Mirror mediated object discrimination and self-directed behavior in a female gorilla

Abstract

ABSTRACT. Mirror mediated object discrimination was investigated in a captive female, humanreared, western lowland gorilla (Gorilla gorilla gorilla) approximately 26 years of age. The gorilla was trained to find a stimulus that was only visible by use of the mirror. The gorilla could not reach the goal object except by observing it in the mirror and her hand movement was not visible through the mirror. Further, it was hypothesized that this mirror mediated object discrimination would enhance the probability of self-directed behavior. GALLUP'S (1970) marking paradigm, excluding the use of general anesthesia, was utilized in assessing self-directed behavior. Mirror-gazing, face-directed, and mark-directed behavior with a mirror were compared before versus after discrimination mirror training. The results supported the hypotheses that gorillas are capable of mirror mediated object discrimination and that mirror training involving a discrimination task would facilitate self-directed behavior.

Pictorial Competence in Primates: A Cognitive Correlate of Mirror Self-Recognition?

“…Some studies indeed showed that gorillas exhibit no mark directed touching [16] nor spontaneous mirrorguided self-exploration [17], while others suggest that gorillas are capable of self-recognition [18][19][20][21]. Still, results are controversial even with mirror procedure adapted to the behavioral gorillas' specificity, and aimed at enhancing the gorillas' exploration of the mirror reflection, for example [22][23][24]. Overall, even if results on gorillas' MSR ability are mixed, according to the studies reporting positive findings, the capacity for self-recognition is at least present in some individuals.…”

Mirror self-recognition: a review and critique of attempts to promote and engineer self-recognition in primates

“…Training was also used in a study of a 26-year-old female gorilla who learned how to use a mirror to solve a discrimination task. She then reportedly passed a version of the mark test, though few details were given (Nicholson and Gould 1995).…”

Mirror responses in a group of Miopithecus talapoin

“…The results obtained so far are controversial, due to variable responses both within and between species. It is widely accepted that the great apes are capable of recognising their image reflected in a mirror, although among gorillas there is scant evidence of self-recognition (Suarez and Gallup 1981;Ledbetter and Basen 1982;Parker 1994;Patterson et al 1994;Swartz and Evans 1994;Nicholson and Gould 1995;Shillito et al 1999). Like chimpanzees, some orangutans (Lethmate and Du¨cker 1973;Suarez and Gallup 1981;Miles 1994) and possibly the lesser apes (Ujhelyi et al 2000) possess this cognitive skill.…”