Effects of emotional variability on social evaluations of faces: An advantage of low variability

When people see another person's face, they can quickly infer traits and make social evaluations from them, a process known as social perception of faces. Previous studies have investigated the effects of emotion on social evaluations but have mainly focused on single expressions. The present study examined how intra-individual emotional variability across multiple faces affects judgements of warmth and competence. In Experiment 1, mixed-valence sets containing both happy and angry faces were used, and emotional variability was manipulated by varying the emotional distance of faces. Results showed that the positive warmth and competence words were perceived as more appropriate to describe faces with low variability compared with high variability (Exp1a). This low-variability advantage persisted after controlling for extreme expressions and generalized to additional warm and competent traits (Exp1b). Experiments 2a and 2b tested the variability effects across happy-only, angry-only, and mixed-valence sets. Positive sets received the highest ratings, mixed-valence sets intermediate, and negative sets the lowest on both dimensions. Importantly, a significant main effect of variability emerged only for competence ratings, with low-variability faces rated higher than high-variability faces. In summary, our study indicates that low emotional variability has an advantage in social evaluations over high emotional variability.