Murderers: is it really their fault?

By Siena Hocking
Nowadays, it is very rare to turn on the news and not hear about a murder. Murder is seemingly a common occurrence, yet it is difficult to understand how anyone could bring himself or herself to commit such a heinous crime. It is difficult to comprehend why a man with a wife and children, who is seen as the typical family man, is able to plan a murder and actually go through with it without anyone noticing any type of strange or suspicious behaviour. So the question is, what makes criminals so different to ‘normal’ people?

Many people blame it on their twisted and dark backgrounds. However, there are significant biological differences between criminals and normal people. The brain works in many different ways and if your brain is damaged it can affect your personality and the way in which you act. For example: Phineas Gage was a construction foreman who as a result of demolition accident, had a tamping rod pierce his cheek, which then shot through the front part of his brain and out through the top of his head again. He remained conscious through all of this and retained his intelligence and memory. However, the damage to his prefrontal cortex caused Gage's personality to change. He became impulsive, selfish and aggressive, which greatly contrasted the gentle, levelheaded personality he possessed before the accident. The characteristics that Gage exhibited after his accident closely resemble some of the symptoms involved with Antisocial Personality Disorder. 

Some of the symptoms included in the DSM-VI are apathy towards others, a disregard for the rights of others, a sense of entitlement, unremorseful, blameful towards others, manipulative, and effectively cold. About a 25% of the US inmate population have this disorder. A 1992 FBI report said that almost half of the killers of law enforcement officers fit the criteria for antisocial personality disorder. The prefrontal cortex is known to inhibit the limbic system, which is an area of the brain that gives rise to aggressive behaviour. Adrian Rain describes the prefrontal cortex as an "emergency brake" that prevents people from lashing out in fits of rage. The right frontal orbital cortex is involved with fear conditioning, which is the non-conscious process of making an association between socially unacceptable behaviour and punishment. Fear conditioning is thought to be important in forming the conscience. However, since individuals with ASPD seem to lack fear, their emotions often seem blunted. Rain describes it by saying, "While some people have biological systems that make it easy, others have biological systems that make it hard. If you're an individual whose right orbital cortex is not functioning well, you're biologically disadvantaged in developing a conscience."

There have also been many studies carried out that examine murderers’ brains. In one such study, PET scans were again used to determine the cell activity of 41 murderers. The results showed a lower level of communication between the two hemispheres of the brain. The activity in the corpus callosum, which is the bridge that links the two sides of the brain, was 18% less active than normal. This is significant because the left side is usually considered the rational side, and the right side is the irrational side. If the bridge that links the two sides were not very active, then the rational and irrational sides would not be communicating very well. In most people, the left side of the brain has more control, but in murderers’ brains neither side rules. The study also showed some evidence that murderers’ emotions might be stronger than normal. The PET scans showed increased activity in the thalamus, amygdale, and limbic system by 6% compared to controls. All of these areas control basic emotions, such as aggression, sexual desire, and anger, and therefore increased activity in these regions would suggest stronger emotions.

In conclusion, is it really their fault that criminals are what they are or are they born like it?