The study involved 30 participants split into two groups as follows :
Group 1: This group consisted of 15 individuals who had been diagnosed with borderline personality disorder (BPD).
Group 2: This was the control group, consisting of 15 individuals who did not have borderline personality disorder (BPD).
How Was The Study Conducted?
All 30 participants in the study were shown pictures of people with four types of facial expressions, these expressions were as follows :
Sometimes, too, the participants had to focus on a single fixation point (rather than a picture of a face).
Functional Magnetic Resonance Imaging :
Whilst each of the participants was looking at each of the four different facial expressions, or at the single fixation point, they underwent a brain scanning process known as functional magnetic resonance imaging (fMRI).
The purpose of undergoing the fMRI whilst looking at the pictures of facial expressions or at the single fixation point was to measure the level of activation in a region of the brain known as the amygdala. The amygdala, among other functions, is involved in generating negative emotions.
What Were The Findings Of The Study?
When participants from GROUP 1 were shown pictures of faces displaying emotions (versus the single fixation point), their amygdalae were found to be more highly activated than were the amygdalae of those from GROUP 2 whilst undergoing the same activities.
Furthermore, interviews after the participants were shown the pictures revealed that some in GROUP 1 had interpreted the neutral faces as being threatening.
What Can We Infer From This Study?
This study suggests that individuals suffering from borderline personality disorder (BPD) can be prone to interpreting the facial expressions of others more negatively (e.g. as being threatening when this is not objectively the case) than those individuals who are relatively psychologically healthy.
According to this study, this would, at least in part, appear to be due to an abnormal physiological response in the brain, namely over activation of the amygdala in response to the emotional facial expressions of others.
This finding goes towards explaining why those with borderline personality disorder (BPD) tend to have severe problems in connection with their interpersonal relationships and often perceive others as threatening and as wanting to hurt them which, in turn, frequently gives rise to overly defensive behaviour.