From the recent announcement of President Obama's BRAIN Initiative to the Technicolor brain scans ("This is your brain on God/love/envy etc") on magazine covers all around, neuroscience has captured the public imagination like never before.
Understanding the brain is of course essential to developing treatments for devastating illnesses like schizophrenia and Parkinson's. More abstract but no less compelling, the functioning of the brain is intimately tied to our sense of self, our identity, our memories and aspirations. But the excitement to explore the brain has spawned a new fixation that my colleague Scott Lilienfeld and I call neurocentrism -- the view that human behavior can be best explained by looking solely or primarily at the brain.
The critical question, though, is whether this neural disruption proves that the addict's behavior is involuntary, and that he is incapable of self-control. It does not.
Sometimes the neural level of explanation is appropriate. When scientists develop diagnostic tests or a medications for, say, Alzheimer's disease, they investigate the hallmarks of the condition: amyloid plaques that disrupt communication between neurons, and neurofibrillary tangles that degrade them.
Other times, a neural explanation can lead us astray. In my own field of addiction psychiatry, neurocentrism is ascendant -- and not for the better. Thanks to heavy promotion by the National Institute on Drug Abuse, part of the National Institutes of Health, addiction has been labeled a "brain disease."
The logic for this designation, as explained by former director Alan I. Leshner, is that "addiction is tied to changes in brain structure and function." True enough, repeated use of drugs such as heroin, cocaine, and alcohol alter the neural circuits that mediate the experience of pleasure as well as motivation, memory, inhibition, and planning -- modifications that we can often see on brain scans.
The critical question, though, is whether this neural disruption proves that the addict's behavior is involuntary and that he is incapable of self-control. It does not.
Take the case of actor Robert Downey, Jr., whose name was once synonymous with celebrity addiction. He said, "It's like I have a loaded gun in my mouth and my finger's on the trigger, and I like the taste of gunmetal." Downey went though episodes of rehabilitation and then relapse, but ultimately decided, while in the throes of "brain disease," to change his life.
The neurocentric model leaves the addicted person (Downey, in this case) in the shadows. Yet to treat addicts and guide policy, it is important to understand how addicts think. It is the minds of addicts that contain the stories of how addiction happens, why they continue to use, and, if they decide to stop, how they manage. The answers can't be divined from an examination of his brain, no matter how sophisticated the probe.
It is only natural that advances in knowledge about the brain make us think more mechanistically about ourselves. But in one venue, in particular - the courtroom - this bias can be a prescription for confusion. The brain-based defense ("Look at this fMRI scan, your Honor. My client's brain made him do it.") is now commonplace in capital defenses. The problem with these claims is that, with rare exception, neuroscientists cannot yet translate aberrant brain functions into the legal requirements for criminal responsibility -- intent, rational capacity and self-control.
What we know about many criminals is that they did not control themselves. That is very different from being unable to do so. To date, brain science cannot allow us to distinguish between these alternatives. What's more, even abnormal-looking brains, have owners who are otherwise quite normal.