How Brain Science Is Changing How Long Teens Spend in Prison
In the 1990s, before scientists had the tools to understand the teenage brain, judges around the country sentenced thousands of adolescents to life in prison without the chance for parole.
Many of these teens, who are now in their 30s and 40s, committed serious crimes like murder and were punished as adults.
At the time, policy makers thought “if you’re old enough to do the crime, you’re old enough to do the time,” said Robert Kinscherff, a senior fellow in law and neuroscience at Harvard University.
But advances in brain science since the early 2000s have proved that adolescents’ minds are fundamentally different from those of adults. Changes in the brain that occur during adolescence make young people more impulsive, less able to make measured decisions and more susceptible to peer pressure. At the same time, the malleable nature of the teenage brain means that people who commit crimes in their youth also have a greater capacity to reform.
This emerging science is reshaping the way juvenile offenders are sentenced in America. The Supreme Court drew on these findings in 2012 when it declared that it was unconstitutional to give children under the age of 18 a mandatory life sentence without the chance for parole. In Miller vs. Alabama, the justices ruled that it was a “cruel and unusual punishment” to force people to die in prison for crimes they committed as kids.
Since then, the court has clarified that its ruling must apply retroactively to thousands of inmates in prisons across the country. Last year, Justice Anthony Kennedy explained that the court’s rulings were based on the understanding that “children who commit even heinous crimes are capable of change.”
Prisoners around the country who were handed harsh sentences as kids were thought of as “adults with fewer miles on them,” said Dr. Frances Elizabeth Jensen, who chairs the neurology department at the University of Pennsylvania.
This flawed understanding, coupled with a general increase in crime in the 1980s and 1990s, fueled hysteria around the “superpredator.” The term — coined by John DiIulio while he was a political science professor at Princeton University in the mid-90s — was used to conjure a coming wave of merciless juvenile criminals who would terrorize America’s urban centers.
Politicians and journalists latched onto the term. Many states, in turn, handed down extreme sentences for crimes committed by teens. But the anticipated teen crime wave never materialized, and the superpredator theory was widely discredited and disavowed.
In recent years, the advent of functional magnetic resonance imaging, or fMRI, has given scientists the ability to get a more accurate understanding of the teenage brain in action.
Research shows that the frontal lobe — the part of the brain that governs planning, decision-making and weighs consequences — is still in training during the teen years. The frontal lobe is the last place in the brain to develop and does not fully mature until adults reach their mid-20s. By comparison, a part of the brain known as the limbic system, which governs emotions and our responsiveness to risk and reward, is well functioning by the teen years.
Jensen, who authored “The Teenage Brain: A Neuroscientist’s Survival Guide to Raising Adolescents,” said this combination of a more developed limbic system and a still maturing frontal lobe means that teenagers are more likely to make risky and impulsive decisions when compared to adults.
“They are experiencing emotion in technicolor and we are experiencing it in black and white,” she said.
One of the vital functions that adults can play in the lives of teenagers, therefore, is to act as an “external brain,” Kinscherff said. “It’s not that adolescents are unintelligent, it’s not as though they can’t foresee consequences, they just see them differently than we do.”
Teenagers are also more susceptible to peer pressure because their brains are wired to seek approval from others. One developmental psychology study by researchers at Temple University showed that teenagers around the age of 14 were twice as likely to perform a risky task if they were being observed by other peers. When the study was replicated while subjects were attached to an fMRI machine, scientists saw that teenagers’ brains were more sensitive to the rewards that might follow a risky decision whereas adults brains were better able to regulate impulses.
Brain science also shows that synapses, which allow information to pass from one neuron to another, have a heightened ability to adapt during adolescence. Some synapses are strengthened with practice while others are “pruned” away if they are unused.
This flexibility allows teenagers to learn a new skill faster and remember things better than adults. However, it also means that teenagers are more likely to develop an addiction if they are exposed to drugs and alcohol since addiction is “just another form or learning,” Jensen said. Law enforcement, therefore, may see more examples of teenage crimes committed under the influence or in a quest to fuel an addiction.
Finally, the science around juvenile’s ability to reform has gained influence as policymakers attempt to figure out how and when to grant parole to people who were sentenced to life in prison as children or teens. Neuroscience shows that young people are much more likely than adults to change over time. In addition to the synaptic “pruning” that occurs during the teen years, human brains also undergo a process known as myelination, where neural pathways are insulated by a fatty tissue called myelin. This insulation helps to speed up the connections between different parts of the brain, including the frontal lobe, which governs decision-making. Research shows that myelin continues to grow until people reach their 30s and 40s.
“We’re just at the beginning, there is a lot to learn,” Kinscherff said.
Both he and Jensen envision a future where brain scans may be used to help teenagers gain a personalized understanding of their brains as they develop.
“But we’re a long way from pointing a magic machine at a kid’s head and saying, nah, this one was old enough, sentence him as an adult,” Kinscherff added.
Correction: An earlier version of this story attributed control of sexual function and responsiveness to risk and reward to the temporal lobes. We have updated the post to clarify that these types of brain functions are governed by the limbic system.