The diversity puzzle explaining clustering and polarization of opinions

PhD ceremony: Mr. M. Mäs, 14.45 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: The diversity puzzle explaining clustering and polarization of opinions

Promotor(s): prof. A. Flache, prof. R.P.M. Wittek, prof. W. Raub

Faculty: Behavioural and Social Sciences

This dissertation is concerned with explaining the dynamics that social influence causes in groups. Under what conditions will the members of a group find a consensus? Is it possible that homogeneous groups split up into clusters with opposing opinions? Why do groups sometimes polarize in the sense that differences between subgroups increase over time?

Existing theories imply that social influence causes convergence cascades which eventually end up with perfect uniformity. Empirical evidence, however, shows that opinion diversity often remains stable and can actually increase over time. In this PhD-thesis, we developed theories that can explain polarization and clustering of opinions besides social influence. We analyzed agent-based computational models of these theories to demonstrate under which conditions the theories predict polarization and clustering. We also reported results from experimental tests of one of the new theories.