Can Competing Demands Affect Pro-Environmental Behaviour : A Study of the Impact of Exposure to Partly Related Sequential Experiments

The study of human behaviour is central to the development of appropriate policies for sustainability. We argue that mathematical models of human choice behaviour may produce biased results if they fail to account for the possibility of spillover effects, in particular the possibility that individual behaviour may change as a result of competing demands, such as in the sequential exposure to partly related choice contexts. Using a sample of 751 individuals and a carefully constructed experiment, we develop mathematical models that jointly explain the choice between different pro-environmental actions and the willingness to donate money for environmental causes. We find that the strength of preferences for behavioural changes leading to greater CO2 reductions is (causally) shaped by participants previously considering other similar behavioural changes. The kind of spillover effects we find are relatively complex and often subtle, and thus warrant further replication studies. Our study demonstrates that choices can be influenced by the type of scenarios, the type of information that is displayed, and the order of the experiments which helped us identify a type of spillover effects