Choice Overload in Crowded Primary Elections

The number of candidates running in U.S. primary elections is increasing. Contested primary elections force voters to decide between candidates that share party labels and are ideologically similar. Similar to contexts of non-partisan elections, an increase in the number of candidates should exacerbate the cognitive demand of voting in primary elections. We expect large candidate fields in primaries make voters (1) spend less time looking at each candidate profile, (2) more likely to abstain, (3) more likely to vote based on ballot position, and (4) more likely to feel overwhelmed with the decision. All four of these expectations were preregistered. We test the effect of large candidate fields on voter behavior using a survey experiment ( n = 2000) fielded by YouGov. We find large candidate fields cause respondents to spend less time looking at candidate profiles, to select candidates in the first half of the ballot, and to feel overwhelmed by the decision-making process. In contrast to our expectations, we find large candidate fields make respondents less likely to abstain.