An extension of Schelling's segregation model: Modeling the impact of individuals’ intolerance in the presence of resource scarcity

Abstract

Individuals often form their identity based on their membership in a group and may exhibit a bias towards favoring members of the in-group (Greenwald and Pettigrew, 2014). When resources are plentiful, individuals are more likely to be tolerant of members of out-group sharing the resources. However, when there is a scarcity of resources, the resource stress could lead to a negative attitude towards members of the out-group as sharing of resources may be viewed as a zero-sum game. Schelling's spatial proximity model (Schelling, 1971; Schelling, 1978) shows how residential segregation emerges even when households only have a slight preference for members of their in-group. The original formulation by Schelling as well as many of its extensions have assumed that the amount of space available to agents to relocate was fixed. Agents' preference for members of the in-group also had been assumed to be invariant during the simulation run. This paper presents an extension of Schelling's model by relaxing these two assumptions to focus on the context of growing scarcity of environmental resources (e.g. habitable land) and the resulting decline in the tolerance for members of the out-group. Drawing upon theories in social psychology, it was assumed that declining resources lead to lower tolerance for members of the out-group as this scarce resource had to be shared. An agent-based simulation examined the impact of varying the degree of intolerance towards members of the out-group on the level of segregation in an artificial society. Several what-if scenarios were analyzed where the availability of an environmental resource (habitable land) declined over time. It was observed that with a high degree of intolerance towards members of the out-group, the degree of segregation in an artificial society while increasing initially became unsustainable and the highly segregated clusters eventually disintegrated.