Immediate relativity: EEG reveals early engagement of comparison in social information processing

Ohmann, K, Stahl, J, Mussweiler, T M and Kedia, G (2016) Immediate relativity: EEG reveals early engagement of comparison in social information processing. Journal of Experimental Psychology: General, 145 (11). pp. 1512-1529. ISSN 0096-3445

Abstract

A wide array of social decisions relies on social comparisons. As such, these decisions require fast access to relative information. Therefore, we expect that signatures of the comparative process should be observable in electrophysiological components at an early stage of information processing. However, to date, little is known about the neural time course of social target comparisons. Therefore, we tested this hypothesis in two electroencephalography (EEG) studies using a social distance effect paradigm. The distance effect capitalizes on the fact that stimuli close on a certain dimension take longer to compare than stimuli clearly differing on this dimension. Here, we manipulated the distance of face characteristics regarding their levels of attractiveness (Study 1) and trustworthiness (Study 2), two essential social dimensions. In both studies, size comparisons served as a nonsocial control condition. In Study 1, distance related effects were apparent 170 milliseconds (VPP) and 200 milliseconds (N2) after stimulus onset for attractiveness comparisons. In Study 2, trustworthiness comparisons took effect already after 100 milliseconds (N1) and likewise carried over to an event-related N2. Remarkably, we observed a similar temporal pattern for social (attractiveness, trustworthiness) and nonsocial (size) dimensions. These results speak in favor of an early encoding of comparative information and emphasize the primary role of comparison in social information processing.