Goal-oriented, flexible use of numerical operations by monkeys

Sumito Okuyama, Jun ichi Iwata, Jun Tanji, Hajime Mushiake

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Previous studies have shown that elementary aspects of numerical abilities have developed in non-human primates. In the present study, we explored the potential for the development of a novel ability in the use of numerical operations by macaque monkeys (Macaca fuscata): adequate selection of a series of numerical actions toward achieving a behavioral goal. We trained monkeys to use a pair of devices to selectively add or subtract items to/from a digital array in order to match a previously viewed sample array. The monkeys determined whether to add or subtract on the basis of the feedback about numerosity given to the monkeys, which was displayed as an outcome of each step of the numerical operation. We also found that monkeys adapted flexibly to changes in the numerical rule that determined the relationship between device use and numerical operation. Our model analysis found that the numerosity-based model was a better fit for the monkeys' performance than was the reward-expectation-based model. Such a capacity for goal-oriented selection of numerical operations suggests a mechanism by which monkeys use numerical representations for purposeful behaviors.

Original languageEnglish
Pages (from-to)509-518
Number of pages10
JournalAnimal Cognition
Issue number3
Publication statusPublished - 2013 May


  • Device use
  • Flexibility
  • Goal-oriented selection
  • Monkeys
  • Numerical operations
  • Problem-solving

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Experimental and Cognitive Psychology


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