Narrator: This is Science Today. New psychological evidence suggests babies and children under the age of four have brains that are smarter, faster and busier than any adult's. Alison Gopnik, a psychology professor at the University of California, Berkeley, says in comparison, adult brains are less flexible.

Gopnik: We're less good at learning new things - at considering and entertaining new possibilities. I think the great advantage that children and babies have is that they're extremely good doing at this. They haven't had all this experience and practice in using information, that they're so much more open to new possibilities. They are literally more active and more connected than adult's brains are.

Narrator: Gopnik stops short of supporting the old theory that a baby's mind is like a sponge.

Gopnik: They're not really like a sponge, if a sponge means that they're just taking everything in. On the contrary, part of the reason exactly why they can learn so much is because they only pay attention to some things, not others. And they change what they think about the world bit by bit - the same way that adult scientists change what they think about the world bit by bit.

Narrator: For Science Today, I'm Larissa Branin.