Psychologically Informed Design of Energy Recommender Systems: Are Nudges Still Effective in Tailored Choice Environments?

Studies in psychology have shown various ways how humans can be influenced in their choices and behavior. Many of these persuasive strategies and nudges are now also used online, affecting how digital choice environments are designed. In the sustainability domain, these strategies have been used to promote specific pro-environmental behaviors, such as through green energy defaults and social norms (e.g., ‘75% of people re-use their towel’). Most of these nudges are, however, evaluated in one-size-fits-all interventions, not reflecting to an extent to which today’s digital environments are personalized. Not only does this call for smarter, personalized nudges, it also overlooks the fact that various nudges would be applied in tailored choice environments. In particular, recommender systems have become ubiquitous, directly tailoring advice to end users, which might deem nudges to become superfluous. Hence, it remains an open question whether nudging is still effective if the advice is also tailored. This chapter explores the effectiveness of different (smart) nudges in the context of tailored choice systems for household energy conservation. We have developed an approach for a psychology-informed recommender system that presents personalized, attitude-tailored energy-saving advice to end users. Our approach comprises an algorithm and interface nudges that are both personalized and operationalized through smart default and social norm interventions. We present the results of multiple studies performed with our energy recommender systems, providing evidence for the limited effectiveness of interface nudges in a personalized advice context. We discuss the design implications and what nudging and persuasion mean in a world in which most decisions are digitized and content is personalized.