Psychology of Crime: Why Do People Become Criminals?

Updated on January 11, 2018
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Anne has a BSc in Applied Psychology and has qualifications in counselling CBT & mindfulness. She teaches mindfulness workshops and courses.

Inside a Dublin Prison
Inside a Dublin Prison | Source

Psychological theories of crime

Many people have their own theories on what makes a criminal. Some of these theories are based on first hand knowledge or experience, some unfortunately may be based on racism or prejudice, and some on scientifically investigated studies.

And there are several psychological theories of crime, most of which have been shown to have a sound scientific basis. However, it is widely accepted that the reasons for crime are seldom one cause or the other, but rather a combination of some.

Biological Theories of Crime

These include genetics, hormones, brain chemistry (neurotransmitters) and brain structure and anatomy.


Because statistically more males commit crimes than females, it was proposed that this must be because of the genetic make-up of males. However, this theory has been largely discredited[1]

Twin studies and crime

But studies with twins have shown that identical twins are more likely to share criminal tendencies than non-identical (or fraternal) twins. This was the case even when identical twins were separated at birth, so environment or upbringing would not necessarily have been a factor [2].

Even so, some psychologists still believe that this is not conclusive evidence of a genetic link.[1]

Brain Chemistry.

Serotonin is a neurotransmitter in the brain that affect mood, which in turn can affect criminal behaviour. Testosterone, the male hormone, is linked to levels of aggression. Omega 3 has been shown to lower levels of aggression, and poor nutrition before the age of 3 has also been linked to higher levels of aggression. All of these come under the heading of Brain Chemistry and all have a link to criminal behaviour.

The Amygdala
The Amygdala | Source

Brain Structure and Anatomy:

The part of the brain associated with or emotions is called the Amygdala (am-ig-d-la). It is believed that damage to the Amygdala can have an effect of criminal behavior. [3] This may be because the person concerned would have a limited fear and conditioning response, thus fear of punishment would not deter them from committing a crime.

The Hippocampus is where we store our memories. Damage to this area could mean we do not remember being punished from our crimes, and so would commit them again and again.

The Frontal Cortex, as the name suggests, is to the front of our brain and would also appear to be involved, among other functions, with our self control-as one famous case-study showed:

Phineas Gage.

The most famous case of brain damage causing a change in self-control is one of a man called Phineas Gage. In 1848, Phineas was a mild-mannered and conscientious railroad worker foreman in Vermont, U.S. He was overseeing the laying of explosives one fateful day. It was the practice to lay sand over the explosives in a hole and then to tap it down with a tamping iron. Phineas was using the tamping iron, which was 3’8” long and 1.5” in diameter, when a spark ignited the explosive and sent the tamping iron straight through his left cheek and out through the frontal cortex, landing several feet behind him. Incredibly, Phineas not only survived, but walked to the cart which was to transport him to a doctor.

Actual Skull of Phineas Gage. Bottom left is the tamping iron shown beside the skull.
Actual Skull of Phineas Gage. Bottom left is the tamping iron shown beside the skull. | Source

"No Longer Gage"

While Phineas later appeared to have made a full recovery, those who knew him before hand said that he was “No longer Gage” He was no longer mild mannered and conscientious, but became verbally aggressive and abusive, unreliable in his work and impatient and impulsive to the extent that the railroad company could no longer employ him.

Was it the brain damage that caused the change?

It appeared that the damage to the frontal cortex caused the change in Phineas. However, it must also be remembered that brain damage also has the potential to cause depression, and that there was also a possibility that Phineas would have suffered from Post Traumatic Stress, either of which could also cause changes in his personal disposition.

Socialisation theories of crime

These include Learning Theories such as:

  • Classical Conditioning-the famous example being Pavlov’s Dogs, in which Pavlov trained the dogs to salivate at the sound of a bell.
  • Operant Conditioning-The Skinner Box, developed by B.F Skinner (who else?) in which he trained rats to press (or ‘operate’) levers in order to get to their food.
  • Observational Learning-“Monkey see-Monkey do”

But humans are not dogs, rats or monkeys. However, it would seem that we do learn by similar methods. If a child is surrounded by crime, either within the family or the community, they are likely to learn criminal behaviour by any or all of the above methods.

A child can learn to get what he wants by other means. (This child is an actor and is now an adult-picture printed with his permission)
A child can learn to get what he wants by other means. (This child is an actor and is now an adult-picture printed with his permission) | Source

Routine Activity Theory

This can tie-in somewhat with Learning Activity; for example, if a child learns that stealing is one way to get what they want, they will do it again. All they need is for three elements to be in place:

1.Motivation: They want something

2.Suitable Target: They see what they want

3.Absence of Guardians: And there’s no one about

They get away with it, and do it again and again, until it becomes routine [4].

Strain Theory:

This is probably one of the best known psychological theories of crime.

A person really wants something, such as material goods, a better lifestyle or even an education, but they can see no possible way of ever achieving it now or in the future. This understandably causes dissatisfaction, perhaps even resentment against the people who do have what they want.

But then they see there is a way to achieve their desires through stealing, drug dealing or other criminal behaviour [5].

Control Theory:

A Marxist theory, which says that the Criminal Justice System is seen as being developed by the dominant classes to the sole advantage of the dominant classes, causing resentment and rebellion. [6]

An ambulance is not penalised for breaking the speed limit.
An ambulance is not penalised for breaking the speed limit. | Source

Social Construction Theory of Crime

Each society has their own view of what is and is not a crime: For example, in Saudi Arabia, public displays of affection are illegal.

Circumstance can also change whether certain behavior is a crime or not. For example, a Police car or an Ambulance may break the speed limit without suffering a penalty.

Society’s view of crime can also change with time; for example, Prohibition, Homosexuality, and more recently, Cyber crimes.

Just some of the theories

These are just some of the more well-known psychological theories of crime.

If you want to learn more, I suggest you consult any good textbook on forensic or criminal psychology.

Meanwhile, take a look at the video below for Rational Choice theory..


[1] Howit, D., (2009), Introduction to forensic and criminal psychology (3rd ed) Harlow, UK, Pearson Education.

[2] Viding, E., Blair, R. R., Moffitt, T. E., & Plomin, R. (2005). Evidence for substantial genetic risk for psychopathy in 7-year-olds. Journal Of Child Psychology & Psychiatry, 46(6), 592-597. doi:10.1111/j.1469-7610.2004.00393.x

[3] Raine, A. (2008). From Genes to Brain to Antisocial Behavior. Current Directions In Psychological Science (Wiley-Blackwell), 17(5), 323-328. doi:10.1111/j.1467-8721.2008.00599.x

[4]Clarke, R. V., & Felson, M. (1993). Routine activity and rational choice. Piscataway, NJ US: Transaction Publishers

[5] Agnew, R. (1993). Why do they do it? An examination of the intervening mechanisms between "social control" variables and delinquency. Journal Of Research In Crime & Delinquency, 30(3), 245-266.

[6] Bonger, W. (1916) Crime and Economic Conditions. Boston. Little Brown.


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      Odhiambo Reagan 6 months ago

      How can you relate and apply sociology in criminology and security studies

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      Florence Emily 14 months ago

      This is a very interesting article. I completely agree with many of these topics and theories. One theory I suggest that I regard quite highly is the patronization of young children in the domestic home. I often find that when older children or verging teenagers are patronized, it invokes in them the response of resentment and inferiority, It also undermines their intelligence, especially whereby they are prone to feeling outbursts of rage at these indictments. Furthermore, being the youngest of five myself, I often feel uncontrolled rage and have a fabulous temper because of this. I therefore feel that in addition to these other theories, people might consider the simple act of how we show respect to children and what effects this may have on their feelings? I also thank you for this blog, it was very helpful in the construction of a project I have been working on.

    • annerivendell profile image

      annerivendell 3 years ago from Dublin, Ireland

      Hi Ifeanyi, Thank you for your comment. Apologies for taking so long in replying: As far as I know, Phineas Gage lived for about 11 years after the accident. He worked in various jobs, but eventually developed severe epilepsy and died during a seizure. Interestingly, since writing this hub, I came across another article which disputed that Gage remained unreliable and unsociable ( Best of luck with your study.

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      ifeanyi 3 years ago

      thanks for ur thought ,,,,,this hub is really a development to my study and so fascinating.....

      please i wana know how many years phineas gage lasted on that brutal condition//????thanks

    • annerivendell profile image

      annerivendell 3 years ago from Dublin, Ireland

      Hi Salmon. What do you need to know, besides what's in the hub? I don't have any crime figures, if that's what you're looking for. Sounds like a fun project. Best of luck with it.

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      Salmon 3 years ago

      Hello. My class is doing a project on changing the world! I chose crime because that's mostly what I talk about (apart from Zombies, Chainsaws and Bloody Murders but anyhow) I would like to learn some more basic facts on crime please help! Laterz Salmon out!

    • annerivendell profile image

      annerivendell 4 years ago from Dublin, Ireland

      Sorry I only saw this commnet now, Cennai! Yes, I agree that family environment has been shown to bea contributing factor in crime.

    • mathira profile image

      mathira 4 years ago from chennai

      Lack of good family life also can make people turn towards violence as they have not experienced love or emotional security. Good hub, annerivendell.

    • annerivendell profile image

      annerivendell 5 years ago from Dublin, Ireland

      I absolutely LOVE TEDtalks! There hasn't been a boring or even indifferent speaker yet. As for poor Phineas Gage-remember that trephination was reputed to take place regularly at one time, (referred to in Philip Pullman's fantastic Trilogy, His Dark Materials, as Treepanning) and they've found skulls to "prove" it! Thank you for your comment.

    • PhilosopherPrince profile image

      Elliott Ploutz 5 years ago from Las Vegas, Nevada

      Gah. Phineas Gage. I was always really wary of his story, like you. It's not good to base theories on one popular example. However, I did hear that they found similar effects in other brain damaged and lobotomized individuals.

      If you haven't heard of it already, I want to tell you about TEDtalks! It's about experts in the field who talk about their research. There's an entire section on criminal psychology, theories, and sociology. I think you might find it interesting.

      Interesting hub!

    • annerivendell profile image

      annerivendell 5 years ago from Dublin, Ireland

      Thank you, Nettlemere. Yes, Phineas Gage is an amazing story. If you put his name into any search engine you'll get plenty of information. We learned about him in Freshman year Psychology, but I did remember hearing something about him before that.

    • Nettlemere profile image

      Nettlemere 5 years ago from Burnley, Lancashire, UK

      That tamping iron through the skull is phenomenal. Poor chap.

      Very interesting hub and well evidenced hub.