The Effects of Rewards on Spillover in Environmental Behaviours: Monetary vs Praise Reward

The paper focuses on the so-called spillover effect in the environmental domain, or the tendency of individuals adopting a specific green behaviour to behave environment-friendly also in other, not related contexts. Different psychological mechanisms explaining this process have been singled out in literature (e.g.: Self Perception Theory, Cognitive Dissonance Theory, etc). However, there is no general agreement neither on the strength nor on the drivers of spillover. The study provides a value added to literature by analyzing the role played by specific factors (so far neglected) in hindering or spurring spillover: monetary and non- monetary rewards. A real-life experiment is carried out on a sample of undergraduate students from Aarhus University (Denmark), based on a panel study with online surveys filled in twice: before and after the experimental intervention. The latter consists of encouraging the uptake of a specific green behaviour (purchase of sustainable products) for a period of 6 weeks, investigating the effects on different behavioural domains and the role played by incentives. Results show how the nature of incentives has a relevant direct impact on the behaviours being incentivized, whereas no significant spillover effect to other behavioural domains is detected.