中文摘要
超级明星企业的崛起使占据支配地位的公司成为现代经济生活的核心，而反垄断执法是规制其市场势力的主要政策工具之一。公众舆论能够影响反垄断执法所处的政治和监管环境，但关于这些偏好由何驱动，直接证据仍然很少。我们对4,000个美国家庭开展了一项预注册的信息提供实验。受访者获知五起真实反垄断案件中的一起，并被随机分配至不同的信息处理组，以研究支持反垄断执法的四项潜在驱动因素：感知市场份额、感知消费者损害、感知不公平竞争以及感知负面形象。四种处理均改变了其旨在影响的信念，但它们对反垄断需求的影响存在显著差异。有关消费者损害的信息产生了最为系统的影响：它提高了对原告的支持，以及对拆分救济和行为救济的支持；这些影响在一个月后仍然可见，并且还外溢至对更广泛反垄断政策的支持。相比之下，与专家预测相反，有关市场份额的信息对反垄断执法需求没有实质性影响。研究结果表明，公众在一个关键方面像经济学家一样思考：他们并不关注市场份额本身，而是会对消费者损害作出反应。核心经济学框架之外的一项因素——感知不公平竞争——同样重要，尽管其影响范围较为有限。我们讨论了这些发现对政策制定者和监管机构的启示。
Abstract
The rise of superstar firms has made dominant companies central to modern economic life, and antitrust enforcement is one of the main policy tools for regulating their market power. Public opinion can shape the political and regulatory environment in which antitrust enforcement takes place, yet there is little direct evidence on what drives these preferences. We conduct a pre-registered information-provision experiment with 4,000 American households. Respondents were told about one of five real antitrust cases and randomly assigned to information treatments designed to study four potential drivers of support for antitrust enforcement: perceived market share, perceived consumer harm, perceived unfair competition, and perceived negative image. All four treatments moved the beliefs they were designed to affect, but their effects on demand for antitrust differed sharply. Information about consumer harm had the most systematic effects: it increased plaintiff support and support for break-up and conduct remedies, with effects remaining visible one month later, and also spilled over to broader support for antitrust policies. By contrast, and contrary to expert forecasts, information about market share had no meaningful effect on demand for antitrust enforcement. The findings suggest that the public thinks like economists in one key respect: they do not care about market share per se, but respond instead to consumer harm. One factor outside the core economic framework, perceived unfair competition, also matters, though its effects are more limited in scope. We discuss implications for policymakers and regulators.