Political polarization is currently a major research theme in American politics, and Dartmouth scholars affiliated with the Program in Quantitative Social Science are working in this area as well. Associate Professor of Mathematics Feng Fu's lab recently published in Humanities and Social Sciences Communications, Polarization, abstention, and the median voter theorem. Professor Fu is a member of the QSS Steering Committee. One co-author is Antonio (Tony) Sirianni, a Postdoctoral Fellow with QSS. Tony taught QSS 41 Analysis of Social Networks last Fall.
The abstract of the article is as follows:
The median voter theorem has long been the default model of voter behavior and candidate choice. While contemporary work on the distribution of political opinion has emphasized polarization and an increasing gap between the "left" and the "right" in democracies, the median voter theorem presents a model of anti-polarization: competing candidates move to the center of the ideological distribution to maximize vote share, regardless of the underlying ideological distribution of voters. These anti-polar results, however, largely depend on the "singled-peakedness" of voter preferences, an assumption that is rapidly losing relevance in the age of polarization. This article presents a model of voter choice that examines three potential mechanisms that can undermine this finding: a relative cost of voting that deters voters who are sufficiently indifferent to both candidates, ideologically motivated third-party alternatives that attract extreme voters, and a bimodal distribution of voter ideology. Under reasonable sets of conditions and empirically observed voter opinion distributions, these mechanisms can be sufficient to cause strategically minded candidates to fail to converge to the center, or to even become more polarized than their electorate.