Sharing joy increases joy: Group membership modulates emotional perception of facial expressions.

When we judge someone's emotional expressions, we often consider the emotions of other people who are present in the same social context. Using a psychophysical method, we estimated the influence of the emotions of contextual faces on the emotional perception of an individual face. Particularly, we hypothesize that a shift in the perceptual judgment occurs when the target individual and others share a Group Membership. To test this hypothesis, we generated artificial images of two sports teams and asked participants to first judge the outcome of the game (win/loss for Experiment 1; win/loss/draw for Experiment 2) by looking at the facial emotions of four members of a team, and then judge the emotional category of the target face presented amid the contextual faces. The expressions of the target faces were gradually morphed (happy to sad for Experiment 1; happy to angry for Experiment 2). In Experiment 1, the perceptual decision threshold of the emotional categories of the target face shifted toward the emotional context of the same group members. However, such shifts did not occur in the different group condition. Experiment 2 showed that the shifted perceptual decision threshold significantly differed from the neutral condition only in the same group condition, which further replicated the results of Experiment 1. Our results indicate that people consider the emotions of others in the context of estimating an individual's emotion when they are socially attached to each other through Group Membership. (PsycInfo Database Record (c) 2022 APA, all rights reserved).