Conceptual Volume Judgments by Squirrel Monkeys

Roger K. Thomas, Donald K. Ingram
1979 American Journal of Psychology  
Using a paradigm which precluded criterion performance on the basis of specific (as opposed to conceptualized) cues, monkeys were to choose the largest object when the objects appeared on a white background, the middlesized on a grey background, and the smallest on a black background among randomized presentations of objects and backgrounds. The monkeys were trained to stringent criteria using only the white background, then the black, then white and black together, then grey, and finally,
more » ... , and finally, white, black, and grey together. Only one monkey met criterion with concurrent presentations of the three backgrounds. Two met criterion through the grey condition, and one through the black and white condition. That three monkeys succeeded through the grey condition suggests this species is capable of conceptual size judgments where relative magnitude must be recognized. The implications of these data for quantitative judgments by animals are discussed.
doi:10.2307/1421477 fatcat:gtlwiufhkzaslkmwmttievekzu