From homophily to exclusion in small social systems.

The actors are placed at nodes of the complete weighted graph. They are endowed with densities of contact with the other actors and with positions in a social hierarchy. These characteristics evolve in time according to the homophily principle and the Matthew effect. The result is that an actor with minimal status is excluded, and all other actors get the same high position. As for examples, the results allow us to make reference to racial criteria of promotion in the London Metropolitan Police, and to the scapegoating phenomenon, described in the literature.