In markets where ethical goods are available, consumers and producers can voluntarily address the negative externality market failure. However, in reality, these goods are often credence goods and the claims are not verifiable by consumers. We design an experiment to explore whether there can be voluntary internalization of negative externalities in markets controlling for different types of information asymmetry, namely credence claims with the potential for false advertisements, the possibility of certifying claims and finally mandatory truthful claims. We observe that there is a limited scope for ethical goods to be traded and negative externalities reduced in all informational setups. However, when false claims can be made, markets will appear very prosocial to the outside observer who will see widespread concerns for externalities and a price premium on allegedly ethical goods relative to conventional ones. In fact, conventional goods are just being falsely advertised as ethical. In addition, the price premium is seldom enough to cover the additional cost of producing a good that minimizes externalities. Even when credence claims are not allowed, the market will only partially internalize negative externalities, leaving thus room for some form of regulatory intervention.

在有道德商品的市场中，消费者和生产者可以自愿解决负面的外部性市场失灵。但是，实际上，这些商品通常是凭证商品，并且索赔不能由消费者验证。我们设计了一个实验，以探索在控制不同类型信息不对称的市场中，是否可以自愿将负外部性内部化，即具有虚假广告潜力的信用声明，证明声明的可能性以及最终的强制性真实声明。我们注意到，在所有信息环境中，道德商品的交易范围有限，并且减少了负面外部性。但是，当可以提出虚假声明时，市场对于外部观察者将显得非常有利，而外部观察者将会看到对外部性的广泛担忧，以及相对于传统产品而言，所谓的道德商品的价格溢价。实际上，常规商品只是被虚假地宣传为道德的。此外，价格溢价很少足以支付生产使外部性最小化的商品的额外成本。即使不允许提出信用声明，市场也只会部分内部消极的外部性，从而为某种形式的监管干预留有空间。