While there are certainly legitimate inspirational rag-to-riches stories out there, the reality is that individual grit and determination are not always enough to elevate a person’s social standing. The sad reality is that children born poor tend to grow up into poor adults, research shows. But that doesn’t mean there aren’t any off-ramps — and one possibly surprising avenue out of poverty may actually be friendships that cut across social classes.

Cross-class friendship matters. A lot

In a new study, researchers analyzed more than 70 million Facebook connections between U.S. accounts, representing 84% of all American adults aged 25 to 44.

This huge nationwide social graph comprising billions of connections revealed a striking pattern: the degree to which rich and poor kids were connected in a neighborhood predicted how well children did later in life. The association was stronger than any other factor, including academic performance, family structure, job availability in the community, and racial composition.

Kids living in poor households who grew up in neighborhoods where 70% of their friends lived in wealthy households saw their income increase by 20%, on average, when they became adults compared to what would be expected without access to that network. The researchers gauged each person’s socioeconomic status using the publicly available average income for a given ZIP code, along with self-reported educational attainment.

“Growing up in a community connected across class lines improves kids’ outcomes and gives them a better shot at rising out of poverty,” said Raj Chetty, an economist at Harvard University and the director of Opportunity Insights, and one of the principal authors of the new study.

Previously, scientists found that poor children who grew up in richer neighborhoods tended to earn more as adults. This just makes sense since wealthier neighborhoods are typically safer, cleaner, and have better schools and job opportunities than neighborhoods occupied by low-income families and individuals. However, even in some neighborhoods with very similar income and social structures, some places had much better social mobility. Now, this big data analysis may explain why.

The authors of the study — which includes economists at Harvard, N.Y.U., Stanford, and the Santa Fe Institute — call the newly observed effect “economic connectedness”, the idea that connecting poor and rich people produces better outcomes.

Growing up being friends with rich kids, along with the perks of living in a better neighborhood, can serve to inspire children from poorer backgrounds. By being intimately acquainted with the lifestyles of their better-off friends and their families, children will tend to emulate the priorities, goals, and life trajectories that their friends’ parents took to provide for their families. Connections with rich childhood friends may also be valuable later in life, helping people access better employment and career opportunities.

Unfortunately, opportunities for connecting children across classes are dwindling.

Virtually all parents want the best for their children, but this has the unintended and undesired effect of contributing to inequalities between poor and rich children. Since the 1990s, families with children in the U.S. have become increasingly segregated by income between neighborhoods. For instance, segregation increased by over 20 percent among families with kids from 1990 to 2010 in large metropolitan areas. Income segregation was nearly twice as high among families with kids as among childless households in 2010, according to Ann Owens, assistant professor of sociology at the University of Southern California. This trend is partly due to the wider effect of growing income inequality over the last 40 years, meaning rich families have become richer and more and more isolated from middle-class and low-income families.

But income segregation is only part of the equation — or half it, to be more precise. The authors of the new study found that the drivers of economic connectedness are “exposure” and “friendship bias”. Exposure refers to the average number of connections to wealthy people that a poor person has in their local community, such as at school, work, church, bars and clubs, and so on. Friendship bias refers to the degree to which a poor person actually befriends and forms connections with individuals from richer social backgrounds. A high friendship bias, for instance, means that rich kids hang out with only other rich kids.

The big data analysis showed that only about half of the lack of economic connectedness could be attributed to lack of exposure. This means that traditional attempts at increasing diversity — things such as multifamily zoning and affirmative action — can only get you so far. Bridging the gap requires more than just putting people in proximity. Whether they form relationships, as well as the strength of these relationships, may be much more important to providing upward social mobility to poorer children.

Enabling cross-class relationships during anxious times of rising income inequality is no trivial task. But it’s not impossible either.

A good place to start is with schools, where it is common for people to form strong social bonds which can last a lifetime. As such, a school’s architecture should be designed to foster unstructured student interactions and lack spaces that encourage the formation of cliques. For instance, Lake Highlands High School in Texas, whose case study was shared in the new study, initially had a high friendship bias, meaning rich kids were separated from poor kids. The management quickly identified the culprit: they had three different cafeterias, which allowed students to sort themselves into distinct homogenous groups. Now, the school is working to create a single lunchroom for everyone, as well as craft new spaces that encourage students of all backgrounds to interact with one another.