How opinion variation among in-groups can skew perceptions of ideological polarization

There is a widespread perception that society has been polarizing into groups with increasingly divergent opinions. Multiple studies have sought to quantify the degree of opinion divergence (or ideological polarization), typically relying on variation among self-reported opinions, and have reached mixed conclusions. Each individual, however, perceives the landscape of public opinion through a subjective lens or viewpoint that is dynamically shaped by their social environment. To account for this subjectivity in perceived polarization, we propose a model of dynamic perception that takes social identity into account. When members of an in-group become increasingly homogeneous on a given topic (that is, when the variance of opinions in that group decreases), they perceive deviant opinions as increasingly distant from their own. Consequently, these individuals may perceive much more polarization than what an objective, neutral observer would perceive. We apply our model to empirical data on the opinions of German citizens about climate change and show that the effect of dynamic opinion perception on polarization can be nearly as substantial as actual opinion divergence. Moreover, we show that the direction of the effect need not be consistent over time, nor across different partisan groups. Our framework helps explain why people might sometimes experience levels of ideological polarization higher than those indicated by opinion surveys, independent of structural divisions, polarization-enforcing biases, or affect-driven attitudes towards out-groups.