Medial Cortical Structures Mediate Implicit Trustworthiness Judgments about Kin Faces, but Not Familiar Faces: A Brief Report

Steven M Platek,Judson C Hendry

doi:10.3390/psych1010037

Abstract

Human kin recognition activates substrates of the extended facial processing network, notably the right-hemisphere structures involved in self-face recognition and posterior medial cortical substrates. To understand the mechanisms underlying prosociality toward kin faces in comparison to other familiar faces, we investigated the neural correlates of implicit trustworthiness ratings to faces of actual kin and personal friends, controlling for activation to distracter faces. When controlling for activation associated with unknown faces, trustworthiness ratings of faces of kin, compared to friends, were associated with increased activation in the dorsal anterior cingulate cortex, posterior cingulate, and precuneous. On the other hand, trustworthiness ratings of friend faces, relative to kin faces, were associated with the lateral occipital gyrus and insular cortex. Trustworthiness ratings for unknown faces were only associated with activation in the fusiform gyrus. These findings suggest that we should employ medial cortical substrates known to be part of the self-other network when making implicit social judgements about kin, but not other classes of facial stimuli.

Highlights

Kin variably evoke a myriad of emotions such as love, irritation, trust, frustration, and altruism, among others
The amygdala appears to be involved in automatic face coding with with respect to impression management [30], and is predicted to drive social responses toward respect to impression management andhave is predicted to drivethat social responses toward individuals individuals
The characterization of a similar response in non-Western cultures would be fascinating, but is beyond the scope of this paper. It appears that implicit prosocial judgments about kin, compared to friends and unknown individuals, is associated with activation in medial substrates that are known to be associated with self-related processing

Summary

Introduction

Kin variably evoke a myriad of emotions such as love, irritation, trust, frustration, and altruism, among others. Impression formation on the basis of facial processing occurs very quickly [30], and implicit trustworthiness judgements have been associated with activation in the limbic system, the amygdala [31,32,33]. These important social judgements appear to occur in the absence of deep processing [34,35,36]. The amygdala has been hypothesized to be involved in automatic face coding with respect to impression management and is predicted to drive social responses, appetitive or aversive, toward individuals. Several studies have demonstrated that attractive faces activate the neural substrates involved in reward processing [37,38,39,40]

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Discussion

Conclusion