Appearance‐based trust processing in schizophrenia

Objectives: Schizophrenia is characterised by impaired social interactions and altered trust. In the general population, trust is often based on facial appearance, with limited validity but enormous social consequences. The aim was to examine trust processing in schizophrenia, and specifically to examine how people with schizophrenia use facial appearance as well as actual partner fairness to guide trusting decisions. Design: An experimental economic game study. Methods: Here we tested how schizophrenia patients and control participants (each N = 24) use facial trustworthiness appearance and partner fairness behaviour to guide decisions in a multi-round Trust Game. In the Trust Game, participants lent money to ‘partners’ whose facial appearance was either untrustworthy or trustworthy, and who either played fairly or unfairly. Clinical symptoms were measured as well as explicit trustworthiness impressions. Results: Overall, the schizophrenia patients showed typical explicit facial trustworthiness impressions and typical facial appearance biases in the Trust Game. Crucially, patients and controls significantly differed so that the schizophrenia patients did not learn to discriminate in the Trust Game based on actual partner fairness, unlike control participants. Conclusion: A failure to discriminate trust has important implications for everyday functioning in schizophrenia, as forming accurate trustworthiness beliefs is an essential social skill. Critically, without relying on more valid trust cues, people with schizophrenia may be especially susceptible to the misleading effect of appearance when making trusting decisions.