New research is showing distinct changes in the brains of young adults, ages 18 to 21, suggesting that they too may be immature in ways that are relevant to justice policy. A new knowledge brief from the MacArthur Foundation Research Network on Law and Neuroscience considers the implications of this research:
The justice system in the United States has long recognized that juvenile offenders are not the same as adults, and has tried to incorporate those differences into law and policy. But only in recent decades have behavioral scientists and neuroscientists, along with policymakers, looked rigorously at developmental differences, seeking answers to two overarching questions: Are young offenders, purely by virtue of their immaturity, different from older individuals who commit crimes? And, if they are, how should justice policy take this into account?
A growing body of research on adolescent development now confirms that teenagers are indeed inherently different from adults, not only in their behaviors, but also (and of course relatedly) in the ways their brains function. These findings have influenced a series of Supreme Court decisions relating to the treatment of adolescents, and have led legislators and other policymakers across the country to adopt a range of developmentally informed justice policies.