Serial killers are a strange combination of terrifying and fascinating in equal measure but to understand what motivates these seemingly normal people to kill time and time again can be difficult to understand.
Both psychologists and neuroscientists are attempting to build up a morbid picture of the disturbing minds behind some of the most horrific crimes that have come to light in recent decades, the Daily Mail reports.
The scientists have discovered surprising similarities between these mass murderers, and might have discovered evidence that a genetic abnormality that may act as a trigger for their more violent impulses.
A forensic psychiatrist based in Chicago, Dr Helen Morrison, has studied and interviewed 135 serial killers, according to an infographic created by the website Best Counseling Degrees.
Morrison believes that in many cases the killers suffered a chromosome abnormality that led them to have an extra chromosome in their DNA.
For example Bobby Joe Long, who sexually assaulted and murdered at least 10 women in the Tampa Bay area and is currently on death row in Florida , had an extra X Chromosome.
This hormonal imbalance led to his body creating excessive amounts of oestrogen which began to cause him embarrassment and anger during puberty when he developed breasts.
Similarly Richard Speck, who tortured, raped and murdered eight student nurses in Chicago, had an extra Y chromosome.
Dr Morrison said another development factor in serial killers was a sense of detachment from the rest of the world from a very early age. Which ultimately leads them lacking empathy for their victims.
Research by Professor Jim Fallon, a neuroscientist at the University of California, Irvine, has been using brain imaging to study the brains of psychopaths.
He discovered low activity in the brain’s frontal lobes seems to be involved in sociopathic behaviours and may cause serial killers trouble in suppressing their rage and violence.
His work has dramatically revealed that some people appear to be hard wired towards violence. While testing the DNA of his family Professor Fallon identified a gene known as the MAO-A gene, which is also known as the ‘warrior gene.’ and regulates the mood in the brain. Most interestingly he discovered that he had all the genetic qualifiers of a psycopath, so why didn’t he turn out a serial killer?
Fallon believes that serial killers experience a ‘trigger’, like a traumatic childhood event which combines with other factors to turn ‘turn on’ their violent impulses.
Writing in The Guardian, Professor Fallon said:
Why, in the light of the fact I have all of the biological markers for psychopathy, including a turned off limbic system, the high risk genetic alleles, and the attendant behaviours, including well over half of those listed in the psychopathy tests and low emotional empathy, did I turn out to be a successful professor and family man?
One most likely reason is that although I have the genetic makeup of a “born” psychopath, some of those very same “risk” genes in someone showered with love (versus abuse or abandonment), from childbirth through the critical first few years of life, appear to offset the psychopathy-inducing effects of the other “risk” genes.
It is hoped that this research may make it easier to identify and catch serial killers in the future.