Abstract:
Political partisanship represents a long-term commitment to a political party. Yet, theories of partisanship as being largely instrumental (representing a summary of political attitudes and ideology) or expressive (representing a psychological, identity-based attachment) in nature present different predictions about how partisans engage with political matters and respond to political elites. This thesis aimed to contribute to knowledge on the motivations behind partisanship in New Zealand, as well as the broader literature on the longitudinal dynamics between ideology, party elite influence, and partisanship. Across six studies, party support in New Zealand was examined across several pertinent areas of research, using a combination of cross-sectional and longitudinal samples from a large national probability study. Study 1 demonstrated that voters for the National, Labour, Green, and New Zealand First parties in New Zealand are divided across various social attitudes and policy issues, but polarization in these attitudes was minimal and non-systematic from 2009 – 2017. Study 2 revealed high levels of test-retest stability in support toward these same parties over two to five-year periods. Study 3 demonstrated that the effect of in-party support on out-party opposition is stronger when party support and political ideology are congruent, but stronger still at higher levels of political identity centrality. Study 4 examined party elite cueing effects during the 2015 – 2016 New Zealand flag referendums. The results revealed New Zealanders shifted their flag attitudes over time to align with the position of their polarized elites. Following this, Study 5 demonstrated that after the referendums, party support was the strongest predictor of New Zealanders’ flag attitudes, yet a range of ideological beliefs, particularly regarding social traditionalism vs. change, remained predictive of flag attitudes. Finally, Study 6 demonstrated that the within-person longitudinal effects of ideological beliefs about group-based equality and social traditionalism vs. change on support for political parties are about twice as strong as the reverse causal effects. Together, these findings contribute nuanced insights into the form and function of partisanship, and particularly emphasise the importance of social identity to partisan attitudes in New Zealand.