Abstract
In the past 8 years, the US Supreme Court has issued landmark opinions in three cases that involved the criminal culpability of juveniles. In the most recent case, in 2012, a ruling prohibited states from mandating life without parole for crimes committed by minors. In these cases, the Court drew on scientific studies of the adolescent brain in concluding that adolescents, by virtue of their inherent psychological and neurobiological immaturity, are not as responsible for their behaviour as adults. This article discusses the Court's rationale in these cases and the role of scientific evidence about adolescent brain development in its decisions. I conclude that the neuroscientific evidence was probably persuasive to the Court not because it revealed something new about the nature of adolescence but precisely because it aligned with common sense and behavioural science.