In a survey, nearly a quarter of U.S. adults without a college degree said they had no close friends.

People without a college degree also reported less participation in social activities like going to parks or restaurants than college-educated adults.

The findings come amid a documented rise in loneliness and social isolation.

Nearly all U.S. adults used to have close friends.

In 1990, the share of the population that said they didn’t was low and roughly the same no matter one’s education level: just 2% for people with college degrees and 3% for those without.

But a recent survey suggests that share has risen overall, particularly among those who did not graduate college — creating a kind of class divide in people’s level of social engagement and connection. Nearly a quarter of U.S. adults with a high school diploma or lower education level said they had no close friends. The number was even higher for Black adults in that group: 35%.

Just 10% of those with a college degree said the same.

The findings come from a survey of around 6,600 adults conducted by the Survey Center on American Life, a nonprofit that researches how people’s lives are shaped by culture, politics and technology.

“Our social fabric seems to have two layers now,” said Daniel Cox, the center’s director and a co-author of a report published this week summarizing the findings. “It has one for college-educated folks that seems to be relatively intact, and then one for those without college degrees, which seems to be in tatters.”

The findings come amid a documented rise in social isolation nationwide. Around 30% of adults say they’ve felt lonely at least once per week over the past year, and 10% say they’re lonely every day, according to a January poll from the American Psychiatric Association.

The U.S. Surgeon General declared loneliness an epidemic last year, citing its links to heart disease, stroke, dementia and premature death. San Mateo County, California, which includes part of Silicon Valley, subsequently declared a public health emergency over high rates of loneliness among residents.

“There’s been considerable decline and atrophy in American social connection,” said Cox, who is also a senior fellow of polling and public opinion at the conservative Washington think tank American Enterprise Institute, adding that although the pandemic helped bring the issue to light, “this decline had gone on for decades before.”

He offered a few ideas that might explain the trend. One is that being alone is less boring now, thanks to video games and streaming services, so people may be less likely to join social groups or spend time with friends or family. Another is that for those without a college degree, there are fewer opportunities to engage in social activities, perhaps because their access to free public spaces is more limited or they lack the time or money to frequent venues like bars and restaurants.

Cox’s survey found that college-educated adults were more likely to go to restaurants or coffee shops and to strike up conversations with neighbors, compared to people without a college degree. They were also more likely to be members of a neighborhood association, sports league or hobby group (like a book club or regular poker game).