# Estimating and learning personality traits of and from women with borderline personality disorder

## TL;DR

People with Borderline Personality Disorder (BPD) tend to see themselves and others negatively, which may explain their social difficulties, but they can still learn about others' personalities effectively.

## Contribution

The study reveals that BPD individuals have negativity biases in self and other evaluations, but their learning mechanisms remain intact.

## Key findings

- Women with BPD rated themselves more negatively than controls on personality traits.
- Both groups found it harder to learn about BPD-like profiles compared to control profiles.
- Learning strategies were intact in BPD individuals, suggesting biases rather than deficits drive social challenges.

## Abstract

Accurately perceiving and learning about others’ personalities is crucial for successful social relationships. Borderline Personality Disorder (BPD) is marked by unstable interpersonal dynamics, an unstable and negative self-concept, and a tendency to evaluate others unfavorably. Individuals with BPD are also more likely to be viewed negatively by others and experience social stigmatization. This study investigated whether women with BPD exhibit negativity biases when evaluating their own and others’ personality traits, and how these biases influence learning about others.

Thirty women with BPD and thirty-one age- and intelligence-matched controls estimated and learned the personality of six individuals (learning profiles) by predicting their self-ratings on 40 personality traits, balanced across the Big Five personality dimensions. After each prediction, participants received feedback with the target’s actual rating, allowing participants to gradually learn each profile’s personality. Three profiles reflected BPD group personality patterns and three profiles reflected control group patterns. Crucially, participants were told that these profiles were from real individuals but were unaware of their clinical status.

As hypothesized, the BPD group rated themselves more negatively than controls, both at the trait level and on standardized personality measures (NEO-FFI, PID-5-BF). When evaluating others, both groups rated BPD profiles similarly, but the control group rated control profiles more favorably. For both groups, accuracy improved slightly over time for control profiles but not BPD profiles, suggesting that BPD trait patterns are inherently harder to learn. Computational modeling indicated that both groups used fine-grained learning strategies—regardless of profile type—with no credible group differences in learning mechanisms.

These findings demonstrate that individuals with BPD exhibit pervasive negativity biases in self- and other-evaluations, yet retain intact social learning capacities. This suggests that interpersonal difficulties in BPD may stem more from negatively biased expectations than from deficits in learning. Moreover, the inherent difficulty in learning about BPD-like personality profiles—observed in both groups—may hinder mutual understanding and contribute to persistent social challenges. Importantly, the intact learning capacity points to a valuable therapeutic resource: targeting negative social expectations may help to reduce bias and improve social functioning in BPD.

The online version contains supplementary material available at 10.1186/s40479-025-00320-4.