Consumer food waste, like many environmental behaviours, takes place in private, and is not directly subject to social monitoring. Nevertheless, social interactions can affect private opinions and behaviours. This paper builds an agent-based model of interactions between consumers heterogeneous in their sociability, their initial opinions and behaviours related to food waste, and their willingness to consider different opinions, in order to assess how social interactions can affect private behaviours. Compared to existing models of opinion dynamics, we innovate by including a range of “cognitive dissonance” between stated opinions and actual behaviours that consumers are willing to accept before changing one of the two. We calibrate the model using questionnaire data on household food waste in Italy. We find that a limited degree of mixing between different socio-demographic groups, namely adult and young consumers, is enough to trigger change, but a certain openness of mind is required from more wasteful individuals. Equally, a small group of environmentally committed consumers can attract a sizeable share of the population towards low-waste behaviours if they show a certain variability of opinions and are willing to compromise with individuals in their close neighbourhood in terms of opinions. These findings can help design effective interventions to promote pro-environmental behaviours, taking advantage of the beneficial network effects while anticipating negative externalities.

与许多环境行为一样，消费者食物浪费是私下发生的，不受社会监督的直接影响。然而，社交互动会影响个人意见和行为。本文建立了一个基于代理的消费者之间的互动模型，他们的社交能力、他们对食物浪费相关的初始意见和行为以及他们考虑不同意见的意愿各不相同，以评估社会互动如何影响私人行为。与现有的意见动态模型相比，我们通过在陈述的意见和消费者愿意接受的实际行为之间的一系列“认知失调”进行创新，然后再改变两者之一。我们使用意大利家庭食物浪费的问卷数据校准模型。我们发现，不同社会人口群体（即成人和年轻消费者）之间的有限混合足以引发变化，但更浪费的个人需要一定程度的思想开放。同样，如果一小群有环保承诺的消费者表现出一定的意见可变性并愿意在意见方面与附近的人妥协，那么他们可以吸引相当一部分人口转向低浪费行为。这些发现可以帮助设计有效的干预措施来促进亲环境行为，利用有益的网络效应，同时预测负面的外部性。但更浪费的人需要一定的思想开放。同样，如果一小群有环保承诺的消费者表现出一定的意见可变性并愿意在意见方面与附近的人妥协，那么他们可以吸引相当一部分人口转向低浪费行为。这些发现可以帮助设计有效的干预措施来促进亲环境行为，利用有益的网络效应，同时预测负面的外部性。但更浪费的人需要一定的思想开放。同样，如果一小群有环保承诺的消费者表现出一定的意见可变性并愿意在意见方面与附近的人妥协，那么他们可以吸引相当一部分人口转向低浪费行为。这些发现可以帮助设计有效的干预措施来促进亲环境行为，利用有益的网络效应，同时预测负面的外部性。