Schelling Segregation Model

==Schelling Segregation Model== is an agent-based model of residential segregation developed by economist Thomas Schelling in 1971. It demonstrates one of the most counterintuitive results in social science: extreme spatial segregation can emerge even when every individual has only a mild preference for neighbors of the same type — and even when everyone would prefer integrated neighborhoods to completely segregated ones.

The model is starkly simple. Agents of two types (e.g., red and blue) are placed on a grid. Each agent is satisfied if at least some fraction of its neighbors — say, one-third — are of the same type. Unsatisfied agents move to the nearest vacant location where they would be satisfied. The simulation proceeds iteratively: dissatisfied agents move, new dissatisfaction arises, more agents move. The equilibrium is almost always highly segregated, with large homogeneous clusters separated by sharp boundaries.

The profound implication is that segregation is not primarily caused by strong racist preferences or discriminatory institutions, though these certainly exist and exacerbate the problem. Schelling showed that segregation is an emergent property of the interaction structure: individual preferences that are tolerant at the local level aggregate into patterns that are intolerant at the global level. No agent wanted segregation. No agent chose segregation. Segregation emerged.

The model connects to game theory, network science, and social dynamics as a paradigmatic example of how micro-motives generate macro-behavior. It has been extended to continuous space, social networks, and heterogeneous preferences. Its core lesson remains unchanged: the aggregate outcome of a social system is not the average of individual intentions. It is the structure of their interactions.