Psychology of criminals

Published 22 Feb 2017

It is a well-known fact that criminals exist. They are there, beside us, every minute, and we know that it so happens that sometimes people steal wallets, and a girl should not walk alone at night because a rapist might attack her, and at times people are murdered for no reason by serial killers. Nobody is safe, the media tells us, bringing us news of further disasters and crime. And we nod knowingly, accepting this fact as if it were natural. We are so used to the very fact of the existence of criminals, that we do not question it whatsoever.

However, we should. Community survival has reached its peak at the moment. Very few humans can survive on their own, without the aid of others. Doing harm to these others, then, eventually reduces the chances for one’s own survival – many criminals are intelligent enough to know that everyone makes mistakes eventually, that getting caught “comes with the territory” – and it is a well-known notion that no person will willingly do evil unto himself. He will either think of it as good of some kind or suffer, soon bringing his crimes to an end because of the pangs of consciousness. Thus, criminals – especially ones that do not one crime, but many – are an abnormality. So why would a person knowingly go against one of the most basic instincts? What can make humans undermine their own chances for survival?

There are many explanations for this abnormal behavior, as there are many traits that are found in criminals – and not all of them overlap all the time. The versions are, therefore, different combinations of these traits, putting emphasis on different similarities in criminals. As Shirley Lynn Scott says in her article “What makes them tick”, “And while many girls are victimized as children, very few grow up to be sadistically violent toward strangers.”(3)

Most experts agree that a complex of factors causes criminal behavior, including upbringing, inborn abnormalities, circumstance, et cetera. However, these factors generally fall into two categories: genotype (inborn) and phenotype (influence of circumstances). Both sets of factors cause criminal behavior; however, it is still unknown which is more determining in making a person into a criminal. We still know very little of what precisely makes people become criminals. As Detective Mark Godo points out in his article, “Bad to the Bone”:

“Criminological theories have gone through an evolutionary process that still continues today. For what seemed like a valid explanation during one era, bordered on the verge of madness the next. And there is probably no other aspect of social science that is so permeated with superstition, quackery, sensationalism and outright fraud as crime theory.” (2)

A prime component of the “nature versus nurture” debate is defining “nature” and “nurture”. By “nature” I define any factors that are inborn – from neurochemistry to certain traits of character. By “nurture” I define any factors that are acquired, be they psychological, social or physical. I will first examine the biological factor and “inborn” theories, and then the phenotype theories. They often overlap, circumstances sometimes producing factors that can be inborn, as well, and no single theory has so far given the motivation for all types of crimes – for instance, the so-called “white collar crimes” are very differently motivated than the crimes of mothers who kill their children. My thesis is that acquired factors cause criminal behavior more, and I will attempt to prove it by examining what is known to us about the reasons of criminal behavior, and show that the outside world influences a person more in general than their inborn predisposition – especially when it comes to abnormalities such as criminal behavior.

A number of important studies have been conducted on the biology of the crime. These also fall into two categories: genetic (twin studies, adoption studies and family studies) and biochemical studies. It must be noted on the latter that biochemical disorders are not only inborn, but can be acquired, as well, thus placing them in both categories. Caitlin M. Jones of the Rochester Institute of Technology details them in her paper “Genetic and Environmental Influences on Criminal Behavior”.

Let us take a look at the genetic studies first. The scientists examining these studies have come to conflicting conclusions. Some, like Tehrani and Mednick, conclude that genetics are the basis for criminal behavior; while others, like Lowenstein, think that there is not enough evidence to conclude that genetics play a role in criminal behavior. (1) However, it is now almost universally accepted that genetics do play a part in criminal behavior, and an important one, at that. This has been studied in a number of ways.

Twin studies (comparing sets of monozygotic twins to dizygotic twins when these twins have been reared apart to see whether there is a higher concordance rate between the identical twins than the fraternal) show that there is a 54% heritability for crime. Other studies done at the time, however, show that the concordance rate isn’t higher than the norm, and there has been evidence of selective research in the twin studies. Jeffrey C. Tatar, commenting on Jones’ article, writes about the newest statistics in twin studies:

“Statistics show a high concordance between identical and non-identical twins for schizophrenia and manic depression. Analysis of the statistics clearly show the genetic basis for these disorders: For schizophrenia the concordance in identical twins was 60%, compared to only 10% in non-identical twins, and the normal frequency being 1% in northern European populations. Similarly, manic depression showed a 70% concordance between identical twins, a 15% concordance between non-identical twins, and again only a 1% frequency in the normal population (Russo & Cove, 1995)” (1)

The adoptive studies of Tehrani and Mednick show that children adopted from incarcerated mothers had a higher crime rate as adults than the control group of children of normal parents given up for adoption. Another study in Denmark showed an interesting point that children whose biological fathers had engaged in property crimes were more likely to engage in similar behavior than those whose fathers had engaged in violent crimes. According to Jay Jones, the majority of researchers now agree that genes are a non-significant influence in violent crime; however, they may bear some influence in property crime. However, there has been no similar research for corporate crime, nor for many other kinds of offense.

Only a small number of family studies have been done so far. The reason is simple: it is very difficult to separate the “nature” aspect from the “nurture” aspect, even more difficult than in twin studies. The earliest studies, such as Dudgale’s study of the Juke family and Goddard’s studies of the Kallikak family have been proven selective, done mostly to prove the researcher’s own convictions. (2) However, Caitlin Jones takes note of a family study by Brunner, Nelen, Breakefield, Ropers, and van Oost, which seems to prove the role of a point mutation in one of the structural genes, influencing the criminal behavior of a number of males in the family. Jones also notes that no follow-up studies have been done yet, which leaves this question also open. (1)

The common problem with all of these studies is the difficulty of telling which of the criminals came from their genetic predisposition, and which were influenced by the environment to become one. This brings us to a number of cases which can be both inborn and acquired. This is the research on neurochemicals and psychological disorders.

There have been a number of studies done on neurochemicals influencing criminal behavior. Without going into the biochemical details, there is a number of substances (serotonin, dopamine, etc.) that, when applied, have a profound effect on the human psyche. These substances may be either applied from the outside (drug abuse is the most well-known instance, and there are numerous crimes done under the influence of drugs, especially alcohol, as in the case of Gacy, for instance)(3) or be synthesized in the body due to a chemical imbalance. The former falls under the “nurture” factors and will be discussed later, and we know very little about the latter – just about only that it happens, and that it can be treated by neutralizing these chemicals. Inborn brain damage falls into this category, however, brain damage can be acquired as well, as shown by the infamous case of Raymond Fernandez.(2)

As for the personality disorders, the relationship between them and criminal behavior has been long proven. Of special importance are three disorders: Conduct Disorder (CD), Attention Deficit Hyperactivity Disorder (ADHD), and Oppositional Defiance Disorder (ODD). What is interesting about these disorders is that they rarely manifest openly in adults; rather, they show in children. These disorders are inborn, theoretically placing criminals on which they have had an influence into the “nature” group. However, as Tatar points out, it is very difficult to distinguish what causes criminals to grow up from this group: is it the genetical difference, criminal activity being a logical development of the disease except in cases where nurture somehow removes the influence, or is it the fact that children with these disorders are usually treated differently, and their criminal behavior is a response to the environment. (1) Also, a predisposition towards a disorder does not a disorder truly make, like a predisposition towards criminal behavior does not yet make a criminal. There have been studies on the influence of other factors, such as television, on disorders, and they have found that the environment also influences these disorders and their severity.

Other disorders, which may or may not be inborn (such as schizophrenia, multiple personality disorder, major depressive disorder, et cetera), also play a relevant part. The rate of the mentally ill among criminals is much higher than among good civilians. What must be noted here is that for nearly any inborn disorder, a similar one can be created by the upbringing. This makes for another gray area in the study of the criminal mind, once again making it very difficult to distinguish which are inborn and which come from the environment. We know that the disorders are there, we do not know what they are more caused by.

Jones gives a proposed division between “primary” sociopaths and “secondary” sociopaths. Primary sociopaths are those who are afflicted mostly by physiological factors. Secondary are those who become sociopaths as a reaction to a hostile environment in which they cannot realize themselves for some reason or other. It seems this distinction can be extended to other kinds of crime, as well. (1)

The other category of factors is the “nurture” category – all acquired factors. As we have previously seen, nearly all instances of inborn disorders can be covered by the influence of environmental factors. However, there are also factors that are environmental-only. These are the sociological factors, which, too, have a dire influence on the behavior of criminals. These factors include upbringing and pressure from society around the person in question. This is only a seeming simplicity, because these two sets of factors are incredibly varied and widespread.

Upbringing plays a major factor in the making of a criminal. Statistics show that abusive families and those with poor connections between the family and the child or children are more likely to produce criminals than families which are well bound and connected. Neglecting a child or abusing a child physically or mentally harms the personality at its most vulnerable stages, producing unstable individuals likely to pursue crime for some reason or other. And not only the parents take a role in the rearing of a child – mass media does, as well. Statistically, a child before the age of 12 will have viewed 8,000 murders on television. (2) It seems impossible to deny that this has no effect on children. Also, the environment which children and adolescents are reared in is of primary importance to their social development – adults may choose the environment, whereas children and adolescents cannot. As such, they are even more subject to social pressure than adults are.

Social pressure is one of the most serious factors in causing criminal behavior. It takes mainly two forms, ones that I will for convenience call “internal” and “external” factors. Internal factors are a person’s private psychological reactions to the circumstances. The feeling of inadequacy, for instance, comes under these internal factors, when a person for some reason feels cheated out of the circumstances that others have – a classic case of jealousy. This is called anomie, a term coined by Merton. Another example of internal problems is when a person feels pushed to the end of his rope, pressured to do something, anything to get out of the desperate situation he feels himself in. An example of this case would be the case of Andrew Kehoe, who killed 42 children and injured 60 in a school explosion, because he had been pressured by the school board for years. On searching his farm, the police found a sign, which read: “criminals are made, not born.”(2) The common denominator in such cases is that the society does not actively pressure the person into doing wrong, unlike in “external” factors. The school board in Kehoe’s case surely had no idea that the man would crack under the circumstances – unlike in other instances.

External factors are instances when a group works actively to get a person to do an act, whether consciously or unconsciously. By “unconsciously” here is meant the so-called “mob” effect, when a group melds into a crowd – a group with one interest, no matter how temporary. Kimball Young in his book “Social Psychology: An Analysis of Social Behavior” gives an instance of “crowd action”:

“When there was potato shortage in Berlin I saw in a market place many hundreds of women waiting in line for potatoes. A farmer appeared driving a small wagon loaded with potatoes. He named a price for his potatoes which was beyond the means of the women. Quickly and spontaneously they raided the wagon, stripped it of potatoes, and dispersed before the police appeared.” (5)

It is extremely unlikely that these women would have been capable of the theft on their own. The group had one pressing interest: that was all it took at the time to commit a crime. This is unconscious pressure.

Conscious pressure is quite a different case. This is the very base of such things as gang dynamics, teenage peer pressure and such, where people go along with unlawful actions because the group wishes them to carry it out, and the victims are too weak-willed to resist. Dr. Francine Hallcom gives a quote from a gang member on her website: “Gustavo: “I’ve done a lot of stupid things just going along, you know? Things where I didn’t have no problem with someone, but one of the other vatos did and I helped. I went along with them just because I was there.” (4) Another common instance of active pressure is teenage peer pressure. As Alexandra Robbins writes in her book “Pledged: the Secret Life of Sororities”, there are instances of drug abuse and criminal behavior, simply because other teens wanted them to occur. For instance, when she attempted to go undercover to examine sororities, one of the initial responses shocked her. An adviser said to her: “And if for some reason they [National office of sororities] do [give you permission to write about sororities], I simply cannot allow you to write about the drugs.” (6)

As we can see, active pressure takes quite a part in criminal activity. It is very dangerous, because it permeates every level of our society, affecting not only teenagers, but adults, as well. Corporate crime is a good example of this: when people steal because it is not considered stealing per se, more like “business” and “making a profit”. The 2002 incident with Enron Corporation shows this sort of active pressure very well (2). None of us live completely out of society, thus, all of us live surrounded by this pressure. Only a small number of people become criminals, yet this is a massive factor, influencing almost everyone, and thus takes its toll on every sort of crime rate imaginable.

In conclusion, I would like to remember a story that is over two thousand years old. A physiognomic once had a look at Socrates, and then announced that this was a man with bad predispositions, and an inborn lack of virtue. Socrates’ friends and pupils were, of course, outraged over this statement – Socrates was one of the very paragons of virtue to them. However, when they began to contradict the physiognomic, Socrates himself calmly stopped them, and noted that the physiognomic is absolutely correct. The great philosopher said that he made himself what he was, despite his original bad inclinations. This is what, to me, it all seems to come down to.

Predispositions are just that; much more important are the active influences everyday life has on all of us – including the influences we make upon ourselves. As I have shown, there is clearly evidence for the reality of the inborn influence; however, this is not the factor which, in the end, makes a criminal. A criminal is made by a combination of factors, a complex interaction between predisposition and environment. However, even the man with the best predispositions can be made into a criminal by circumstance, and even the worst man can be taught to keep himself in his hands. Besides this, there are simply more factors that influence criminal behavior that are purely environmentally caused than there are purely genetically caused, making it statistically more important. Thus, I conclude that “nurture” is much more important than “nature” in this case.

Works cited

  • Caitlin M. Jones, Genetic and Environmental Influences on Criminal Behavior, (Including peer commentaries by Lisa C. Burt, Jeffrey C. Tatar and Maureen E. Wood) retrieved March 10, 2005, from
  • Mark Gado, Bad to the Bone, retrieved March 10, 2005
  • Shirley Lynn Scott, What Makes Serial Killers Tick, retrieved March 10, 2005
  • Dr. Francine Hallcom, An Urban Ethnography of Latino Street: Gangs in Los Angeles and Ventura Counties, retrieved March 10, 2005, from
  • Kimball Young, (1930) Social Psychology: An Analysis of Social Behavior, retrieved March 10, 2005
  • Alexandra Robbins, (2004), Pledged: the Secret Life of Sororities, retrieved March 10, 2005
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