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Crime And the adolescent brain

How should development affect sentencing?

By: Emalee Sekely

Picture yourself at 16. You are at a party with friends, all drinking underage, when your family calls you home. You make a decision on an impulse. “I’ve only had a few beers; I can drive the 10 minutes it takes to get home.” You get behind the wheel. In the same position 10 years later, you are more likely to think about the potential consequences and hand your keys over to someone else. 


Neurological studies show the adolescent brain is still developing even through early adulthood. The frontal lobes – the part of the brain most engaged when we weigh the possible outcomes of our actions – are one of the last areas to mature. That fact begs the question: If the human brain is not actually fully developed by the time society expects it to be, how responsible should adolescents be held for their actions?  

Until very recently, the juvenile justice system in the United States did not account for the neurological development of juveniles in the court of law. Now, research shows definitive evidence that this issue is a lot more complicated than past court decisions accounted for. 

In recent years, knowledge on the structure and functions of the brain has greatly expanded. Specialists have also made substantial discoveries about how and when the brain develops through adolescence. Although scientists dispute over the exact age at which the brain becomes fully mature, most experts agree that brain development stops by the age of 24-25.  According to The University of Rochester’s Medical Center, the last part of the brain to mature is the “prefrontal cortex,” which is what adults think with. This part of the brain is responsible for impulse control, reasoning and judgment. The brain scans below highlight this region of the brain and give evidence to just how long it truly takes to mature. 


Adolescents, ages 12-18, exhibit “a disproportionate amount of reckless behavior, sensation seeking, and risk taking,” according to studies found in volume 24, issue 4 of Neuroscience and Biobehavioral Reviews. As a result, their decision making is vastly different and potentially more damaging than that of a person beyond the age of 24. These findings have raised questions about how the American court system should be dealing with juveniles who are still years from full maturity, when statistics show many will “outgrow” criminal behavior. The graph below shows the direct correlation between the number of people arrested for violence and the age at which they committed the act.  





The graph reflects how brain development can either hinder or help a person’s ability to react in nonviolent ways, depending on what stage of life he or she is in. The age at which adolescents are most violent, according to this graph, peaks around 18-19. After that, the violent behavior dwindles.


Until very recently, with U.S. Supreme Court decisions like Miller v. Alabama in 2012 and Montgomery v. Louisiana in 2016, courts rarely considered brain development and social factors that affect juvenile offenders. Judges were often reluctant to entertain evidence that juveniles’ behavior was affected by their social backgrounds or simply by the fact that their brain had not caught up with everyone else yet.  

Different brains develop at different rates, and studies have shown that social factors (such as abuse and neglect) can also hinder development. Juveniles who are tried in adult court and sentenced to adult prisons are less likely to receive rehabilitation that might help their development. The dangers of simply sentencing these children to jail and not helping them can be seen in the following study described in the same issue of Neuroscience and Biobehavioral Reviews, which deals with problem behaviors in adolescent development:  

“In one report of 11–15 year-olds, 80% exhibited one or more problem behaviors during the previous month; these behaviors included disobeying parents, school misconduct, substance use and antisocial behaviors (including theft or fighting). Indeed, with half or more of adolescents exhibiting drunk driving, sex without contraception, use of illegal drugs, and minor criminal activities, ‘reckless behavior becomes virtually a normative characteristic of adolescent development.’” 

Juveniles who do not receive helpful guidance after exhibiting these reckless behaviors are increasingly more likely to have them become “normative characteristics” for years to come. The juvenile lifers who are now being resentenced, then, perhaps never had the chance to progress past the violent behavior they were jailed for decades ago.  

Jane Moriarty, Duquesne University law professor and expert in criminal justice and brain development, believes rehabilitating these juveniles might be more effective than incarcerating them for years. Even though the courts are now taking the neuroscience research into account when sentencing juveniles, Moriarty said, more work needs to be done to get the country’s whole criminal justice system to recognize the potential of rehabilitation. See the interview below:

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