The effectiveness of sustainability social marketing use of fear and guilt appeals to influence the behavioural intention of millennials

PurposeThis study aims to understand if the appeals often used in social marketing, namely, fear and guilt, are effective in changing South African millennials' intention to behave more pro-environmentally. Design/methodology/approachA primary quantitative research method was followed with a between-subject experimental design approach. The treatment took the form of fear- and guilt-based sustainability advertisements. Questions were asked in the form of a survey with the determinants of the theory of planned behaviour (TPB) model (i.e. attitude, subjective norm and perceived behavioural control) as its constructs. FindingsAnalysis of the collected data revealed that adding the appeal of fear or guilt to advertisements does not significantly change South African millennials' intention to behave pro-environmentally. Furthermore, a deeper analysis of the TPB model's determinants showed that attitude had the strongest effect on behavioural intention. Also, the use of fear or guilt in sustainability social marketing does not affect the subjective norms of South African millennials. Research limitations/implicationsThe study offers a greater understanding of customer engagement and motivational factors in the mobile instant messaging (MIM) environment. Future studies could consider more complex relationships with customer engagement in using MIM apps focussed on a younger generation. Practical implicationsIt is therefore recommended that to significantly increase the South African millennials' intention to behave pro-environmentally, social marketers should use other advertising tools or appeals, namely, positive attitude change. Originality/valueThe results of this study represent a contribution to the limited literature on TPB determinants and how they drive behavioural intention.