Waste threatens human health and the environment. How can we persuade people to participate in waste separation?

In order to answer this question, a research team led by Dr. LIU Pingping, from the Institute of Psychology of the Chinese Academy of Sciences performed an experimental study based on the social influence theory and the value-identity-personal norm model. This study recruited 280 participants to investigate the effects of perceived importance (high, medium, low) and language intensity (assertive, non-assertive) on people’s intention to separate waste (see Fig. 1).

Fig. 1. The experimental procedure (a) and poster stimuli (b) in this study. Image by XU Yaojing.

The results showed that high perceived importance and assertive language were positively and significantly associated with waste separation intention (see Fig. 2). By emphasizing the perceived importance of waste separation, policymakers can raise awareness and motivate individuals to take action. Additionally, using assertive language in pro-active material for communication and campaigns can enhance the persuasiveness of the message and encourage behavior change.

Fig. 2. An interaction between perceived importance (PI) and language intensity (assertive vs. non-assertive) on waste separation intention. Error bars represent the standard error. Image by XU Yaojing.

Furthermore, the mediating analysis revealed that environmental self-identity and personal norm were serial mediators of the relationship between perceived importance and waste separation intention (see Fig. 3). This finding suggests that individuals' importance perception of waste separation can reinforce their identification as environmentalists. If the perception of waste separation can be internalized, its intention or behavior tends to be automatic processing. Over time, this identification can cultivate a moral obligation and responsibility towards waste separation that is internalized and stable.

Fig. 3. Serial mediation model with environmental self-identity and personal norm as mediators of perceived importance on waste separation intention. Notes. *** p < 0.001. Image by XU Yaojing.

Last but not least, environmental agencies must recognize that not all people are equally concerned about the environment. Therefore, they could adjust their assertive messages to target more environmentally concerned individuals. On the basis of perceived importance, policymakers can further aim to foster individuals' environmental self-identity and cultivate a sense of personal norm to engage in waste separation behaviors. Individuals can be encouraged to recognize their social responsibility in environmental protection by education and community campaigns, thereby forming the solid environmental awareness.

By incorporating these insights into communication strategies and environmental education initiatives, we can effectively cultivate individuals' importance perception, environmental identification and personal norm of waste separation. These can encourage individual intentions to engage in it, thus fostering a collective commitment to environmental conservation and sustainable waste management practices.

This study was supported by the National Natural Science Foundation of China, the Scientific Foundation of the Institute of Psychology, Chinese Academy of Sciences, and the joint program of the Chinese Academy of Sciences and the Japan Society for the Promotion of Science. The research was published online in Journal of Environmental Management in February, 2024.

LIU Chen
Institute of Psychology
Chinese Academy of Sciences
Beijing 100101, China.
E-mail: liuc@psych.ac.cn