8 Cognitive Studies Conducted with Non-Human Primates and Their Findings

2. Numerical Cognition - Counting and Mathematics in Monkeys

Rhesus macaques and other primate species have demonstrated remarkable numerical abilities that rival those of young human children, as revealed through decades of carefully controlled experiments examining mathematical cognition in non-human primates. Research conducted by Elizabeth Brannon and Herbert Terrace showed that macaques can learn to order sets of objects numerically from one to nine, demonstrating an understanding of numerical relationships that transcends simple pattern recognition. These studies revealed that monkeys possess an approximate number system that allows them to discriminate between different quantities, perform basic addition and subtraction operations, and even understand numerical ratios and proportions. Particularly striking findings emerged from experiments where macaques were trained to touch computer screen stimuli in ascending numerical order, showing they could generalize this knowledge to novel number combinations they had never encountered before. The neural mechanisms underlying these abilities have been traced to specific brain regions, including the intraparietal sulcus, which shows similar activation patterns in both human and non-human primates during numerical tasks. These discoveries suggest that mathematical thinking has deep evolutionary roots and that the cognitive foundations for arithmetic and numerical reasoning existed millions of years before the emergence of human civilization, challenging assumptions about the uniqueness of human mathematical abilities.