Afterimage induced neural activity during emotional face perception

Implicit weight bias: shared neural substrates for overweight and angry facial expressions revealed by cross-adaptation

The perception of facial expression plays a crucial role in social communication, and it is known to be influenced by various facial cues. Previous studies have reported both positive and negative biases toward overweight individuals. It is unclear whether facial cues, such as facial weight, bias facial expression perception. Combining psychophysics and event-related potential technology, the current study adopted a cross-adaptation paradigm to examine this issue. The psychophysical results of Experiments 1A and 1B revealed a bidirectional cross-adaptation effect between overweight and angry faces. Adapting to overweight faces decreased the likelihood of perceiving ambiguous emotional expressions as angry compared to adapting to normal-weight faces. Likewise, exposure to angry faces subsequently caused normal-weight faces to appear thinner. These findings were corroborated by bidirectional event-related potential results, showing that adaptation to overweight faces relative to normal-weight faces modulated the event-related potential responses of emotionally ambiguous facial expression (Experiment 2A); vice versa, adaptation to angry faces relative to neutral faces modulated the event-related potential responses of ambiguous faces in facial weight (Experiment 2B). Our study provides direct evidence associating overweight faces with facial expression, suggesting at least partly common neural substrates for the perception of overweight and angry faces.

Semantic satiation of emotional words impedes facial expression processing in two stages

To explore the mechanism of emotional words semantic satiation effect on facial expression processing, participants were asked to judge the facial expression (happiness or sadness) after an emotional word ((cry) or (smile)) or a neutral word ((Ah), baseline condition) was presented for 20 s. The results revealed that participants were slower in judging valence-congruent facial expressions and reported a more enlarged (Experiment 1) and prolonged (Experiment 2) N170 component than the baseline condition. No significant difference in behavior and N170 appeared between the valence-incongruent and the baseline condition. However, the amplitude of LPC (Late Positive Complex) under both valence-congruent/incongruent conditions was smaller than the baseline condition. It indicates that, in the early stage, the impeding effect of satiated emotional words is specifically constrained to facial expressions with the same emotional valence; in the late stage, such an impeding effect might spread to facial expressions with the opposite valence of the satiated emotional word.