Hare, B and Tomasello, M},
Title = {Human-like social skills in dogs?},
Journal = {Trends in cognitive sciences},
Volume = {9},
Number = {9},
Pages = {439-444},
Year = {2005},
Month = {September},
ISSN = {1364-6613},
Abstract = {Domestic dogs are unusually skilled at reading human social
and communicative behavior--even more so than our nearest
primate relatives. For example, they use human social and
communicative behavior (e.g. a pointing gesture) to find
hidden food, and they know what the human can and cannot see
in various situations. Recent comparisons between canid
species suggest that these unusual social skills have a
heritable component and initially evolved during
domestication as a result of selection on systems mediating
fear and aggression towards humans. Differences in
chimpanzee and human temperament suggest that a similar
process may have been an important catalyst leading to the
evolution of unusual social skills in our own species. The
study of convergent evolution provides an exciting
opportunity to gain further insights into the evolutionary
processes leading to human-like forms of cooperation and
communication.},
Doi = {10.1016/j.tics.2005.07.003},
Key = {fds240403}
}
@article{fds240404,
Author = {Hare, B and Plyusnina, I and Ignacio, N and Schepina, O and Stepika, A and Wrangham, R and Trut, L},
Title = {Social cognitive evolution in captive foxes is a correlated
by-product of experimental domestication.},
Journal = {Current biology : CB},
Volume = {15},
Number = {3},
Pages = {226-230},
Year = {2005},
Month = {February},
ISSN = {0960-9822},
Abstract = {Dogs have an unusual ability for reading human communicative
gestures (e.g., pointing) in comparison to either nonhuman
primates (including chimpanzees) or wolves . Although this
unusual communicative ability seems to have evolved during
domestication , it is unclear whether this evolution
occurred as a result of direct selection for this ability,
as previously hypothesized , or as a correlated by-product
of selection against fear and aggression toward humans--as
is the case with a number of morphological and physiological
changes associated with domestication . We show here that
fox kits from an experimental population selectively bred
over 45 years to approach humans fearlessly and
nonaggressively (i.e., experimentally domesticated) are not
only as skillful as dog puppies in using human gestures but
are also more skilled than fox kits from a second, control
population not bred for tame behavior (critically, neither
population of foxes was ever bred or tested for their
ability to use human gestures) . These results suggest that
sociocognitive evolution has occurred in the experimental
foxes, and possibly domestic dogs, as a correlated
by-product of selection on systems mediating fear and
aggression, and it is likely the observed social cognitive
evolution did not require direct selection for improved
social cognitive ability.},
Doi = {10.1016/j.cub.2005.01.040},
Key = {fds240404}
}
@article{fds240401,
Author = {Hare, B and Tomasello, M},
Title = {Chimpanzees are more skilful in competitive than in
cooperative cognitive tasks},
Journal = {Animal Behaviour},
Volume = {68},
Number = {3},
Pages = {571-581},
Publisher = {Elsevier BV},
Year = {2004},
Month = {September},
Abstract = {In a series of four experiments, chimpanzees, Pan
troglodytes, were given two cognitive tasks, an object
choice task and a discrimination task (based on location),
each in the context of either cooperation or competition. In
both tasks chimpanzees performed more skilfully when
competing than when cooperating, with some evidence that
competition with conspecifics was especially facilitatory in
the discrimination location task. This is the first study to
demonstrate a facilitative cognitive effect for competition
in a single experimental paradigm. We suggest that
chimpanzee cognitive evolution is best understood in its
socioecological context. © 2004 The Association for the
Study of Animal Behaviour. Published by Elsevier Ltd. All
rights reserved.},
Doi = {10.1016/j.anbehav.2003.11.011},
Key = {fds240401}
}
@article{fds240402,
Author = {Call, J and Hare, B and Carpenter, M and Tomasello,
M},
Title = {'Unwilling' versus 'unable': chimpanzees' understanding of
human intentional action.},
Journal = {Developmental science},
Volume = {7},
Number = {4},
Pages = {488-498},
Year = {2004},
Month = {September},
Abstract = {Understanding the intentional actions of others is a
fundamental part of human social cognition and behavior. An
important question is therefore whether other animal
species, especially our nearest relatives the chimpanzees,
also understand the intentional actions of others. Here we
show that chimpanzees spontaneously (without training)
behave differently depending on whether a human is unwilling
or unable to give them food Chimpanzees produced more
behaviors and left the testing station earlier with an
unwilling compared to an unable (but willing) experimenter
These data together with other recent studies on
chimpanzees' knowledge about others' visual perception show
that chimpanzees know more about the intentional actions and
perceptions of others than previously demonstrated},
Doi = {10.1111/j.1467-7687.2004.00368.x},
Key = {fds240402}
}
@article{fds240400,
Author = {Tomasello, M and Call, J and Hare, B},
Title = {Chimpanzees versus humans: It's not that
simple},
Journal = {Trends in Cognitive Sciences},
Volume = {7},
Number = {6},
Pages = {239-240},
Publisher = {Elsevier BV},
Year = {2003},
Month = {June},
Doi = {10.1016/S1364-6613(03)00107-4},
Key = {fds240400}
}
@article{fds240398,
Author = {Tomasello, M and Call, J and Hare, B},
Title = {Chimpanzees understand psychological states - The question
is which ones and to what extent},
Journal = {Trends in Cognitive Sciences},
Volume = {7},
Number = {4},
Pages = {153-156},
Publisher = {Elsevier BV},
Year = {2003},
Month = {April},
Abstract = {New data suggest that relatively drastic revisions are
needed in our theoretical accounts of what other animal
species understand about the psychological states of others.
Specifically, chimpanzees seem to understand some things
about what others do and do not see, or have and have not
seen in the immediate past, as well as some things about
others' goal-directed activities. This is especially so in
competitive situations. They clearly do not have a
human-like theory of mind, however, and so the challenge is
to specify precisely how ape and human social cognition are
similar and different.},
Doi = {10.1016/S1364-6613(03)00035-4},
Key = {fds240398}
}
@article{fds240399,
Author = {Hare, B and Addessi, E and Call, J and Tomasello, M and Visalberghi,
E},
Title = {Do capuchin monkeys, Cebus apella, know what conspecifics do
and do not see?},
Journal = {Animal Behaviour},
Volume = {65},
Number = {1},
Pages = {131-142},
Publisher = {Elsevier BV},
Year = {2003},
Month = {January},
Abstract = {Capuchin monkeys were tested in five experiments in which
two individuals competed over food. When given a choice
between retrieving a piece of food that was visible or
hidden from the dominant, subordinate animals preferred to
retrieve hidden food. This preference is consistent with the
hypotheses that either (1) the subordinate knew what the
dominant could and could not see or (2) the subordinate was
monitoring the behaviour of the dominant and avoiding the
piece of food that it approached. To test between these
alternatives, we released subordinates with a slight head
start forcing them to make their choice (between a piece of
food hidden or visible to the dominant) before the dominant
entered the area. Unlike chimpanzees, Pan troglodytes,
subordinates that were given a head start did not
preferentially approach hidden pieces of food first.
Therefore, our experiments provide little support for the
hypothesis that capuchin monkeys are sensitive to what
another individual does or does not see. We compare our
results with those obtained with chimpanzees in the same
paradigm and discuss the evolution of primate social
cognition. © 2003 The Association for the Study of Animal
Behaviour. Published by Elsevier Science Ltd. All rights
reserved.},
Doi = {10.1006/anbe.2002.2017},
Key = {fds240399}
}
@article{fds240395,
Author = {Hare, B and Brown, M and Williamson, C and Tomasello,
M},
Title = {The domestication of social cognition in
dogs.},
Journal = {Science (New York, N.Y.)},
Volume = {298},
Number = {5598},
Pages = {1634-1636},
Year = {2002},
Month = {November},
Abstract = {Dogs are more skillful than great apes at a number of tasks
in which they must read human communicative signals
indicating the location of hidden food. In this study, we
found that wolves who were raised by humans do not show
these same skills, whereas domestic dog puppies only a few
weeks old, even those that have had little human contact, do
show these skills. These findings suggest that during the
process of domestication, dogs have been selected for a set
of social-cognitive abilities that enable them to
communicate with humans in unique ways.},
Doi = {10.1126/science.1072702},
Key = {fds240395}
}
@article{fds240376,
Author = {Hare, B},
Title = {Can competitive paradigms increase the validity of
experiments on primate social cognition?},
Journal = {Animal Cognition},
Volume = {4},
Number = {3-4},
Pages = {269-280},
Publisher = {Springer Nature},
Year = {2001},
Month = {December},
ISSN = {1435-9448},
Abstract = {Experiments vary in their ability to distinguish between
competing hypotheses. In tests on primate cognition the
majority of this variation is due to an experimenter's
ability to test primates in valid settings while providing
the adequate amount of experimental control. While
experimenters studying primate cognition can use methods of
control perfected in captivity, it is still very unclear how
to design and then objectively evaluate the external
validity of new experimental paradigms. I recommend that
more effort be allocated to specify how to create relevant
test settings for primates. Primate social life is highly
competitive. This means that all aspects of primates
themselves, including their cognitive abilities, have likely
been shaped by the need to out-compete conspecifics. Based
on this hypothesis, sophisticated cognitive abilities of
primates might best be demonstrated in competitive contexts.
Thus, it is suggested that one possible measure of validity
is whether investigators integrate a competitive component
into their experimental designs. To evaluate this
methodological prediction I review the literature on
chimpanzee perspective- taking as a case study including
several recent studies that include a competitive component
in their experimental designs. © Springer-Verlag
2001.},
Doi = {10.1007/s100710100084},
Key = {fds240376}
}
@article{fds240396,
Author = {Tomasello, M and Hare, B and Fogleman, T},
Title = {The ontogeny of gaze following in chimpanzees, Pan
troglodytes, and rhesus macaques, Macaca
mulatta},
Journal = {Animal Behaviour},
Volume = {61},
Number = {2},
Pages = {335-343},
Publisher = {Elsevier BV},
Year = {2001},
Month = {January},
ISSN = {0003-3472},
Abstract = {Primates follow the gaze direction of conspecifics to
outside objects. We followed the ontogeny of this
social-cognitive skill for two species: rhesus macaques and
chimpanzees, in the first two experiments, using both a
cross-sectional and a longitudinal design, we exposed
individuals of different ages to a human looking in a
specified direction. Rhesus infants first began reliably to
follow the direction of this gaze at the end of the early
infancy period, at about 5.5 months of age. Chimpanzees did
not reliably follow human gaze until 3-4 years; this
corresponds to the latter part of the late infancy period
for this species. In the third experiment we exposed
individuals of the same two species to a human repeatedly
looking to the same location (with no special object at that
location) to see if subjects would learn to ignore the
looks. Only adults of the two species diminished their
gaze-following behaviour over trials. This suggests that in
the period between infancy and adulthood individuals of both
species come to integrate their gaze-following skills with
their more general social-cognitive knowledge about other
animate beings and their behaviour, and so become able to
deploy their gaze-following skills in a more flexible
manner. © 2001 The Association for the Study of Animal
Behaviour.},
Doi = {10.1006/anbe.2000.1598},
Key = {fds240396}
}
@article{fds240397,
Author = {Hare, B and Call, J and Tomasello, M},
Title = {Do chimpanzees know what conspecifics know?},
Journal = {Animal Behaviour},
Volume = {61},
Number = {1},
Pages = {139-151},
Publisher = {Elsevier BV},
Year = {2001},
Month = {January},
ISSN = {0003-3472},
Abstract = {We conducted three experiments on social problem solving by
chimpanzees, Pan troglodytes. In each experiment a
subordinate and a dominant individual competed for food,
which was placed in various ways on the subordinate's side
of two opaque barriers. In some conditions dominants had not
seen the food hidden, or food they had seen hidden was moved
elsewhere when they were not watching (whereas in control
conditions they saw the food being hidden or moved). At the
same time, subordinates always saw the entire baiting
procedure and could monitor the visual access of their
dominant competitor as well. If subordinates were sensitive
to what dominants did or did not see during baiting, they
should have preferentially approached and retrieved the food
that dominants had not seen hidden or moved. This is what
they did in experiment 1 when dominants were either
uninformed or misinformed about the food's location. In
experiment 2 subordinates recognized, and adjusted their
behaviour accordingly, when the dominant individual who
witnessed the hiding was replaced with another dominant
individual who had not witnessed it, thus demonstrating
their ability to keep track of precisely who has witnessed
what. In experiment 3 subordinates did not choose
consistently between two pieces of hidden food, one of which
dominants had seen hidden and one of which they had not seen
hidden. However, their failure in this experiment was likely
to be due to the changed nature of the competition under
these circumstances and not to a failure of social-cognitive
skills. These findings suggest that at least in some
situations (i.e. competition with conspecifics) chimpanzees
know what conspecifics have and have not seen (do and do not
know), and that they use this information to devise
effective social-cognitive strategies. © 2001 The
Association for the Study of Animal Behaviour.},
Doi = {10.1006/anbe.2000.1518},
Key = {fds240397}
}
@article{fds240375,
Author = {Agnetta, B and Hare, B and Tomasello, M},
Title = {Cues to food location that domestic dogs (Canis familiaris)
of different ages do and do not use},
Journal = {Animal Cognition},
Volume = {3},
Number = {2},
Pages = {107-112},
Publisher = {Springer Nature},
Year = {2000},
Month = {December},
ISSN = {1435-9448},
Abstract = {The results of three experiments are reported. In the main
study, a human experimenter presented domestic dogs (Canis
familiaris) with a variety of social cues intended to
indicate the location of hidden food. The novel findings of
this study were: (1) dogs were able to use successfully
several totally novel cues in which they watched a human
place a marker in front of the target location; (2) dogs
were unable to use the marker by itself with no behavioral
cues (suggesting that some form of human behavior directed
to the target location was a necessary part of the cue); and
(3) there were no significant developments in dogs' skills
in these tasks across the age range 4 months to 4 years
(arguing against the necessity of extensive learning
experiences with humans). In a follow- up study, dogs did
not follow human gaze into "empty space" outside of the
simulated foraging context. Finally, in a small pilot study,
two arctic wolves (Canis lupus) were unable to use human
cues to locate hidden food. These results suggest the
possibility that domestic dogs have evolved an adaptive
specialization for using human-produced directional cues in
a goal-directed (especially foraging) context. Exactly how
they understand these cues is still an open question. ©
Springer-Verlag 2000.},
Doi = {10.1007/s100710000070},
Key = {fds240375}
}
@article{fds240393,
Author = {Wrangham, R and Wilson, M and Hare, B and Wolfe, ND},
Title = {Chimpanzee predation and the ecology of microbial
exchange},
Journal = {Microbial Ecology in Health and Disease},
Volume = {12},
Number = {3},
Pages = {186-188},
Year = {2000},
Month = {January},
Abstract = {Hunting provides one mechanism for the transmission of
microbes across host species boundaries. It has generally
been assumed that this mechanism leads to unidirectional
transmission to humans. We report that wild chimpanzees
occasionally prey on human children. This result and other
evidence of chimpanzee hunting show the need for
consideration of more complex predation-mediated host
networks.},
Doi = {10.1080/089106000750051855},
Key = {fds240393}
}
@article{fds240394,
Author = {Hare, B and Call, J and Agnetta, B and Tomasello,
M},
Title = {Chimpanzees know what conspecifics do and do not
see},
Journal = {Animal Behaviour},
Volume = {59},
Number = {4},
Pages = {771-785},
Publisher = {Elsevier BV},
Year = {2000},
Month = {January},
ISSN = {0003-3472},
Abstract = {We report a series of experiments on social problem solving
in chimpanzees, Pan troglodytes. In each experiment a
subordinate and a dominant individual were put into
competition over two pieces of food. In all experiments
dominants obtained virtually all of the foods to which they
had good visual and physical access. However, subordinates
were successful quite often in three situations in which
they had better visual access to the food than the dominant,
for example, when the food was positioned so that only the
subordinate (and not the dominant) could see it. In some
cases, the subordinate might have been monitoring the
behaviour of the dominant directly and simply avoided the
food that the dominant was moving towards (which just
happened to be the one it could see). In other cases,
however, we ruled out this possibility by giving
subordinates a small headstart and forcing them to make
their choice (to go to the food that both competitors could
see, or the food that only they could see) before the
dominant was released into the area. Together with other
recent studies, the present investigation suggests that
chimpanzees know what conspecifics can and cannot see, and,
furthermore, that they use this knowledge to devise
effective social-cognitive strategies in naturally occurring
food competition situations. (C)2000 The Association for the
Study of Animal Behaviour.},
Doi = {10.1006/anbe.1999.1377},
Key = {fds240394}
}
@article{fds240389,
Author = {Hare, B and Tomasello, M},
Title = {Domestic dogs (Canis familiaris) use human and conspecific
social cues to locate hidden food},
Journal = {Journal of Comparative Psychology},
Volume = {113},
Number = {2},
Pages = {X173-X177},
Year = {1999},
Month = {January},
ISSN = {0735-7036},
Abstract = {Ten domestic dogs (Canis familiaris) of different breeds and
ages were exposed to 2 different social cues indicating the
location of hidden food, each provided by both a human
informant and a conspecific informant (for a total of 4
different social cues). For the local enhancement cue the
informant approached the location where food was hidden and
then stayed beside it. For the gaze and point cue, the
informant stood equidistant between 2 hiding locations and
bodily oriented and gazed toward the 1 in which food was
hidden (the human informant also pointed). Eight of the 10
subjects, including the one 6-month-old juvenile, were above
chance with 2 or more cues. Results are discussed in terms
of the phylogenetic and ontogenetic processes by means of
which dogs come to use social cues to locate
food.},
Doi = {10.1037//0735-7036.113.2.173},
Key = {fds240389}
}
@article{fds240391,
Author = {Itakura, S and Agnetta, B and Hare, B and Tomasello,
M},
Title = {Chimpanzee use of human and conspecific social cues to
locate hidden food},
Journal = {Developmental Science},
Volume = {2},
Number = {4},
Pages = {448-456},
Publisher = {WILEY},
Year = {1999},
Month = {January},
Abstract = {Two studies are reported in which chimpanzees attempted to
use social cues to locate hidden food in one of two possible
hiding places. In the first study four chimpanzees were
exposed to a local enhancement cue (the informant approached
and looked to the location where food was hidden and then
remained beside it) and a gaze/point cue (the informant
gazed and manually pointed towards the location where the
food was hidden). Each cue was given by both a human
informant and a chimpanzee informant. In the second study 12
chimpanzees were exposed to a gaze direction cue in
combination with a vocal cue (the human informant gazed to
the hiding location and produced one of two different
vocalizations: a 'food-bark' or a human word-form). The
results were: (i) all subjects were quite skillful with the
local enhancement cue, no matter who produced it; (ii) few
subjects were skillful with the gaze/point cue, no matter
who produced it (most of these being individuals who had
been raised in infancy by humans); and (iii) most subjects
were skillful when the human gazed and vocalized at the
hiding place, with little difference between the two types
of vocal cue. Findings are discussed in terms of
chimpanzees' apparent need for additional cues, over and
above gaze direction cues, to indicate the presence of
food.},
Doi = {10.1111/1467-7687.00089},
Key = {fds240391}
}
@article{fds240392,
Author = {Tomasello, M and Hare, B and Agnetta, B},
Title = {Chimpanzees, Pan troglodytes, follow gaze direction
geometrically},
Journal = {Animal Behaviour},
Volume = {58},
Number = {4},
Pages = {769-777},
Publisher = {Elsevier BV},
Year = {1999},
Month = {January},
ISSN = {0003-3472},
Abstract = {Two experiments on chimpanzee gaze following are reported.
In the first, chimpanzee subjects watched as a human
experimenter looked around various types of barriers. The
subjects looked around each of the barriers more when the
human had done so than in a control condition (in which the
human looked-in another direction). In the second
experiment, chimpanzees watched as a human looked towards
the back of their cage. As they turned to follow the human's
gaze a distractor-object was presented. The chimpanzees
looked at the distractor while still following the human's
gaze to the back of the cage. These two experiments
effectively disconfirm the low-level model of chimpanzee
gaze following in which it is claimed that upon seeing
another animate being's gaze direction chimpanzees simply
turn in that direction and look around for something
interesting. Rather, they support the hypothesis that
chimpanzees follow the gaze direction of other animate
beings geometrically to specific locations, in much the same
way as human infants. The degree to which chimpanzees have a
mentalistic interpretation of the gaze and/or visual
experience of others is still an open question.},
Doi = {10.1006/anbe.1999.1192},
Key = {fds240392}
}
@article{fds240390,
Author = {Tomasello, M and Call, J and Hare, B},
Title = {Five primate species follow the visual gaze of
conspecifics},
Journal = {Animal Behaviour},
Volume = {55},
Number = {4},
Pages = {1063-1069},
Publisher = {Elsevier BV},
Year = {1998},
Month = {January},
ISSN = {0003-3472},
Abstract = {Individuals from five primate species were tested
experimentally for their ability to follow the visual gaze
of conspecifics to an outside object. Subjects were from
captive social groups of chimpanzees, Pan troglodytes, sooty
mangabeys, Cercocebus atys torquatus, rhesus macaques,
Macaca mulatta, stumptail macaques, M. arctoides, and
pigtail macaques, M. nemestrina. Experimental trials
consisted of an experimenter inducing one individual to look
at food being displayed, and then observing the reaction of
another individual (the subject) that was looking at that
individual (not the food). Control trials consisted of an
experimenter displaying the food in an identical manner when
the subject was alone. Individuals from all species reliably
followed the gaze of conspecifics, looking to the food about
80% of the time in experimental trials, compared with about
20% of the time in control trials. Results are discussed in
terms of both the proximate mechanisms that might be
involved and the adaptive functions that might be served by
gaze-following.},
Doi = {10.1006/anbe.1997.0636},
Key = {fds240390}
}