Risk, efficacy, and the moderating role of policy effectiveness in microplastic reduction intentions

Microplastics pose serious threats to both the environment and human health. Although governments have introduced various policies and promoted international cooperation to address this issue, the effectiveness of these efforts is closely linked to the importance of individuals’ engagement, which is shaped by their perceptions. However, limited research has examined how such perceptions interact with perceived policy effectiveness in shaping pro-environmental behavioral intentions. To address this gap, this study aims to examine how risk perceptions (perceived severity and perceived vulnerability) and efficacy beliefs (self-efficacy and response efficacy) influence behavioral intentions to reduce microplastic emissions within the framework of protection motivation theory, and whether perceived policy effectiveness moderates these relationships. We conducted a nationwide survey of South Korean adults and analyzed the data using hierarchical regression to test the proposed hypotheses. The results revealed that both risk perception and efficacy had significant positive effects on behavioral intentions, with response efficacy emerging as the strongest predictor, followed by perceived severity, self-efficacy, and perceived vulnerability. Perceived policy effectiveness did not directly affect behavioral intentions but moderated the relationship between self-efficacy and behavioral intentions. The moderation effect indicated that higher perceived policy effectiveness attenuated the positive relationship between self-efficacy and pro-environmental behavioral intentions, suggesting a potential motivation crowding-out effect. These findings highlight the importance of integrating psychological factors and perceptions of policy effectiveness into policy design. They offer valuable insights for environmental campaigns, communication strategies, and governance efforts aimed at promoting sustainable behaviors to mitigate microplastic emissions.