Individual differences in trust evaluations are shaped mostly by environments, not genes

Abstract

People evaluate a stranger’s trustworthiness from their facial features in a fraction of a second, despite common advice “not to judge a book by its cover.” Evaluations of trustworthiness have critical and widespread social impact, predicting financial lending, mate selection, and even criminal justice outcomes. Consequently, understanding how people perceive trustworthiness from faces has been a major focus of scientific inquiry, and detailed models explain how consensus impressions of trustworthiness are driven by facial attributes. However, facial impression models do not consider variation between observers. Here, we develop a sensitive test of trustworthiness evaluation and use it to document substantial, stable individual differences in trustworthiness impressions. Via a twin study, we show that these individual differences are largely shaped by variation in personal experience, rather than genes or shared environments. Finally, using multivariate twin modeling, we show that variation in trustworthiness evaluation is specific, dissociating from other key facial evaluations of dominance and attractiveness. Our finding that variation in facial trustworthiness evaluation is driven mostly by personal experience represents a rare example of a core social perceptual capacity being predominantly shaped by a person’s unique environment. Notably, it stands in sharp contrast to variation in facial recognition ability, which is driven mostly by genes. Our study provides insights into the development of the social brain, offers a different perspective on disagreement in trust in wider society, and motivates new research into the origins and potential malleability of face evaluation, a critical aspect of human social cognition.

Within-Person Variability in First Impressions From Faces

“…We correlated participants’ initial ratings of 100 images and subsequent ratings of the same images and found good consistency in participant judgements. However, our test–retest correlations were weaker than those of other recent studies (e.g., Kramer et al., 2018; Sutherland et al., 2020); it is not clear why this was the case. Researchers should strive to include test–retest reliability measures in their studies to shed light on factors that influence within-participant consistency in trait judgements.…”

“…Therefore, if some traits are predominately derived from stable cues (e.g., attractiveness), and if stable cues are used to recognise an identity, then trait impressions might share common underlying processes with facial recognition. Researchers may wish to extend upon Sutherland et al.’s (2020) work by investigating the relationship between trait judgements and recognition performance across multiple images of the same face. Future research should also explore how trustworthiness, dominance, and attractiveness relate to processes underlying facial recognition.…”

The differential power of extraneous influences to modify aesthetic judgments of biological and artifactual stimuli

“…Hence, we believe that what is shared is not shared because of environmental influence but because of a common inheritance that leads to common brain concepts. Our belief is strengthened not only by the results of this study, but also by studies that have shown that infants tend to look more at faces that are reliably classified as attractive by adult individuals (Slater et al, 1998). We note that although our participants were drawn from 19 countries, most were nevertheless from Western countries.…”

Listeners’ perceptions of the certainty and honesty of a speaker are associated with a common prosodic signature

“…Studies involving bigger sample sizes and specifically designed to address this issue are needed to further understand how gender, other personal traits, as well as socialization and personal experiences, relate to the interpretation of (un)reliable prosodic displays. Relatedly, recent research involving twins showed that face impressions of trustworthiness are mostly determined by personal experiences rather than genes or shared environments 70 .…”