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Everyone has dreams, but some people are better at remembering them than others. Scientists aren't sure why we dream, but remembering them has a lot to do with the activity in your brain, and with how well you sleep.

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This episode is sponsored by Audible.

To get started, go to audible.com/scishowpsych or text “scishowpsych” to 500 500. [♪ INTRO]. It seems like some people can regale you with every last detail of the dream they had last night while others can’t remember whether or not they even had a dream.

No matter which camp you fall in, everybody does have dreams; it’s just that some people are better at remembering them than others. And whether or not you remember those surreal, unconscious experiences has a lot to do with the activity in your brain, and with how well you sleep. Scientists still aren’t totally clear on why we dream in the first place, but they have a decent idea of what our brains are up to when we do.

We dream the most when we’re in a stage of sleep called REM. REM stands for Rapid Eye Movement, and it’s a stage of deep sleep that gets its name from the way our eyes move back and forth while we’re in it. We typically have a few REM cycles through the night, beginning around ninety minutes after we fall asleep, and each cycle can last between a minute and an hour.

Even though you’re sleeping deeply during your REM cycles, your brain actually acts a lot like it does when you’re awake. For instance, while you’re awake, there’s lots of blood flowing to the cerebral cortex, the thin layer that surrounds the largest part of your brain, which plays a role in making decisions and thinking creatively. Blood is also flowing to the limbic system, a set of structures that control your emotional response to the things you experience.

During REM sleep, those same parts of the brain are active. Even your heart rate and blood pressure are similar to what they are when you’re awake. So you’re having lively, emotional experiences a lot like the ones you’d have when you’re awake.

The main difference is that, while you’re asleep, your brain kindly paralyzes you so that you don't act your experiences out. They can still feel very real, though. So, during REM, almost everyone is having dreams, and often vivid ones!

But not everyone remembers them. In part, that’s because some people just have more brain activity during REM sleep. The more blood you have flowing to the cerebral cortex, the more active that part of the brain will be.

More brain activity creates more vivid dreams, and more vivid dreams tend to be more memorable. But another big reason you either remember your dreams or don’t has to do with your levels of a hormone called norepinephrine. Whether you’re awake or asleep, norepinephrine helps you remember things.

Whenever you have an emotionally stimulating experience, your brain releases this hormone. As it rushes through your brain, it binds to the nerve cells that help us learn new information, creating pathways between them. Later on, electric signals in your brain can travel back down those pathways to help you recall the experience you were having when they formed.

Norepinephrine is always present at some level while you’re awake. When you fall asleep though, your norepinephrine levels drop. That’s true for everyone, and it’s especially true during REM cycles.

But from then on, the amount of norepinephrine in your brain has a lot to do with how well you sleep. If you knock right out and don’t wake up till morning, your norepinephrine levels probably rarely rise to the point where you start creating memories. But if you’re a light sleeper, you likely get a little rise in norepinephrine every time you stir awake.

And that norepinephrine helps your brain cells create connections that make you more likely to form a memory of the dream you were having. So being able to remember your dreams isn’t exactly the superpower it might seem like; the truth is you probably just don't sleep very soundly. And if you’ve never been great at remembering your dreams, that's not a bad thing.

But if you’re really curious about the places your subconscious mind wanders while you sleep, there are things you can do to get better at remembering. For instance, right when you wake up, you can keep your eyes closed and attempt to think back on what you’ve dreamt as you gradually become more conscious. Since you’re slowly entering awake mode, you’ll be more likely to retain the memory.

That’s because when you wake up abruptly, your levels of cortisol, the body’s stress hormone, tend to take over and focus you on the day ahead, which gets in the way of your brain forming memories. So when you wake up more slowly, you have a better shot. And then, you can also do this trick, you can just drink a lot of water before bed.

If you keep having to go to the bathroom, you will get the benefit of the norepinephrine rise each time you drag your foggy-brained self out of bed. And if you do manage to remember something from a dream, you might want to write it down before you fall back asleep! But if even you never remember anything, you can be pretty sure that your subconscious self is still having lively adventures while you sleep.

You might not remember your dreams, but if you’re interested in a lively story that will take you all over the place and surprise you at every turn,. I just finished Blake Crouch’s Recursion on Audible. It was very good!

I was on the edge of my seat, I was terrified for a lot of it,. I didn’t know what was going on and then when you do, you’re like, ‘This is happening?!’. It’s wonderful.

Blake Crouch is a master, and the Audiobook was very well done. With an Audible membership, you can get access to one free audiobook every month, easy exchanges, and 30% off all regularly priced audiobooks. Audible’s library can help you achieve your goals, like being a more empathic leader or finishing more stories or trying out a guided meditation program.

If you try Audible for 30 days, you can get your first audiobook for free plus two Audible Originals. Visit audible.com/scishowpsych or text “scishowpsych” to 500 500. That’s “scishowpsych”, P-S-Y-C-H. [♪ OUTRO].