The limbic system explodes during puberty, but the prefrontal cortex keeps maturing for another 10 years.

The chance you passed up or missed could have had any number of different outcomes, and it's easy to fantasize about how much better every one of those outcomes would have been.

The essence of play is that the sequence of actions is fluid and scattered.

I'm a freelance writer, and I work alone at a big desk in the living room of my apartment. There are many days when I don't utter a single word to anyone but my husband.

There's very little about being in a functional-M.R.I. scanner that is natural: you are flat on your back, absolutely still, with your head immobilized by pillows and straps. The scanner makes a dreadful din, which headphones barely muffle.

Alright, alright, I admit it: my husband is the quiet, kind, accepting parent, and I'm the one who wants so much to be part of our two daughters' lives than I can't even let them finish a story without interrupting.

As people construct a life narrative, researchers have found, they tend to remember more events from the teens and twenties than from any other time. It's called the 'reminiscence bump.'

Some people, no matter how robust their stock portfolios or how healthy their children, are always mentally preparing for doom. They are just born worriers, their brains forever anticipating the dropping of some dreaded other shoe.

The music that was popular in your youth seems to be the music you recall most vividly - and most nostalgically - for the rest of your life. But so is the music that was popular in your parents' youth.

Scientists who study play, in animals and humans alike, are developing a consensus view that play is something more than a way for restless kids to work off steam; more than a way for chubby kids to burn off calories; more than a frivolous luxury.