Towards a Neurometric-based Construct Validity of Trust

Trust is a nebulous construct central to successful cooperative exchanges and interpersonal relationships. In this study, we introduce a new approach to establishing construct validity of trust using "neurometrics". We develop a whole-brain multivariate pattern capable of classifying whether new participants will trust a relationship partner in the context of a cooperative interpersonal investment game (n=40) with 90% accuracy and find that it also generalizes to a variant of the same task collected in a different country with 82% accuracy (n=17). Moreover, we establish the convergent and discriminant validity by testing the pattern on thirteen separate datasets (n=1,427) and find that trust is reliably related to beliefs of safety, inversely related to negative affect, but unrelated to reward, cognitive control, social perception, theory of mind, and self-referential processing. Together these results provide support for the notion that the psychological experience of trust contains elements of beliefs of reciprocation and fear of betrayal aversion. Contrary to our predictions, we found no evidence that trust is related to anticipated reward. This work demonstrates how "neurometrics" can be used to characterize the psychological processes associated with brain-based multivariate representations.