Boundary Conditions of Dynamic Norm Messages in Reducing Plastic Consumption: “Less is More” and “Keep the Distance”

Convincing people to lead a more sustainable lifestyle can have a significant positive impact on our environment. Social media represent an ideal scalable platform for sustainable messages. This study investigates the efficacy of dynamic norm interventions, disseminated by social media influencers, in prompting reduced consumption of PET bottles. Drawing on established research confirming the efficacy of such interventions in fostering sustainable behavior, three studies were conducted (Nsum=1,329) to ascertain the impact of these interventions within the context of influencer communication. Findings indicated that the length of the message and the strength of parasocial relationship with the influencer were moderators of the effect of dynamic norms on the evaluation of the message. Dynamic norms had a greater direct influence on the persuasiveness and the attitudes towards the message and greater indirect influence on behavioral intentions related to the message, when the parasocial relationship was less intense and the message was concise. These insights extend the scope and application of dynamic norm interventions in environmental sustainability efforts on social media.