Response of face-selective brain regions to trustworthiness and gender of faces

Abstract

Neuropsychological and neuroimaging studies have demonstrated a role for the amygdala in processing the perceived trustworthiness of faces, but it remains uncertain whether its responses are linear (with the greatest response to the least trustworthy-looking faces), or quadratic (with increased fMRI signal for the dimension extremes). It is also unclear whether the trustworthiness of the stimuli is crucial or if the same response pattern can be found for faces varying along other dimensions. In addition, the responses to perceived trustworthiness of face-selective regions other than the amygdala are seldom reported. The present study addressed these issues using a novel set of stimuli created through computer image-manipulation both to maximise the presence of naturally occurring cues that underpin trustworthiness judgments and to allow systematic manipulation of these cues. With a block-design fMRI paradigm, we investigated neural responses to computer-manipulated trustworthiness in the amygdala and core face-selective regions in the occipital and temporal lobes. We asked whether the activation pattern is specific for differences in trustworthiness or whether it would also track variation along an orthogonal male-female gender dimension. The main findings were quadratic responses to changes in both trustworthiness and gender in all regions. These results are consistent with the idea that face-responsive brain regions are sensitive to face distinctiveness as well as the social meaning of the face features.

The neuropsychology of first impressions: Evidence from Huntington's disease

“…Although research has often looked separately at facial expression recognition and social inferences from faces, a growing body of evidence points to a possible relationship between both processes, as summarised in the emotion overgeneralisation hypothesis (Montepare & Dobish, 2003). This behaviourally established relationship suggests that facial expression recognition and inferences of trustworthiness may share some of the same neural mechanisms (Mattavelli, Andrews, Asghar, Towler, & Young, 2012;Said, Haxby, & Todorov, 2011). Importantly, trustworthiness ratings of faces by M A N U S C R I P T (Willis, Palermo, & Burke, 2011;Sutherland, Young, & Rhodes, in press).…”

“…Other studies associate evaluation of facial trustworthiness with the amygdala (Adolphs, Tranel, & Damasio, 1998;Engell, Haxby, & Todorov, 2007;Hall, et al, 2010;Mattavelli, et al, M A N U S C R I P T Todorov, 2008;Todorov & Engell, 2008;Winston, et al, 2002), the fusiform gyrus, and the insular cortex (Winston, et al, 2002). Moreover, the fusiform gyrus, the superior temporal gyrus and the lingual gyrus are associated with evaluation of dominance from facial appearance and dominant head postures (Chiao, et al, 2008).…”

“…To achieve a sensitive behavioural measure well-suited to this purpose, we used computer image manipulation methods equivalent to those validated in previous studies (Mattavelli, et al, 2012;Sutherland, et al, 2013) to create continua of images that varied in perceived trustworthiness or dominance. We then measured how well these subtle gradations in manipulated trait impressions were perceived by people with HD and by control participants, and established the relation between performance deficits and other behavioural measures including measures of emotion recognition.…”

“…Decisions about a person's trustworthiness or dominance based on their face are of course of low validity, though many researchers take seriously the possibility that there may be an underlying 'kernel of truth' (Bruce & Young, 2012 This approach creates images that capture a range of everyday cues to the appropriate trait, and has been validated in previous studies (Mattavelli, et al, 2012;Sutherland et al, 2013;Sutherland, Young, Mootz, & Oldmeadow, 2015;Vernon, Sutherland, Young, & Hartley, 2014). Figure 1a and 1b about here, please…”

“…The matrix was created as follows, using similar procedures to a previous study (Mattavelli, et al, 2012). Photographs of 500 adult male and 500 adult female faces were collected from the internet.…”