Michael J. Beran, Ph.D.
Curriculum Vitae

Journal Articles
Sites of Interest

Contact Me:  [email protected]

Last updated: 
September 1, 2021



Beran, M. J. (2008). Monkeys (Macaca mulatta and Cebus apella) track, enumerate, and compare multiple sets of moving items. Journal of Experimental Psychology: Animal Behavior Processes, 34, 63-74.

Despite many demonstrations of numerical competence in nonhuman animals, little is known about how well animals enumerate moving stimuli. In this series of experiments, rhesus monkeys (Macaca mulatta) and capuchin monkeys (Cebus apella) performed computerized tasks in which they had to enumerate sets of stimuli. In Experiment 1, rhesus monkeys compared two sets of moving stimuli. Experiment 2 required comparisons of a moving set and a static set. Experiment 3 included human participants and capuchin monkeys to assess all 3 speciesí performance and to determine whether responding was to the numerical properties of the stimulus sets rather to some other stimulus property such as cumulative area. Experiment 4 required both monkey species to enumerate subsets of each moving array. In all experiments, monkeys performed above chance levels, and their responses were controlled by the number of items in the arrays as opposed to nonnumerical stimulus dimensions. Rhesus monkeys performed comparably to adult humans when directly compared although capuchin performance was lower.

Return to Top