In a quiet survey room, Dutch residents faced a simple choice: which neighborhood to move to, which club to join. The variables looked mundane: rent, travel time, friendliness. But hidden in each profile was the social makeup of the setting.
Again and again, participants steered toward the option where people looked more like them. The study, published in PNAS Nexus, involved over 8,100 participants and demonstrated how social bubbles form not just by accident but by preference. Led by Kasimir Dederichs, the research found that most people prefer neighbors and club members of the same age, ethnicity, and education level, with one exception: those without college degrees were indifferent about educational differences.
The Quiet Power of Ingroup Preference
Conjoint experiments provided the test bed. Participants repeatedly compared fictional neighborhoods and civic organizations that varied across cost, distance, social cohesion, and demographics. The results were striking. Younger adults were willing to commute five extra minutes to avoid older peers in clubs. Respondents without a migration background were ready to add ten minutes to their daily errands to bypass neighborhoods with a modest share of Turkish or Moroccan residents. The preferences, though subtle on the surface, added up to strong patterns of segregation.
“Individuals consistently prefer settings where they can expect to encounter more people of similar age, ethnicity, and education as themselves,” the authors wrote.
Segregation as a Cycle
The tendency proved strongest among those already embedded in homogenous settings. In other words, people surrounded by their own kind wanted more of the same. This creates a feedback loop: limited exposure to difference strengthens the desire to avoid it. The researchers caution that such cycles can entrench segregation over time, making bubbles harder to break.
“Ingroup preferences and limited outgroup exposure reinforce each other,” the team explained. “The result may be a vicious cycle where ingroup exposure and ingroup preferences mutually reinforce each other.”
A Subtle Exception
Education was the only wrinkle. College graduates showed strong preferences for their own, while those without degrees did not. The researchers suggest this could reflect status-seeking motives or the assumption that better-educated communities provide safer, higher-quality environments. In effect, the privileged bear more responsibility for sustaining educational segregation than the less-educated.
Breaking the Bubble
The findings hint at ways forward. Sports clubs, especially for younger people, showed weaker ethnic ingroup preferences than other organizations. Spaces organized around shared goals—playing soccer, caring for a community garden, staging a performance—might blunt the pull of similarity. But the authors warn that exposure alone may not change hearts. Without deliberate practices that highlight commonalities, the bubble effect will persist.
Policy solutions often focus on disadvantaged groups, such as subsidized housing or relocation programs. Yet this study makes plain that majority groups and the college-educated also drive segregation. Unless their preferences shift, desegregation efforts risk running into the same wall of human choice.
Explainer: What is an Ingroup Preference?
Ingroup preference is the tendency to favor people who share your own characteristics, such as age, ethnicity, or education. In practice, this means individuals are more likely to choose neighborhoods, workplaces, or clubs where they expect to find people like themselves. Even weak preferences can lead to strong segregation, because once a few people cluster, others follow, and contact with different groups diminishes. Researchers use experiments to tease apart these preferences from financial or geographic constraints. The concept helps explain why diverse societies often remain socially divided despite growing demographic change.
Journal: PNAS Nexus. DOI: 10.1093/pnasnexus/pgaf256
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