Neuroscience, Free Will, and the Law

As Chelsea Ursin's series on the neuroscience of free will continues this week, a morning session at the American Association for the Advancement of Science conference reminded me that the subject of free will is not of purely philosophical and scientific interest. It has deep implications for our legal system and for the way that our society thinks about how and why we punish. For some defendants, the sharp line between life and death may even be drawn by the neuroscientists, philosophers, and legal scholars who ponder the fuzzy question of free will.

If free will is an illusion--if our actions are elaborate reflexes pre-programmed by biology and experience--then an individual is not "responsible" for committing even the most heinous crime. Michael Zigmond, professor of neurology at the University of Pittsburgh, puts it this way: Our behavior is nothing more or less than our brain activity, and brain activity is a function of our genes and our environment. When we punish an individual, then, we're not reprimanding poor choices, we "are punishing electrical and chemical events in the brain."

Nita Farahany, a professor of law and philosophy at Vanderbilt, rejects the notion that our choices can be reduced to such brain static. Brain science cannot absolve individuals of responsibility for their actions, says Farahany. Yet some discoveries from neuroscience are already making their way into the courtroom. Farahany estimates that, between 2005 and 2009, the number of judicial opinions making note of neuroscience doubled, and the rise has been even more dramatic since then. Drug and alcohol addicts argue that their addictions rendered them unable to exercise free choice; defendants claim that they were neurologically incapable of premeditating their crimes; serotonin levels are submitted as evidence of impaired impulse control.

But the biggest changes have come in the sentencing of young offenders, says Farahany. As neuroscience has given us greater insight into the brain's continuing development through adolescence and into adulthood, young people are found to have "less culpability" for their crimes. In the United States, the death penalty was abolished for juvenile offenders in 2005, and in 2010, the Supreme Court ruled that juveniles could no longer be sentenced to life without parole, except in homicide cases.

How far should we take this? If "my brain made me do it" (or, "my brain didn't stop me from doing it") works for some defendants, why not all of them? As Richard Dawkins has written, "Doesn't a truly scientific, mechanistic view of the nervous system make nonsense of the very idea of responsibility, whether diminished or not?"

Yet most of us cherish the notion of free will and the responsibility that comes with it. We value our sense that we are agents of our own destiny. (In fact, individuals who believe in their own free will are more likely to act ethically--more on that later this week from Chelsea.) So, can neuroscience shape our criminal justice system while keeping free will in the picture?

Peter McKnight thinks so. Neuroscience gives us tools to evaluate whether an individual is capable of reason, and the criminal justice system helps work the levers on that reasoning system by meting out punishments that (in some cases, at least) deter would-be criminals.

Most importantly, we can hope that neuroscience will one day give us the tools to rehabilitate offenders instead of serially imprisoning them. Perhaps we can even imagine a future in which we so deeply understand the interaction of nature and nurture that we can help rehabilitate at-risk individuals before they ever commit a crime.

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