Why act sustainable? : Exploring what can be learnt from different approaches to motivations for pro-environmental behaviour

Abstract: To combat anthropogenic climate change, greenhouse gas emissions need to be reduced. Though one person’s actions cannot turn the tide, so to say, the combined effort of many individuals can. To this end, numerous studies have investigated theoretically supported motivations – for example financial, environmental, hedonistic, moral, or normative motivations – underlying pro-environmental behaviours. To understand the causal relationship between these motivations and behaviours, studies tend to look at how such variables are associated across individuals. In observational studies, it is not easy to infer whether associations indicate a causal process or emerge from confounding pathways. This implies that positive associations between motivations and behaviour in an observational study do not necessarily imply that increasing individuals’ motivations will increase pro-environmental behaviour.This thesis presents and discusses studies that investigated associations between motivations and intentions to engage in pro-environmental behaviour using two different research designs – observational and experimental – and by looking at inter- and intraindividual variation in observational data. Papers I-III reveal that in data from observational designs, associations between motivations and intentions differ contingent on whether one uses an inter- or intraindividual approach to variation. Concretely, while financial and normative motivations were not predictive of variation in intentions between individuals, they were predictive of variation in intentions within individuals. That is, those with stronger financial and normative motivations compared to others did not have stronger intentions, per se, yet, when an individual reported a stronger financial or normative motivation for a specific behaviour compared to other behaviours, they tended to have stronger intentions towards the behaviour. In Paper III, an experimental manipulation that raised environmental motivations was not found to raise intentions. Overall, when associations are investigated in a way that is more closely aligned with the theoretically proposed mechanism (i.e., causal processes occurring within individuals), there seems more support for the motivational hypotheses predicted by theories.