Self-other distinction and borderline personality disorder features: Evidence for egocentric and altercentric bias in a self-other facial morphing task

Self-other distinction (SOD) refers to the ability to distinguish one's own body, actions, and mental representations from those of others. Problems with SOD are considered to be a key feature of borderline personality disorder (BPD). However, empirical studies on SOD in BPD are scarce. Here, we present a study providing preliminary support for the usefulness and validity of a self-other facial morphing task to capture the capacity for SOD in a sample of nonclinical participants high (n = 30) and low (n = 32) in BPD features. Participants had to watch a video sequence in which their own face was gradually morphed into the face of an unfamiliar other (self-to-other) or vice versa (other-to-self), requiring them to indicate at which point they judged the morph to look more like the target face than the starting face. Consistent with predictions, results showed that participants in the high-BPD group judged the morph to look like themselves for longer in the self-to-other direction (suggestive of egocentric bias), but only with a relatively more attractive target face. In the other-to-self direction, the high-BPD group had more difficulty recognizing their own face (i.e., an altercentric bias), but this time only with the relatively less attractive face. Further research is needed to replicate these findings in clinical samples, but overall they suggest that the current task might be suited to investigate SOD problems in BPD. (PsycInfo Database Record (c) 2021 APA, all rights reserved).