Conference Agenda

Understanding when and why nudges work is crucial for designing interventions that consistently and reliably change behaviour. This paper explores the relationship between decision-making speed and the effectiveness of two nudges – carbon footprint labelling and menu repositioning – aimed at encouraging climate-friendly food choices. Using an incentivized online randomized controlled trial with a quasi-representative sample of British consumers (N=3,052) ordering meals through an experimental food-delivery platform, we introduced a time-pressure mechanism to capture both fast and slow decision-making processes. Our findings suggest that menu repositioning is an effective tool for promoting climate-friendly choices when decisions are made quickly, though the effect fades when subjects have time to revise their choices. Carbon labels, in contrast, showed minimal impact overall but reduced emissions among highly educated and climate-conscious individuals when they made fast decisions. The results imply that choice architects should apply both interventions in contexts where consumers make fast decisions, such as digital platforms, canteens, or fast-food restaurants to help mitigate climate externalities. More broadly, our findings suggest that the available decision time in different contexts might at least partly explain differences in effect sizes found in previous studies of these nudges.

We run a randomized field experiment to evaluate the impact of small incentives on waste sorting. For implementing incentives, we exploit a card-scanning technology that tracks bio-waste sorting in real-time. We provide a theoretical model to interpret the finding of our experiment in a context of a prosocial activity where cheating can arise. The model shows that the removal of incentives, provides an excellent opportunity for quantifying the price effect, identifying cheating and exploring changes in intrinsic motivation.

Our results show that incentives increase recycling. However, the effect declines over time while incentives are in place and no difference in the trend is observed when removing the incentive. These findings are compatible with crowding-in of intrinsic motivation and incompatible with cheating.

How do environmental information and awareness interact to improve environmental quality by changing consumer behavior and firm strategies? This article provides theoretical insights using an original differentiation model within a general framework whose specific cases have been studied previously. On the demand side, only informed consumers differentiate brown from green product quality, while uninformed consumers consider these perfect substitutes. Moreover, all informed consumers value the green product and devalue the brown product as a result of an aversion effect but are heterogeneous in their environmental awareness. On the supply side, two firms offer different environmental qualities and compete on price. We consider two types of environmental campaigns: one that increases the number of informed consumers and one that increases the environmental awareness of informed consumers. We show that these campaigns crucially determine three market configurations: segmented; fragmented, with a brown product that appeals to both uninformed consumers and a fraction of informed consumers; and covered. Assuming that the greenest consumer behavior is abstention, we find that both campaigns do not always lead to better environmental quality; that is, a situation in which all consumers are informed and some highly environmentally aware is not necessarily the greenest situation. Depending on the aversion effect, the budget of the campaign organizer, and their relative cost-effectiveness, information and awareness-raising campaigns must be carefully combined to achieve the best possible environmental quality.