As I was listending to all the recent news about mobster James “Whitey” Bulger, I felt both a personal, and a professional, connection. For years, I’ve shown my psychology classes the FBI’s “most wanted” poster for Bulger, which lists eighteen counts of murder, racketeering, money laundering, and extortion. What makes Whitey’s case so interesting is the stark contrast between him and his brother William, who also got famous, but for very different reasons. While Jimmy was breaking rocks in Alcatraz, Billy was slaving over the books at Boston University. Besides becoming president of the state Senate, Billy went on to some success in the academic world, earning a post as president of the prestigious University of Massachusetts.
I can relate to the Bulger family. I also grew up poor in a shantytown Irish family, and I also had a brother James. And while I was studying for my Ph.D., my brother James was doing time in Sing Sing.
Bulger’s family, and mine, provide some perspective on the evidence suggesting “criminal genes.” The same families who produce antisocial criminals can also produce bookish academic nerds, and it might even be that the same genetic proclivities can help two brothers “succeed” in both endeavors.
Terri Moffitt is a professor at Duke University and University College, London, who studies the factors leading some children to turn into life-long criminal offenders. Whitey Bulger fits the prototype: As a teenager, he was a vicious fighter, and had already been arrested several times; in the military, he spent time in the brig; in his twenties, he turned to robbing banks; as a middle-aged man, he became a murderous mobster. Professor Moffitt notes that over 100 different studies have examined genetic influences on criminality, and from these she concludes “that genes influence 40 to 50% of population variance in antisocial behavior.”
Genes influence eye color in a very direct way, before you are born. But any genes involved in criminal behavior unfold in complex interactions with our environments. As Moffitt observes: “Crime is not inherited. So what is?” Researchers have suggested some candidates: the inclinations to seek out excitement, to be fearless, to have problems controlling your impulses, or to be insensitive to other people’s pain, for example. Genes influencing behavior need not produce complicated brain mechanisms; they can operate in much simpler indirect ways. The tendency to grow tall is heritable, and dramatically changes your odds of becoming a professional basketball player. The tendency to grow muscular is also heritable, and changes the odds that you will enjoy getting into fights.
Is it necessarily “bad genes” that lead to criminal behavior? When researchers look for the causes of problem behaviors, they have traditionally thought in terms of a medical model – leading them to search for something diseased, or malfunctioning, in the system. Poor impulse control, intellectual deficiencies, or insufficient empathy seem to fit that model. But University of Arizona psychologists Bruce Ellis and A.J. Figueredo have begun looking at antisocial behavior through an evolutionary lens, and suggesting that some traits involved in criminal behavior might have an adaptive side. Evolutionary biologists view any animal’s traits in terms of “trade-offs.” In the natural world, nothing comes for free: The same bright colorful feathers that attract mates also attract predators. The same aggressive tendency can help an animal defend its territory, but also increase its chances of getting seriously injured.
Might the very same tendencies inspire some young men to antisocial behavior and others to academic success? Consider the simple case of testosterone levels. Psychologists Jim Dabbs and Robin Morris examined the criminal records for 4,462 men whose testosterone levels were measured in the army. High testosterone levels were strongly associated with later antisocial behavior, but only for fellows from underprivileged backgrounds. Other research suggests that high testosterone levels trigger not violence, per se, but a motivation to compete for status. Violence is one way to rise in the social hierarchy, but it is a costly and dangerous one. If you are a rich kid, you can compete on the tennis court or the stock market. If you are doing well in school, like me or Billy Bulger, you can hit the books, and get into graduate school as a pathway to a professional career. But if you are a kid from the wrong side of the tracks who has already blown his chances in school, like our two brothers, then becoming an outlaw may become a more attractive career option.
Douglas T. Kenrick is a professor of psychology at Arizona State University, and author of The Rational Animal: How evolution made us smarter than we think. Check out this 3 minute video in which he and coauthor Vlad Griskevicius discuss the books 2 main themes.
Dabbs, J. M., & Morris, R. (1990). Testosterone, social class, and antisocial behavior in a sample of 4,462 men. Psychological Science, 1(3), 209-211.
Ellis, B. J., Figueredo, A. J., Brumbach, B. H., & Schlomer, G. L. (2009). The impact of harsh versus unpredictable environments on the evolution and development of life history strategies. Hum. Nat, 20, 204-268.