UNBC research suggests psychopaths can’t tell when someone is in pain

A new study on psychopathy conducted by researchers from UNBC and UBC Okanagan has been published in the Journal of Personality Disorders.

The study suggests that the manipulative and sometimes violent behaviour of psychopaths might not just be attributed to a lack of empathy, but that psychopaths have a decreased ability to even sense someone else’s pain.

The research was led by Kimberley Kasewater, a postdoctoral fellow in psychology at UBCO, and was co-authored by UNBC’s Erin Browne and Kenneth Prkachin.

The study showed that higher levels of psychopathic traits, particularly callous affect and antisocial behavior, were associated with a decreased ability to discriminate others' pain.

These findings provide novel insights into the influence of psychopathic traits on emotional processing.

“A lot of the literature has focused on those basic emotions and psychopathy, like anger, fear and sadness,” said Kaseweter, in a news release. 

“Almost no research has really focused on pain, which I found surprising because of the association between pain and violent behaviour.”

The literature on psychopathy is still unclear on the underlying causes behind these facets of psychopathy, but Kaseweter said this study has shown that one possible mechanism might be a reduced ability to see other people’s pain.

The violence inhibition mechanism model suggests that in order to experience empathy, people have to first be able to accurately perceive someone’s distress to then withdraw from violent behaviour.

This study, she says, supports that theory.

Can they see others' pain, or do they just not care? 

Participants in this study first completed the Self-Report Psychopathy Scale to assess psychopathic traits.

The researchers looked at four different facets of psychopathic traits: callous affect, interpersonal manipulation, antisocial behaviour and erratic lifestyle.

Participants also watched video recordings of patients moving their injured shoulders in range-of-motion tests.

The participants then had to rate both the intensity and unpleasantness of the pain from patients’ facial expressions.

These recordings from actual patients showed spontaneous and natural expressions of pain that had been intensely coded frame by frame. The patients also self-reported their pain from these manipulations.

Kaseweter and her team were interested in whether psychopathic traits were connected to differences in how these participants might perceive others’ pain. 

They also wanted to know if that difference was due to what is called conservative response bias (consistently rating all perceived pain lower on the pain scale) or reduced perceptual sensitivity (inaccurate ratings, whether higher or lower), or both of these factors.

“We were able to break those two factors apart and tease that apart, which I think really gets at answering our questions. Do individuals who were high in psychopathic traits have an inability to see the facial expression of pain? Or if they can actually see it and just don’t care,” she said.

The study found that while people with psychopathic traits did not have a response bias—or they were no more or less likely in general to attribute pain to people—they were significantly less accurate in their ratings of pain in other people’s facial expressions.

This reduced sensitivity to other people’s pain was most associated with callous affect and antisocial behaviour.

Kaseweter said this finding is not surprising, giving callous affect is related to low empathy and reduced concern for others while antisocial behaviour involves engaging in criminal acts.

What do these findings mean?

While psychopaths have high rates of criminal behaviour, rehabilitation efforts with current treatments for these individuals have been largely ineffective, if not at times counterproductive.

Kaseweter said she is hopeful that this study could help isolate an area to direct more successful treatment in the future, especially with the clarification between response bias and actual inaccuracies in pain sensitivity.

“I think it’s a very important distinction. So how do we help? Is it just that people high in psychopathic traits don’t care? Then we have to teach them empathy in a different way. Or is it that they’re not seeing facial expressions accurately?”

She said the study’s findings suggest the latter—and that this decreased ability to detect pain accurately may underlie the lack of empathy seen with psychopathy.

“If this is the case, then training interventions designed to improve pain detection may, in turn, reduce the callous affect and antisocial behaviour characterizing psychopathy.”