Do We Dream in Only One Kind of Sleep?

People often say that dreams belong to only one kind of sleep.

There is a belief that you can find in school books, on posters and all over the internet: we dream only in REM sleep, the stage of sleep in which the eyes move quickly under the closed lids. Outside that stage, it is said, the mind is simply switched off, like a radio with its plug pulled out of the wall.

The first half of that is close to the truth, and the second half is not. REM sleep is when dreams tend to be most vivid, most like stories, and easiest to remember. But people woken from the other kind of sleep, non-REM sleep, also report dreams quite often. These are usually shorter and plainer, more like a thought or a single picture than a film, but they are dreams all the same. The radio is never quite unplugged. At some hours it plays a full song, and at others only a few notes drift in between the stations.

My brother found this out on a rainy evening in late spring, and at first he refused to believe it.

My brother fell asleep over his homework in the rain.

It had rained all day. I came home from the bakery at noon, slept until five, and woke to the sound of water running off the workshop roof into the old tin bath our grandmother kept under the gutter. She used that rainwater to rinse the parts of bicycle chains, because she said tap water left spots.

My brother was lying on the sofa with a chemistry book open on his chest. He had been asleep, I think, for ten minutes or a little more. When I came in, he sat up quickly, as people do when they are embarrassed to be caught napping.

"I saw her hands," he said. "Just her hands. Sorting screws into the tin with the dent in the lid. Big ones on the left, small ones on the right."

"That's a dream," I said.

"It can't be," he said. "I was barely asleep. You only dream in REM, and REM doesn't come until later. I read it."

He was so certain, and so pleased to have a fact to hold, that I almost let it go. But the picture he described was very clear, and it had come to him in the way such pictures often come in light sleep: no story, no talking, only a pair of hands doing one familiar thing, over and over, like a short film looping in a shop window.

My own sleep that spring was cut into pieces by the bakery. I often woke at three with a scrap of something in my head, a tray of rolls, a voice calling an order, a door I could not open. I had never once found her in those scraps, and I envied him a little.

Something to Try Tonight

Before we argued about it, we did something I had started doing on the nights when sleep felt far away. I suggested it to my brother because his shoulders were up near his ears, and I will suggest it to you.

Lie down and choose a journey you know well. It might be a bus route, a train line, or the walk from your home to a friend's house. Breathe in slowly while you count to four, and as you breathe out, a little longer, name the first stop on that journey in your head. On the next breath, name the second stop. Keep going, one stop for each breath, and do not hurry.

If you lose your place, it does not matter. Go back to the start of the line and begin again, the way a bus returns to its depot and sets out on the same route. Most nights I fall asleep somewhere between the fourth and ninth stop.

My brother chose the night bus our grandmother took to visit our great-aunt by the sea. He knew all the stops because she used to recite them to him when he was little. He got as far as the bridge, then opened his eyes and said he was too awake now to sleep, and that he still did not believe me about the dreams.

A night of sleep runs like a stopping train.

So I tried to explain it the way our grandmother would have, with a timetable.

A night's sleep is not one long, flat stretch. It runs in cycles, and each cycle takes roughly an hour and a half, give or take. In each cycle the sleeper goes down from light sleep into deep sleep, comes back up, and then usually enters a stretch of REM sleep before the next cycle begins. A full night has several of these cycles, one after another, like a slow train calling at the same kinds of stations again and again on a long line. Toward morning the REM stretches tend to grow longer, and the deep sleep shorter.

"So it's a loop," my brother said.

"More like a route with repeats," I said. "Light, deep, light again, then REM. Then round again."

He liked that. He took a pencil and drew it on the back of his chemistry homework as a line with dots on it, the way the map inside a bus shelter shows the stops. Then he looked at the drawing and frowned, because there was nothing on it that said dreams could only happen at one kind of dot.

The quiet stations have their own dreams.

What the old belief misses is that every station on the line has some kind of life in it, even late at night. In REM sleep, the dreams are often long and strange, with places that change and people who talk. In light non-REM sleep, especially just as we are falling asleep, the mind often shows us short, plain pictures: a face, a hand, a phrase, a sense of falling. In deep sleep, dreams are reported less often, but they are reported.

People who study sleep have tested this in laboratories. They wake volunteers at different points in the night and ask what was passing through their minds just before. Woken from REM sleep, the sleepers very often describe a dream. Woken from non-REM sleep, many of them still describe something: an image, a thought, a scrap of a scene, sometimes a whole small story.

A short nap on a sofa on a rainy evening is exactly the kind of sleep in which a single clear picture might appear. Our grandmother's hands sorting screws were not a story. They were one frame, held still, like a slide left in a projector after the show.

My brother turned his drawing round and round.

"So she can turn up anywhere on the line," he said at last.

I said that was one way of putting it, and that I liked it better than the way the posters put it.

The rain kept the workshop smelling of oil and dust.

After supper the rain grew heavier. We went into the workshop, because its little stove was the warmest thing in the house, and my brother lit it the way our grandmother had taught him, with newspaper and two sticks laid crosswise.

The workshop on a wet night smells of oil, rust, old wood and something sweet that I have never been able to name. The stopped clocks stood on their shelves. A bicycle without its front wheel leaned against the wall, waiting for a part that would now never come. My brother picked up the tin with the dent in the lid and shook it. It was full of screws, big ones and small ones, all mixed together.

Rain on a workshop roof is a sound I will always connect with her. On wet days nobody brought bicycles in, so she would mend radios instead, turning the dial slowly through the hiss until a voice came out, then turning on to the next, as if she were checking that every station was still there.

"She'd hate them all mixed up like this," he said, and began to sort them, left and right, by the light of the stove.

While he sorted, I told him a story about a man who used a skull as a pillow. He said it sounded like the start of a horror film. I promised him it was not.

Tonight's Story

The story comes from an old book of Chinese thought named after its author, Zhuangzi, who lived more than two thousand years ago. The book is full of jokes, talking animals, wise old craftsmen and tricky questions, and it often laughs at people who are too sure of themselves.

In one chapter, Zhuangzi is on a journey when he comes across an old skull lying by the road. It is dry and white, but it still keeps its shape. He taps it with his riding whip and starts asking it questions, partly in pity and partly, I think, out of habit, because he is a man who cannot stop asking questions.

Did you die, he asks, because you wanted life too greedily and lost your sense? Or were you put to death when your state was overthrown? Or did you do something shameful, and could not bear to face your family? Or did you die of cold and hunger? Or did you simply reach the end of your years?

The skull does not answer, of course. Night falls. Zhuangzi pulls the skull over to him, lays his head on it as a pillow, and goes to sleep.

In the middle of the night, the skull appears to him in a dream and speaks.

You talk like a clever debater, it says. Everything you asked me about belongs to the troubles of the living. The dead have none of those troubles. Would you like to hear what it is like to be dead?

Zhuangzi says that he would.

Among the dead, says the skull, there is no ruler above and no servant below. There are no chores to do as the seasons turn. We let the whole of heaven and earth be our spring and autumn. Not even a king on his throne is as happy as we are.

Zhuangzi does not believe it. Suppose, he says, I asked the keeper of fates to give you back your body, your bones and flesh and skin, and to send you home to your parents, your wife and your children, your village and your friends. Would you like that?

The skull frowns deeply in the dream. Why would I throw away a happiness greater than a king's, it asks, and go back to all the labors of the human world?

And there the story ends. There is no last line telling us what to think.

The same old book has a man drumming at a funeral.

My brother stopped sorting screws. "So the dead are fine," he said. "Is that the point?"

I told him that with this book, nobody can be completely sure what the point is, and that this is part of its charm. But I also told him about another passage in the same chapter. When Zhuangzi's own wife dies, a friend comes to comfort him and finds him sitting on the ground with his legs stretched out, beating on a tub like a drum and singing. The friend is shocked. Zhuangzi explains that at first he grieved like anyone else. Then he thought about how she had come into life out of nothing, and how she had now gone on, the way the seasons follow one another, spring to summer, autumn to winter. Weeping and wailing over that, he says, would show that he did not understand how things go. So he stopped, and he drummed.

My brother looked at the drumsticks sticking out of his back pocket. "That's a bit much," he said. Then, after a moment, "But I get it."

The skull's freedom belongs to the dead, not to us.

I want to say clearly what I said to him next, because it matters. The skull's story is a story about the dead being at rest. It is not a story about the living wanting to join them. The skull is free of chores and rulers because its life is finished. Ours is not. Zhuangzi himself, as far as anyone can tell from his book, went on living and arguing and laughing for a long time after that night on the road.

What I took from the skull that night was smaller and kinder. Our grandmother's last months had been full of hospital forms, a bad knee, and the frustration of hands that would no longer do fine work. In my brother's nap, her hands had been sorting screws easily, the way they used to. Maybe that picture was his own mind's way of letting her be free of all that, the way the skull is free of chores. Whatever the dream was, it had given her back her skill.

The rain drummed on the roof all the while, steadily, like a train crossing a long bridge.

My brother asked a question I could not answer.

By ten the screws were sorted, big ones on the left and small ones on the right. My brother closed the dented lid and put the tin back on the shelf where it had always lived.

"Zhuangzi's dream," he said. "How long do you think it lasted? He has this whole conversation with a skull. Was that hours, or did it all happen in a second, like they say on the films?"

I did not know. I had always half believed what the films say, that a long dream flashes by in a moment, like a whole landscape seen from an express train. I told him I would find out. I wrote that night down as this chapter, and his question became the next chapter, because the answer turned out to be one of the stranger things I learned that year.

He turned the stove down, and we stood for a while in the doorway of the workshop, listening to the rain fill the old tin bath under the gutter.