  The aim of this paper is to study the derivation of appropriate meso- and
macroscopic models for interactions as appearing in social processes. There are
two main characteristics the models take into account, namely a network
structure of interactions, which we treat by an appropriate mesoscopic
description, and a different role of interacting agents. The latter differs
from interactions treated in classical statistical mechanics in the sense that
the agents do not have symmetric roles, but there is rather an active and a
passive agent. We will demonstrate how a certain form of kinetic equations can
be obtained to describe such interactions at a mesoscopic level and moreover
obtain macroscopic models from monokinetics solutions of those.
  The derivation naturally leads to systems of nonlocal reaction-diffusion
equations (or in a suitable limit local versions thereof), which can explain
spatial phase separation phenomena found to emerge from the microscopic
interactions. We will highlight the approach in three examples, namely the
evolution and coarsening of dialects in human language, the construction of
social norms, and the spread of an epidemic.
