Spatiotemporal pattern of appraising social and emotional relevance: Evidence from event-related brain potentials

Abstract

Social information is particularly relevant for the human species because of its direct link to guiding physiological responses and behavior. Accordingly, extant functional magnetic resonance imaging (fMRI) data suggest that social content may form a unique stimulus dimension. It remains largely unknown, however, how neural activity underlying social (versus nonsocial) information processing temporally unfolds, and how such social information appraisal may interact with the processing of other stimulus characteristics, particularly emotional meaning. Here, we presented complex visual scenes differing in both social (vs. nonsocial) and emotional relevance (positive, negative, neutral) intermixed with scrambled versions of these pictures to N = 24 healthy young adults. Event-related brain potentials (ERPs) to intact pictures were examined for gaining insight to the dynamics of appraisal of both dimensions, implemented within the brain. Our main finding is an early interaction between social and emotional relevance due to enhanced amplitudes of early ERP components to emotionally positive and neutral pictures of social compared to nonsocial content, presumably reflecting rapid allocation of attention and counteracting an overall negativity bias. Importantly, our ERP data show high similarity with previously observed fMRI data using the same stimuli, and source estimations located the ERP effects in overlapping occipitotemporal brain areas. Our novel data suggest that relevance detection may occur already as early as around 100 ms after stimulus onset and may combine relevance checks not only examining intrinsic pleasantness/emotional valence but also social content as a unique, highly relevant stimulus dimension.

Keywords: Affective picture processing; Appraisal; Emotional valence; Event-related brain potentials (ERPs); Relevance; Social content.

Fig. 1

Valence and arousal image ratings. a Valence ratings (on a scale from 1 to 100; y-axis) for all six image categories. b Arousal ratings (on a scale from 1 to 100; y-axis) for all six image categories. Error bars represent 1 SEM

Fig. 2

a Grand average ERPs, contrasted for social, nonsocial × positive (pos), negative (neg) picture content, time-locked to stimulus onsets at selected ROI electrodes. The colored bars above the x-axis mark the significant main effects of the factors social content (gray), emotional content (blue), and their interaction (green). Inserted heads highlight selected ROI electrodes. b Scalp distribution of ERP effects within the P1 (left) and EPN (right) time windows, and c respective source localizations of the social > nonsocial ERP differences within these intervals. d ERP mean amplitudes (with SEMs) for the social by emotional content interaction within the P1 (left panel) and the EPN (right panel) time windows. e Scalp distribution of the ERPs to positive and negative content (small maps) and of ERP difference waves between negative and positive content (large maps) within the three time windows of significant emotion effects. (Color figure online)

Fig. 3

ERP effects of social relevance during neutral picture processing. a Grand average ERPs, contrasted for social and nonsocial content. The gray bar above the x-axis marks the significant main effect of the factor social content. b Scalp distributions of grand average ERPs and their difference between 200 and 320 ms; neu= neutral. (Color figure online)

Fig. 4

a Grand average ERPs, contrasted for all six experimental conditions, synchronized to stimulus onsets, at the P1 (upper panel) and posterior ROI (lower panel). b ERP mean amplitudes (with SEMs) during the four time windows of interest; pos= positive, neg= negative, neu= neutral. (Color figure online)