Dean Regis here, astronomer and host of Looking Up.

I journey to the far reaches of the universe, hearing from scientists, astronauts, and geeky celebs along the way.

We cover everything from black holes to the latest in science fiction.

Listen now to the Looking Up podcast from the NPR Network and Cincinnati Public Radio.

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From NPR.

There's this idea that something happens in the human brain when we turn 25.

Suddenly we're developed.

We can finally make rational decisions.

And we might even regret some of our past indiscretions.

I thought that I was so adult as a 20-something year old.

I thought I was so mature.

And even now I look back and I remember various things I said or did.

Not like big things actually, but there's little things that sort of fill me with embarrassment.

Duncan Astell is a neuroscientist and professor at the University of Cambridge,

and he says that there is some truth to this anecdotal reverence for the age of 25.

The cortex of our brain, its outermost layer, is filled with neurons.

So it's kind of computational center for your brain.

It's at its thickest point when we're around three or four years old.

And then it gradually starts thinning.

Around age 25, the executive control center of your brain, the frontal lobe, is done thinning out.

But the question of when the human brain stops developing?

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