The incentives may not be the incentive: a field experiment in recycling of residential food waste

Recycling of residential food waste is urgently needed in cities worldwide to mitigate issues of greenhouse gases, pollution, and resource wastage. Poor waste-sorting behaviour of residents is a key barrier: academics put forward general principles for behaviour change, but none resulting in successful large-scale and effective recycling programs. The complexity of factors influencing this behaviour has historically made the development of prescriptive theories – theories which can predict useful program interventions for a range of situations- impossible. Here we present our sixth study in a research-through-design series to develop a general prescriptive theory of residential recycling behaviour. We used five residential compounds in modern China (and controls) to experimentally test the impact of suspending household ‘Incentives’ on recycling tonnages, while varying ‘Social Influences’. The results confirmed these as causal determinants, alongside ‘Habit’, which was found well-formed after 12 months. The relative determinant influences in months 10-11 (months 14-23) were: habit 50% (80-90%); social influences 50% (10-20%); incentives 12% (5%). Surprisingly, ‘Social Influences’ dominated ‘Incentives’. Exploratory interviews indicated that Interpersonal Interactions comprised an important element of ‘Social Influences’. In addition, 10-20% participants were inconvenienced by the time-window imposed for depositing their food waste. These two factors deserve more careful consideration by planners, and testing in the Prescriptive Theory-building.