S2-4: On the (in)Dependence of Visual Cues and Cortical Regions for Judging Trustworthiness and Sex from Faces: TMS, Behavioural, and Human Lesion Evidence

Judging sex from faces relies on cues related to facial morphology and spatial relations between features, whereas judging trustworthiness relies on both structural and expressive cues that signal affective valence. I will present evidence of both asymmetric and symmetric dependence between the processing of a face's sex and trustworthiness. In one study, we used event-related, fMRI-guided repetitive transcranial magnetic stimulation (rTMS) to test whether 2 face-selective regions–right occipital face area (rOFA) and posterior superior temporal sulcus (pSTS)–have functionally dissociable, critical roles in sex and trustworthiness judgments. Sex judgments were disrupted when rTMS was delivered over right OFA (relative to sham stimulation) but not when it was delivered over right or left pSTS, whereas trustworthiness judgments were disrupted when rTMS was delivered over right or left pSTS but not rOFA. Nonetheless, analysis of the reaction time distributions revealed a possible critical role also for rOFA in trustworthiness judgments, limited to faces with longer RTs, perhaps reflecting the later, ancillary use of structural cues related to the sex of the face. New evidence from an individual (DF) with lesions encompassing bilateral occipital cortex indicates that significantly above-chance discrimination of the sex and trustworthiness of faces is possible in the absence of OFA–but only for untrustworthy males and trustworthy females, consistent with the RT data of healthy participants in the TMS study. Further evidence of restricted dependence between perceptions of trustworthiness and sex is provided by a RT-interference experiment with neurologically healthy volunteers using the Garner paradigm