Article
Size Matters: Impact of Item Size and Quantity on Array Choice by Chimpanzees (Pan troglodytes)
Journal of Comparative Psychology
(2001)
Abstract
The authors previously reported that chimpanzees (Pan troglodytes) showed a striking bias to select the larger of 2 candy arrays, despite a reversed reward contingency in which the animals received the smaller, nonselected array as a reward, except when Arabic numerals were used as stimuli. A perceptual or incentive-based interference occurred that was overcome by symbolic stimuli. The authors of the present study examined the impact of element size in choice arrays, using 1 to 5 large and small candies. Five test-sophisticated chimpanzees selected an array from the 2 presented during each trial. Their responses were not optimal, as animals generally selected arrays with larger total mass; thus, they received the smaller remaining array as a reward. When choice stimuli differed in size and quantity, element size was more heavily weighted, although choices reflected total candy mass. These results replicate previous findings showing chimpanzees' difficulties with quantity judgments under reverse reward contingencies and also show that individual item size exerts a more powerful interference effect.
Keywords
- Chimpanzees -- Psychology -- Testing,
- Chimpanzees -- Behavior,
- Chimpanzees -- Development,
- Cognition in animals,
- Comparative psychology
Disciplines
Publication Date
2001
DOI
10.1037/0735-7036.115.1.106
Publisher Statement
Originally appeared in the Journal of Comparative Psychology, published by the American Psychological Association. May be found at http://dx.doi.org/10.1037/0735-7036.115.1.106
In compliance with the publisher’s copyright and archiving policies, this is a post-print version of the document. Post-print materials contain the same content as their final edited versions, but are not formatted according to the layout of the published book or journal.
Note: At the time of writing, Kimberley Mukobi was affiliated with Ohio State University.
Citation Information
Boysen, S. T., Berntson, G. G., & Mukobi, K. L. (2001). Size matters: Impact of item size and quantity on array choice by chimpanzees (Pan troglodytes). Journal of Comparative Psychology, 115(1), 106-110.
http://dx.doi.org/10.1037/0735-7036.115.1.106