Why does segregation exist even when we aren’t actively discriminating?

With issues like gentrification and redlining, the stratification of ethnic, racial, and economically-different groups are ever-increasing. While in a majority of situations, these clusters form as a result of dislike towards another group, there are situations that exist where segregation arises even when individuals do not hold discriminatory attitudes. The Schelling model is a fascinating agent-based approach that helps us examine just why that happens.

What exactly is this model?

The model starts with a grid, where each cell is either empty or occupied by an individual of one of two groups, denoted as "X" and "O". Each individual has a preference for the fraction of their neighbors that are from the same group as them. For example, an X individual may prefer to have at least 50% of their neighbors be Xs.

In the model, individuals who are dissatisfied with their current neighborhood move to a new location if they can find a place where their preference is satisfied. The simulation continues until the system reaches a state of equilibrium, where no one is motivated to move anymore.

The Schelling model shows that even if individuals only have a small preference for being with others of their own group, it can lead to a high level of segregation in the system as a whole. This is because once a group starts to cluster together, it becomes increasingly difficult for individuals to find a new location where their preferences are met.

Let’s explore the following question using the Schelling model: How does the degree of segregation change as the threshold for satisfaction is varied?

By changing the threshold, we can see how it affects the overall level of segregation in the system.

To solve this problem, we should first create a grid and populate it with X and O individuals. Next, we would set the initial threshold for satisfaction and run the simulation until it reaches equilibrium. We would then measure the degree of segregation using a metric such as the Gini coefficient or the entropy index. Finally, we would repeat this process for different threshold values to see how the level of segregation changes.

Let’s look into another question: How can we examine the effect of different grid sizes on the level of segregation?

By changing the grid size, we can see how it affects the ability of individuals to find locations that meet their preferences.

To solve this problem, we would create grids of different sizes and run the simulation with the same initial conditions. We would then measure the level of segregation and compare it across the different grid sizes to see if there are any trends. This can help us understand how the spatial structure of a society affects the level of segregation.