Doctoral Dissertation Research in Political Science: Partisan and Ideological Sorting in the United States

几十年来，政治学家一直在争论美国是否正在发生政治两极分化。然而，对于什么是两极分化并没有一个共同的定义，对于什么可能导致两极分化也没有达成一致。该项目旨在通过明确和一致地定义两极分化的概念，并通过确定两极分化存在及其在过去五十年中增加的原因来改变这场辩论的条件。该项目将政治两极分化定义为公民从中间派、温和的政治信仰或行为转向更极端的信仰或行为的过程。该项目表明，美国公民可能在问题立场或行为上两极分化，而这两件事不必同时发生。因此，虽然问题立场的两极分化程度可能很低，但行为两极分化——以激进主义、不宽容和愤怒的程度增加为特征——可以而且今天正在不可否认地上升。在过去的几十年里，政党和意识形态的逐渐统一助长了这种日益加剧的行为两极分化。美国公民在政治上更加活跃、不宽容和愤怒，因为政党身份与其他政治身份（意识形态、宗教和种族）一致。其他研究表明，当多重身份一致时，公民对他人的宽容程度会降低。该项目进一步认为，当政治认同一致时，政党认同得到加强。研究还表明，那些身份认同更强的人更不宽容，并且会为自己所属的群体采取更多行动。该项目认为，这种心理反应本质上是情绪化的，与衡量问题的考虑无关。如果这一论点成立，那么游击队员有很深的不文明的心理动机，而且这些动机的强度自20世纪60年代以来有所增加。该研究通过收集具有全国代表性的美国成年人样本的数据来检验其论点。具体来说，一项基于网络的调查将用于评估一系列政治身份（党派、意识形态、宗教、种族和基于问题的）之间的关系，以及这些身份对政治行为的影响。此外，该调查将用于检验问题立场极端对政治行为的作用。如果这里的推理是正确的，问题立场极端在激发政治激进主义、不宽容和愤怒方面的作用应该小于政治认同力量。此外，最重要的是，政治认同高度一致的个人应该比那些政治认同不一致的人更积极、更不宽容、更愤怒。该项目将在两个领域提供重要的见解。首先，它将通过引入一个精确的定义和确定起作用的因果机制，推进一场长期存在的学术辩论。其次，该项目将揭示两极分化和不宽容的党派辩论的心理动机。

For decades, political scientists have argued about whether political polarization is occurring in the United States. Yet there has been no common definition of what polarization is and no agreement as to what might cause it. This project aims to change the terms of this debate, both by defining the concept of polarization clearly and consistently and by identifying the reasons for the existence of polarization and for its increase over the last fifty years. The project defines political polarization as a process by which citizens move from centrist, moderate political beliefs or behavior to more extreme beliefs or behavior. The project suggests that US citizens can be polarized over issue positions or in their behavior, and that these two things need not happen at the same time. Hence, while levels of issue position polarization may be low, behavioral polarization--characterized by increased levels of activism, intolerance and anger--can be and is today undeniably on the rise. This increased behavioral polarization has been fueled by the gradual alignment of party and ideological identities over the last few decades. US citizens are more politically active, intolerant and angry because party identities have come into alignment with other political identities (ideology, religion, and race). Other studies have shown that when multiple identities come into alignment, citizens become less tolerant of others. This project further contends that when political identities come into alignment, party identities are strengthened. Studies have also shown that those with stronger identities are more intolerant, and take more actions on behalf of the group to which they belong. This project argues that this psychological reaction is emotional in nature and is unrelated to measured considerations of issues. If this argument holds, then partisans have deep psychological motivations to be uncivil, and the strength of these motivations has increased since the 1960s. The research examines its arguments by collecting data from a nationally representative sample of adult Americans. Specifically, a web-based survey will be used to assess the relationships among an array of political identities (partisan, ideological, religious, racial, and issue-based), and the effect of these identities on political behavior. In addition, the survey will be used to examine the role of issue position extremity on political behavior. If the reasoning here is right, issue position extremity should play a smaller role in motivating political activism, intolerance, and anger than does political identity strength. Furthermore, and most importantly, individuals with high levels of alignment among their political identities should be more active, intolerant and angry than those whose political identities are not in alignment. This project will provide crucial insight in two arenas. First, it will move forward a long-standing academic debate, by introducing a precise definition and identifying causal mechanisms at work. Second, the project will shed light on the psychological motivations of polarized and intolerant partisan debate.