Sustainable Consumption Practices: Evidence on the Role of Subjective Norms Across Consumption Phases Among Young Adults

Sustainable consumption, understood as the acquisition, usage, and disposal of goods, constitutes a cumulative source of environmental and social pressure through everyday practices. Enforcement of informal institutions through subjective norms may shape sustainable consumption practices. This study integrates the Theory of Planned Behavior with the New Institutional Economics approach to identify and examine relationships between disaggregated subjective norm items and sustainable practices across three consumption phases among young adults. The empirical research was conducted in Poland using non-probability quota sampling and computer-assisted web interviewing (CAWI). The final sample comprised 300 respondents aged 18-29. Relationships between subjective norm items and binary sustainable practices covering acquisition, usage, and disposal were examined using chi-square tests, while the effects of subjective norm items on the odds of engaging in these practices were assessed using binary logistic regression models. The results indicate that subjective norms exert the strongest effects on practices in the acquisition phase, moderate effects on usage practices, and weaker effects on disposal practices. Approval from close friends and family emerges as the most influential informal enforcement mechanism across the three phases. The results suggest that norm-based interventions may be particularly promising in the acquisition phase, while sustainable usage and disposal practices may require complementary formal institutions and supportive infrastructure.