VISUAL WORKING MEMORY REPRESENTATIONS OF TRUSTWORTHY AND UNTRUSTWORTHY FACES: AN EVENT-RELATED POTENTIAL INVESTIGATION

One critical evaluation concurring to the first impression of others is related to their perceived trustworthiness, conveyed by a set of facial features, in order to avoid untrustworthy individuals (and consequent risky social interactions), and to approach trustworthy individuals for immediate or future cooperation. However the cognitive mechanism supporting trustworthiness appraisal is poorly understood. We propose that when we process a face, visual working memory (VWM) holds an online representation that is sensitive to degree of the face trustworthiness (or un-trustworthiness) features. In order to verify this prediction, participants performed a change detection paradigm that required processing the identity of faces, while we recoded an EEG marker for the amount of information that is represented in VMW (the sustained posterior negativity, or SPCN). The results revealed that VWM representations (as indicated by SPCN amplitude) were sensitive to the face trustworthiness features although these features were task irrelevant. In addition, SPCN differences between trustworthy and untrustworthy faces correlated with the individual state and social anxiety. This pattern of results is discussed in terms of the high flexibility of aversive/avoidance and appetitive/approach motivational systems.