Link to preprint

In many cultures, humans use symbolic counting systems to represent large exact numbers. Evidence suggests that large exact number representations are unique to individuals who count: non-human animals and humans who do not use counting systems represent large numbers only approximately. However, some of the exact number principles that underlie counting, like the logic of one-to-one correspondence, may be acquired independently of symbolic systems. Alternatively, some theorize that exact number principles are acquired only through learning to count, specifically, after acquiring the cardinal principle. We tested whether two- to four-year-old children in the early stages of learning to count, and monkeys, who never learn to count, could use one-to-one correspondence cues to make precise quantity discriminations.

Methods

Children and monkeys each completed a discrimination task where food items (cheerios, raisins, or cheese puffs) were presented in or out of one-to-one correspondence. Participants simply chose one of the two caches.

Participants

Results

Accuracy on difficult ratios (difficult ratios ≥ 0.8; chance = 50%)

Cardinal-principle knowers and some monkeys used one-to-one cues to make more precise discriminations than when only approximate strategies were available, suggesting that one-to-one correspondence can support exact numerical reasoning independently of counting or language. See our paper for full results, analysis, and discussion.