Acceptability of a behaviour change intervention aimed at increasing the use of a reusable hot drink cup

Plastic pollution is an acute issue, with single-use plastic contributing to it significantly. It is beneficial for the planet if we engage in more sustainable behaviors, such as using reusable items instead of single-use ones, thus reducing plastic pollution. We implemented an intervention to increase the use of reusable coffee cups, by employing behavior change techniques that targeted values towards environment, intention to use a reusable cup, and habit. The intervention was successful in increasing the participants' use of reusable cups. The aim of the current study was to evaluate the acceptability of the intervention and research methods, as well as opinions of participants about the process and intervention effectiveness, using a mixed methods approach. Participants (N = 156) answered open and closed survey questions about the acceptability of the intervention, and 11 participated in interviews regarding their experience of intervention. The intervention was deemed acceptable and useful by all participants, regardless of which intervention condition they were allocated to, according to both survey and interview data. Men, however, evaluated the intervention as less personally relevant than women, with overall participation of men in the intervention being smaller than women. Recommendations for implementing similar interventions and future research are offered.