Different effects of fear and happiness on visual organization

How emotional factors influence visual organization remains incompletely understood, particularly beyond early sensory processing. Across three experiments, we investigated whether emotional facial expressions modulate perceptual grouping and whether individual affective factors contribute to this modulation. Participants judged the global orientation of stimuli defined by visual contrast while fearful, happy, or neutral faces served as task-irrelevant primes. Study 1 replicated the contrast-dependent reduction in grouping-related decision efficiency reported by Han and Humphreys (1999). In Studies 2 and 3, primes produced emotion-specific effects. Happy faces slowed responses, particularly under low-contrast conditions, whereas fearful faces were associated with faster and more uniform responses when emotional context was stable. Individual differences in mood and interoceptive awareness predicted performance primarily under happy or neutral conditions but showed minimal influence under fearful priming. Together, these findings indicate that fear and happiness modulate perceptual grouping in a context- and state-dependent manner, highlighting how external emotional cues and internal affective states jointly shape perceptual organization.