ABSTRACT Consumers' delivery choices for online purchases shape not only how, when and where parcels arrive, but also the environmental and societal externalities of the last mile. Yet, sustainability messaging at checkout is often absent or inconsistently presented and even when present, evidence of behavioural impact is mixed. This paper therefore tests whether sustainability information increases preferences for more sustainable options and examines how financial and non‐financial messages reweight trade‐offs among price, convenience and speed when information is shown. We conducted three choice‐based conjoint studies. Guided by behavioural change theory, we operationalised three theory‐consistent sustainability messages: (1) a traffic‐light eco‐label, (2) the same label plus a descriptive‐norm message and (3) the same label plus an environmental surcharge that varied by sustainability score. Results show that better sustainability scores increase selection of the most sustainable option. Messages that introduce a social dimension further amplify this effect and begin to shift attention away from price towards sustainability. The environmental‐cost message produces the largest behavioural change. It increases choices of high sustainability scores, discourages low scores and reduces price sensitivity, especially among consumers with lower prior environmental concern. However, credibility perceptions are more sceptical for the two added messages the simple label, underscoring the need for transparent, trustworthy implementation. Theoretically, we demonstrate how distinct nudges reweight decision criteria in multi‐attribute delivery choices at checkout. Practically, we offer guidance for e‐retailers, logistics providers and policymakers on designing sustainability messaging that promotes more sustainable choices.
Cauwelier et al. (Sun,) studied this question.