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The Mystery Behind Serial Killing And How It Comes To Be

octubre 16, 2017

Brain scan could predict repeated criminal behavior.

Article written by the Psychologist: Natalie Ramos Clarkson.

Resultado de imagen de crime brain

Serial killing is a rare phenomenon of murder that continues to impact us more so than other cases of murder in which a motive is apparent. It is a phenomenon that first became recognized in the 20th century, and is seemingly one that will continue into the future. What distinguishes a serial murder from genuine murder is that it does not seem to be committed based on political, domestic or for reasons of profit as seen in other murder cases, it is an act committed by an individual who seems to have an increasing rage against some specific element or aspect of society (Innes, 2006). The Violent Criminal Apprehension Programme (VICAP) is a member of the FBI´s Behavioural Science Unit defines serial murderer as: “… a person who kills more than three victims, during more than three events, at more than three locations, with a cooling off period in between” (Holmes & Holmes, 2010). Serial murders account for the less than one percent of total murders in a given year and is more commonly seen in the US and South Africa. The US alone accounts for over three thirds of all serial murders in the total population, as of September 4, 2016, the database contains information on 4,743 serial killers and 13,105 victims1 of serial killers (Aamodt, 2016).

Who are the individuals who commit these types of murders and what are their motives?

Neuroscience Research conducted by psychologists in the area of serial killing suggests that there is a general consensus that the creation of a serial killer tends to lie in severe childhood neglect and physical and/ or abuse. Studies conducted by Fallon (1968) show that from a sample of 50 serial killers, 70 percent experienced some form of maltreatment (physical, sexual or emotional) and 50 percent experience psychological abuse growing up. Childhood experiences are key in the behavioural onset of a serial killer. This leads us to wonder, is there a way we can begin to identify the potential of a child in the formation of becoming a serial killer? Forensic Psychiatrist J.M McDonald (1963) proposed a triad of traits also known as the ´McDonald Triad’ seen in children that have later developed into notorious serial killers. Early symptoms shown were bedwetting, fire setting and cruelty to animals.

Fuente: MacDonald Triad of Serial Killers (1963)

This leads us to wonder whether there is a possibility that we can identify specific behavioural traits in children which can be aided towards the prevention of serial killing. However, unfortunately normal adults have also displayed these traits at given times and therefore it seems unlikely and henceforth almost impossible to be able to detect a serial killer in formation.


Research conducted through brain resonance imaging looks to identify the neurological functions and the subsequent neuroscience that is involved in the thought process of a serial killer. Dr. Helen Morrison studied and interviewed 135 serial killers and finds several chromosome abnormalities that can be seen across serial killers. Subsequently, Jimmy Fallon studies the minds of psychopaths for over 20 years to discover more specific neurological functioning in these types of perpetrators. He finds that there is low orbital cortex activity in a serial killer. What this means is the area of the brain that is believed to be involved in ethical behaviours and decision making, as well as impulse control means that it is more difficult for these individuals to control emotions such as rage, violence, eating, sex and drinking (Fallon, 1969). He also discovers a gene known as the MAO-A gene with is associative with that of criminal behavior. This gene is one that produces an enzyme called monoamine oxidase A, which serves to regulate levels of serotonin (mood levels) in the brain. “Men which lower MAO-A are three times more likely to commit a crime to be convicted of a violent crime than those who have high MAO-A activity (Allely et al. 2014).


An extra Y-chromosome has also been identified in cases of serial killing such as that of Arthur Shawcross and Bobby Joe Long. An extra Y chromosome leads to excessive amounts of oestregen in males. Bobby Joe Long suffered from this and caused him to grow breasts during adolescence leading to extreme anger and embarrassment. An extra Y chromosome in males can lead a male to hyper-masculinity, henceforth demonstrating excessive violence and other behaviours which can lead to behaviours which are noted in convicted serial killers (Fallon 1986 as cited in Gray 2016).

Head trauma has also been associated with criminal behavior. A study conducted by Stone (2009) suggested that one in four serial killers may have suffered severe head trauma or in other rare occasions a condition (such as meningitis) which may have affected the brain. Consequently, damage to the frontal lobe, hypothalamus and limbic system can be considered attributable to severe aggressive behavior.

How do they choose their victims? What are the chances of becoming a serial killer victim?

Resultado de imagen de serial killer

Fuente: Netflix.

Serial killers can often be very cunning in their crimes and very often opportunistic. Many tend to select victims such as prostitutes or homeless people- those who they might feel their disappearances will go undetected and elude police radar compared to those who come from loving families. It seems many serial killers have a vision of what their “ideal victim” is. When looking at victims of specific serial killers you tend to see that they have similar race, gender, physical characteristics and qualities. Unfortunately, encountering a serial killer tends to be the “wrong place at the wrong time” scenario, in which victims are swiped when the perpetrator sees it to be a fit opportunity. However, it is important to remember that from a population of 464 million individuals, you have a .00039% chance of becoming a serial killer victim (Rodgers, 2016). Therefore there is no need to panic!


Aamodt, M. G. (2016, September 4). Serial killer statistics. Retrieved (insert date of retrieval) from killer information center/project description.htm


From → Neurociencia

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