The teenage years can be mystifying for parents. Sensible children turn scatter-brained or start having wild mood swings. Formerly level-headed adolescents ride in cars with dangerous drivers or take other foolish risks.

A flood of new research offers explanations for some of these mysteries. Brain imaging adds another kind of data that can help test hypotheses and corroborate teens’ own accounts of their behavior and emotions. Dozens of recent multiyear studies have traced adolescent development through time, rather than comparing sets of adolescents at a single point.  Click here to read more