How To Sleep Like a Hunter-Gatherer

Not all people sleep in "giant sleep machines," like we do.

Wednesday, January 02, 2008
RELATED TAGS: SLEEP

What’s really going on inside your head when you sleep, dream, or are wide-awake? In his fascinating new book, The Head Trip: Adventures on the Wheel of Consciousness (Random House, $24.95), science writer Jeff Warren explores some familiar and some less familiar states of consciousness, everything from daydreams to lucid dreams. Warren talked to scientists and Buddhist monks, slept in sleep labs, and spent time in a secluded mountain cabin to experience firsthand various states of consciousness. Along the way, he discovered perception-shifting information about how people sleep in different cultures. Westerners prefer a quiet bedroom, sleeping alone or with a partner. Egyptians commonly sleep with several family members in the same room and, even in a noisy city like Cairo, with the windows wide open. In the excerpt below, Warren meets with one of the few anthropologists who study the culture of sleep. —Jane Bosveld


When I flew down to Atlanta to interview Carol Worthman, the director of the Laboratory for Comparative Human Biology at Emory University, she greeted me in her office, among the stacks of research monographs and the photos of her with beaming tribal groups from several continents. I asked why she had first thought to study sleep, and she smiled. “It was a true ‘aha’ experience. I was sitting in my office when a friend of mine who was studying mood disorders called me up and asked me what anthropologists knew about sleep.”

She laughed and paused for a moment of dramatic emphasis. “Nothing!” She widened her eyes behind the thick lenses. “We know nothing about sleep! I think of all the places I’ve slept around the world, all the groups I’ve studied. . . . I mean, here I was, part of this discipline dedicated to the study of human behavior and human diversity, and yet we knew next to nothing about a behavior that claimed one-third of our lives. I was stunned.”

So Worthman began to comb the literature, interviewing ethnographers, sifting through fifty-odd years of published work. What she found, she said, shouldn’t have surprised her: “The ecology of sleep is like the ecology of everyday life.” Sleep, it seems, comes in many cultural flavors.

Worthman flipped open a book and showed me photographs of big families piled into large, sprawling huts, little kids peeking up from the arms of Mom, older generations wrapped leisurely around the fireplace. “Forager groups are a good place to start, because for much of human history we’ve been occupied with their mode of existence,” she said. “There are the !Kung of ­Botswana and the Efe of Zaire. For both of these groups, sleep is a very fluid state. They sleep when they feel like it—during the day, in the evening, in the dead of night.”

This, said Worthman, is true of other groups too—the Aché of Paraguay, for example. Late-night sleep, when it happens, is practically a social activity. In addition to procreation, the night is a time of “ritual, sociality, and information exchange.” People crash together in big multigenerational heaps—women with infants, wheezing seniors, domestic animals, chatting hunter buddies stoking the fire—everyone embedded in one big, dynamic, “sensorily rich environment.” This kind of environment is important, said Worthman, because “it provides you with subliminal cues about what is going on, that you are not alone, that you are safe in the social world.”

The more Worthman learned about the communal and interactive nature of non-Western sleep, the more she came to see Western sleep as the strange exception. She laughed again. “It’s funny, because as an anthropologist I’m used to getting weirded out a bit—I mean, you wouldn’t believe the things people do. So after collecting all this material I look at my own bed and go, ‘This is really weird.’”

Western sleep, said Worthman, is arid and controlled, with a heavy emphasis on individualism and the “decontextualized person.” Contact is kept to a minimum. The apparent conflict with marriage co-sleeping norms, she notes elsewhere, “has been partially mitigated for Americans by the evolution of bed size from twin, to double, to queen, to king.” She lifted her thin arms and drew a big box in the air. “I mean, think about it—this thing, this bed, is really a gigantic sleep machine. You’ve got a steel frame that comes up from the floor, a bottom mattress that looks totally machinelike, then all these heavily padded surfaces—blankets and pillows and sheets.”

It’s true. Most of us sleep alone in the dark, floating three feet off the ground but also buried under five layers of bedding. I had the sudden image of an armada of solitary humanoids in their big puffy spaceships drifting slowly through the silent and airless immensity of space. “Whoa,” I said.

Worthman nodded. “I know, I know, so weird.”

By contrast, village life is one big, messy block party, crackling with sex, intrigue, and poultry. In these cultures, interrupted or polyphasic sleep is the norm, which jibes with findings about still other cultures, like the Temiars of Indonesia and the Ibans of Sarawak, 25 percent of whom are apparently active at any one point in the night.

Even more intriguing are some of the culturally specific practices around sleep. Worthman flipped to a sequence of photos showing a tribe of bare-chested Indonesians gathered in a big circle. “These are the Balinese, and this is an example of something called ‘fear sleep’ or ‘todoet poeles.’ See these two guys?” She pointed to the first picture, where two men cowered on the sand in the center of the group. “They just got caught stealing from the village kitty, and they’ve been hauled out for trial.” The villagers all had angry faces and open mouths. The two men looked terrified.

“You can see the progression. He’s starting to sag”—in the next photo one of the thieves had his eyes closed and had begun to lean over—“and here in the last photo you can see he’s totally asleep.” The same thief was now slumped and insentient, snoozing happily amid the furious village thrum. “Isn’t that amazing?” Worthman shook her head. “In stressful situations they can fall instantly into a deep sleep. It’s a cultural acquisition.”

We moved out of her office and made our way down to the laboratory, where Worthman pulled out a big cardboard box. “We wanted to look at sleep in non-Western cultures firsthand, so we decided to initiate a study.” She opened the box. “We went to Egypt, because, well, hunter-gatherer types are interesting, but they’re not really relevant now. Cairo is an old civilization in a modern urban environment. We wanted to look at a pattern that everyone knows is historic in the Mediterranean area. They sleep more than once a day—at night and the midafternoon.”

I nodded. Of course, the siesta—or Ta’assila, as it’s known colloquially in Egypt. Worthman reached into the box and lifted out a set of black paisley headbands, all of them threaded with thin wires and dangling sensors. “So we studied six households in Cairo, and we made everyone wear one of these headbands at all times. One of these little sensors is a motion detector, the other is a diode that glues onto the upper eyelid in order to detect whether or not you’re in REM sleep.”

Thus outfitted, the families went about their daily business, supplying a steady stream of information for the visiting anthropologists. What they found was that Egyptians on average get the same eight hours that we do, they just get it by different means: about six hours at night and two in the afternoon. They also sleep in radically different sleep environments—rarely alone, almost always with one or more family members, in rooms with windows open to the roar of outside street traffic.

“Listen to this.” She pressed play on a tape recorder and the sound of traffic blared out of the little speakers. She raised her voice to yell: “I mean, I’m a pretty sound sleeper, but I couldn’t sleep in Cairo. It was too noisy!” I yelled back, “I see what you mean!” It sounded like 200 years of industrial noise pollution pressed into a single recording. She slid me a photo of a Cairo street, a narrow alley crisscrossed with laundry and jam-packed with donkey carts, trucks, cars, camels, and buses. “Every imaginable form of human transport, right below your window!” She hit stop and the room went quiet. “Despite all this ambient noise, Cairoans don’t seem to have any trouble falling asleep.”

For Worthman, the conclusion was obvious. All these different sleep patterns suggested that the regulatory processes governing “sleep-wake transitions” could be shaped by cultural conditions. Sleep, it seemed, was putty—some cultures stretched it out, some chopped it up, and others, like our own, squeezed it into one big lump.


From The Head Trip by Jeff Warren. Copyright © 2007 by Jeff Warren. Published by arrangement with Random House, an imprint of Random House Publishing Group, a division of Random House Inc.

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