Digital nudging for healthy and sustainable food choice in online supermarkets: the role of transparency for nudging acceptability

Online supermarkets offer consumers a convenient means to purchase groceries remotely. Given the important role of the user interface (UI) in this context, system designers have explored how subtle UI changes can influence or ‘nudge’ consumers towards healthy and sustainable food choices. However, the use of digital nudging raises important ethical concerns about user manipulation, especially when nudging occurs without users’ awareness. Hence, recent research explored how transparency in the use of digital nudging may increase its acceptability. However, only limited research examined the role of transparency in nudging acceptability for online supermarkets and the results are mixed. To address this gap, we build on Reactance Theory to develop a theoretical model on (1) how transparency about the use of digital nudging in online supermarkets may increase user perceptions of nudging acceptability, and (2) how this influence may be moderated by the intended nudging purpose (i.e. promoting healthy or sustainable food choice). We evaluate this model using an online experiment with 332 participants. By clarifying how transparency and purpose shape nudging acceptability, our research offers important theoretical and practical insights into how system designers can increase the ethicality of digital nudging in online supermarkets.