Regina Barber

And then the next thing you know, your car is barely out of control on the highway.

You're going around that turn.

But you're in the back seat.

You can't reach the brakes.

At least, that's my reoccurring nightmare.

But when I told that to Michelle Carr, she wasn't phased.

As a sleep scientist at the University of Montreal, her job is basically watching people sleep.

So when it comes to dreams and nightmares, she's pretty much heard it all.

Michelle is the author of the new book called Nightmare Obscura.

In it, she explores the science of dreams, nightmares, even something called dream engineering, where people are able to influence their own dreams while they sleep.

But why we dream or get nightmares is still a bit mysterious for scientists.

And since humans spend somewhere around one-third of our lives asleep, we had to know more.

So today on the show, why your nightmares go bump in the night.

We dive into the science of our sleeping life with Michelle Carr and make nightmares a little more known, a little less scary.

I'm Regina Barber, and you're listening to Shortwave, the science podcast from NPR.

Michelle, sleep happens in cycles.

So can you just walk us through the four different stages of sleep?

It seems like, at least for me and many people, like there's an emotional component to sleep.

And in your book, Nightmare Obscura, you write about a study you love where participants watched embarrassing videos of themselves singing and then their brain showed signs of shame.

But that changed after a night of sleep.