The impact of group identity on coalition formation

Date: 2015-09-03
By: Denise Laroze (University of Essex)
David Hugh-Jones (University of East Anglia)
Arndt Leininger (Hertie School of Governance)
Bargaining and coalition building is a central part of modern politics. Typically, game-theoretic models cannot predict a unique equilibrium. One possibility is that coalitions are formed on the basis of social identity loyalty to a gender, ethnic or political in-group. We test the effect of gender, race and ideological distance on coalition formation in a majority-rule bargaining experiment. Despite the absence of any incentives to do so, we find that ideological distance significantly affects offers made to potential coalition partners. As a result, coalitions tend to be ideologically coherent, even though there is no ideological policy output. We conclude that social identity considerations can determine equilibria in coalition formation.
Keywords: coalition formation, laboratory experiments, Baron and Ferejon model, legislative bargaining, social identity