Publications [#250962] of Elizabeth M. Brannon

Journal Articles

1. EM Brannon and HS Terrace, Representation of the numerosities 1-9 by rhesus macaques (Macaca mulatta), Journal of Experimental Psychology: Animal Behavior Processes, vol. 26 no. 1 (2000), pp. 31-49, ISSN 0097-7403
   (last updated on 2016/06/25)

   Abstract:
   Three rhesus monkeys (Macaca mulatta) were trained to respond to exemplars of 1,2,3, and 4 in an ascending, descending, or a nonmonotonic numerical order (1→2→3→4, 4→3→2→1, 3→1→4→2). The monkeys were then tested on their ability to order pairs of the novel numerosities 5-9. In Experiment 1, all 3 monkeys ordered novel exemplars of the numerosities 1-4 in ascending or descending order. The attempt to train a nonmonotonic order (3→1→4→2) failed. In Experiment 2A, the 2 monkeys who learned the ascending numerical rule ordered pairs of the novel numerosities 5-9 on unreinforced trials. The monkey who learned the descending numerical rule failed to extrapolate the descending rule to new numerosities. In Experiment 2B all 3 monkeys ordered novel exemplars of pairs of the numerosities 5-9. Accuracy and latency of responding revealed distance and magnitude effects analogous to previous findings with human participants (R. S. Moyer & T. K. Landaeur, 1967). Collectively these studies show that monkeys represent the numerosities 1-9 on at least an ordinal scale. Copyright 2000 by the American Psychological Association, Inc.