A new study published in the Proceedings of the National Academy of Sciences has revealed a significant link between the expansion of personal social networks and the intensification of societal polarization. The research, conducted by the Complexity Science Hub Vienna, found that as people’s close friend groups expanded from two to five members during the rise of social media (2008-2010), polarization in society surged. Researchers suggest that this connection may provide a fundamental explanation for why societies are increasingly fragmenting into ideological bubbles. The study’s findings confirm that increased polarization is not merely perceived but is objectively measurable. “And this increase happened suddenly, between 2008 and 2010,” says Stefan Thurner, a researcher from the Complexity Science Hub. The question that remains is: what caused this sudden shift? The researchers argue that the sharp rise in both polarization and the number of close friends occurred precisely when social media platforms and smartphones first achieved widespread adoption. This technological shift may have fundamentally changed how people connect with each other, indirectly promoting polarization. According to Thurner, democracy depends on all parts of society being involved in decision-making, which requires that everyone be able to communicate with one another. But when groups can no longer talk to each other, this democratic process breaks down. Tolerance plays a central role in maintaining social cohesion. Thurner explains that with fewer friends, individuals tend to be more tolerant, as they must maintain all relationships. However, as the number of friends increases, tolerance decreases, as people can rely on “backups” if conflicts arise. This erosion of tolerance contributes to the long-term weakening of democratic structures. To prevent societies from increasingly fragmenting, Thurner emphasizes the importance of learning early how to engage with different opinions and actively cultivating tolerance. The study’s insights highlight the complex interplay between technological adoption and social dynamics, offering a critical perspective on the challenges facing modern societies.