NOVA

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Instructor

Are you ready? Yeah! (items jingling) (playful music) A zet! We're teaching children novel words for completely novel objects. Look at these! We use this completely new information so we can measure the brain's ability to form completely novel, completely new memories. Hey, a beev! (giggling) So in essence, we're measuring brute force memory. What's this? -

Narrator

The kids are shown four objects they've never seen before that have been given nonsense names like, zet. Wow, a zet. Cool! -

Narrator

Mup. A mup. Hey. -

Narrator

Beev. A beev. -

Narrator

And toap. A toap. Toap. -

Narrator

They get a chance to look at the objects. Look at these. -

Narrator

And even touch them. Then, half of the toddlers go home for their afternoon nap while the other half don't nap for hours. Or perhaps not at all. The next day, they're back. -

Instructor

Where's the zet? -

Narrator

How much do they remember? -

Rebecca

What we found is that, the children who nap soon after learning- -

Instructor

Mup. -

Rebecca

Remembered words about 80% of the time. Toap. -

Instructor

Where's the zet? -

Rebecca

In contrast, the kids who, went through a long period of time before they napped. -

Instructor

Where's the zet? -

Rebecca

only remembered the words about 30% of the time. Where's the toap? There? So, you see a huge difference between 80% of the time and 30% of the time and that's difference the nap makes. Where's the mup? Right here. -

Narrator

Why did a nap make all the difference? The key lays inside a tiny organ found deep within the brain, the hippocampus. We have one in each hemisphere and they play a critical role in helping us learn and remember. So, think of it this way, I have a little filing drawer beside my desk and throughout the day as papers come in, I toss them in this drawer. It's my mail that came today, its some papers that I had from a class. That's my temporary storage. The hippocampus is like that short-term filing drawer, a mish-mash of information, getting squeezed in and there's a limited amount of room there for that. But, at the end of the day, I could take that information and turn around my whole huge filing cabinet, which in this case is the cortex. The cortex, it's bigger and it has a really nice sorting mechanism. You can sort things by their visual components, by their auditory components. That memory becomes easier to find. So, the role of slow wave sleep is to take that information that's been stuffed in the hippocampus and help move it, to it's more efficient filing system out in the cortex. (dynamic music) Things that you learned yesterday are now transferred to a safer storage location. But, the second when you wake up in the morning, your hippocampus is now being cleared out and you have a refreshed capacity for new file acquisition all over again. -

Narrator

And that brings us back to our toddlers and the power of the midday nap. Why does it make such a big difference? Why is it so important for toddlers to clear out the short term filing drawer? Researchers have a theory. Young children, their brains are still developing and in fact, the hippocampus is still in the process of developing all across the childhood years. So, it does seem that the hippocampus, when it's young and immature, such as in infancy and early childhood, perhaps those memories need to be stored more frequently or moved to the cortex more frequently. (bright music)