Social Norms and Economic Incentives: An Experimental Study on Household Waste Management

We study the introduction of a social information program on waste disposal in a setting characterized by varying economic incentives. Households pay for unsorted waste a fixed amount if their yearly disposal is below a pre-defined cap, and pay per disposal after exceeding the cap. We randomise the receipt of a report informing customers of their disposal relative to that of similar neighbours. An additional treatment couples the social comparison with information on the customer’s disposal cap. We find that the report containing the social norm alone leads to a 7% reduction in the volume of unsorted waste, while making the cap salient reduces the effectiveness of the social norm. Both types of treatments have the same effect on the likelihood of exceeding the disposal cap. The reduction in unsorted waste is partly achieved through an increase in waste sorting, and is not accompanied by any increase in illegal disposals or a decrease in the quality of sorted waste. Our results confirm the effectiveness of descriptive norms in coordinating behaviour in a novel decision domain and in the absence of economic benefits resulting from changing behaviour. They indicate that their effectiveness as focal points is undermined by the provision of alternative reference points.