Ignoring science, from the bench

On Monday, the Supreme Court issued a split (5-4) decision that ruled that mandatory incarceration for life, without the possibility of parole, was a cruel and unusual sentence if the convicted defendant committed the crime while a juvenile. This builds upon their decision in 2005 that the death penalty is a cruel and unusual sentence for the same people.

What does this have to do with scientists and scientific activism? Everything.

Over the past 10 years or so, there has been an enormous explosion of research in the area of “developmental cognitive neuroscience” – basically, in the systematic study of how the brain develops and shapes our behavior. Everyone knows that juveniles and adolescents act differently than adults. The average child and teenager is more easily distracted than adults. S/he is more impulsive. Their decision-making and cognition are not yet at adult levels. What is less well known is that developmental trajectories in the brain explain these phenomena quite well.

We are all subject to temptations; these are usually a result of strong emotions: desire for pleasure, anger, fear, disgust, etc. Those emotions are rooted in parts of the brain that develop early in childhood, which is why most children exhibit normal emotional responses to events. They take pleasure in ice cream. They fear snakes. They cry when they are left alone. This suggests that these emotional circuits develop to near adult levels early, and brain imaging studies confirm that.

On the other hand, the emotional responses of children and pre-teens are often exaggerated, and they can sometimes be overwhelmed by them… This is a crucial point.

One of the functions of the frontal lobe is the inhibition of emotions and behaviors. Every time we suppress an emotion, resist a temptation or inhibit an inappropriate behavior, we do this by turning on parts of our frontal lobe. This part of the brain inhibits those responsible for the emotion or impulsive behavior, in the first place. When the frontal lobe is deficient, the likelihood that one can inhibit the emotion or behavior is lowered.

The cartoon shows the localization of the frontal lobe, above the eyes, relative to a part of the brain more involved in emotion (the amygdala)

Importantly, parts of the frontal lobe do not fully develop into adult levels until quite late in adolescence. We know, mostly from studies of rodents, that the molecular landscape of the frontal lobe continues changing right through adolescence, only reaching its adult form much later than most brain regions. This fact explains the results of brain imaging studies that show that the ability to turn on frontal lobe, and inhibit behaviors and feelings, does not reach adult levels until quite late in human development.

Put differently, juveniles and teens have a brain fully capable of feeling powerful emotions (like anger), but their ability to resist those emotions and to behave in a socially appropriate manner (like to inhibit aggressive reactions) is not at adult levels. The 5 justices who struck down harsh penalties for child offenders recognized this; it was a crucial part of their logic in this, and the earlier death penalty, case.

But like a frightening number of people in our society, the other 4 justices viewed the science as either being wrong or irrelevant. Their own ethical or philosophical views about crime and punishment appeared to trump their interest in scientific principles and facts. In this regard, they are not unlike strident animal rights activists opposed to biomedical and behavioral research involving animals.

What is shocking about their point of view is that the justices are ignoring a principle of enormous importance and broad implication. This pattern of development explains a large number of factors, including why adolescents are more likely to engage in high-risk behaviors (from unprotected sex to driving while intoxicated) and why they are at greater risk for trying drugs. The science of frontal lobe function has huge implications for the legal responsibility of adults with frontal brain damage or other forms of organic frontal lobe impairment. And finally, an understanding of these mechanisms have enormous consequence for our understanding of drug addictions – in which frontal lobe is compromised, leading directly to uncontrolled drug use (this topic is a primary focus of work in my laboratory).

None of this is meant to support the conclusion that kids should never be legally responsible for their actions, or that adults always must be. It should also be clear that the fact that the law recognizes 18 years of age as the “magic line” is biologically arbitrary (on average, frontal lobe function is mostly developed by then, but it also differs a lot between individuals).

Certainly, none of this is meant to suggest that brain scans or neuroscience can revolutionize the legal system at this time (the issues involved here are very complex and will no doubt require in depth discussion).

What it is meant to suggest is that, as we come to understand how specific mechanisms in brain contribute to thinking, emotions, decision-making and cognition, we come to understand the biological determinants of criminal or unhealthy behaviors. It is at this point that we should pay more, not less, attention to scientific facts. Instead of being discarded for being in conflict with our ethical and philosophical points of view, scientific facts should change our ethical and philosophical views. I hope that is the case some day for the 4 justices in the minority.


  1. I did not read the opinion but it seems to me the issue is not one of unusual and cruel punishment, but whether we can assign full moral responsibility to individuals whose brains are not fully developed. The answer is clearly ‘no’. Are those justices in the minority against an age limit for voting or drinking?

    1. I believe the argument is that harsh sentences for those with compromised moral responsibility amounts to cruel and/or unusual punishment (violating the 8th amendment) – i.e., a moral issue becomes a Constitutional one.

      1. If it is cruel it is cruel for everyone… is it not? In fact, one may argue that a life sentence may be less cruel for someone mentally incapacitated, as s/he may not fully understand the consequences of the decision.

      2. There is no question that the Constitutional issue being addressed by the court was an 8th amendment (cruel and unusual punishment) question, so the decision necessarily focused on that issue.

        Being sent to jail for life may well be cruel for anyone (bearing in mind that almost all these people are 18+ when they start their terms because of the many years it takes for a case to be prosecuted), but is it unusual in light of the facts? And is it any less cruel than letting someone off completely because of the rightful needs of the victims for justice?

        Additionally, is it less cruel to be sentenced to a term 1 yr less than life in prison? That is still allowed. What isn’t allowed is mandatory sentences of life in prison without parole.

        I think the court took a positive step in terms of striking down a sort of legislative extremism that said no considerations of causes and mitigating factors in a particular case was possible, at sentencing. The minority favored the extremism (no questions, no excuses, etc.). Now, individual courts can assert their individualized decision making, which presumably will take into consideration the full range of mitigating factors.

        Granted, the extremism still applies for adults in some states, but only for adults deemed intellectually competent (the court struck down death penalties for the mentally hypocompetent quite some time ago and may well end up addressing this issue [life in prison] for the mentally hypocompetent in the near future). Apparently, one of the few saving graces of Justice Kennedy is that he does seem to have some compassion for defendants that are at the margins.

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