Psychopaths do not lack empathy, rather they can switch it on and off at will, according to new research aimed at identifying why such criminals are callous and charming. A study by academics from the University of Groningen in the Netherlands, published in the journal Brain, found that psychopathic criminals could empathise with people when they were asked to.

The team proposed that with the right training, it could be possible to help psychopaths activate their "empathy switch", which could bring them a step closer to rehabilitation. Psychopathy is a personality disorder characterised by superficial charm, pathological lying and a reduced ability to empathise with others or show remorse.The study included 18 individuals with psychopathy and a control group, and consisted of three parts.

All participants first watched short movie clips of two people interacting, but with the camera zoomed in on their hands. The clips showed one hand touching the other in a loving, a painful, a socially rejecting or a neutral way. At this stage, participants were asked to look at the movies just as they would watch a film. Next, the participants watched the same clips again but were prompted explicitly to empathise with one of the actors in the movie. In the final part of the research, similar hand interactions were performed with the participants themselves, while they were lying in the scanner, having their brain activity measured.

The human brain is equipped with what scientists call a ‘mirror system’. Scientists have previously found that when people watch others move their body, or see those people being touched, or have emotions, these same brain regions are activated. This ‘mirror system constitutes a crucial part of our ability to empathise with other people and it has been previously shown that the less this system is activated, the less the person empathises with other people. It has been suggested that individuals with psychopathy might suffer from a broken ‘mirror system’, resulting in a diminished ability to empathise with their victims.

However, the situation is more complex, according to Professor Christian Keysers, head of the Social Brain Lab at the University Medical Center in Groningen (UMCG), and senior author of the study. When asked to just watch the film clips, the individuals with psychopathy did activate their mirror system less. "Regions involved in their own actions, emotions and sensations were less active than that of controls while they saw what happens in others,” he said. "At first, this seems to suggest that psychopathic criminals might hurt others more easily than we do, because they do not feel pain when they see the pain of their victims."

But the second part of the study revealed that instead of generally activating their mirror system less, individuals with psychopathy rather seem not to use this system spontaneously, but can use it when asked to. "When explicitly asked to empathise, the differences between how strongly the individuals with and without psychopathy activate their own actions, sensations and emotions almost entirely disappeared in their empathic brain,” saidValeria Gazzola, assistant professor at the UMCG and second author of the paper. "Psychopathy may not be so much the incapacity to empathise, but a reduced propensity to empathise, paired with a preserved capacity to empathize when required to do so.”

The data suggests that by default, psychopathic individuals feel less empathy than others. But if they try to empathise they can switch to 'empathy mode'.  The researchers suggest there are two sides to their findings. The first is that this reduced spontaneous empathy but reserved capacity for it could explain the typical psychopath personality traits of appearing charming, but also being callous. It may also suggest that therapies for such people may need to focus on making the existing capacity for empathy more automatic to prevent them from further harming others. But how to do so remains uncertain. Whether individuals with psychopathy autonomously switch their empathy mode on and off depending on the requirements of a social situation however remains to be established, the researchers added.