This study distinguishes interpersonal trust learning with a novel trust learning paradigm in participants high (H-BPD) and low (L-BPD) in BPD features. Neutral faces were paired with trust-relevant behaviors in four conditions: trustworthy, untrustworthy, ambiguously trustworthy, and mixed trustworthiness. After training, participants rated faces on untrustworthiness as electroencephalographic measures were recorded. H-BPD rated neutral faces as significantly more untrustworthy than L-BPD at both time periods. Negative and ambiguous trustworthiness pairing conditions led to higher ratings of untrustworthiness, whereas trustworthy and mixed descriptors led to lower ratings of untrustworthiness. Learning enhanced the amplitude of an early sensory event-related potential (ERP) component (i.e., P1) for both groups. The slow-wave ERP, an index of sustained attention, revealed greater focus after learning to trustworthy descriptors in H-BPD and to untrustworthy descriptors in L-BPD. H-BPD utilized greater effort to overcome an inherent mistrust bias and L-BPD to overcome unexpected untrustworthy information.
Keywords: borderline personality disorder; electroencephalogram; neuroplasticity; social cognition; trust.