Gray likens these aspects of the hunter-gatherer lifestyle to the carefree adventures of many children in developed countries, who at some point in life are expected to put away childish things. But that hasn’t always been the case. According to Gary Cross’s 1990 book A Social History of Leisure Since 1600, free time in the U.S. looked quite different before the 18th and 19th centuries. Farmers—which was a fair way to describe a huge number of Americans at that time—mixed work and play in their daily lives. There were no managers or overseers, so they would switch fluidly between working, taking breaks, joining in neighborhood games, playing pranks, and spending time with family and friends. Not to mention festivals and other gatherings: France, for instance, had 84 holidays a year in 1700, and weather kept them from farming another 80 or so days a year.

　　This all changed, writes Cross, during the Industrial Revolution, which replaced farms with factories and farmers with employees. Factory owners created a more rigidly scheduled environment that clearly divided work from play. Meanwhile, clocks—which were becoming widespread at that time—began to give life a quicker pace, and religious leaders, who traditionally endorsed most festivities, started associating leisure with sin and tried to replace rowdy festivals with sermons.

　　As workers started moving into cities, families no longer spent their days together on the farm. Instead, men worked in factories, women stayed home or worked in factories, and children went to school, stayed home, or worked in factories too. During the workday, families became physically separated, which affected the way people entertained themselves: Adults stopped playing “childish” games and sports, and the streets were mostly wiped clean of fun, as middle- and upper-class families found working-class activities like cockfighting and dice games distasteful. Many such diversions were soon outlawed.

　　With workers’ old outlets for play having disappeared in a haze of factory smoke, many of them turned to new, more urban ones. Bars became a refuge where tired workers drank and watched live shows with singing and dancing. If free time means beer and TV to a lot of Americans, this might be why.

　　At times, developed societies have, for a privileged few, produced lifestyles that were nearly as play-filled as hunter-gatherers’. Throughout history, aristocrats who earned their income simply by owning land spent only a tiny portion of their time minding financial exigencies. According to Randolph Trumbach, a professor of history at Baruch College, 18th-century English aristocrats spent their days visiting friends, eating elaborate meals, hosting salons, hunting, writing letters, fishing, and going to church. They also spent a good deal of time participating in politics, without pay. Their children would learn to dance, play instruments, speak foreign languages, and read Latin. Russian nobles frequently became intellectuals, writers, and artists. “As a 17th-century aristocrat said, ‘We sit down to eat and rise up to play, for what is a gentleman but his pleasure?’” Trumbach says.

　　It’s unlikely that a world without work would be abundant enough to provide everyone with such lavish lifestyles. But Gray insists that injecting any amount of additional play into people’s lives would be a good thing, because, contrary to that 17th-century aristocrat, play is about more than pleasure. Through play, Gray says, children (as well as adults) learn how to strategize, create new mental connections, express their creativity, cooperate, overcome narcissism, and get along with other people. “Male mammals typically have difficulty living in close proximity to each other,” he says, and play’s harmony-promoting properties may explain why it came to be so central to hunter-gatherer societies. While most of today’s adults may have forgotten how to play, Gray doesn’t believe it’s an unrecoverable skill: It’s not uncommon, he says, for grandparents to re-learn the concept of play after spending time with their young grandchildren.

　　When people ponder the nature of a world without work, they often transpose present-day assumptions about labor and leisure onto a future where they might no longer apply; if automation does end up rendering a good portion of human labor unnecessary, such a society might exist on completely different terms than societies do today.

　　So what might a work-free U.S. look like? Gray has some ideas. School, for one thing, would be very different. “I think our system of schooling would completely fall by the wayside,” says Gray. “The primary purpose of the educational system is to teach people to work. I don’t think anybody would want to put our kids through what we put our kids through now.” Instead, Gray suggests that teachers could build lessons around what students are most curious about. Or, perhaps, formal schooling would disappear altogether.