The neuronal defense

There's been a lot of discussion recently about structural and hormonal changes in the brain being to blame for misbehavior, whether it's a philandering husband (or senator) or a psychopath. To some extent these are valid arguments; higher testosterone levels have been linked to sensation seeking and greater sexual desire, and abnormalities in the limbic system, particularly the amygdala which processes fear and emotion, and the frontal cortex, which is in charge of inhibition and rational thought, are often seen in persons who commit crimes. However, to use these structural phenomena as excuses or arguments as in, "My brain made me do it", is the same as proclaiming, "Yes, I did this". Obviously there are times of rare and extenuating circumstances when an individual's actions are truly no longer under their own control, such as in the case of a tumor in the frontal lobe changing the temperament and personality of an individual. However, for the vast majority of individuals, we are our brains, and saying you are "pre-wired" to cheat or fight or steal is not an excuse. If anything, it is a greater indication for potential recidivism and an added incentive for either punishment or preventative measures. Excess testosterone is not a pathology like schizophrenia or mental retardation, which can be used as defenses in court for criminal actions. Additionally, if you blame chemicals like testosterone or a lack of oxytocin for misbehavior, then what is to stop us from exonerating people who commit crimes because they are on a synthetic drug, like crack cocaine or PCP? And, seeing as how presumably not all men with increased testosterone cheat and not all individuals with abnormal amygdalas commit crimes or become sociopaths, it is difficult to argue that your brain and neurotransmitters make you do something when these same conditions do not compel another to a similar path.

David Eagleman's article in The Atlantic is a particularly insightful and eloquent investigation into both sides of this issue, which I highly recommend. Instead of focusing on the question of guilt and the implications that recent advances in neuroscience and neuroimaging have on culpability, Eagleman wisely shifts his focus to sentencing and the more constructive ways to incorporate our new crude knowledge of the brain into the justice system. He suggests concentrating on the potential for recidivism and reform when determining sentencing, instead of retribution. Drug courts have already started shifting towards this perspective, supported by the recent initiative by the Global Commission on Drug Policy, marking the 40 year anniversary of the War on Drugs. Not only is it important to help drug users receive treatment instead of punishment, our economy simply can not accommodate the deluge of drug related crimes into the penal system, most strikingly demonstrated by the decision in California this month to release 3,000 prisoners before their sentences were up due to a lack of resources.

Child criminal courts have also dealt with this issue of neuroanatomical defenses for quite some time, as it is widely established that the frontal cortex is the last area of the brain to finish developing, not reaching full maturation until the mid-20s. Countless juvenile defenders have used this argument to insist that their client was not a rational individual at the time of their crime, and therefore should not be held accountable for their impulsive and illegal actions. While this is certainly a valid point, and one that is typically taken into consideration when distributing sentencing, with prolonged punishments thought to be excessive and insensitive to changes the individual will undergo in the next 5-10 years, it is important to bear in mind that not all 15 year-olds commit crimes. Therefore, this universal neural stage of adolescence that we all pass through is not necessarily a credible criminal defense, as otherwise all teenagers would be running rampant and wreaking even more havoc than they already do. Also, there are innumerable studies citing the increased risk of offense in impoverished or violent areas, yet this is not used as an excuse for a crime when poor behavior is conducted. It is absolutely a reason to reform the social system that creates these pockets of poverty and risk, but it does not compel juries to acquit defenders of their crimes simply because of the neighborhood they were raised in.

At some point, people must take responsibility for their actions and face up to the consequences, not blaming an integral part of them for going rogue and acting out of character. When you make a decision it is your brain acting and your neurons firing; you can not excuse an action because you claim you could not control these impulses. There is no outside force urging you to act or not, for that is your own will being administered and carried out. Eagleman's idea of a spectrum of culpability is a sensible one that I support, and I fully agree that in the vast majority of offenses reform and rehabilitation should be the goal, rather than retribution, however this still leaves the topic rife with ambiguity for where do you draw the line? At what point we will stand up and take responsibility for our own actions?

(Thanks to Tristan Smith for The Atlantic article.)

Dana Smith

PhD student in Experimental Psychology at the University of Cambridge