Political polarization as a co-adaptive process

Abstract Political polarization is often characterized as a consequence of changes in media content or technology. We argue, in contrast, for an account that views polarization in media and the public as a co-adaptive process. This paper begins with a brief review of cultural evolution and co-adaptation and then considers the application of similar ideas to changes in media and the public over time. Using formal models, we suggest that—in combination with the human tendency toward in-group bias—a co-adaptive (rather than unidirectional) relationship can best account for real-world dynamics. We consider the implications of these findings for our understanding of media effects and technological innovation in polarization, representative democracy, and mass-mediated communication more broadly.