For most of human history, people were hunter-gatherers. They lived in large camps, depending on one another for food, childcare, and everything else—all without walls, doors, or picket fences. In comparison, the number of people living in most households in today’s developed countries is quite small. According to the Census Bureau, fewer than three people lived in the average American household in 2010. The members of most American households can be counted on one hand, or even, increasingly, one finger: Single-person households only made up about 13 percent of all American households in 1960. Now, that figure is about 28 percent.

Belonging to a relatively small household has become the norm even though it can make daily life more difficult in many ways. Privacy may be nice, but cooking and doing chores become much less time-consuming when shared with an additional person, or even several people. Water, electric, and internet bills also become more bearable when divided among multiple residents. There are social downsides to living alone, too. Many elderly people, young professionals, stay-at-home parents, and single people routinely spend long stretches of time at home alone, no matter how lonely they may feel; more distressingly, many single parents face the catch-22 of working and paying for childcare. Living in smaller numbers can be a drain on money, time, and feelings of community, and the rise of the two-parent dual-earning household only compounds the problems of being time-poor.

It wasn’t always like this. Living arrangements have been changing for thousands of years, and the concept of the nuclear family originated relatively recently. Even as the economy has moved away from the sort of agricultural labor that would encourage large households, people still have just as much of a need for the support of friends, family, and neighbors. Perhaps that is why so many people today—from young coders to lonely septuagenarians to families—are experimenting with communal living, a way of life that, whether they know it or not, echoes how things worked for most of human history. This sort of experimentation is all too appropriate at a time when, for the typical American child, having two married parents is on the decline, and there is no longer a single dominant family structure as there was a half-century ago.

Tens of thousands of years ago, all living was communal. Being a hunter-gatherer meant being free of many of the distinctions that govern life today. “There’s no division between your social life and your private life,” says Mark Dyble, a postdoctoral researcher at University College London who studies modern-day hunter-gatherers in the Philippines. “Your whole life is open to other people. There’s no way to be isolated.” The hunter-gatherer camps Dyble studied, whose members change week by week, consist of anywhere from five to 18 deeply interdependent “households,” each usually made up of parents, their children, and perhaps another relative or two. These households are involved in virtually every aspect of each others’ lives.

While relatives often stick together, these families are anything but self-sufficient. “A chimp mother is capable of feeding herself and her offspring. That’s not the case with humans,” Dyble says, pointing out that human children take a long time to mature and take care of themselves. “By our biology, we are obliged to have support from others. You couldn’t survive as a single-family household among hunter-gatherers.”

The Middle Ages, when homes were essentially gathering places for small groups of revolving residents, represent a conceptual midpoint between hunter-gatherers’ living arrangements and those common today. As the historian John Gillis described in his 1997 book A World of Their Own Making: Myth, Ritual, and the Quest for Family Values, people in medieval Europe lived with a mix of friends and extended family. At that time, single-family households were uncommon in most of the world, and Western Europe became, around the 12th century, one of the first places where households were organized around monogamous couples and their children. But these households still didn’t look much like today’s nuclear families. In addition to parents and their children, medieval households frequently included various townspeople, poor married couples, other people’s children, widows, orphans, unrelated elderly people, servants, boarders, long-term visitors, friends, and assorted relatives.

On top of that, people moved constantly among houses. “Home was the place that sheltered you at the moment, not the one special place associated with childhood or family of origin,” Gillis writes. Single people sometimes ran households, and marriage was not as narrowly defined as it is today. Most kids spent time living away from their families, especially as teenagers. Living with strangers was common, and locals would often treat houses like public property. “People entered without knocking, even without acknowledgement,” writes Gillis. “It was often difficult to tell which family belonged where … In big as well as little houses, the constant traffic of people precluded the cozy home life we imagine to have existed in the past.”

By the 1500s, the idea of a household as a father, a mother, and their biological children caught on among Europe’s new urban middle class, at least as something to strive for. This “godly household” owes a lot to the Protestant Reformation, in which religious leaders started rejecting the Catholic Church as the center of life and replaced it with a domestic divine: the father as a stand-in for God, the mother for a priest, and the children for congregants. It’s around this time that nativity scenes became popular, emphasizing Jesus’s role as a member of a nuclear family rather than as a lone preacher.

For all its popularity as a comforting idea, the godly household was hardly common 500 years ago. It was completely unrealistic for most people to find the time, money, and resources to run a household on their own. Even those who did usually had big households full of unrelated people; they relied on the larger community far too much to survive as a single-family unit.

It wasn’t until the 1800s that people began drawing a sharp distinction between family and friends when it came to who they lived with. So, during the latter half of the 19th century, the godly family started to take shape in reality. Industrialization made extended communities less vital for earning a living. When societies were mostly agricultural, production was centered near the home, and families needed all the labor they could get to run the farm during busy seasons. But as industrialization took hold, people started leaving home to go to work, commuting to factories and, later, offices. Something communal was lost, and by the early 20th century, industrial efficiency permitted a lifestyle of domestic privacy: Households shrank down to nuclear families, much more closed-off from relatives and neighbors than ever before.

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Homeownership is still viewed as a central component of living out the American dream, but the ways that many present-day Americans are pushing back on modern living arrangements closely resemble what came centuries, even millennia, before in other parts of the world.  Family members, relatives, neighbors, and strangers are coming together to live in groups that work for them—a bit like medieval Europe. “Today, all across the nation, Americans are living the new happily ever after,” writes the social psychologist Bella DePaulo in her 2015 book How We Live Now: Redefining Home and Family in the 21st Century. “The ‘new’ part is that people with whom they are sharing homes and lives are not just spouses or romantic partners.”

Instead of limiting their households to children, parents, and grandparents, plenty of people are going a step further, making homes with friends and even strangers. Cohousing, in which a large community lives together and shares household duties, is gaining popularity. In cohousing, individuals or families generally have their own houses, bedrooms, or apartments but share things like kitchens and community spaces. They’ll commonly trade off on responsibilities like cooking and chores. Milagro Housing, for instance, is a cohousing community located in Arizona’s Sonoran Desert. There, families, couples, and single people live in 28 homes in a tight-knit community that shares a kitchen, laundry room, library, meeting room, playroom, and storage rooms.

And Milagro Housing isn’t all that unusual; the Fellowship for Intentional Community, an organization that champions communities "where people live together on the basis of explicit common values," lists 1,539 cohousing communities around the country, some already formed and others in the process of forming. That’s likely a low estimate, since plenty of shared-living communities aren’t reported to any national databases. While some residents hire developers to build cohousing villages from scratch, most have turned already-existing houses and apartments into shared communities.

Cohousing has shown itself to be a useful living arrangement for groups of people with all sorts of priorities. In Silicon Valley’s hacker houses, dozens of computer programmers, most of them very young, bunk together while they work at start-ups or on their own projects. The website CoAbode links single mothers who want to live and raise children together. In Los Angeles, about a dozen young adults live together in one large house called Synchronicity LA. There, they make art together, hold salons, divide up chores, and trade off cooking communal meals four days a week. “It really feels like living in a big family,” Grant Hoffner, a longtime Synchronicity resident, told me.

Cohousing models can get pretty creative. In Hope Meadows, a neighborhood near Chicago that DePaulo describes in her book, retired people live together with at-risk foster kids. There, retired folks, many of whom used to describe their lives as boring and lonely, raise the kids together. And in Deventer, a town in the eastern region of the Netherlands, that model is flipped: Some college students there live in nursing homes alongside elderly people, who they socialize with and assist with various chores.

The modern cohousing movement began in Denmark in the 1970s, and there are now more than 700 “living communities” in Denmark alone, according to DePaulo. In each, dozens or even hundreds of Danish families live in homes built around shared spaces and common houses. “The residents wanted to see each other over the course of their everyday lives, and be there for each other in ways large and small,” writes DePaulo. The idea spread to several other countries, and Sweden even has a number of state-owned cohousing buildings, each populated by hundreds of residents. And that’s just this particular brand of shared living; 120,000 Israelis live in communal villages called kibbutzim, which originated about 100 years ago.

Developers are starting to see how appealing cohousing is to some people. Commonspace, for instance, is a company that designs and runs apartments consisting of about 20 small units around a common area occupied mostly by young and single people, sort of like a dorm for adults. The first distinctive cohousing setup in the U.S. was built by developers 25 years ago, but the concept hasn’t gained much traction, as there are now only 160 American cohousing communities built from scratch. Perhaps that will change as developers court young people who envision a lifestyle different than the one they’ve inherited from the 20th century.

Among other things, many residents are drawn to the company that cohousing offers, which DePaulo says is the main reason people choose to live like this. Cohousing can feel a bit like summer camp, with people always around to talk to and spend time with. But it also provides deep support systems. “If someone is hospitalized, cohousing friends are there to visit,” writes DePaulo. “When a cohouser is ailing at home, neighbors show up with chicken soup and the latest news from the community.”

One anthropologist DePaulo interviewed decided to live with more people after being unhappy on her own, even though her boyfriend lived nearby and she had some friends in her building. “I would come home and cry,” Leanna Wolfe, the anthropologist, told DePaulo. “I was just so lonely.” She wasn’t the only one: Americans have fewer close friends than they used to. Since 1985, the number of Americans who have no friends to confide in has tripled, reported a 2006 American Sociological Review study.

In addition to the sense of community it builds, there’s an obvious upside to shared living: saving time and money. In a typical American house or apartment, individuals or small families are in charge of each meal themselves. But cohousing communities can divide up cooking schedules. Many residents only cook once a week and come home to cooked meals everyday.

One of cohousing’s biggest draws is that it eases the burdens of child-rearing. It takes a village to raise a child, as the saying goes, and most modern-day parents could use the help. Among the Efe, a group of hunter-gatherers in the Congo, some infants more than three weeks old spend 80 percent of their time with someone other than their mothers. By comparison, the majority of American communities are designed to keep people apart. “I like to think of dwellings as people: If a group of people wanted to get to know each other, they would not line up facing each other in two straight, rigid rows, too far apart to really see anyone else clearly,” writes DePaulo. “That’s how houses are arranged on many conventional streets.” Under other housing models, a village really could raise a child.

DePaulo argues that it would be particularly helpful to integrate cohousing into public-housing policy. “People who work on housing for the poor have to deal with people’s whole lives,” she argues in her book. “They can’t just give them a place to live and forget about them.” Keeping rent affordable is the foremost concern for people in charge of managing public housing, but cohousing can fill in other difficulties of living without much money: Splitting cooking, childcare, and household expenses can save lots of time and money. For these reasons and others, Danish and Swedish governments have long supported cohousing. American governments (especially local ones) could do the same, perhaps by converting abandoned hotels into mixed-income cohousing, building affordable shared-living buildings, or even just by connecting interested locals and helping them refashion their neighborhoods into something that better fosters community.

Humans have never lived the same way for long, and many people are finding today’s urban and suburban neighborhoods, which are based on an idealized version of home that is by now hundreds of years old, to be lacking. Humans may never return to the days of having strangers and distant relatives dropping in to live for extended periods of time, but it’s clear that a group of people are tapping into the past that John Gillis wrote about: “Until well into the nineteenth century, heaven was represented not as a community of families but as one large community of friends.”