Author(s): de Veer MW, Gallup GG Jr, Theall LA, van den Bos R, Povinelli DJ
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Abstract In a previous cross-sectional study of mirror self-recognition involving 92 chimpanzees, Povinelli et al. [Journal of Comparative Psychology 107 (1993) 347] reported a peak in the proportion of animals exhibiting self-recognition in the adolescent/young adult sample (8-15 years), with 75\% being classified as positive. In contrast, only 26\% of the older animals (16-39 years) were classified as positive, suggesting a marked decline in self-recognition in middle to late adulthood. In the present study, all of the chimpanzees from the 8-15-year-old group in the Povinelli et al. study (n=12) were again tested for self-recognition, 8 years later. Using the same criteria, 67\% of the animals were classified the same. Although a higher proportion of the adult animals in this study (50\%) exhibited self-recognition than would be inferred on the basis of the previous study (25\%), all changes in self-recognition status were in the negative direction. These results show that mirror self-recognition is a highly stable trait in many chimpanzees, but may be subject to decline with age. Connections with human research are briefly discussed.
This article was published in Neuropsychologia
and referenced in Journal of Primatology