SELF-RECOGNITION IN PRIMATES - PHYLOGENY AND THE SALIENCE OF SPECIES-TYPICAL FEATURES

Self-recognition has been explored in nonlinguistic organisms by recor ding whether individuals touch a dye-marked area on visually inaccessi ble parts of their face while looking in a mirror or inspect parts of their body while using the mirror's reflection. Only chimpanzees, gori llas, orangutans, and humans over the age of approximately 2 years con sistently evidence self-directed mirror-guided behavior without experi menter training. To evaluate the inferred phylogenetic gap between hom inoids and other animals, a modified dye-mark test was conducted with cotton-top tamarins (Saguinus oedipus), a New World monkey species. Th e white hair on the tamarins' head was color-dyed, thereby significant ly altering a visually distinctive species-typical feature. Only indiv iduals with dyed hair and prior mirror exposure touched their head whi le looking in the mirror. They looked longer in the mirror than contro ls, and some individuals used the mirror to observe visually inaccessi ble body parts. Prior failures to pass the mirror test may have been d ue to methodological problems, rather than to phylogenetic differences in the capacity for self-recognition. Specifically, an individual's s ensitivity to experimentally modified parts of its body may depend cru cially on the relative saliency of the modified part (e.g., face versu s hair). Moreover, and in contrast to previous claims, we suggest that the mirror test may not be sufficient for assessing the concept of se lf or mental state attribution in nonlinguistic organisms.