Brian Boutwell writes in the Boston Globe:
THE COUNTRY 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.
