The spillover effect of separating household waste on water conservation: A perspective of self-determination theory

Taking the view that pro-environmental behaviors can have spillover effects, this study examines how household waste separation (an environmental behavior with a high degree of difficulty) impacts consumers’ water-saving efforts (an environmental behavior with a low degree of difficulty). We assess the mediating effects of self-efficacy and ego depletion in this relationship and the moderating effect of the need for self-determination in the mediated relationships. The results show separating household waste significantly enhances consumers’ water-saving efforts. Both self-efficacy and ego depletion partially mediate the relationship between household waste separation and efforts to reduce water consumption. Specifically, if consumers engage in pro-environmental behaviors based on their internal, rather than external sense of moral identity, their sense of self-efficacy increases after separating household, which motivates them to engage in subsequent water-saving behaviors. In addition, consumers’ sense of ego depletion declines when they engage in household waste separation, which increases subsequent water-saving behavior. Compared to low-level self-determination needs, high-level self-determination needs weaken the positive impact of household waste separation on consumers’ perceived self-efficacy, but strengthens the negative impact of household waste separation on consumers’ perceived ego depletion and promotes subsequent water-saving behavior. These findings suggest policymakers should pay attention to the spillover effects pro-environmental behaviors and use household waste separation policies to promote other pro-environmental behaviors such as reducing water consumption.