How Are Communities Contagious?
How Are Communities Contagious? Community Contagion Small-area variables reveal how place spreads behavior, opportunity, and constraint. Framing the Question Small-area variables help us see that communities are contagious not because people copy each other blindly, but because places make certain behaviors easier to notice, repeat, reward, and normalize. A neighborhood is not just a backdrop. It is a daily operating system of cues, constraints, relationships, and expectations. Census tracts are a useful entry point. Designed to be relatively stable and similar in population and living conditions, they reveal local patterns that citywide averages bury. Why This Question Matters Communities are contagious the way weather is contagious. No one catches a neighborhood. But when enough people live under the same conditions — schools, sidewalks, rents, transit, safety, social networks, job access, and norms — the environment begins shaping what feels possible. We consistently explain behavio...