论文标题
为什么美国政党如此两极分化？ “满意”动力学模型
Why are U.S. Parties So Polarized? A "Satisficing" Dynamical Model
论文作者
论文摘要
自1960年代以来，美国国会的民主党人和共和党人采取了越来越两极化的立场，而公众的政策立场仍然是中间派和温和的。我们通过开发一个预测政党意识形态立场的动力学模型来解释这一明显的矛盾。我们的方法解决了将有限的理性纳入数学模型的挑战，并整合了令人满意的决策制定的经验发现---选民们在决定为谁投票时就解决了“足够好”的候选人。我们在过去150年中使用美国国会的数据测试该模型，并发现我们的预测与两个主要政党的历史轨迹一致。特别是，该模型解释了自1960年代以来民主党与共和党之间的两极分化是如何导致当事方内部意识形态同质性增加的结果。
Since the 1960s, Democrats and Republicans in U.S. Congress have taken increasingly polarized positions, while the public's policy positions have remained centrist and moderate. We explain this apparent contradiction by developing a dynamical model that predicts ideological positions of political parties. Our approach tackles the challenge of incorporating bounded rationality into mathematical models and integrates the empirical finding of satisficing decision making---voters settle for candidates who are "good enough" when deciding for whom to vote. We test the model using data from the U.S. Congress over the past 150 years, and find that our predictions are consistent with the two major political parties' historical trajectory. In particular, the model explains how polarization between the Democrats and Republicans since the 1960s could be a consequence of increasing ideological homogeneity within the parties.
