Negative emotion alignment: The assimilation effect of facial emotion perception in a negative emotional crowd.

Emotion perception of the target face within an emotional crowd is influenced by the intensity of surrounding emotional faces. The present study investigated whether participants perceived the target face's emotional intensity as more aligned with the crowd's emotional intensity (i.e., assimilation effect of facial emotion perception in an emotional crowd). Participants estimated the emotional intensity of the target face within a crowd consisting of multiple emotional faces (angry/happy crowd in Experiment 1 and Experiment 3; angry/happy/fearful crowd in Experiment 2). Results across the first two experiments established a consistent assimilation effect: when embedded within a low-intensity angry or fearful crowd, negative target faces were perceived as less intense than their objective baseline. After accounting for potential confounds related to facial morphological features, Experiment 3 replicated these findings, confirming the stability of this perceptual bias. Notably, this assimilation effect was valence-specific, appearing consistently for negative emotions but failing to emerge for happy faces. Additionally, we found that individuals with a higher level of depression tended to underestimate the happy intensity of the happy face within a happy crowd. Across three experiments, the present study revealed that the negative face's emotional intensity perception within a negative crowd exhibited an assimilation effect.