Beyond the Favorite Issue: Experimental Tests of Heterogenizing Voters´ Issue Preferences

There is a growing evidence about the aim of political parties to simplify complex electoral competition into a handful of salient issues. Recent research (Lucas et al. 2024) has suggested that political parties not only actively employ these strategies but also regard them as clearly profitable..To better understand the potential of such electoral competition and its strategic appeal to political parties, it is essential to also examine the demand side. Specifically, we need to assess whether parties’ highly selective focus on certain issues can, at least temporarily, shift the intensity with which voters prioritize political issues – ideally to the extent that they become single-issue voters (SIV), assigning disproportionate weight to one issue over all others when making their electoral choice. This research has a longer tradition in two-party systems, with the most frequently mentioned characteristics of SIV being disproportionate policy influence (Bouton et al. 2021; Cox & Shapiro 2025) or even posing a challenge to democratic quality ( Aragonès et al. 2015). We transfer our interest in single-issue voters to European multiparty systems, where our ongoing research in Czechia and Slovakia has revealed a surprising spread of very narrow issue preferences among voters, including a significant share of SIVs. At the workshop, we propose to discuss part of our SIV research which experimentally focuses into ways of mitigating overly narrow issue orientation. We report an experimental study from the Czech Rep. (June 2025) which employed interventions commonly used to reduce attitude extremity (e.g., Fernbach et al. 2013), such as tasks designed to disrupt the “illusion of understanding”. We found some potential of these techniques to foster more heterogeneous issue preferences.