More studies are coming out showing the many physical differences between the brains of murderers and psychopaths and brains or "normal" people. It’s hoped that isolating the causes could lead to treatments to fix those changes and possibly prevent murderers from killing again. Although such treatments are decades in the future, identifying brain abnormalities can be done in the present time.
Brain scans done Clinical Neuroscience Research Centre in Kent in 2000 compared the scans of normal people doing a simple task compared to those of killers. They were all given photos of people they recognized. An area of the brain that helps with memory is clearly damaged or impaired in killers’ brains. In normal people, areas of the brain associated with emotion are also stimulated. A killer’s brain would not be so stimulated.
This might explain the lack of emotion or cold-heartedness shown by many killers and by psychopaths (people who are diagnosed with psychopathy). It could also explain violence done to others, including long-time friends and immediate family members, when a person is in the grip of a psychotic episode.
Problem in grey matter
Studies published in 2012 at King’s College London’s of Psychiatry showed that psychopaths and violent offenders have less grey matter in areas that control emotion. This lack of emotions can lead not only to murder, but also to a general lack of empathy. They also do not feel guilt or fear that normal people would have when contemplating murder.
Not all psychopaths are murderers or potential murderers. Many can lead productive lives and even become millionaires, according to “The Psychopath Test” by Jon Ronson (Riverhead; 2011).
Stanley Milgram’s experiment
Before normal people feel comfortable knowing that their normal brains would ever allow them to kill, let’s take a look at a landmark experiment done by Stanley Milgram in the 1960s. In the study, volunteers told that they had to deliver electric shocks to a person in another room. This person could not see the volunteer.
Unknown to the volunteer, the person was an actor and was not actually given any electric shocks. But the vast majority of volunteers administered what would have been lethal doses of electric shocks because an authority figure told the volunteers do so. These were normal people with normal brains theoretically killing people just because they were instructed to do so.