To be sure, most psychopaths neither have Hannibal Lecter’s brilliant mind nor his rather peculiar culinary taste. They usually do not eat the liver of their victims. And yet, Lecter’s character does illustrate one of the conundrums of psychopathy: they can be socially cunning if they want to. They are able to seduce their victims into a dark alley, and, seconds later, turn into cold-blooded rapists or murderers. Unlike most murderers, who act in the heat of a passion, and later feel guilty about what they have done, psychopaths feel no such remorse.
So far, the dominant understanding of psychopathy was that they basically lack emotions such as fear or distress. If you clap your hands behind someone’s back, she will startle, and you can measure how her palms get sweaty. If you do that with individuals with psychopathy, experiments have shown that their response is flattened. They barely startle and their hands stay dry. Now imagine, if you had never felt real fear or distress, how could you empathize with the fear or distress of others?
Empathy is key to our normal moral development. As kids, we are told not to hurt others, and we are told not to speak with our mouth full. Kids quickly come to feel very different about violating these two types of rules. Empathy is what makes the difference. Each time you hurt someone, that person’s distress becomes your pain, and you start to associate your vicarious pain with harming others. Violence then starts to feel intrinsically bad. Helping others, on the other hand, makes you feel their happiness, and will start to feel good.
If you were to lack empathy, this would never happen. Hurting others would leave you numb, and be as trivial as eating with your mouth full - just another convention. In that case, the only reason for doing neither would be fear of punishment – not guilt or compassion. If such an unempathic man would be alone in a dark alley with an attractive women and no one to punish him what would stand in the way of his lust?
To better understand whether a lack of empathy could explain why psychopathic offenders fail to feel bad about hurting others, we teamed up with a Dutch forensic clinic to investigate what happens in the brain. Over the last two decades, work from our lab and others has identified the neural signature of empathy. We all activate brain regions involved in our own actions, when we see the actions of others–even monkeys do so, as our work on mirror neurons has shown. We activate our somatosensory cortex, a region involved in sensing touch, when we see someone else touched on her skin. We activate our insula and cingulate cortex, regions involved in our own emotions, when we see the emotions of others. So if we witness a victim of violence wince in pain, our brain activates our own wincing and pain–we share her suffering. Using functional magnetic resonance imaging, we can quantify this empathy by simply measuring the activity in motor, somatosensory and emotional brain regions while witnessing the predicament of others.
To test if psychopathic individuals lack this empathic brain activation, the clinic transported 21 convicted violent psychopathic offenders to our scanner. One by one, in bulletproof minivans. Because metal cannot be brought in the vicinity of a magnetic imaging scanner, the guards were unarmed, but the patients had wooden sticks sawn into their trousers and plastic handcuffs to keep them from running away or hurting anyone.
Each patient was then shown movies of people hurting each other while brain activity was measured using fMRI. First, patients were simply told to watch the movies carefully. Later, Harma Meffert, the doctoral student who conducted the study (now at NIMH in Bethesda) went into the scanner room and slapped the patients on their hands to localize brain regions involved in feeling touch and pain. We could then zoom into these brain regions to see if the patients activated their own pain while viewing that of others. We did the same with 26 men of similar age and IQ. The results of the study, which are published today in the journal Brain, indicate that the vicarious activation of motor, somatosensory and emotional brain regions was much lower in the patients with psychopathy than in the normal subjects. The theory seemed right: their empathy was reduced, and this could explain why they committed such terrible crimes without feeling guilt.
But then, how can they be so charming at times? I remember chatting with one of the patients, Patient 13, a particularly severe psychopath (he had scored the full 40 points on the psychopathy checklist). Surrounded by the guards, he seemed a most pleasant person. He was smiling, engaging, and seemed to feel exactly what we wanted from him. Many of our ‘normal’ participants seemed rough and unfriendly in comparison. Valeria Gazzola, with whom I lead the lab, suggested that we let the patients watch the movies again, but asking them to try and empathize with the victims in the movies. What we found was that this simple instruction sufficed to boost the empathic activation in their brain to a level that was hard to distinguish from that of the healthy controls. Suddenly, the psychopaths seemed as empathic as the next guy. Their empathy was switched on.
So psychopathic individuals do not simply lack empathy. Instead, it seems as though for most of us, empathy is the default mode. If we see a victim, we share her pain. For the psychopathic criminals of our study, empathy seemed to be a voluntary activity. If they want to, they can empathize, and that explains how they can be so charming, and maybe so manipulative. Once they have seduced you into doing what serves their purpose, the effortful empathy would though probably disappear again. Free of the constraints of empathy, they is then little to stop them from using violence.
How can psychopathic individuals switch their empathy on and off? All of us have such a switch. We are more empathic towards the pain of our friends, than towards the misery of the people on the other side of the globe. Acupunctures learn to supress their empathy to the sight of a needle entering skin. Reducing empathy, sometimes, has clear evolutionary benefits: if you need to defend your family from an attack, you cannot afford to empathize with your aggressor. Our default mode, however, seems to have our empathy on. Individuals with psychopathy seem to have a slightly different switch: their default mode seems to be off.
Much still needs to be understood about why and how individuals with psychopathy seem to have the potential to empathize sometimes but have this capacity switched off by default. For therapists, our finding suggests that the best approach may not be to teach them empathy - they already seem capable of empathy. Instead, therapies may need to learn to be empathic always. How to do so is unclear, but it might be best to start such training early, before violence has become a way of life. A recent study from the group of Essi Viding at the UCL in London has shown that a callous, unemotional subgroup of kids with conduct disorder already seem to lack spontaneous empathy: they also activate their empathic brain less when simply watching others in pain. These kids are known to have a heightened risk of becoming psychopathic adults. Intervening early, in these children, to make empathy automatic, might be a promising approach.
For more information about the neural basis of empathy and psychopathy, have a look at the book The Empathic Brain.