April 5, 2011
A human brain is three pounds of the most complex material in the universe. It is the mission control centre that drives the operation of your life, gathering dispatches through small portals in the armoured bunker of the skull. This pink, alien computational material, which has the consistency of jelly and is composed of miniaturised, self-configuring parts, vastly outstrips anything we’ve dreamt of building.
Using those brains, humans have done something unique. As far as we know, we’re the only system on the planet so complex that we’ve thrown ourselves headlong into the game of deciphering our own programming language. Imagine that your desktop computer began to control its own peripheral devices, removed its own cover and pointed its webcam at its own circuitry. That’s us.
What we’ve discovered by peering into the skull ranks among the most significant intellectual developments of our species: the recognition that the innumerable facets of our behaviour, thoughts and experience are inseparably yoked to a vast chemical-electrical network called the nervous system. The machinery is utterly alien to us, and yet, somehow, it is us.
The first lesson we learn from studying our own circuitry is shocking: most of what we do and think and feel is not under our conscious control. The vast jungles of neurons operate their own programs. The conscious you – the I that flickers to life when you wake up in the morning – is the smallest bit of what’s transpiring in your brain. Although we are dependent on the functioning of the brain for our inner lives, it runs its own show. Your consciousness is like a tiny stowaway on a transatlantic steamship, taking credit for the journey without acknowledging the massive engineering underfoot.
At first blush, this viewpoint sounds absurd to many people. I know this because I ask strangers their opinion about it when I sit next to them on aeroplanes. And they usually say something like “Look, all that stuff – how I came to love my wife, why I chose my job, and all the rest – that has nothing to do with my brain. It’s just who I am.” And they’re right to think that the connection between one’s essence as a person and a sea of cells seems distant at best. Our decisions come from our minds, not from electrical bolts and chemical surges. Right?
In fact, we are dependent entirely on our biology. If you were to lose the tip of your little finger in an accident, you’d be saddened, but your conscious experience would be no different. By contrast, if you were to damage an equivalently sized piece of brain tissue, this can change your capacity to understand music, name animals, see colours, judge risk, make decisions, send signals to your muscles, use verbs or perform any of the other hidden, daily feats that we pull off seemingly without effort.
Thousands of natural experiments with brain tumours, degenerative disorders, genetic mutations, drug addictions and traumatic brain injury have taught a simple lesson: our hopes, ideas, desires and behaviours depend directly on the state of the enigmatic lump of thinking stuff. The physical and mental are so closely aligned that they appear, as far as modern science can currently tell, identical. This viewpoint changes our notions of ourselves – and it will almost certainly change the legal system as well.
The problem is that the law rests on two assumptions that are charitable, but demonstrably false. The first is that people are “practical reasoners”, which is the law’s way of saying that they are capable of acting in alignment with their best interests, and capable of rational foresight about their actions. The second is that all brains are created equal. Everyone who is of legal age and above an IQ of 70 is assumed, in the eyes of the law, to have the same capacity for decision-making, understanding, impulse control and reasoning. But these ideas simply don’t match up with the facts of neuroscience.
Along any axis that we measure, brains are different – whether in aggression, intelligence, empathy and so on. Brains are more like fingerprints: we all have them, but they are not exactly alike. As Lord Bingham, the senior law lord, put it, these myths embedded in the legal system do not provide a “uniformly accurate guide to human behaviour”.
The legal system needs an infusion of neuroscience. It needs to turn away from an ancient notion of how people should behave to understand better how they do behave.
A natural concern is that a deeper understanding of the brain will equate to exculpation. If free will isn’t what we imagined it to be, but instead depends on your genetics, environment and neural circuits, shouldn’t everyone be let off the hook? But these concerns are misplaced. We will continue to take violators of social norms off the streets; we will still assign values right and wrong to behaviours. Instead, the change will be in the refinement of our sentencing.
Currently, our patterns of punishment are founded on the concepts of personal volition and the attendant culpability. But a shift in our understanding of individual differences suggests a move toward prison sentences tailored to the risk of recidivism rather than the desire for revenge.
Some people will say that bringing science into sentencing removes its humanity. But as it stands now, research shows that ugly people get longer sentences than beautiful people, and psychiatrists and parole boards, when tested, have no predictive power in guessing who will reoffend.
Beyond modulating sentences, a deeper understanding of the brain will allow us to move beyond treating incarceration as a one-size-fits-all solution. In most countries, prisons have become de facto mental health care systems. It is more cost-effective, and less likely to encourage criminal behaviour, to divert the mentally ill to mental health courts designed to deal with them.
Similarly, we have spent billions on the war on drugs, but a better approach would be to address demand instead of supply, by understanding the brain of the addict.
Neuroscience can offer customised, brain-based approaches to rehabilitation, in which people are helped to overcome mental illness, drug addiction or even poor impulse control. This could replace the blunt assumption that prison is always the best approach.
On a broader level, the legal system can use neuroscience to achieve a realistic understanding of incentives and deterrents, which take advantage of our inborn neural mechanisms and encourage social behaviour. As understanding of the neurobiology of behaviour develops, societies can design modern, evidence-based policy.
It is time to let go of our intuitions about how people should behave and pay attention to how they do behave – to run our legal system as rigorously as a science experiment. Careful attention to detail will allow us to clean up the streets with less cost, slow the revolving doors of the penal system and divert resources into effective programmes rather than simply build more prisons. A brain-based approach can be more cost-effective, humane and successful. If we desire our medical treatments to be biologically informed, shouldn’t we demand the same from our courtrooms?