How groups coordinate without talking to each other

A population's growth is modeled as individuals responding independently to a noisy, shared measurement of their collective state—like each person glancing at a crowded room without talking. This feedback mechanism produces coordinated behavior and generates geometric Brownian motion as a limiting case, while varying measurement quality produces different growth patterns. The work suggests coordination emerges naturally from imperfect information rather than optimization, with implications for understanding both biological populations and economic systems.