Last September in Italy, a man convicted of what would, in this country, be called second-degree murder or manslaughter had his 9-year sentence reduced on appeal on the grounds that he exhibited
abnormalities in brain-imaging scans and in five genes that have been linked to violent behaviour — including the gene encoding the neurotransmitter-metabolizing enzyme monoamine oxidase A (MAOA). … Giving his verdict, [the judge] said he had found the MAOA evidence particularly compelling.
The ruling marks the first time a defense based on behavioral genetics — the argument that a defendant’s genes caused him to commit the crime — has affected the outcome of a criminal case in any European court. To my knowledge, no defendant has ever succeeded with this argument in America, either, though many have tried.
I have written before about the implications of behavioral genetics for criminal law, which is built on the assumption that we are generally responsible for our own actions. Surely this is an issue the criminal courts will have to face: some people may indeed be genetically hard-wired for violence. But this decision comes as a surprise to me because the science does not seem to justify it, not yet. We simply don’t know that a single gene like MAOA causes specific behaviors, even in very specific gene-environment interactions. It is a bad decision but a telling one: as the science of behavioral genetics advances, at some point the courts will find it impossible ignore. (To learn more, a great scholarly article by law professor Owen D. Jones is here.)
For now, though, the idea of a “murder gene” is the stuff of novels, not science. My own next novel takes up this very issue. It involves a man named Andy Barber, who descends from a long line of violent men and whose teenage son Jacob is accused of murdering a classmate. Jacob, it turns out, also carries the MAOA gene variant — sometimes called the “warrior gene.” Preparing for his son’s murder trial, Andy says,
The legal question we discussed most … was the relevance of Jacob’s violent bloodline. We referred to this issue as the “murder gene” to express our contempt for the idea, for its backwardness, for the way it warped the real science of DNA and the genetic component of behavior, and overlaid it with the junk science of sleazy lawyers, the cynical science-lite language whose actual purpose was to manipulate juries, to fool them with the sheen of scientific certainty. The murder gene was a lie. It was also a deeply subversive idea. It undercut the whole premise of the criminal law. In court, the thing we punish is the criminal intention — the mens rea, the guilty mind. There is an ancient rule: actus non facit reum nisi mens sit rea — “the act does not create guilt unless the mind is also guilty.” This is why we do not convict children, drunks, and schizophrenics: they are incapable of deciding to commit their crimes, not with a true understanding of the significance of their actions. Free will is as important to the law as it is to religion or any other code of morality. We do not punish the leopard for its wildness. But that is the argument Logiudice [the prosecutor] would make if he had the chance: born bad. He would whisper it in the jury’s ear, like a gossip passing a secret. We were determined to stop him, to give Jacob a fair chance.
The murder gene may indeed be junk science, for now at least, but it is a haunting idea. We are quite comfortable with the idea that certain benign traits may inherited — musical talent, athleticism. Why not a talent for violence?
Image: Bryan Christie, “Pharmaceutical Brain”
Michael Malone says
Fascinating stuff, William. And it begs all sorts of questions not least of which is, could the people with this gene be detected and locked up to save the rest of us from their “talent”? Can we educate them out of it? Looking forward to reading what you come up with.
Michael makes a good point. It really does set up quite a dilemma: on the one hand an individual isn’t responsible for his actions so shouldn’t be punished for them, but on the other hand, if he is violent and can’t control his actions . . . heaven help us if we set him free to roam the streets.
No answers here, just questions. . .
William Landay says
It’s interesting to think about, isn’t it? More so as writers and readers than as lawyers. Certainly it makes a great dramatic device.
I think the thing to keep in mind is that the mechanism isn’t as simple as the genetic coding for physical traits like red hair or left-handedness, where a certain DNA sequence leads directly to those specific expressions. The cause-effect is much more contingent in the case of genetically triggered behavior. Violent behavior only seems to be triggered under very particular circumstances. The environment piece — the nurture as opposed to the nature — is essential, and even under just-right conditions aggressive behavior does not automatically trigger.
So I think Michael is basically right, that we can “educate” people out of it, that is, we can be sure people with a genetic susceptibility to violence are not raised in toxic, violent environments. But that too raises constitutional questions about surveillance and equal protection, doesn’t it? I suspect we’ll be talking about this issue for a very long time.
The idea of locking people up for crimes they have not yet committed or even contemplated is rich material for a story. Any takers?
Mikael Aizen says
I started a blog discussion on this topic. Hoping to get some comments:
I am halfway through reading “Defending Jacob.” It raises many questions in addition to the murder gene issue. “How well do we really know another person?” “Do decisons parents make truly affect how a child turns out?” “Can we truly love another person if they do things we think are immoral?” “What limits are there to how much a parent will do to protect a child?” Personally, I think we are all capable of violence, given extreme stress, but that we still have free will.
I finished reading Defending Jacob last night. Great book, but very disturbing.
Bill Landay says
Obviously they still have to be punished or treated for their actions, they can’t just be released from their charges.