Temporal course of emotional negativity bias: an ERP study.

There is considerable evidence that people are especially sensitive to emotionally negative materials. However, the temporal course of the negativity bias is still unclear. To address this issue, we observed the changes of P2, late positive components (LPC) and lateralized readiness potential (LRP) under positive, negative and neutral conditions, with International Affective Picture System (IAPS) pictures as emotional stimuli. We found that the amplitude of P2 in the negative block was significantly larger than that in the positive block, indicating that the attentional negativity bias occured very early in emotion perception. The LPC amplitude evoked by negative pictures was larger than that by positive and neutral pictures, suggesting that the negativity bias also occurred in a later evaluation stage of emotion processing. The response-locked LRP interval was shortest in the block of negative pictures, indicating that the negative contents elicited a reaction priming effect. Above all, this research showed that emotional negativity bias could occur in several temporal stages distinguished by attention, evaluation and reaction readiness periods.