Doctoral Dissertation Research in Political Science: How Elite Polarization Constrains Leader Rhetoric

我的论文旨在帮助我们理解公民如何做出参与或忽视党派政治事件的决定，以及这种行为对政治行为者和机构（特别是美国总统）的影响。在民主党和共和党之间存在极端党派偏见和分歧的时期，某些类型的党派人士可能会对挑战现有政治信仰的政治言论或事件进行预防。党派人士期望他们的政党表现得更好，产生高质量的候选人，并采取适当的立场（例如，Gerber & Huber 2010; Taber and Lodge 2006; Gerber, Huber, & Washington 2010）。当党派之争成为政治中一个更突出的因素时——例如，在党派两极化时期——个人倾向于更深入地参与他们的党派身份，并用它来评估他们周围的政治世界。然而，对党派身份的依赖带来了一个潜在的重大责任：它使公民容易对政治世界产生扭曲的看法。在党派言论和政治运动的激烈中，党派身份变得更加突出，导致公民持有共和党人，民主党人或独立人士的情境自我概念，并从“我们”与“他们”的角度思考政治。为了保持期望和保护他们的党派身份，人们经常进行选择性暴露和动机推理，倾向于选择暴露自己的信息，只是验证他们的党派身份，并以只支持先前信念的方式对新信息作出反应。当面对不一致的信息时，他们倾向于忽视，贬低或反驳它（Taber和Lodge 2006）。我猜测，这可能会给总统和总统沟通带来问题，因为总统通常被视为既是政党领袖，也是整个国家的代表。通过调查和原始实验数据，我将表明，日益党派化的环境往往会(1)阻止总统接触并影响志同道合的党派和理论家以外的听众；(2)增加个体在面对新信息时依赖党派关系而不是更新其信念的可能性；(3)提供额外的激励，以避免挑战现有政治态度的言论。这些发现的含义是，总统和他的言论可能影响有限，只会对志同道合的党派产生日益强烈的影响，而对另一个政党几乎没有影响。该项目旨在调查党派极化、党派偏见、选择性曝光和动机推理的影响。然而，在更广泛的层面上，这是在询问我们对美国自由流动、开放的思想市场的重视程度，以及一个政党高度分化的政治制度的功能。考虑到精英两极分化、党派之争的突出和有偏见的推理之间的关系，我们可能有理由相信，超越党派界限的有意义的政治辩论可能正在减少。令人担忧的是，是否只有那些已经认同政治理念、政策和官员的人才会接触到这些理念、政策和官员。作为仅有的两名全国选举产生的官员之一，由于党派的转变，总统作为一个团结的领导人可能会变得不那么有效。与其在政党领袖和国家舆论领袖之间进行选择，总统可能不再有这个选择。与此相关的是，政治态度可能变得更加根深蒂固，特别是考虑到个人可以自我选择支持现有信念的信息，并且可以抵制用新信息更新自己的信念。最后，本项目将讨论这一最近现象对总统职位、政党和协商民主的影响以及可能的补救措施。公众和民选官员之间进行有力的、知情的辩论具有内在价值；选择性曝光和有偏见的党派推理的趋势，对任何培养真正的、审慎的民主的努力都是一个潜在的危险。

My dissertation seeks to contribute to our understanding of how citizens make decisions to engage with or to ignore partisan political events and the implications of that behavior on political actors and institutions- specifically, the Presidency of the United States. During times of extreme partisanship and disagreement between Democrats and Republicans, certain types of partisans may inoculate themselves against political rhetoric or events that challenge existing political beliefs. Partisans expect their party to perform better, to produce high-quality candidates, and to take appropriate issue stands (e.g., Gerber & Huber 2010; Taber and Lodge 2006; Gerber, Huber, & Washington 2010). When partisanship is a more prominent element of politics- during times of party polarization, for example- individuals tend to engage with their partisan identity more deeply and to use it to evaluate the political world around them. Reliance on partisan identity, however, carries a potentially major liability: it predisposes citizens to a distorted view of the political world. In the heat of partisan rhetoric and political campaigns, partisan identities become more salient, leading citizens to hold situational self-conceptions as Republicans, Democrats, or Independents, and to think about politics from an "us" verses "them" perspective. To preserve expectations and to protect their partisan identities, people often engage in selective exposure and motivated reasoning, the tendency to choose to expose themselves to information that simply validates their partisan identities and to react to new information in ways that only supports previous beliefs. When confronted with uncongenial information, they tend to ignore, to discount, or to counter-argue it (Taber and Lodge 2006). I hypothesize that this may cause problems for the President and Presidential communication since the President is often viewed as both a party leader and a representative of the nation as a whole. Using survey and original experimental data, I will show that an increasingly partisan environment tends to (1) prevent Presidents from gaining access to and affecting an audience outside of like-minded partisans and ideologues; (2) increase the likelihood that individuals rely on partisanship rather than update their beliefs when confronted with new information; and (3) provide added incentives to avoid rhetoric that challenges existing political attitudes. The implications of these findings are that the President and his rhetoric may have limited influence, only having an intensifying effect for like-minded partisans while having little or no effect on the other party. This project seeks to investigate the impacts of party polarization, partisanship, selective exposure, and motivated reasoning. On a broader level, however, it is asking the value we place on a free-flowing, open marketplace of ideas in the United States and the functionality of a political system with highly polarized parties. Given the relationship between elite polarization, salience of partisanship, and biased reasoning, there may be reason to believe that meaningful political debate that transcends party lines may be in decline. It is concerning if exposure to political ideas, policies, and office holders only occurs among those who already agree with them. The President, one of only two nationally elected officials, may be becoming less effective as a uniting leader as a result of this partisan shift. Rather than having the option of pivoting between roles of party leader and national public opinion leader, the President may no longer have that option. Relatedly, political attitudes may be becoming more entrenched, particularly given that individuals can self-select the information that supports existing beliefs and can resist updating their beliefs with new information. Finally, this project will discuss the implications of this recent phenomenon on the Presidency, on political parties, and on deliberative democracy as well as possible remedies. There is inherent value in robust, informed debate between the public and our elected officials; a trend toward selective exposure and biased partisan reasoning is a potential hazard to any attempt to cultivate a genuine, deliberative democracy.