An interesting idea in the NYTimes Ideas issue from Bruce Charlton, a doctor and psychology professor at Newcastle University in Britain. What looks like immaturity — or in Charlton’s kinder terms, the “retention of youthful attitudes and behaviors into later adulthood” — is actually a valuable developmental characteristic, which he calls psychological neoteny. "So, the next time you see a mother of three head-banging to death metal or a 50-year-old man sporting a faux-hawk, don’t laugh...In a recent issue of Medical Hypotheses, a journal he edits, Charlton argues that unlike previous, more settled societies that could afford to honor a narrow and well-defined worldview (that is, a “mature” one), modern life is tumultuous and ever-changing. Accordingly, it rewards those who retain a certain plasticity of mind and personality. In a psychological sense, some contemporary individuals never actually become adults."