中文摘要
我们基于内生社会身份，提出了一种关于政治极化维度变化的理论。我们按照Bonomi、Gennaioli和Tabellini（2021）的方法将选民身份形式化，但增加了在政策上竞争并通过传播刻板印象来说服选民的政党。政党在历史上与不同的社会群体相关联，这些群体的成员更容易接受相应政党的信息。从阶级身份向文化身份的内生转变解释了三个主要变化：（i）选民与政党之间日益加剧的文化冲突；（ii）尽管不平等加剧，再分配冲突却有所缓和；（iii）下层阶级选民从左翼向右翼的重新结盟。政党传播刻板印象的动机是身份驱动型极化的一个关键驱动因素。利用调查数据和国会演讲，我们表明——与我们的模型一致——在“中国冲击”（Autor、Dorn、Hanson和Majlesi，2020）引发的选民重新结盟中，存在支持（i）和（ii）的证据。
Abstract
We offer a theory of changing dimensions of political polarization based on endogenous social identity. We formalize voter identity as in Bonomi, Gennaioli, and Tabellini (2021), but add parties that compete on policy and spread stereotypes to persuade voters. Parties are historically connected to different social groups, whose members are more receptive to the party messages. An endogenous switch from class to cultural identity accounts for three major changes: (i) growing cultural conflict between voters and parties; (ii) dampening of redistributive conflict, despite rising inequality; (iii) a realignment of lower class voters from the left to the right. The incentive of parties to spread stereotypes is a key driver of identity‐based polarization. Using survey data and congressional speeches, we show that—consistent with our model—there is evidence of (i) and (ii) in the voting realignment induced by the “China Shock” (Autor, Dorn, Hanson, and Majlesi (2020)).