In our recent "Blame" episode, we explored the tricky ethical questions that arise when criminal defendants put their own neurobiology in front of a jury. The thick line between innocent and guilty quickly becomes very, very faint: is a murderer with an injured frontal cortex less guilty than a murderer with a healthy frontal cortex? This all comes rushing back in the case of John McCluskey, which Greg Miller describes in his new Wired article, "Did Brain Scans Just Save a Convicted Murderer From the Death Penalty?"
McCluskey was an escaped convict who was found guilty of two counts of murder in October. When it came time to sentence him, the jury had to choose between life in prison and the death penalty. They were torn. McCluskey's crimes were unquestionably reprehensible, but his lawyers argued that his brain was riddled with abnormalities that interfered with his impulse control. To punish him for his faulty biology would be unfair.
When you read the details of McCluskey's crime, it feels like you’re catching a glimpse of evil incarnate. This is a man who carjacked a retired couple in New Mexico, drove them to a remote area, shot them, and burned their bodies, all because he wanted to get a good night's sleep in their pickup truck. The easiest explanation is that McCluskey is just a moral vacuum, a man who lives for violence. A man who needs to be punished.
But when you see the scans of his brain, and when you read the mechanical descriptions of how that brain apparently misreads the world around it, the word "man" starts to feel like too simple a description of a complicated process. John McCluskey isn’t only a murderer. He’s an endless series of decisions that are being made by a malfunctioning brain: an amygdala that sends faulty "danger" signals, a cerebellum damaged by stroke, a malformed frontal lobe that doesn't allow him to ignore impulses. It may even be that the world as he sees it is not the world as we see it.
It's not that John McCluskey is a good person – it’s that he is, to a degree, a victim of his own brain. At least, that's basically the argument the defense made, and it may be the reason the jury ultimately decided not to give McCluskey the death penalty.
After reading about this case, my fellow producer Lynn Levy made a call to Dr. David Eagleman, the neuroscientist whose ideas about blame first sparked our interest in the topic.
To Dr. Eagleman, it was no surprise that John McCluskey’s brain showed evidence of abnormalities. “We already know that mental function is linked to brain function,” he said—that what you think, feel and do is based in something physical (and, as technologies improve, increasingly visible) inside your skull. “The question is: what result could we possibly have found about McCluskey's brain that would be surprising? There's going to be something out of the norm because his behavior is so out of the norm.”
But cases like this one raise another question for Dr. Eagleman, one he's been mulling for years. “To my mind,” he said, “it's not clear whether the evidence of these brain abnormalities should be considered mitigating or exacerbating.”
In other words, let's say you're in charge of sentencing a criminal. Looking at the evidence, you're convinced that this man is unable to control his impulses—that's just the way he's wired. Unfortunately, those impulses lead him to do violent, unspeakable things. And since we don't have the tools (so far) to fix his faulty wiring, he's likely to act the same way next time an impulse strikes.
Does that mean he should get a lighter sentence because his wiring isn't his fault? Or does it mean he should get a harsher one, to prevent the future crimes he seems bound to commit?