I'm Steve Strogatz, and this is The Joy of Why, a podcast from Quantum Magazine that takes you into some of the biggest unanswered questions in math and science today.

In this episode, we're going to be talking about dreams. What are dreams exactly? What purpose do they serve? And why are they often so bizarre?

We've all had this experience.

You're dreaming about something fantastical, some kind of crazy story with a narrative arc

that didn't actually happen with people we don't necessarily know in places we may have never

even been. Is this just the brain trying to make sense of

random neural firing? Or is there some evolutionary reason for dreaming? Dreams are inherently

hard to study. Even with all the advances in science and technology, we still haven't really

found a way to record what someone else is dreaming about.

Plus, as we all know, it's easy to forget our dreams as soon as we wake up,

unless we're really careful to write them down.

But even with all these difficulties, little by little, dream researchers are making progress

in figuring out how we dream and why we dream.

Joining me now to discuss all this is Dr. Antonio Zadra, a professor at the University of Montreal and a researcher at the Center for Advanced Research in Sleep Medicine. His specialties include

the study of nightmares, recurrent dreams, and lucid dreaming. He's also the co-author of the recent book

When Brain's Dream, Exploring the Science and Mystery of Sleep. Tony, thank you so much for joining

us today. Thank you for having me. I'm very excited to talk to you about this. So let's start

with thinking about the science of dreams as you and your

colleagues see it today. Why are dreams so hard to study? One of the biggest difficulties in

studying dreams is that we don't study dreams directly. What we study our dream reports, either

what people tell us they dreamt about or what they write down. So much of the

work is done if you want after the fact. Even when dreams are studied in the laboratory, you can look

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