The violence geneDeborah Denno in The Sydney Morning Herald, March 12, 2014
The violence gene
Published: March 12, 2014
By noon, the temperature was steaming in eastern Arkansas, and the mosquitoes were swarming clouds in the humid, fetid air. As church services at Ellis Chapel concluded, Dixon Platt, the pastor of the United Methodist community in the town of Wynne, wondered why 80-year-old Lillian Wilson, one of the most devoted of his flock, hadn't shown up to worship that morning. It was all the more curious because he had agreed to have lunch with her.
Platt tried to track her down, but no one knew her whereabouts. Eventually, he made his way over to the Central United Methodist Church, where the group sometimes met on Sundays, and where Wilson had been working earlier that week, putting together disaster buckets for folks in need. He opened up the doors of the church, and there, underneath a pew, a few feet from the entrance was a body, a female, with blood on her pants.
Wilson had been murdered, and it didn't take much for the police to work out what had happened.
In the trial of Rene Patrick Bourassa Jr, the defendant and his attorneys made no effort to deny he had killed Wilson. Bourassa even walked the authorities through the murder, re-enacting it for them. He had been sleeping at the church that week, first outside, and then in the chapel, presumably to escape the heat and mosquitoes. When Wilson walked into the church that morning, Bourassa picked up a brass cross from the Communion table, beat her to death, and stole her car.
The crime could have been set in 1930 or 1970; most of the details seemed familiar, almost old-fashioned. But what was decidedly modern was the question of moral culpability that arose during the trial: The lawyers didn't argue over whether Bourassa had committed the crime; they argued over whether his brain made him do it.
The criminal justice system is based on responsibility: For someone to be convicted of a crime, it has to be shown they were consciously aware of what they did, when they did it. The problem, according to Deborah Denno, a professor at the Fordham University School of Law, is that almost all US 50 states still define consciousness based on what's in the Model Penal Code - a document published by the American Law Institute in 1962, and derived almost entirely from Freudian texts.
The Freudian view - at least as interpreted by the Institute in its formulation of the mens rea, or "guilty mind" - is that science and the law can clearly demarcate between someone who chooses their actions, and who did not. It's the basis for the insanity defence, which argues that a person charged with a crime is so far gone they are essentially unconscious actors, and the reason why the law has developed a spectrum of murder charges ranging from first degree (willful and premeditated) to voluntary manslaughter (unplanned, but intentional, the result of circumstances which could have generated a "reasonable" fit of anger).
But as the fields of genetics and neurosciences have advanced, so has our understanding of human behavior: It is now thought that, instead of there being a clear line between conscious and unconscious processes, a fluid interplay exists between the two sides. "People don't have the degree of control over their behaviour that we thought," Denno says. "That doesn't mean to suggest that there's no control over their behavior - but that some of us have higher hurdles than others."
This is intriguing in the abstract, but in the practical world of the legal system, it forces a troubling question: If a person is predisposed to a certain type of behaviour, is it his fault for acting as he did? From one vantage point, Bourassa's choice to kill was never made; the illusion of free will masks the reality that he followed the plans laid out by a small anomaly, buried deep in his genes, that drove him to violence.
The field of behavioural genetics is the branch of science that seeks to answer the complex and often politicised question of nature vs. nurture, by looking at the interplay between genetic markers and human action. It's also a field that has developed an outsized influence on forensic science, particularly since the moment in the late 1970s when a group of women in the Netherlands came to the University Hospital in Nijmegen seeking help. The men in their family were very aggressive; so much so that acts of violence - including arson and attempted rape and murder - were all over the family tree. Geneticist Hans Brunner decided to investigate. It took about 15 years, but eventually, Brunner isolated a gene, shared by all the men, causing the violent behavior: a mutated variant of the monoamine oxidase A (MAOA) gene. Or, as it has come to be known in popular media, the warrior gene.
Every human has an MAOA gene - so-called because it encodes the enzyme monoamine oxidase A, which in turn breaks down key neurotransmitters in the brain, like dopamine, norepinephrine and serotonin. The MAOA gene is located on the X chromosome, which means that while women have two copies, men only have one - so any problems with the gene are much more likely to affect men. There are a few variants of the gene, one of which - MAOA-3R, present in about 30 percent of men - has been shown over and over again, in both controlled animal studies in labs and in real-world testing scenarios, to be correlated to increased aggressive behaviour. (Brunner's patients had an extreme mutation in the gene that went way beyond the common "violent" variant.)
Bourassa had the MAOA-3R variant, so, as the science goes, was from birth more likely to hurt others.
Of course, as every genetic researcher is quick to point out, there is no such thing as nature or nurture; they are inextricably entwined. "The expression of genes is fundamentally dependent on environmental inputs - they work in concert, hand in glove," says Rose McDermott, a professor of political science at Brown University, who has extensively studied the MAOA gene. A recent meta-analysis that looked at 27 different MAOA studies confirmed that maltreatment as a child was a key influence in way that the MAOA gene was ultimately expressed.
In extensive psychiatric interviews with Bourassa, psychiatrist James Walker discovered that he had been sexually molested at the age of 4 by a friend of his father; in the fifth grade, he was repeatedly raped by an older boy; and at age 21, he was brutally beaten in a mugging. As the science goes, Bourassa was from adolescence more likely to hurt others.
Though Bourassa's actions in that Georgia church were undoubtedly brutal, if you read the science closely, you might surmise that he had no control over what he did, because the deck was so blatantly stacked against him. And a jury of his peers agreed. Bourassa was found guilty of capital murder, but was not sentenced to death; he got life in prison without parole. The relatively lenient verdict in Bourassa's trial was the result of a criminal defence argument that has, in recent years, become de rigueur in capital cases nationwide: shifting the blame for behavior, just ever so slightly, away from the individual defendant, and toward uncontrollable biological factors
An extremely high-profile example of how genetics enter the fray can be found in the case Jared Lee Loughner, who was charged with 19 counts of murder and attempted murder, including the shooting of then US representative Gabrielle Giffords. At the time of his arrest, Loughner was visibly unhinged; for months, one of the primary questions of the case was whether or not he was competent to stand trial. Loughner's defence team, led by stalwart capital punishment opponent Judy Clarke, filed subpoenas for the public health records of his relatives, going as far back as 1893. When, during the plea bargain, Loughner's team revealed that a number of his maternal relatives suffered from "extreme bouts of mental illness," their strategy became clear.
Even if a person is considered insane, proving that person acted without consciousness at any given time - in Loughner's case, at the time of the shooting - is essentially impossible, and can be tough to sell in the courtroom. On the other hand, if there is something in the person's genetic history that might indicate a tendency toward violent or otherwise crazy behaviour, it makes a strong case that the person should not be held fully responsible for his actions. Loughner ultimately avoided the death penalty; he was sentenced to life without parole as part of a guilty plea bargain. Clarke will also be defending Dzokhar Tsarnaev, the man accused of carrying out the Boston Marathon bombing.
To date, behavioral genetics have been applied mostly to capital cases, but, according to Stephen Biskar, who has served as a California public defender for more than 30 years, the only reason this type of defense isn't used in all criminal trials is a lack of resources. Public defenders can't "spend the time and money on a case in which the sentence will ultimately be shorter than the investigation," he tells Newsweek. Loughner's trial, for example, spanned 11 months and involved a raft of legal and forensic experts flown in from all corners of the country.
Given the reliability of this type of evidence (identifying the existence of the MAOA-3R variant is eminently replicable), it's no surprise it has become a staple in the courtroom. Critics, however, contend that biological explanations for illegal and violent behavior work too well. A 2012 study, for example, made waves after claiming to have found that if judges were given evidence of a "biomechanical cause of the convict's psychopathy" during the sentencing phase of a trial, they would pass a more lenient sentence. Though the study's authors didn't make the argument explicitly, they implied that courts were to some extent blinded by the light of science.
On one level, the argument makes sense. After all, law school curriculums do not require any training in the sciences, and, despite their prominence in cases ranging from paternity suits to shaken baby investigations, the bar does not test knowledge in these areas. There is no science or technology training required as part of the minimum continuing medical education for lawyers or judges across the country. Classes in science are offered - but judges need to seek them out. (One major source of scientific training for judges, the Advanced Science & Technology Adjudication Resource Center, has been shuttered due to lack of funds since 2011.)
But then again, judges in the past were never expected to undertake studies in courses of psychoanalysis or moral philosophy. And now, in 2014, instead of just listening to psychiatrists hold court, judges and juries are seeing brain scans and genetic sequences - concrete, visible evidence. "It's changing the landscape of the criminal justice system," argues Denno. "It's making it much more transparent and keeping experts honest."
Eventually, behavioural genetics might lead to a profound change in our penal system. "I predict it might undermine the death penalty," says Dr William Bernet, a forensic psychiatrist from Vanderbilt University, who did the genetic testing on Bourassa and testified at his trial. Bernet argues that the concept of premeditation might come under greater scrutiny as science uncovers more about what drives behavior.
Despite how popular media makes it seem, insanity pleas (and other claims to "unconscious" action) are quite rare; in the history of the American legal system, the majority of defendants have been deemed to be conscious actors, 100 per cent scientifically and morally responsible for their behaviour. Common sense would question these outcomes; it's not a stretch to suggest that nearly everybody that commits a murder is, in some way, neurologically damaged, whether from nature or nurture.
But a new model of behaviour and volition is emerging, a framework that relies more on hard science than ever before. At the same time, it may be raising more questions of moral responsibility than it answers. Though researchers have sequenced the entire human genome, they still know the meaning of only a tiny fraction of the massive chain, and there may yet be dozens, or even hundreds, of MAOA-like genes as yet uncovered. Bernet, for one, predicts that genetic markers for sado-sexual violence will emerge, and become a key influence in forecasting repeat offenders. This may complicate the picture even further, as lawmakers will have to make tough decisions about whether or not to identify a class of people who are responsible for their actions, and another whose genetic and environmental background makes them, essentially, unconscious actors in the eyes of the law.
Already, science has begun to see an individual like Bourassa as the sum total of all that came before, all the events and actors in both his life and the lives of his parents, and so on. In this model, he is just the final cog in an infinitely complex machine. But if that really is the case, who in the end is actually responsible for his actions?