Behavioral and ERP effects of encoded facial expressions on facial identity recognition depend on recognized facial expressions

Behavioral and event-related potential (ERP) studies have shown that the expressions of a face displayed in the encoding phase (encoded facial expressions) influences identity recognition of this face in a later recognition phase. As facial expressions displayed in the recognition phase (recognized facial expressions) might also influence facial identity recognition, the current study investigated whether the effect of encoded facial expressions on facial identity recognition changed depending on recognized facial expressions. Therefore, participants were asked to learn facial identities displaying angry, happy or neutral expressions during the encoding phase. In the subsequent recognition phase, participants were presented with the learned identities and several novel identities and asked to judge whether the prompted identities had been learned. Each identity displayed angry, happy and neutral expressions. The results showed that d' scores were smaller for happy-recognized identities (i.e., learned identities displaying happy expressions during the recognition phase) in the angry-encoded (i.e., learned identities that had displayed angry expressions during the preceding encoding phase) condition than in the neutral-encoded condition and for neutral-recognized identities in the angry-encoded condition than in the happy-encoded condition. ERP results showed that angry-encoded identities elicited less negative responses in the P200 and early posterior negativity (EPN)/N250 components and less positive responses in the late positive potential (LPP) component than happy-encoded identities. For neutral-recognized identities, LPP responses were reduced in the angry-encoded condition compared with those in the neutral-encoded condition. These findings might contribute to understanding the influence of previous and current facial expressions on facial identity recognition.