Abstract
This paper applies error management theory (EMT) (Haselton and Buss 2000) to explore how disruptions in epistemic trust-trust in communicated information-can be understood as adaptive responses to early adversity in individuals with borderline personality disorder (BPD). I propose that epistemic mistrust (EM) and epistemic credulity (EC), characterized by inappropriate trust patterns, arise from the differential costs of trusting unreliable versus mistrusting reliable information. Although these biases may seem maladaptive, they function as evolutionary survival mechanisms in response to harsh environments. Signal detection analysis can provide empirical evidence for these trust biases by assessing how individuals with BPD make trust-related decisions. Clinically, understanding these biases as evolutionary adaptations helps reduce stigma and informs evolutionary-informed interventions to recalibrate trust responses and improve interpersonal relationships. This approach highlights the significance of integrating evolutionary perspectives in treating trust disturbances in BPD.