Psychology of Murder

Nature and Nurture: The Origins of Violence

There are so many aspects of human behaviour that still baffle us as researchers, scientists and psychologists.  Why some people exhibit violent and aggressive behaviour where others are entirely passive and non-violent is a question that has received particular attention. In searching for answers on the origins of violence, the debate of nature and nurture revolves at the center.

Nature vs Nurture

As humans we are all made up of genetics; genes, cells, DNA, neurotransmitters and we know that this biological make-up can operate differently across individuals.  This is the ‘nature’ aspect of the debate.  Those factors that are uncontrolled by us, things that we cannot choose or in theory influence, and these have a significant impact on our behaviour and how our minds work.

On the other side are the environmental aspects, the ‘nurture’ side where what we have experienced in our lives, the lessons and influences on us as we were growing up which includes the environment we were brought up in, and how our parents treated and provided for us, shapes us as individuals.

More personal aspects come into play here; whether we receive love as children or whether we were neglected. Whether our home and social environment was nurturing and beneficial for learning those key parts of humanity; empathy, care, sympathy, love or whether we were surrounded by violence, neglect and abuse.

Which one of these, nature or nurture, is more important for shaping us as adults and driving our behaviour?

For decades psychologists have argued over these two umbrella terms and what they signify.  You have the more scientifically driven who place their belief in nature, in genetics and biology, as the most significant and influential driving force.

Related: Can Criminal Behavior Be Predicted Using Brain Scans?

If there are faults in this biology, connections that are just not there, genes which predispose a person to violent behaviour, areas of the brain which have not developed fully or have developed abnormally then these, and these alone, are responsible for the behaviours displayed. Furthermore, if these are present then an individual is on a crash course.  They are essentially ‘born evil’ and there is little that could have been or could now be done to change it.

Alternatively there is the belief that we are all born with basically the same mechanics. We all have a blueprint that we start with biologically and none of it can be considered evil at the starting line. This belief advocates that the reason some are violent and some are not is down to environmental factors, external influences which have moulded an individual.

“I don’t deny the importance of genetics.  However, the fact that I might be altruistic isn’t because I have a gene for altruism; the fact that I do something for my children at some cost to myself comes from a history that has operated on me.”– B.F. Skinner

The development of a child is an extremely important stage which no one can deny. How a child learns what is appropriate behaviour and what isn’t, how to regulate their own behaviour and emotional responses to others, along with appropriate social behaviours is through the environment they develop in.  These examples are set by others; the behaviours they witness as a child are significant.

Imagine, a child who grows up in a household with no rules and no boundaries, with parents who pay them little attention,  who are involved in criminal behaviour, who mix with others of a similar ilk. This is what a child thinks is ‘normal’.  The behaviours they witness, the possible violence, the lack of caring they experience is what they internalize into their own psyche and into their own developing personalities.

In comparison, a child who is loved, whose parents provide care and support, engage in play and activities to teach them how to share, to teach them others have feelings, moulds an entirely different normality for that child and this is more than likely the developmental path they will follow.

Related: Teenage Brain Development and Criminal Consequences


Sociology and psychology film producer and author Chris Livesey has recently directed a documentary film featuring Professor James Fallon and exploring his research, his discoveries and what this means for our understanding of criminal behaviour, violence and aggression and the nature-nurture debate.

It is an excellent film, breaking down the components in a complex debate and explaining their significance.  It is an opportunity to listen to Professor Fallon discuss his work and this theories in his own words, giving a real insight into the current thinking in this field of research at this time.

Furthermore, this film from Short Cuts TV reveals his thoughts on how nurture may in fact be able to change nature, alter those genes and biological factors and ignite them in a way which can have devastating consequences.

Nature and Nurture?

It has become apparent in recent years that a more accurate picture of what makes up an individual and the influencing factors on behaviour are a combination of nature and nurture rather than one or the other.

Genes and biological brain development do influence a developing mind as does how a person grows up and those external influences and experiences they develop within.  While this combined perspective and theory sounds more reasonable and more appropriate, the mechanics of how this works is still something which has not become clear.

Advancements in technology has helped greatly in this search for answers into the roots and origins of human behaviour, particularly when it comes to criminal behaviour, violent aggression and the acts against others which are especially brutal.  This is why the behaviours of serial killers can often be at the center of these investigations.

Multiple murderers represent individuals in society who appear to have no conscience.  They do not seem to feel anything for their victims and they have the capacity in many cases to carry out cruel and brutal acts to the clear distress and pain of those they are hurting.

Some get a kick out of this behaviour; they enjoy inflicting pain on their victims.  Many enjoy the fear that their victim displays when they have been captured and realize what is about to happen to them.  Not only can these individuals carry out these acts, they do so repeatedly.

“Greed is a bottomless pit which exhausts the person in an endless effort to satisfy the need without ever reaching satisfaction” – Erich Fromm

They are not repelled or repulsed by their behaviour, they are curious and keen to carry it out again to achieve the same feelings they got the first time. The idea that multiple murderers may have some form of addiction to killing has been suggested, almost akin to a drug or alcohol addiction.  The act of killing and the particular way they carry out the murder gives them an emotional reward of some kind. For some this may be a feeling of power, for others it is a sexual gratification.

It is clear that it is not the same for all killers, it varies just as their modus operandi and signatures differ. These individuals are a sample pool of humans where their psychology and now it appears their biological make-up, is most probably flawed.  Something has gone wrong somewhere and we want to know what it is.

Related: Clutches of Madness: The Real Faces of Serial Killers [Book Review]

As the above film demonstrates, the research of Professor James Fallon has been very influential in this field.  A geneticist in origin, Fallon found himself studying the brain scans of individuals in search of markers for Alzheimer’s disease and in doing so he became somewhat of an expert on the analysis of brain patterns and the interpretation of brain scans.  Inevitably along the line he was asked to review the brain scans of a large sample of criminals, most of whom were convicted serial killers and many were hoping a default in their brain would equal exoneration from responsibility for their crimes, or at least ensure they avoided the death penalty.

What Professor Fallon found was especially interesting and it was novel.  He found distinct brain patterns on MRI scans for serial killers compared to non-serial killers.  All had the same pattern, a pattern which suggested a lack of activity in the frontal lobe area of the brain.  Being so consistent across his sample this is a finding which was begging to be followed up and explored further.

Professor Fallon’s book ‘The Psychopath Inside’ is quite a fascinating read.  A book which is a documentation of his life, study and career on one side and a journey of discovery about his own brain, personality and behaviours on the other.

For a man who had dedicated his life to science and was very much of the opinion that our behaviours as humans were at least 80% due to our genetics and biology and entirely from nature, this journey and his discoveries came as quite a shock. A shock not only personally but professionally, resulting in a back tracking of his original theories and a development of new ones very much incorporating and giving great weight to the nurture side of the nature-nurture debate.

“What is necessary to change a person is to change his awareness of himself” – Abraham Maslow

Anyone who his familiar with Fallon’s research will know the surprising discovery he made about his own brain. A discovery that his brain pattern matched the brain patterns of the serial killers he had been studying. A pattern that he had found to be consistent with violent psychopaths who can and have done great harm to others.  While this came as a surprise it also came with an air of curiosity. If he had the same brain pattern, the same lack of activity in those frontal areas of the brain which by his own theory was a strong signal that the owner of that brain was a psychopath with violent tendencies, then why wasn’t he a serial killer?  Why didn’t he have a history of violence against others?

This proved that such brain patterns alone and therefore biology alone cannot account for these types of behaviours and why these individuals are as they are. As a further route of investigation he checked his genes, his genetic code, to see if he had the gene set that indicate a predisposition for violence (the so-called ‘warrior gene’) and found once again he was the odd one out in his sample.

It was his genetics which showed these markers, but again if he had the genetics and the biological brain patterns, why wasn’t he a serial murderer?

These are some of the key questions that Professor James Fallon and his colleagues within neuroscience, psychology and criminology are trying to answer and they are unlikely to be answered soon. However, the impact of these findings are clear; the nature vs nurture debate has transformed into a nature and nurture interaction.  An interrelationship which may hold the key to why some individuals display such violent aggression.  The potential of these research findings, these new theories on nature and nurture is substantial and it is exciting.  Modern science and research is taking us one step closer to that understanding of human behaviour which many have been searching for.

To cite this article: Guy, F. (2016, May 16) Nature and Nurture: The Origins of Violence. Crime Traveller. Retrieved from


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  • I wonder how much research has been done looking at serial killers for example and their childhoods. I guess most of them had a background that could explain their behaviour. If they have genetics and biology that is wrong in the first place then add possible abuse and violence into the equation it is not surprising they have grown up showing some very nasty behaviour towards others. Interesting area of research.

  • Hi Jina, thank you, I am glad you are enjoying the site and posts. If you would like to keep up to date with new posts and articles, you can sign up to the monthly newsletter ( which will deliver straight into your email inbox at the end of each month for free!

  • Thanks for stopping by Shelley! I do find the nature and nurture debate a fascinating topic and with the introduction now of new methods and techniques such as imaging and genetic testing, it will be interesting to see where it goes in the future.

  • In the research I did; I went back as far as I could exploring the childhood of a particular serial killer. There were a lot of missing pieces to the information available, but the childhood was terrible for that particular killer. I consider the nurture factor for a child not only to be that which he receives from his family, but from the other people in their lives as well, such as, teachers, classmates, and neighbors. I finally came to the conclusion that for whatever reason, that particular serial killer, had developed deviant coping mechanisms rather than normal coping mechanisms. I also decided that society had created the serial killer that was eventually unleashed upon them because of the things he endured during his childhood and early teen years included society as a whole.

  • Grrr, I have a blog on my website and it sucks. I actually removed it, but may have to bring it back. I was given by you motivation! Keep on writing!

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