Simple but Powerful Models of Stereotype Formation

We propose simple models aiming at explaining the formation of stereotypes. A stereotype is an overall judgment brought by an observer over a group of individuals or objects. For each member of the group, we suppose that we observe a characteristic that belongs to a denumerable set. The formation of a stereotype about the group is governed by a perception function. Our basic model consists in decomposing a perception function into three steps: 1) characteristics are recoded numerically so that higher numbers mean a higher support for the stereotype, 2) this vector of numbers is consistently aggregated into a single number, and 3) this number is compared to a threshold and the stereotype is accepted if the threshold is exceeded. We characterize perception functions that can be explained using such a model. We then study various extensions of our basic model.