Digital Nudge Stacking and Backfiring: Understanding Sustainable E-Commerce Purchase Decisions

Abstract Background: The consumption of ‘fast fashion’, which is expedited by cost-effective e-commerce systems, represents one of the major factors contributing to the acceleration of climate change. An emerging approach to steer consumers in the direction of more sustainable purchase decisions is digital nudging. This paper explores digital nudging in the context of green fashion e-commerce by testing the effectiveness of two nudging strategies on the decision to choose green fashion products (GFP) over regular fashion items. Method: This study was conducted as a between-subject online experiment (n=320) with four conditions simulating an e-commerce scenario. The participants were presented with different products: one was ecologically friendly, and another was the regular option. Depending on their randomized group allocation, the participants experienced a default nudge, a social norm nudge, a combination of both strategies, or no nudge. In addition, we conducted 10 qualitative interviews to gain a deeper understanding of consumers’ decision process. Results: Our experiment failed to demonstrate statistically significant relationships between the various nudging strategies and GFP purchase decisions. However, additional explorative analyzes confirmed a backfire effect for the combination of nudging strategies. This reveals the previously overlooked influence of participants’ identification on the effectiveness of digital nudging strategies. In addition, qualitative interviews revealed individual factors that influence sustainable e-commerce purchase decisions. Conclusion: This study contributes to information systems research by explaining the differences in the effectiveness of different nudging strategies regarding high-involvement compared to low-involvement products. Moreover, it provides empirical evidence of a backfire effect resulting from a combination of digital nudging strategies (i.e., digital nudge stacking). Finally, the study underscores the leverage that individual factors have on both GFP purchase decision and the effectiveness of nudges.