Long‐term retention of self‐recognition by chimpanzees

Abstract

Two young chimpanzees showed retention of self-recognition after 1 year without access to mirrors. A year earlier the animals were positive on the Gallup dye test. One year later they were once again anesthetized, marked on the brow and ears, and following recovery, exposed individually to a large mirror. Both demonstrated mirror-orientated mark-directed responses. Time-sample observations of behavior toward the mirror further support self-recognition. The chimpanzee's self-awareness, as inferred from its self-recognition, appears to be a stable characteristic of the animal.

Not all chimpanzees (Pan troglodytes) show self-recognition

“…To date, 18 of 20 socially experienced chimpanzees tested have shown evidence of self-recognition according to the mark test following extended mirror experience GALLUP et al, 1971;SUAREZ & GALLUP, 1981;LETHMATE & DUCKER, 1973;ROBERT, 1986;CALHOUN & THOMPSON, 1988). The two who did not show evidence of self-recognition according to the mark test were an ll-month-old who had had only 46.5 hr of mirror exposure (ROBERT, 1986) and an adult who had rubbed his head against the wet surface of his cage, resulting in the removal of most of his mark prior to the test (SUAREZ & GALLUP, 1981).…”

“…To date, the only species to have clearly demonstrated self-recognition in variants of this procedure have been human infants approximately 2 years of age (AMSTERDAM, 1972;BERTENTHAL & FISCHER, 1978;LEWIS & BROOKS-GUNN, 1979;JOHNSON, 1983), chimpanzees GALLUP et al, 1971;SUAREZ & GALLUP, 1981;LETHMATE & DUCKER, 1973;CALHOUN & THOMPSON, 1988), and orang-utans (LETHMATE & DUCKER, 1973;SUAREZ & GALLUP, 1981). Despite repeated and often creative efforts, no one has been able to obtain evidence for self-recognition in monkeys (see ANDERSON, 1984b, for a review), nor in gorillas (SUAREZ & GALLUP, 1981;LEDBETTER & BASEN, 1982).…”

Do rhesus monkeys recognize themselves in mirrors?

“…We predict that if the acrylic block was removed and the wound allowed to heal, these ''self-recognizing'' monkeys would show no signs whatsoever that they recognized their own reflections. In contrast, once they learn to recognize themselves in mirrors, chimpanzees show immediate and compelling evidence of self-recognition upon being confronted with a mirror after prolonged periods, even years, without any intervening mirror exposure [Calhouhn & Thompson, 1988;De Veer et al, 2003].…”

Kinesthetic‐Visual Matching and the Self‐Concept as Explanations of Mirror‐Self‐Recognition

“…In addition, normal children self-recognize by 18 months of age on average (Neuman and Hill, 1976;Lewis and Brooks-Gunn, 1978;Hart and Fegley, 1994), but do not even begin to understand their own or others' mental states (or attribute mental states to others) until 30 months of age (see, e.g., Flavell, 1988;Gopnik and Meltzoff, 1994;Bartsch and Wellman, 1995). Chimpanzees self-recognize at 3-4 years of age (Hill, Bundy, Gallup and McClure, 1970;Gallup, McClure, Hill and Bundy, 1971;Calhoun and Thompson, 1988;Lin, Bard and Anderson, 1992;cf. Povinelli, Rulf, Landau and Bierschwale, 1993; see discussion in Swartz and Evans, 1997), but continue to fail to understand the nature of seeing even at 6 years of age (Povinelli and Eddy, 1996).…”