The following is an excerpt from The World Until Yesterday: What Can We Learn from Traditional Societies? by Jared Diamond (Viking, 2012).

How much freedom or encouragement do children have to explore their environment? Are children permitted to do dangerous things, with the expectation that they must learn from their mistakes? Or are parents protective of their children’s safety, and do parents curtail exploration and pull kids away if they start to do something that could be dangerous?

The answer to this question varies among societies. However, a tentative generalization is that individual autonomy, even of children, is a more cherished ideal in hunter-gatherer bands than in state societies, where the state considers that it has an interest in its children, does not want children to get hurt by doing as they please, and forbids parents to let a child harm itself.

That theme of autonomy has been emphasized by observers of many hunter-gatherer societies. For example, Aka Pygmy children have access to the same resources as do adults, whereas in the U.S. there are many adults-only resources that are off-limits to kids, such as weapons, alcohol, and breakable objects. Among the Martu people of the Western Australian desert, the worst offense is to impose on a child’s will, even if the child is only 3 years old. The Piraha Indians consider children just as human beings, not in need of coddling or special protection. In Everett’s words, “They [Piraha children] are treated fairly and allowance is made for their size and relative physical weakness, but by and large they are not considered qualitatively different from adults … This style of parenting has the result of producing very tough and resilient adults who do not believe that anyone owes them anything. Citizens of the Piraha nation know that each day’s survival depends on their individual skills and hardiness … Eventually they learn that it is in their best interests to listen to their parents a bit.”

Some hunter-gatherer and small-scale farming societies don’t intervene when children or even infants are doing dangerous things that may in fact harm them, and that could expose a Western parent to criminal prosecution. I mentioned earlier my surprise, in the New Guinea Highlands, to learn that the fire scars borne by so many adults of Enu’s adoptive tribe were often acquired in infancy, when an infant was playing next to a fire, and its parents considered that child autonomy extended to a baby’s having the right to touch or get close to the fire and to suffer the consequences. Hadza infants are permitted to grasp and suck on sharp knives. Nevertheless, not all small-scale societies permit children to explore freely and do dangerous things.

On the American frontier, where popâ€¨ulation was sparse, the one-room schoolhouse was a common phenomenon. With so few children living within daily travel distance, schools could afford only a single room and a single teacher, and all children of different ages had to be educated together in that one room. But the one-room schoolhouse in the U.S. today is a romantic memory of the past, except in rural areas of low population density. Instead, in all cities, and in rural areas of moderate population density, children learn and play in age cohorts.

School classrooms are age-graded, such that most classmates are within a year of each other in age. While neighborhood playgroups are not so strictly age-segregated, in densely populated areas of large societies there are enough children living within walking distance of each other that 12-year-olds don’t routinely play with 3-year-olds.

But demographic realities produce a different result in small-scale societies, which resemble one-room schoolhouses. A typical hunter-gatherer band numbering around 30 people will on the average contain only about a dozen preadolescent kids, of both sexes and various ages. Hence it is impossible to assemble separate age-cohort playgroups, each with many children, as is characteristic of large societies. Instead, all children in the band form a single multi-age playgroup of both sexes. That observation applies to all small-scale hunter-gatherer societies that have been studied. In such multi-age playgroups, both the older and the younger children gain from being together. The young children gain from being socialized not only by adults but also by older children, while the older children acquire experience in caring for younger children. That experience gained by older children contributes to explaining how hunter-gatherers can become confident parents already as teenagers. While Western societies have plenty of teenage parents, especially unwed teenagers, Western teenagers are suboptimal parents because of inexperience. However, in a small-scale society, the teenagers who become parents will already have been taking care of children for many years.

Another phenomenon affected by multi-age playgroups is premarital sex, which is reported from all well-studied small hunter-gatherer societies. Most large societies consider some activities as suitable for boys, and other activities as suitable for girls. They encourage boys and girls to play separately, and there are enough boys and girls to form single-sex playgroups. But that’s impossible in a band where there are only a dozen children of all ages. Because hunter-gatherer children sleep with their parents, either in the same bed or in the same hut, there is no privacy. Children see their parents having sex. In the Trobriand Islands, one researcher was told that parents took no special precautions to prevent their children from watching them having sex: they just scolded the child and told it to cover its head with a mat. Once children are old enough to join playgroups of other children, they make up games imitating the various adult activities that they see, so of course they have sex games, simulating intercourse.

Reprinted by arrangement with Viking, a member of Penguin Group (USA) Inc., from The World Until Yesterday by Jared Diamond. Copyright © 2012 by Jared Diamond.