Abstract
Bruce and Young's (1986) model of face recognition proposed that facial identity and emotional expression are processed independently. Yet, it has been argued that certain processes such as the perception of configural information are an important part of both face recognition and expression perception that can be marred by contrast negation and inversion (Calder & Jansen, 2005; Hole, George, & Dunsmore, 1999). Previously we reported a dichotomy between the effect of contrast-negation on gender and emotion discrimination, with a devastating effect of contrast-negation on gender judgments. To investigate the neural basis of this dichotomy, we used an adaptation paradigm to measure aftereffects from contrast-negated gender and emotion adaptation. If facial expression processing and gender discrimination are fully separated, then in accordance with our previous results adaptation to a contrast-negated angry male face would produce an aftereffect in positive contrast emotion categorization but not positive contrast gender categorization. However, if emotion and gender discrimination share in their initial perceptual processing and the effect of contrast-negation occurs later, then adaptation to a contrast-negated face would produce equal aftereffects in emotion and gender categorization in the positive testing face. We found significant aftereffects for contrast-negated face adaptation in both gender and emotion categorization (Exp 1), with no significant difference in effect size between gender and emotion. Moreover, this pattern of results was identical to that obtained with inverted face adaptation (Exp 2). In both experiments, adaptation to the original angry male face produced a larger aftereffect than contrast-negated or inverted face adaptation. Contrast negation destructs the otherwise highly stable ordinal luminance relations between a few face regions (Gilad, Meng, & Sinha, 2009). In combination with our previously reported findings, our results suggest that these luminance relations are crucial for gender discrimination at the stage when facial expression processing and facial identity are separated.