Affective picture processing: The late positive potential is modulated by motivational relevance

TLDR

The late positive potential (LPP) is consistently enhanced for emotionally intense pictures, whether presented in oddball paradigms or in random, context‑free sequences. To reconcile differing interpretations of the LPP, the authors recorded ERPs to randomly ordered pictures presented rapidly (1.5 s per image) in sequences of six, mirroring oddball designs that vary evaluative distance. The results showed that pleasant and unpleasant pictures elicited larger LPPs than neutral ones, with high‑arousal images producing even greater responses. These findings indicate that late positivity is modulated by both intrinsic motivational significance and the evaluative context of picture presentation.

Abstract

Recent studies have shown that the late positive component of the event-related-potential (ERP) is enhanced for emotional pictures, presented in an oddball paradigm, evaluated as distant from an established affective context. In other research, with context-free, random presentation, affectively intense pictures (pleasant and unpleasant) prompted similar enhanced ERP late positivity (compared with the neutral picture response). In an effort to reconcile interpretations of the late positive potential (LPP), ERPs to randomly ordered pictures were assessed, but using the faster presentation rate, brief exposure (1.5 s), and distinct sequences of six pictures, as in studies using an oddball based on evaluative distance. Again, results showed larger LPPs to pleasant and unpleasant pictures, compared with neutral pictures. Furthermore, affective pictures of high arousal elicited larger LPPs than less affectively intense pictures. The data support the view that late positivity to affective pictures is modulated both by their intrinsic motivational significance and the evaluative context of picture presentation.