Weber's Law influences numerical representations in rhesus macaques (Macaca mulatta).


Journal Article

We present the results of two experiments that probe the ability of rhesus macaques to match visual arrays based on number. Three monkeys were first trained on a delayed match-to-sample paradigm (DMTS) to match stimuli on the basis of number and ignore continuous dimensions such as element size, cumulative surface area, and density. Monkeys were then tested in a numerical bisection experiment that required them to indicate whether a sample numerosity was closer to a small or large anchor value. Results indicated that, for two sets of anchor values with the same ratio, the probability of choosing the larger anchor value systematically increased with the sample number and the psychometric functions superimposed. A second experiment employed a numerical DMTS task in which the choice values contained an exact numerical match to the sample and a distracter that varied in number. Both accuracy and reaction time were modulated by the ratio between the correct numerical match and the distracter, as predicted by Weber's Law.

Full Text

Cited Authors

  • Jordan, KE; Brannon, EM

Published Date

  • July 2006

Published In

Volume / Issue

  • 9 / 3

Start / End Page

  • 159 - 172

PubMed ID

  • 16575587

Pubmed Central ID

  • 16575587

Electronic International Standard Serial Number (EISSN)

  • 1435-9456

International Standard Serial Number (ISSN)

  • 1435-9448

Digital Object Identifier (DOI)

  • 10.1007/s10071-006-0017-8


  • eng