In 2005’s Roper v. Simmons decision, the Supreme Court ruled that you can’t execute someone for a crime committed before the age of eighteen. The appropriate reasoning was straight out of chapters 6 and 7: the brain, especially the frontal cortex, is not yet at adult levels of emotional regulation and impulse control. In other words, adolescents, with their adolescent brains, aren’t as culpable as adults.
