I was recently watching the show Dexter, which is about the life of a serial killer who only kills other bad serial killers. It made me wonder about serial killers among of the psychopathic individuals and why they have disconnects with social interaction and emotion and what possible difference in the brain could be an explanation for this.
Many serial killers are sociopaths or psychopaths of some kind, which gives them the characteristics that can lead a person to become a killer. One way of studying such cases is through patients with Cluster B personality functions. People with Borderline Personality Disorder, Antisocial Personality Disorder, and Narcisstic Personality Disorder all display qualities that can be seen in many serial killers. In several cases patients have been shown to have reduced prefrontal gray matter, amygdala abnormalities, and asymmetric hippocampi areas. Some of these effects lead to symptoms such as emotional instability, anxiety, psychotic symptoms, paranoia and suspicion of others, impulsive aggression, lack of empathy, and low heart rate and levels of serotonin, which has lead to SSRI’s being used to try and treat some of these disorders.
In studies done on the brains of murders it was also found that they had significantly lower PFC activity and low orbital cortex activity. These can lead to less suppression of behaviors such as rage and violence as well as sexual behaviors, eating, and drinking. These neurological factors could also play a role in their lack of normal emotional attachment and sense of place with people and in society.
Studies have suggested that the vast majority of serial killer and psychopaths have several factors that result in their behaviors. Things such as genetics, childhood, and traumatic or abusive background all have a contributing role in these people.
Jim Fallon conducted a study looking at the brain characteristics that predisposed people to have violent and psychopathic tendencies. In the study he compared his own brain to several convicted murderers. To his surprise he found that he had many of the same brain patterns as the other killers. These included lack of activity in the limbic system, temporal lobes, and orbital cortex. Interestingly he also had many of the same genes connected with psychopathic behaviors. These qualities showed in his personality as his family pointed out. As he put it himself there are many things that he “knew were wrong, but didn’t care” which shows the emotional connection and attachment to things and people in life.
I found it interesting that he is not a serial killer however like many other people are with his same brain and gene structure. This shows how while brain structure can be a precursor for something, it does not necessarily seal your fate. In class we talked about how brain function can predict behavior, but the brain’s plasticity through ones life can cause different outcomes, which I thought fit well with Fallon’s story.
This video shows some of Fallon’s finding when looking at scans of his own brain.
This image shows the difference in brain activity between a normal person (left) and a serial killer (right). It can clearly be seen that the normal subject has a great deal more activity in the PFC than the serial killer, which perhaps equates for the tendencies to be emotionally detached from others and unable of empathy.