Scholars disagree about how people form attachments to parties. One camp views these attachments as a social identity, inherited like a religious affiliation and tending to persist over an individual’s life. A second camp views party attachments as a “running tally” of a citizen’s evaluations of the parties over time. From this perspective, partisanship is not an identity but rather a product of voters maximizing their expected utility gains from each party.
Empirically, the debate between these two perspectives has centered on the degree of partisan stability: findings that partisanship fluctuates from year to year are taken as evidence against the social-identity perspective and for the running tally, since evaluations also fluctuate regularly. But the logic behind these conclusions assumes that the objects of identity – parties – are themselves fixed. If we instead allow that party brands change over time, then partisan instability may be perfectly consistent with a social-identity conception of partisanship.
My article “Party Brands and Partisanship: Theory with Evidence from a Survey Experiment in Argentina” demonstrates that a social-identity conception of partisanship need not imply partisan stability. I develop a branding model of partisanship in which voters learn about party brands by observing party behavior over time and base their psychological attachment to a party on these brands. The model suggests that convergence by rival parties, making their brands less distinguishable, should weaken party attachments.
Testing this implication empirically is challenging. We could simply ask survey respondents whether or not they identify with a party and correlate that with how much distance they perceive between their party and other parties. But it is likely that partisans will either rationalize their identity by claiming that other parties are very different, or project differences onto other parties. In either case, we would be demonstrating a correlation, but with the causal relationship going from partisanship to perceived divergence, rather than the other way around.
To better identify the causal relationship implied by my model, I embedded an experiment in a 2009 survey of voters in Argentina. By randomly assigning respondents to treatment and control, experiments make treatments exogenous to observed outcomes and allow us to identify causal relationships. In my experiment, I tested whether party convergence weakens partisanship by providing respondents with different types of information about the Argentine political parties – information that distinguishes parties from one another and information that blurs the lines between them – and examining its effect on their party attachments.
I found that providing respondents with distinguishing information about the parties increased partisanship and the strength of those attachments. Conversely, providing respondents with information about alliances and switching among the parties decreased partisanship and weakened partisan attachments. These effects also seemed to be attenuated by age and political information, consistent with my model. My analysis also offers suggestive evidence that the mechanism underlying these observed effects is consistent with the theory. The survey experiment thus offers convincing evidence for the causal effect of party convergence on partisanship.
These results highlight that we should not ignore the behavior of parties when studying citizen’s attachments to them. Once we take party brands into account, new questions emerge about the mass effects of recent developments like party polarization in the US, party convergence in Western Europe, and the kinds of major policy switches prevalent in Latin America during the 1980s and 1990s. It also suggests that if we want to understand party strategy, we must consider how a party’s choices affect its partisan base.
About the Author: Noam Lupu is Assistant Professor of Political Science and Trice Faculty Scholar at the University of Wisconsin-Madison. His article, “Party Brands and Partisanship: Theory with Evidence from a Survey Experiment in Argentina” appeared in the January 2013 issue of the American Journal of Political Science.