Abstract

Previous research has shown that individuals with higher levels of social anxiety tend to perceive a more negative average emotion from facial sets. However, these studies overlooked the individual differences in perception of specific facial expressions by each participant. The current study investigated the relationship between social anxiety and ensemble coding of facial crowd emotions through an experimental task tailored to consider these individual differences. A total of 100 undergraduate and graduate students participated in the study, completing both the task and assessments of social anxiety and depression. During the experiment, the participants’ thresholds for detecting happiness (positive) and anger (negative) were assessed using a psychophysical approach. We used these individually determined thresholds to generate customized facial crowd stimuli for the average emotion inference task. In this task, participants viewed stimuli comprising 12 faces and assessed whether the average emotion expressed was positive or negative. These facial crowds were presented in seven different positive-to-negative ratios (0:12, 2:10, 4:8, 6:6, 8:4, 10:2, 12:0). Participants’ responses were then fitted to a cumulative normal distribution to establish a point of subjective equality. The results revealed that higher social anxiety correlated with a tendency to perceive facial crowds’ average emotion as more negative, even after controlling for depression. These findings highlight that social anxiety influences how individuals statistically summarize group emotional expressions, underscoring the significance of therapeutic interventions aimed at correcting these emotion perception biases.