Affective polarization and democratic erosion: evidence from a context of weak partisanship
Affective polarization and democratic erosion: evidence from a context of weak partisanship (DOI: https://doi.org/10.1017/psrm.2025.10019) was written by Loreto Cox, Pedro Cubillos, and Carmen Le Foulon in 2025. It was published in Political Science Research and Methods.
The authors use the November 2021 presidential runoff election and the September 2022 constitutional plebiscite as binary classifiers to study affective polarization (i.e., for the plebiscite, 'Approve' voters and 'Reject' voters form exclusive groups).
Chile also offers a compelling case study for validating polarization theory because...
- it saw a general breakdown of its two party system in 2020
- "nearly a third of Chileans (31%) do not position themselves on the left–right axis (CEP 2022)"
Chile has a recent history of dictatorship
The authors recreate the experiment of Simonovits, McCoy, and Littvay (2022); the treatment cohort is primed with a prompt like "Thinking of [outgroup] voters, please list a few things you dislike about them." The control cohort is asked about promotional phone calls instead.
The survey used the Netquest web panel and was fielded 2 weeks ahead of the 2022 plebiscite. Quotas were used to balance the sample by socioeconomic characteristics, geography, gender, and age. There are 1,499 respondents. They were asked, in randomized order, their sentiment (0=very negative, 10=very positive) towards e.g. Approve voters, Reject voters, and so on. Affective polarization is the distance between the in-group and the out-group.
The authors use OLS to estimate the treatment effect. The effect is not significant for the overall population, but is significant for most subpopulations that self-identified a vote choice, e.g. self-identified as either an Approve voter or a Reject voter.
Reading Notes
The supplemental materials reveal that the sample really isn't representative of the overall population. And since the plebiscite was mandatory, the overall population is the electorate in this case. That isn't to say that the inference is invalid, but that more could be done to ensure this study is representative.
Regardless, this is a validation of a Eurocentric theory in a third world setting, which is great for the larger body of research.