psychopath stare © Getty

Could you spot a psychopath by just looking at them? A new AI can

Published: 12th August, 2021 at 16:31
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A recent study monitoring US prisoners has found a link between psychopathic personality traits and subtle behaviours during interviews.

Imagine, right now, you’re tasked with interviewing a prison inmate. Your mission: to identify whether this person is a psychopath or not. What tool might you need? The answer according to a team of University of New Mexico psychologists: an AI that monitors head movement.


Using a machine learning programme to monitor 507 incarcerated American adult men during interviews, they discovered inmates with higher levels of antisocial elements of psychopathy were more likely to keep their heads stationary.

“Such a result might help people in other situations (i.e. law enforcement) understand the personality of the person being interviewed," said Professor Kent Kiehl, one of the study’s authors.

“I’ve been interviewing individuals high on psychopathic traits for more than 20 years. During these interviews, the presentation style of such individuals is different from others."

Each interview lasted between one and four hours, with the head-tracking algorithm processing at least 36,000 frames of footage of each inmate, tracking six facial reference points.

To identify inmates’ level of psychopathy, the researchers used the Hare Psychopathy Checklist-Revised, a test analysing interpersonal, emotional, lifestyle and antisocial traits.

Assessing 20 criteria in total, the test scores a person from 1 to 40, with a score of 25 indicating an individual has high levels of psychopathic traits. In the US, this threshold is slightly higher at 30.

“As predicted, dwell times indicate that those with higher levels of psychopathic traits are characterised by more stationary head positions, focused directly towards the camera/interviewer, than were individuals low in psychopathic traits,” the study – published in the Journal of Research in Personality – concluded.

Read more about the science of psychopaths:

So why would individuals with higher levels of psychopathic traits limit their head movements? While the data gathered in this study doesn’t offer solid answers, the authors speculated on possible explanations – including the functioning of a person's amygdala, a brain region involved in emotional processing.

“Nonverbal behavioural cues associated with psychopathy may be partly reflective of neurobiological underpinnings of the condition, and partly due to conscious and effortful interpersonal manipulations,” they say.

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"Amygdala dysfunction is a hallmark neurobiological feature of psychopathy, affecting emotional processing, reinforcement learning, and interpersonal interactions...[this behaviour] may reflect impairments in amygdala function in psychopathy as these are also characteristic of patients with amygdala damage.”

However, the researchers also highlighted the limits of their new head-monitoring software. Not only is it untested against female and adolescent inmates, but the algorithm does not monitor eye movement.

In future, they hope to incorporate other “nonverbal, subconscious behaviours” into the algorithm, such as speech patterns and hand movements to identify psychopaths more accurately.

Read more about the science of psychopaths:



Thomas Ling
Thomas LingStaff Writer, BBC Science Focus

Thomas is a Staff Writer at BBC Science Focus and looks after all things Q&A. Writing about everything from cosmology to anthropology, he specialises in the latest psychology and neuroscience discoveries. Thomas has a Masters degree (distinction) in Magazine Journalism from the University of Sheffield and has written for Men’s Health, Vice and Radio Times. He has been shortlisted as the New Digital Talent of the Year at the national magazine Professional Publishers Association (PPA) awards.


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