Cognitive load modulates the effects of social contexts on facial expression processing.

Emotion perception mostly occurs in social contexts where people engage in emotional communication. Research has revealed that contextual faces affect facial expression perception through 2 distinct ways: congruence and functional relation. However, their robustness under varying levels of cognitive load remains unclear. Thus, this study utilized event-related potentials to explore how cognitive load modulated these effects in facial expression processing. Participants performed a facial expression recognition task under different cognitive load conditions, identifying the emotional expression of a centrally presented target face, while a peripherally presented contextual face displayed a dynamic emotional expression and gazed toward the target. Behavioral results showed fearful faces were recognized faster under low than high cognitive load, but no significant difference for angry faces. Event-related potential results found cognitive load modulated both early and late stages of facial processing. Importantly, when recognizing fearful target faces, late positive potential amplitudes under low cognitive load were more positive after angry than fearful contextual faces (functional-relational context effects). In contrast, under high cognitive load, late positive potential amplitudes were more positive after fearful than angry contextual faces (congruence effects). These findings suggested cognitive load modulated both effects on facial expression processing, with this modulation occurring during late-stage processing.