Have you ever wondered if criminals commit crimes because of their genetic makeup or brain structure? This article will discuss evidence suggesting criminals are genetically different from the ‘average’ person.
A genetic analysis of almost 900 offenders in Finland revealed two genes associated with violent crime. The study found that those with the genes linked to violent crime were thirteen times more likely to have a history of repeated violent behaviour. During the analysis each prisoner was categorised into violent or non-violent. The researchers found the association between genes and violent behaviour was strongest for the prisoners categorised as extremely violent. The prisoners in the extremely violent category were found to all carry a low activity version of the MAOA gene, also known as the ‘warrior gene’ due to its links to aggressive behaviour. The MAOA gene codes for the enzyme monoamine oxidase A, which controls the amount of serotonin (feel good hormone) and dopamine (happy hormone) in the brain. In addition, the researchers found another gene caried by the violent offenders called CDH13, which has previously been associated with substance abuse. The offenders classified as non-violent were not found to have this genetic profile. A deficiency in MAOA creates a lack of control in monoamine oxidase, which can result in dopamine hyperactivity. The genetic profile of the violent offenders has been shown to be different from the non-violent offenders, which would suggest genetic make-up (nature) is largely significant in who we are.
Research finds that criminals share similar brain structures, that psychologists have linked to crime. In a neuroimaging study led by Dustin Pardini, PHD, regarding the amygdala (a part of the brain involved in fear, aggression and social interactions), his team found that 26-year-old men with lower volumes of Amygdala were three times more likely to be aggressive or violent or show psychopathic traits then men of the same age with normal sized Amygdala. Adrian Raine, DPhil, led a study with Yu Gao, PHD, in Brooklyn that looked at fear conditioning (which is controlled by the Amygdala). They looked at a group pf 1,795 three-year-olds. Electrodes were placed on the fingers of the children, while two tones were played: one that was followed by a loud noise and one that was played alone. A difference in the sweat response indicated the child’s fear conditioning. Twenty years later the team identified participants who had commited crimes when they grew up. The participants who grew up to commit crimes were found to of not displayed fear conditioning during the original study. As a result of a smaller amygdala, these participants were fearless were most would be fearful making them more likely to commit crime.
These studies point out evidence suggesting that there are genetic differences between criminals and the ‘average’ person.
By Matt E