Criminology, Genetics, Social Science
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Is Crime Genetic? Scientists Don’t Know Because They’re Afraid to Ask

The U.S. has made unprecedented strides in the fight against crime. Both violent and non-violent crime are way down from their highs in decades past. This is great news, of course, but the success could easily lull us into a false sense of security, believing that we have the problem solved. Indeed, what if much of what we know about the causes of crime is either deeply flawed or flat out wrong?

Imagine the trial of a new drug for an ailment that is as intractable as it is lethal. Researchers find 100 people with the disease and give the new drug to the first 50 patients who show up to the clinic. The next 50 trial participants are placed into a control group and given no treatment. The drug has a truly shimmering success rate.

As you may have guessed, problems abound with this experimental design. For starters, because it isn’t randomized and because preexisting differences among the participants aren’t taken into account, the study can’t answer the question: Did the new drug cause anyone to get better? Such a study would be laughed out of the medical research community. And yet much of the knowledge concerning the causes of crime (as well as a host of other issues in the social sciences) stems from designs that aren’t much better than the poorly executed drug trial example.

Social scientists generally, and criminologists especially, often lack the ability (usually due to both ethical and practical concerns) to perform randomized controlled trials, the gold standard of research. We might expect, for instance, that having low levels of self-control is a cause of criminal behavior. In fact, some of the most powerful explanations of crime have been built on this idea, and there is much evidence to support it. We might also hypothesize that bad parenting causes children to develop low levels of self-control. Yet we can’t randomly assign people to have different levels of self-control, and we most assuredly can’t randomly assign kids to parents. All of this is to say that criminologists may never know for sure whether parenting causes self-control and whether, in turn, self-control causes crime.

While criminologists typically can’t use randomized trials, they do use a variety of statistical methods to study parenting and self-control, and self-control and crime. They attempt to rule out the most likely alternative explanations for why bad parenting leads to less self-control and why less self-control leads to criminal behavior. This research has consistently revealed that parenting styles correlate with self-control development in children, and self-control in childhood predicts a variety of important outcomes, including criminal behavior. Criminologists make their living uncovering precisely these types of associations.

Yet these studies will never achieve the accuracy of a randomized controlled trial, because all of those factors, like self-control, delinquent peer affiliation, etc., are also, to some degree, heritable.

Ah, heritability. A term that is much maligned in disciplines like criminology and often serves as a wellspring of confusion. Humans differ in height, weight, personality style, and behavioral tendencies — not everyone is nice and outgoing, just like not everyone is as tall as a professional basketball player. But here’s the important part, heritability has to do with the origins of these differences. To say that something is heritable is to say that genetic differences play a role in creating observable differences.

Variety in our gene pool matters when we seek to understand why some people can dunk a basketball or compose a sonnet, and why some people persistently break the law. The effects of genetic differences make some people more impulsive and shortsighted than others, some people more healthy or infirm than others, and, despite how uncomfortable it might be to admit, genes also make some folks more likely to break the law than others.

The hypothetical drug trial didn’t do a good job of accounting for everything that might explain differences between the treatment and control group participants, which opened the door to alternative explanations for why participants in the treatment group got better. In a similar vein, the finding that most human outcomes are heritable means that studies of behavior should account for heritability in order to rule it out as an alternative explanation.

Imagine that you’re curious whether certain parenting styles influence self-control in children. It’s not hard to find evidence that the way parents treat their children is associated with the child’s level of self-control later in life. But parents don’t just pass on life lessons for learning self-control to their kids, they also pass along their genetic material. Half of your genetic material was inherited from Mom and half came from Dad. If you ignore the element of genetic transmission, you might falsely attribute any correlation between parent and child as being due to social transmission.

The way parents treat children is, in part, a product of their own personality and temperament. Personality is partly heritable, so the observation that parents and children tend to have similar levels of self-control could be due to social transmission, genetic transmission, or both.

Most of the evidence about the causes of crime overlooks genetic transmission. Yet, some research has found that once you account for genetic influences on self-control, previously identified social transmission effects (read: parenting) on the child’s self-control become unstable. In other words, when you control for genetic transmission (the alternative explanation that most criminologists overlook), the effect of parenting on self-control diminishes or goes away entirely.

Consider another type of parenting effect — one that shows up in the news frequently — spanking. Not long ago, we examined the relationship between spanking and behavioral problems in children. Once we controlled for genetic transmission, there was no spanking effect in the way that most scholars think about spanking effects. Put another way, our evidence did not support the conclusion that spanking causes behavioral problems in the sense that most psychologists would argue.

The conundrum of heritability transcends parenting. For instance, it’s obvious that crime isn’t randomly distributed across neighborhoods. It seems to be a relatively stable factor that defines an area over many generations. Equally nonrandom, though, is the process by which people sort themselves into neighborhoods. People cluster into areas based on a host of factors, including the primary factor of income. Here’s the kicker, if any of the traits that affect residential choices are heritable and you ignore that influence, your findings regarding the impact of neighborhood factors on crime could be in jeopardy.

A remarkable study in Sweden recently found that highly disadvantaged neighborhoods had more crime. Yet that neighborhood effect disappeared when risk factors concentrated within certain families were taken into account. Once again, social transmission effects weakened (and, in this case disappeared) when other factors like genetic transmission were controlled for. Does this finding guarantee that similar results will emerge in other samples around the world? No. But criminologists rarely consider the possibility that their own studies could be polluted by hidden genetic effects.

The more technical term for this phenomenon is genetic confounding, and there is reason to believe that it is endemic to much of the research coming out of the social sciences in general, and criminology in particular. Our own research into the issue suggests that even a modest amount of unmeasured genetic influence can pollute and infect your findings. As a result, much of what we think we know about the causes of crime could be overstated or just flat wrong.

Our goal here is not to pick on social scientists; after all, we are social scientists. But social scientists in general, and criminologists in particular, should embrace research designs that allow one to account for genetic confounding. To do so, it will be necessary to adopt designs capable of pulling apart genetic and environmental factors. This translates into a need to analyze data from relatives.

Sampling one child, from one family — as social scientists typically do — is similar to performing a weak drug trial. For decades, behavior geneticists have been analyzing sibling data (mostly twins), which is one of the most powerful methods for probing the relationship between two variables.

Yet most criminologists do not utilize these designs. Not for any good methodological reason, at least none of which we are aware. Instead, it seems that the word “gene” makes social scientists nauseated. Not long ago, in fact, the top journal in the field of criminology published an article calling for an end to twin studies. Let that resonate a moment. There was an actual call to remove a perfectly good research technique from the field, one that also happens to be exceedingly valuable when trying to rule out widespread problems like genetic confounding.

If criminology and the social sciences wish to continue maturing into powerful scientific enterprises, we must stop conducting studies like they are bad drug trials.

 

Brian Boutwell is an Associate Professor of Criminology and Criminal Justice at Saint Louis University. Follow him on Twitter @fsnole1

J.C. Barnes is an Associate Professor of Criminology and Criminal Justice at the University of Cincinnati.

This article was originally published in the Boston Globe.

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27 Comments

  1. Samedi says

    I suspect the the aversion to twin studies and genetic explanations comes, at least in part, from its association with “determinism”. Their reasoning may go something like this, “If X is true then that is deterministic, but determinism is bad so X cannot be true.”

    Genetic causality is not the only taboo in the social sciences. Social class is also taboo. I haven’t seen social class included among potential causes in any recent sociological study. Of course, it is also very hard to measure so I imagine that is also a reason for its absence. I suspect social class is also a major confounder.

    Social scientists do not have an easy task. Their domain involves highly complex environmental, genetic, and cultural factors. Hopefully, empirical research methodologies will emerge that can properly account for the variety of contributory factors and replace the ideology-driven goals which frequently dominate the research.

  2. Is Crime Genetic?

    No, certain dispositions and behavioral patterns have a heritable component which absorbs some of the variation in their manifestation.

  3. Individuals and societies treat people differently based on how they look. This factor trips up gender and race studies, as well as studies of hair-color, facial symmetry, and so on.

    To create a control for this, you would have to find a society to raise kids in which is literally physically blind. Tallness correlates to confidence and popularity, and this is due at least somewhat to the way people defer to the tall (especially tall men).

    This type of effect won’t be easy to ferret out within a single society, even if you try to control for nature vs nurture causality such as twin studies.

    You literally have to combine data from different decades & continents – and even here, there are probably strong concepts and prejudices which are consistent among the mileu under consideration and can’t be filtered out as if controlled.

    If certain ethnicities are pushed to areas where they are exposed to higher stress, crime, and pollutants such as lead paint, it stands to reason that their children will have some predisposition to lesser cerebral functioning regardless of any specific genetic vector.

    • everlastingphelps says

      “Stands to reason” is always a “red siren blaring klaxon” warning word when dealing with science. Standing to reason is just the first step — forming a hypothesis. It then has to be tested. The testing has been done, and it shows that the logic doesn’t hold. There is no effect on crime rates. More importantly, the hypothesis is falsified in that these factors don’t effect OTHER ethnicities to cause them to come anywhere near the criminality of our “certain ethnicities.”

      That you aren’t even willing to call “certain ethnicities” black is the primary reason that we can’t get good science on this subject.

  4. Rex Mars says

    How, exactly, does a gene know what a “law” is let alone predispose a person to break it?

    For this to be a credible argument, you must first define what you understand a gene to be. My understanding is that genes are molecular sequences that encode for proteins. That’s it. There are now an exorbitant amount of steps required to even get to the basic biological elements that compose a human body, let alone the complex mechanics of human behavior.

    You can’t just assert the existence of a “genetic predisposition” for “breaking the law” (itself a mutable concept) without breaking down and detailing the mechanism by which that would work. Otherwise, it sounds an awful lot like you’re talking about “essence” which is just a hop and a skip left of appeals to the supernatural and immaterial “soul.”

    To be clear, I’m not asserting outright that genes play absolutely zero role in our psychological development, but I do think in order for this to be a credible argument you must establish a clear chain of causality between how an assortment of DNA molecules compounds to have a distinct influence over the choices and behavior of an individual. Simply asserting that “parents pass on their personality traits” because we also observe how parents pass on physical features needs an incredible amount of rigorous, molecular level evidence and elaboration. It can’t simply be stated as self-evident.

    Furthermore, you must isolate that sequence of events from the not-trivial influence of external and cultural factors. Making appeals to notions of “self-control” can’t be useful if you don’t first establish what “self-control” means in a specific context. Do you simply mean “an inability to follow rules when faced with a consequence?” In that case, any and all rejection of authoritarianism would be considered a “lack of self-control” and those who resist a dictator may, on paper, be technical “criminals” but few believers in democracy would seriously label them as having a “genetic defect” which predisposes them to behave that way. Even if they did, the context in which that “criminality” is expressed and what its ultimate effects are vastly differ from other forms of crime like theft, rape and murder.

    The assertion that genes—in the end mere molecules—have a direct correlation with man-made political and social constructs like law and order is an extraordinary claim, and as such requires extraordinary evidence.

    • Lawrence says

      The theory of evolution requires that genes affect behavior. If they did not, then mutations in genes could not lead to more or less fit behaviors, which could be subject to natural selection.

      Yes, connecting the dots from a string of proteins, to a person’s inability to control anti-social impulses is very difficult, and has not been done. So, yes it is possible those dots are not there. But if they are not, a huge amount of biological science is back to the drawing-board, because they now have to explain animal behavior without reference to genes, and consequently, evolution.

    • Um, what? Rex, you either don’t understand biology, or you are deliberately trying to muddle the issue, because you don’t like the implications of genetics. There is tremendous evidence that “molecular sequences that encode for proteins” lead to differences in observable phenotypes, including physical characteristics and behaviors. In fact, every single trait we observe (from eye color to complex behaviors) is reducible to genes–because that’s what we “are” in a deep, fundamental sense. We can see this obviously in the many, many diseases that are caused by single mutations in genetic sequences. There are literally many thousands of studies demonstrating that mental illnesses are deeply related to molecular biochemistry and ultimately genetics.

      The notion that genetics leads to behavior is literally the opposite of “essence” or “soul”. Those are both non-verifiable concepts. Genes are physical entities we can measure and change. If you think it’s a leap of faith to believe that changes in molecular sequences lead to changes in organismal behavior, then you just don’t understand biology.

      You say, “for this to be a credible argument you must establish a clear chain of causality between how an assortment of DNA molecules compounds to have a distinct influence over the choices and behavior of an individual.” But are you simply unaware of neuroscience? We know, from many many studies, that genetic differences lead to huge differences in biochemistry–for example genetic changes can alter production of signaling molecules, or receptor proteins for those signals…a single genetic change can result in dopamine receptors that have low affinity for dopamine, and thus make an individual less sensitive, which changes the brain and thus behavior. That’s why adding chemicals (drugs, both legal and not) lead to changes in behavior. Do you have a problem with the notion that “molecules” in drugs alter human behavior? If so, then your opinions aren’t based on science. If not, then maybe you just don’t understand that changes in DNA molecules lead to changes in the molecules our body produces (both proteins and the products of enzymes), which are the basis of our biochemistry, and thus all of our behaviors.

      Of course there’s a complicated relationship between behavior and criminality, and there’s an arbitrary social component to all of it (societies decide what’s ‘criminal’) but that’s not really relevant. You can get as fancy as you want with sociological notions, but you can’t refute the repeatedly observed fact that changes to genetics change human behavior. If those behavioral changes result in people who have less compassion, self control, or whatever, they will result in behaviors than nearly all societies consider ‘criminal’.

  5. David Drumright says

    “How, exactly, does a gene know what a “law” is let alone predispose a person to break it?”

    You’re missing a crucial point, which the author also misses. Breaking a law and being a criminal are only vaguely correlated actions.

    Professional criminals are a distinct class, innately devoted to taking and harming. When given a choice between honest and dishonest ways to get something, the pro criminal will pick the dishonest way even when it takes more work and risk.

    Written laws, especially in modern Western countries, have very little connection with natural law. Laws penalize unfashionable behavior, or penalize actions that compete with the authority and greed of bureaucrats and corporations. People who break written laws are often more honest than people who don’t break written laws.

  6. JunkMan says

    Back in the 70’s my brother married quickly a woman who’s family has a history of criminality. He had 2 children with her (male/female). They divorced; she had 2 more fathered by different men. She went on to become a petty criminal, homeless, and abandoned her kids. Older brother stepped in and tried to raise the last two children. But it didn’t matter. They all exhibited deviant behavior as children and nothing ever changed.

    ALL of these people are older now and have been in constant trouble with the law. They simple have no impulse control, despite being taught otherwise and raised with some sense of values. They continually lie non-stop about everything, steal, use heavy drugs, are felons and have ruined the lives of all around them. And now they’re passing it down to their children.

    After 4 decades of this, there is no doubt in any of my family members that our initial fears about the future of these children from back in the late 70/80’s (and now their children) are forever confirmed. Genetics won, and will continue to win. Appears that good parenting really doesn’t matter if such people are predisposed to think and act like criminals.

    Words cannot express what misery these 4 people have brought to my family, and the costs to my parents, who suffered so much after sacrificing everything to give us opportunities in life. What should been a great middle-age time of family gatherings was always marred by the intrusion of dealing with the never-ending criminality of 4 incredibly selfish people.

    There’s a reason parents should ask questions about those their children would breed with.

  7. Way, way too many variables to control.

    Scientists (not the dabblers in the social ‘sciences’) are not ‘afraid to ask’. What a silly headline. Sime in the social sciences might be reluctant to ask because these are captives of political correctness.

  8. gospace says

    There have always been people who have been identified at very young ages as being “bad eggs”. People from good families, people from bad families. When they finally do something bad enough to warrant arrest and punishment, nobody goes, “Oh, what went wrong? He was a good kid!” Instead they go, “Well, he finally did it.” If you think back on your own life, you probably knew one of these people in kindergarten. I know I did. I can remember him still today, and I’m in my 60s.

    But then, in most small towns, there’s a family that no one who knows anything ever expect anyone to come out of without a criminal record. Got such a family around the block from me now. In those cases, arguing whether it’s genetics or memetics is pointless. If mom sends her 8 year old into a store to shoplift after showing where to hide something, how do you expect the kid to turn out? And yes, that happens. You know the kid isn’t in church on Sunday learning the 10 Commandments.

  9. Jim Kerns says

    Family cultural attitudes towards crime, work, ethics and other people in their community seems to be as strong a distinguishing feature as many other possibilities like class or genetics. Family culture is also not dealt with in social research. It’s a dangerous topic in a world that wants to embrace there being no right or wrong and rewarding every family culture as ok.
    Different localized family cultural clusters(not based on genetics heritage whatsoever) create tremendously different communities and outcomes. Cultural imprinting happens very early in a child’s life.
    Sure, some people’s genetics make them stronger or weaker in many areas. But I still think a person is affected more strongly by the choices they make, often in an underlying pattern based on their original families actions and beliefs than by economic class. People that come from a higher economic, social or academic class, often lose it all and continue to raise children to be just as successful as if there had been no setback. Is this culture or genetics?

    • Samedi says

      “Is this culture or genetics?” Why not both? I think the point of this article was that heritability could play a role in criminality just as it does in other areas and is therefore worth studying. And, that excluding it for political reasons is not good science. The book, “The Nurture Assumption”, addresses the topic of family culture along with heritability .

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  11. To think that one can adjudicate causal factors of thinking and acting is to already transcend those factors to some extent in order to decide the truth of the matter—and in a causally self-exempted way.

    As David Berlinski asked: Is a person’s capacity to believe in molecular genetics linked to a brain chemical? lol

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