中文摘要
许多消费者关心气候变化以及与其购买行为相关的其他外部性。我们从三个方面分析此类“具有社会责任感的消费者”的行为及其市场效应。第一,我们构建了一个灵活的理论框架,用以研究理性的后果主义消费者所处的竞争均衡。在违背价格接受行为的情况下,均衡反馈会以非平凡的方式削弱个人消费对总消费的影响,从而削弱缓解外部性的动机。这导致一种新型市场失灵:即使消费者完全“将外部性内部化”,也会过度消费产生外部性的商品。与此同时,具有社会责任感的消费者会改变税收、上限及其他政策在降低外部性方面的相对有效性。第二,由于消费者对自身市场影响的信念和偏好在我们的框架中发挥着关键作用,我们通过一项专门设计的调查对其进行实证研究。与我们的模型一致,消费者往往持后果主义立场,且许多人认为自己对总消费的影响会受到削弱。然而,与我们的模型不一致的是,我们还发现许多受访者预期自己会对总消费产生一比一的影响。因此,第三,我们分析此类“天真型”消费者如何改变我们的理论结论。在单一商品经济中,他们的消费少于理性消费者;但在存在跨市场溢出的多商品经济中,他们的消费可能更多。天真型消费者与理性消费者混合存在,可能导致最差的结果。
Abstract
Abstract Many consumers care about climate change and other externalities associated with their purchases. We analyze the behavior and market effects of such “socially responsible consumers” in three parts. First, we develop a flexible theoretical framework to study competitive equilibria with rational consequentialist consumers. In violation of price taking, equilibrium feedback nontrivially dampens the impact of a person’s consumption on aggregate consumption, undermining the motive to mitigate. This leads to a new type of market failure, where even consumers who fully “internalize the externality” overconsume externality-generating goods. At the same time, socially responsible consumers change the relative effectiveness of taxes, caps, and other policies in lowering the externality. Second, since consumer beliefs about and preferences over their market impacts play a crucial role in our framework, we investigate them empirically via a tailored survey. Consistent with our model, consumers are often consequentialist, and many believe that they have a dampened impact on aggregate consumption. Inconsistent with our model, however, we also find many respondents who expect to have a one-to-one impact on aggregate consumption. Third, therefore, we analyze how such “naive” consumers modify our theoretical conclusions. They consume less than rational consumers in a single-good economy, but may consume more in a multigood economy with cross-market spillovers. A mix of naive and rational consumers may yield the worst outcomes.