Why so many killers are male

Story highlights

  • Nine people were shot dead at a church in Charleston on Wednesday
  • James Garbarino: Vast majority of killers are male

James Garbarino is author of "Listening to Killers: Lessons Learned from My 20 Years as a Psychological Expert Witness in Murder Cases," and professor of psychology at Loyola University Chicago. The views expressed are his own.

(CNN)It looks like it has happened again. A young male has allegedly killed. In this case it is nine people at a church in South Carolina. Anyone who is paying attention hears the news and thinks, "Here we go again." But why? After spending 20 years interviewing killers as a psychological expert witness in murder cases I have some thoughts about this.

Males are disproportionately over-represented in the ranks of America's killers -- about 90%, in fact. Why is that? Some of it appears to lie in the biological vulnerability of males. About 30% of males (versus 9% of females) have a form of the MAOA gene that impairs their ability to deal effectively and pro-socially with stressful situations (like living in an abusive family). Thus, the vast majority of males who have this genetic vulnerability and who live in abusive families end up engaging in a chronic pattern of aggression, bad behavior, acting out and violating the rights of others by the time they are 10 years old.
James Garbarino
It's a childhood pattern that is often the gateway to seriously violent delinquency and perhaps murder. This genetic vulnerability is part of a larger pattern for males. But this is only a part, perhaps a small part, of the larger story.
    The reality is that males are also typically more immersed than females in a culture that glorifies and justifies violence, and particularly male violence. For example, the effect of TV violence upon aggressive behavior is about as strong as the effect of smoking in causing lung cancer: Most people who smoke don't get cancer, but smoking increases the risk significantly. Violent images are like smoking for the brain, but instead of the physical problem of lung cancer the result is the behavioral cancer of violent behavior.
    I have found in interviewing men in murder cases that virtually every act of violence "makes sense" to the killer. Therefore, in a very real sense there is no such thing as a "senseless act of violence." Inside the mind of the killer the act of lethal violence fits into an idea of right and wrong (whether we on the outside recognize that idea as delusional or not).
    This is vitally important, because as a society, we often "promote" the various socially toxic cultural messages to which boys and men are exposed -- racism, misogyny, the belief that "it is better to be mad than to be sad," and the like. These cultural messages and themes poison male consciousness. To put it bluntly, even "crazy people" act within a cultural framework. They respond to cultural scripts that tell them "if this, then that."
    Sadly, there is a long tradition of killing black people in America that resonates across the decades and centuries. This extends from the thousands lynched in the South until well into the 1960s, to the repeated shooting of unarmed black boys and men by police and civilians in recent years. The same goes for violence against women. Some males latch onto these scripts as a way to make sense of their lives, whether it be their anger, their resentment, their sense of entitlement, their sense of being belittled -- whatever it is in their individual or collective case. People die from these socially toxic ideas in the hands of troubled people.
    Then there is the matter of youth. In recent decades, neuroscience researchers have demonstrated that human brains do not mature fully until people reach their mid- or even late 20s, for the most part. These immature brains are particularly prone to make mistakes in interpreting the meaning of emotions in others, of judgment, and in assessing the risks and benefits of action. They suffer from problems with both "emotional regulation" (managing emotions effectively and realistically) and "executive function" (making well-reasoned decisions that guide behavior). When kids have had an accumulation of adverse childhood experiences, the odds that they will have problems with both emotional regulation and executive function increase. That's why wise parents, educators, professionals and policymakers recognize that kids need to be in a kind of "protective custody" in many ways and in many matters until they mature.
    Finally, of course, there is the matter of arming troubled young males with lethal weapons. It is the access to guns that makes young males so dangerous, especially when they are troubled, angry, or somehow "crazy." It is guns that make American suicide attempts so deadly (85% lethal vs. 10% for pills). It is guns that make domestic disputes so dangerous. It is guns that make cop-civilian confrontations so deadly. And it is access to guns that means racist ideologies in the heads of troubled young males too often leads to tragic ends like the nine dead bodies in a church in South Carolina, because "guns don't kill people; people with guns kill people."