This kind of insight raises the possibility of personalized sentencing, taking into account things like brain abnormalities. A proponent of this approach is David Eagleman, who runs the Initiative on Neuroscience and Law at Baylor University’s College of Medicine in Houston. He dismisses the idea that sentencing criminals based on their brain biology is akin to letting them off the hook. Instead, he argues, “we should be thinking, given that your brain is like this, what can we do to help?”
One of the biggest factors that should be taken into account, he argues, is the age of the accused. The hard cut-offs societies use to determine the age of responsibility for crimes may not be rooted in science but research now shows that certain parts of the brain develop at very different rates. For example, recent studies of the maturation of the prefrontal cortex, which is involved in decision-making processes, suggest that it does not reach full maturity until the late 20s or early 30s. It is a finding that suggests a more subtle way of categorising offenders may be needed; for example biological maturity, a measure of the brain’s plasticity – or how easily it can be modified.
Children’s brains are more plastic than adults, which is why they are able to learn more quickly. Eagleman says neuroscience might one day be able to provide a way to measure the specific plasticity of an individual brain. “If at 20 years of age, someone commits a crime and they have a shrunken frontal lobe and are never going to learn the rules – they might have to be put away for longer.” Mo Costandi, a neurobiologist and science writer based in London, says the new research “will eventually lead to us rethinking the way we punish adolescents.”
Already changes are afoot. On 25 June 2012, the US Supreme Court barred mandatory life sentences for juveniles convicted of murder. The ruling was made, in part, because of this growing mass of scientific research indicating that there’s a difference between adult and juvenile brains, and that juvenile brains develop at different rates. It follows two previous rulings that outlawed the death penalty for juveniles and life sentences for crimes other than murder.
It is a decision that Eagleman says was “long overdue” as juvenile brains are fundamentally different from adult brains. Costandi also maintains it was a “sensible decision” based on recent findings. “Adolescents often make poor decisions that are easily influenced by peer pressure,” he adds. “They also have difficulty controlling their impulses and predicting the consequences of their actions, and all of this has profound implications for how they are treated within the legal system.”
But not everyone is enthusiastic about the prospect of personalised sentencing. “Individualised justice and determination of responsibility are much more costly to society,” says Vanderbildt’s Jones, compared to a one size fits all approach. But Eagleman has heard this argument often. “The numbers work out,” he says. In 2008, for instance, the US government spent nearly $75 billion on correction, most of it on incarceration. “It costs so much to put people in jail and we know it has very low utility – you’ve broken their social circles, their employment opportunities – so they’ll come right back round through that revolving door.”
The changes open up the possibility of other factors being taken into consideration sentencing. For example, roughly a third of US prisoners have a mental illness. Some also have drug addictions. Both are poorly tackled by the criminal justice system, says Eagleman who argues the prison system has become the “de facto mental health system”.