The negativity bias in affective picture processing depends on top-down and bottom-up motivational significance

It is widely believed that negative information is psychologically more meaningful than positive information, a phenomenon known generally as the negativity bias. However, findings concerning the possibility of a negativity bias in emotional picture processing have been mixed, with recent studies indicating the lack of such a bias in event-related brain potentials (ERPs) when pleasant and unpleasant images are equated for motivational relevance. Here, we investigated 2 factors that could influence the detection of a negativity bias: picture-presentation paradigm and specific picture content. Across 2 studies, participants viewed pleasant affiliative, pleasant thrilling, unpleasant threatening and neutral images presented in the context of oddball, blocked, and random viewing paradigms. Across paradigms, emotional images elicited larger responses in the late positive potential (LPP) than did neutral images. A negativity bias was detected in the oddball paradigm and when thrilling, rather than affiliative, pleasant stimuli were used. Findings are discussed in terms of factors known to influence LPP amplitude and their relevance to differential effects across picture-viewing paradigms.