It doesn't matter how you feel. The facial identity aftereffect is invariant to changes in facial expression

Previous studies have shown that facial expression aftereffects are modulated by the identity of the adapting face, suggesting both identity-dependent and identity-independent representations of facial expression. In this study, we asked whether facial identity aftereffects were similarly modulated by expression. In Experiment 1, the congruency of expression between adapting and test faces did not affect the identity aftereffect for novel faces, suggesting that the neural representations activated by novel identities are independent of expression. In Experiment 2, we examined whether expression dependency might be found with more familiar faces but still did not find any modulation of identity aftereffects by the congruency of expression. In Experiment 3, we measured the similarity between faces used to probe expression and identity adaptation, using both an ideal observer and human subjects, to determine if the discrepancy between the results of these two studies is related to greater similarity between faces from the same person with different expressions than between faces of different people with the same expression. However, the contrast thresholds required to discriminate between faces of differing expression were similar to those for faces with differing identity. We conclude that, in contrast to the significant identity-dependent component seen in representations of expression, representations of facial identity are independent of variations in expression.