Further reflections on self-recognition in primates

Abstract

A review of the literature, together with a reanalysis of existing data and some additional data, was used to show that Heyes' (1994, Anim. Behav., 47, 909–919) recent critique of self-recognition research in primates is without merit. Heyes' contention, that self-recognition is an artefact of incomplete recovery from anaesthetization and species differences in ambient face touching, is contrary to (1) the temporal parameters of the mark test, (2) responses that chimpanzees, Pan troglodytes, make to control body marks (i.e. those that can be seen without a mirror), (3) results from studies that have not used anaesthesia, (4) responses that chimpanzees make to unmarked portions of the face, (5) the absence of a correlation between developmental changes in face touching and self-recognition, (6) differences among chimpanzees in patterns of mirror self-directed behaviour and normal self-grooming and (7) the absence of substantial species differences in face-touching behaviour.