Perceived descriptive norms strengthen the global human identification—general pro-environmental behavior association: Empirical evidence from survey studies

Limiting climate change requires the concerted efforts of all human beings, and thus focusing on global human identification, numerous studies identified a positive association between such a personal identity and pro-environmental behavior. However, the effect sizes of their association varied widely among previous studies, making it difficult to utilize global human identification to improve pro-environmental behavior. The variations in effect sizes indicate that some situational boundary conditions are likely to fluctuate the strength of the association between global human identification and pro-environmental behavior. In order to shed light on the situational factor that may boost the positive effect of global human identification on pro-environmental behaviors, the current research systematically examined the moderating role of perceived descriptive norms in the focal relationship, drawing on the theories regarding social identity and social norms. Specifically, we conducted an online questionnaire survey to measure all the core variables (Study 1) as well as an online survey experimental study to manipulate perceived descriptive norms (Study 2). The results of two studies consistently showed that participants with high global human identification demonstrated more general pro-environmental behavior only when they perceived that others were also behaving in an eco-friendly way. By uncovering the potential of perceived descriptive norms to amplify the facilitating effect of global human identification on general pro-environmental behavior, our findings provide empirical evidence for the social identity model of pro-environmental action and highlight the joint impact of personal and situational factors on eco-friendly behaviors.