brains take far longer to mature than previously thought.
Does this mean we should put up with sulky teenagers who act stupidly? Or treat them like toddlers? Not sure the average 16yo would take kindly to the naughty step. 
And does it mean well-behaved teenagers just happen to have matured early - it's like early walking in babies, nothing the parent (or child) can control?
(Btw, apologies if this research has been posted before, have had a look and can't see it.)