The case against social media has become familiar, with concerns that it can increase loneliness, divide people into ideological groups, and create echo chambers where individuals only interact with those who share their views. A pediatrician and researcher at the University of Pennsylvania has noted that while the effects of this dependency are well documented, the underlying cause remains less clear. The researcher argues that our reliance on social media creates a kind of "deficiency disease"—not from something harmful being consumed, but from something our online lives have prevented us from receiving: meaningful, in-person social interaction. This insight came from time spent at Harford Park in Wayne, Pennsylvania, a 30-acre off-leash dog park established in 1997. The park has become a meeting place for regulars, including the researcher, who often visit. These interactions, while not always deep or formal, foster a sense of community and shared experience. The researcher describes the park as similar to a neighborhood bar, where regulars develop familiarity and running jokes, even if they differ on topics like favorite restaurants, income, age, or values. Sociologist Ray Oldenburg called such spaces "third places"—informal, voluntary gathering spots outside of home and work, like pubs or local stores. These places have been declining, but off-leash parks have grown rapidly over the past two decades. A study in the Journal of Urban Affairs found that dog park users often reported stronger social connections and a greater sense of neighborhood unity. The researcher emphasizes that the value of these spaces lies in the unplanned interactions they encourage. These encounters can reduce prejudice and increase empathy, as shown in a meta-analysis of 515 studies by Thomas Pettigrew and Linda Tropp. Their research suggests that contact between different groups helps reduce anxiety and increases understanding, even without deep knowledge of the other group’s beliefs. In contrast, the researcher highlights the limitations of online interactions. Exposure to opposing views on social media doesn’t equate to real-world engagement. In an experiment, sociologist Christopher Bail and colleagues found that Republicans who followed bots representing opposing views on Twitter became more conservative, while Democrats shifted slightly left but not significantly. This suggests that online exposure doesn’t lead to the same level of understanding or tolerance as in-person interaction. The researcher argues that the shift from communities based on geography to those formed by algorithms may slowly increase intolerance and mistrust. While there is growing research on social media and anxiety, little of it treats the lack of in-person interaction as a health issue. Social platforms, the researcher notes, have become experts at creating selective homogeneity, sorting people by interests, identities, and grievances, making it easy to stay among people who feel familiar. This phenomenon is compared to the early postwar suburban developments known as Levittowns, where identical homes were built on farmland and sold to buyers who were often screened by price. These communities had strict rules, such as barring Black families. The researcher draws a parallel to the algorithmic sorting that has become common in the digital age. In contrast, repeated, low-stakes, in-person contact—like the interactions between regulars at a dog park or corner bar—creates space for tolerance and trust. People return, notice when others are absent, and share attention around a task, a place, or a dog, rather than focusing on presenting themselves or defending a position. The researcher concludes that deficiency diseases are easily treatable—they don’t require removing something, but adding something else: meaningful, in-person social connection.