Beyond good and evil: the time-course of neural activity elicited by specific picture content

The present study examined electrocortical evidence for a negativity bias, focusing on the impact of specific picture content on a range of event-related potentials (ERPs). To this end, ERPs were recorded while 67 participants viewed a variety of pictures from the International Affective Picture System. Examination of broad categories (i.e., pleasant, neutral, unpleasant) found no evidence for a negativity bias in two early components, the N1 and the Early Posterior Negativity (EPN), but revealed that unpleasant images did elicit a larger late positive potential (LPP) than pleasant pictures. However, images of erotica and mutilation elicited comparable LPP responses, as did affiliative and threatening images. Exciting (i.e., sports) images and disgusting images elicited smaller LPPs than other emotional images, similar to neutral images containing people-which were associated with the largest LPPs among neutral pictures. When these three anomalous categories (exciting, disgusting, and scenes with people) were excluded, unpleasant images no longer elicited a larger LPP than pleasant images. Thus, including exciting images in pleasant ERP averages disproportionately reduces the LPP. The present findings are discussed in light of the motivational significance of specific picture subtypes.