Age differences in the ability of chimpanzees to distinguish mirror-images of self from video images of others

• Published in: Journal of comparative psychology (1983) Vol. 110; no. 1; p. 38
• Main Authors: Eddy, T J, Gallup, Jr, G G, Povinelli, D J
• Format: Journal Article
• Language: English
• Published: United States 01.03.1996
• Subjects: Aging - psychology; Animals; Body Image; Discrimination Learning; Facial Expression; Female; Male; Pan troglodytes - psychology; Social Environment; Visual Perception
• ISSN: 0735-7036
• DOI: 10.1037/0735-7036.110.1.38

To evaluate Heyes's (1994) claim that chimpanzees are incapable of using mirrored information to obtain otherwise unavailable information about the self, we exposed two different age groups of chimpanzees (3-year-olds and 7- to 10-year-olds) to mirrors and video images of conspecifics. Their reactions to these stimuli were videotaped and were later scored for behavioral indices of self-recognition by a trained observer who was blind to the purpose and conditions of the study. Some types of behavior (contingent facial and body movements) were clearly influenced by the type of stimulus that the chimpanzees were viewing but not by age; however, other behaviors (self-exploration) were affected by age in conjunction with the type of stimulus the animals were viewing. The results suggest that, unlike self-exploratory behavior, contingent facial and body movements may not, by themselves, be reliable indicators of self-recognition.