An objective measure of the effect of adaptation on recognition of famous faces

Abstract

Adaptation to faces has been shown to influence judgments of normality, emotion, gender, race, and identity of subsequently viewed faces (Webster et al 1999, 2004; Leopold et al 2001). The general method used is to adapt subjects to a face at one extreme of a continuum and measure people's subjective reports of the aftereffect on neutral or average faces. Here we use an objective recognition paradigm to show that adaptation can help or hinder subjects in identifying famous faces. 2 unknown faces were each morphed with 4 different famous faces (8 morphs total). Stimuli were grey-scale photographs of faces circumscribed by ovals which masked the ears and hairline. Subjects either adapted to one of the unknown faces or did not adapt to a face (baseline condition). Test faces from the morphs were presented in blocks with the amount of famous face present in the test faces increasing as the experiment progressed. At no time before or during the experiment were subjects told the identity of the famous faces used in the morphs. Results showed that if adaptation was to the unknown face used to make a morph, subjects needed less of a famous face to be present in the morph in order to identify it, relative to no adaptation. However, adaptation to a face not present in a morph made recognition worse than baseline. A replication using new stimuli and subjects produced similar results. Implications of the findings for models of face spaces and recognition are discussed.