A Behavioral Instrument for Measuring Political Overconfidence: Implications for Understanding Affective Polarization in the United States

Traditional measures of political knowledge have proven insufficient for understanding contemporary political attitudes and behaviors, particularly the rise of affective polarization. While existing research has explored the interplay between political knowledge and affective polarization, this study introduces a novel theoretical distinction between political knowledge and political overconfidence. Using American National Election Studies (ANES) data from 2020 and 2024 (N = 6,323 and N = 3,030), we develop a scale to measure political overconfidence and explore its relationship with affective polarization. Our findings reveal a consistent correlation between political overconfidence and heightened levels of affective polarization (β = 14.1–35.7, p < 0.05), whereas political knowledge exhibits smaller, less robust associations (β = 4.6–4.9). This pattern holds across partisan groups, though the strength of the association varies significantly, with the overconfidence effect more than doubling between 2020 and 2024. These results highlight the importance of political overconfidence in understanding affective polarization in an era of information abundance and suggest the need for further exploration into whether political overconfidence mediates, moderates, or covaries with other drivers of partisan animosity.