政治制度對情感極化的影響：以制度組合為解釋途徑

Abstract

本文欲討論政治制度如何影響選民對政黨的情感極化（affective polarization），將探討以下問題：在低中度社會分歧，即社會零碎化程度（social fragmentation）較低的社會結構中，何種政治制度組合最有利於緩解情感極化？本文使用Comparative Study of Electoral Systems（CSES）第一波至第五波的調查資料，並以民主國家作為量化分析的對象。同時，本文也以Reiljan等人（2024）的指標計算出各國國會選舉年的情感極化程度。經過資料分析，本文發現：在低中度社會分歧的結構條件下，「政府體制為總統制與國會選制為比例性選制」的制度組合，相較其他制度組合，最能緩解國家的情感極化。本文後續將國會選制替換成有效政黨數與政府類型，也極大程度上，證實前述結果。最後，在總統制與半總統制國家，本文也發現在同樣的社會條件下，「總統權力大與有效政黨數高」的制度組合，對比其他制度組合，最能緩解國家的情感極化。

This study aims to explore how political institutions influence affective polarization. Therefore, it poses the following question: Which combinations of political institutions are most effective in reducing affective polarization in societies with low to moderate social fragmentation? This study utilizes data from the Comparative Study of Electoral Systems (CSES) Modules 1 to 5, focusing exclusively on democratic countries. Simultaneously, it adopts the formula developed by Reiljan et al. (2024) to calculate affective polarization for each election year. The study reveals three key findings: First, compared to other institutional combinations, the combination of a presidential system and proportional representation is the most effective in mitigating affective polarization under conditions of low to moderate social fragmentation. Second, replacing the electoral system with the effective number of parties and government types substantially supports the aforementioned result. Finally, under similar levels of social fragmentation, the combination of high presidential power and a high number of effective political parties proves most effective in reducing affective polarization compared to other combinations.