Thinking fast, slow delivery: nudging sustainable choices among Gen Z consumers

Online grocery shopping with doorstep delivery is reshaping everyday decisions, often prioritising speed and convenience at the cost of higher transport emissions. Consumer choices are therefore central to promoting sustainability in this context. Grounded in the SHIFT model, this study explores how nudging strategies can promote sustainable behaviour among Generation Z consumers. Drawing on behavioural insights from Kahneman's book ‘Thinking, Fast and Slow’, which investigates how subtle cues influence decision-making. Two online surveys using a randomized experimental design tested nine nudging strategies. Among these, financial penalties and eco-label prompts proved most effective in encouraging slower delivery choices. Participants with prior pro-environmental awareness were less inclined to choose an express delivery, while older Gen Z respondents (closer to 30) tended to favour express delivery regardless of the nudge, suggesting that lifestyle differences shape responsiveness to nudges. These findings indicate that the success of a nudge depends not only on its design but also on consumers' prior awareness and demographic profiles. By focusing on the underexplored Generation Z segment and comparing a diverse range of nudges, this study contributes to behavioural research and offers actionable insights for retailers and policymakers aiming to reduce the environmental impact of last mile delivery.