The news of the past decade or so is that the human brain continues its maturational march between the ages of 10 and 20. The frontal cortex and other areas needed for mature thought are not fully developed until at least the end of that period. Meanwhile, the average age at which children reach puberty (as defined by hormonal change) has dropped at least two or three years over the past two centuries. That is not evolution but revolution, and it is likely that the endocrine change now occurs earlier in relation to brain development as well as to chronological age. If so, we have an even starker problem than the slowness of brain growth: hormonal surges at ever-younger brain ages and ever-lower levels of inhibition. The implications for schooling, for the increasing sexualization of the young, and for the culpability of juvenile offenders are potentially transformative.
(Image: By Daniel Mihailescu/Getty)