Theories of vote choice predict that ideological identity, among other things, influences voting. Citizens tend to choose parties they view as ideologically similar to themselves. From a social psychological view of voting, this is because they are motivated to act in accordance with their sense of who they are. Since each voter carries multiple social identities, the impact of ideological identity should be determined by the relative salience of this identity vis-à-vis others. Since the mass media are a major source of information and thereby shape citizens’ frames in thought, the influence of ideological identities on vote choice should vary with the salience of ideologically relevant objects on the media agenda. Since not all voters are the same, this general expectation merits differentiation. Specifically, the sensibility to the media context might vary with political involvement and partisan identity. Political involvement enhances the amount of media content individuals are exposed to, which might increase media content sensibility. Furthermore, politically involved citizens have belief systems which are larger and more tightly organized. This increases the number of associations a given media report activates, which in turn might also increase the media effects on the influence of partisan identities. Party affiliations are important political identities which are likely to overlap with ideological identities and possibly dominate them. They bias information intake and processing as well as influence vote choice directly and indirectly, which might reduce the effects of ideological identities.
Against this theoretical backdrop, the paper tests several hypotheses about the effects of ideological identification on vote choice in different media contexts. If objects with symbolic meaning for the left are relatively salient in the media, citizens who identify with the left should be more likely to rely on this identity when choosing a party. Analogously, if objects with symbolic meaning for the right are relatively salient in the media, citizens who identify with the right should be more likely to rely on their ideological identity when choosing a party. As for individual level moderators, the context dependency of the effect of ideological identities should increase with political involvement. Furthermore, the context dependency of the effect of ideological identities should be stronger among citizens without rivalling partisan loyalties. The empirical analysis will focus on micro level variation using the long time series of the German Politbarometer.
