  This paper presents two models that exemplify psychological factors as a
determinant and as a consequence of social network characteristics. There is an
endogeneity considered in network formation: while the social experiences have
impacts on people, their current psychological states and traits affect network
evolution. The first model is an agent-based model over Bianconi-Barabasi
networks, used to explain the relation between network size, extroversion, and
age of individuals. The second model deals with the emergence of urban tribes
as a consequence of a smaller propensity to communicate with different with
different traits and opinions.
