Economic incentive and social influence to overcome household waste separation dilemma: A field intervention study

China has experienced a rapid growth of solid waste over the years, household waste source-separation is becoming a nationwide strategy for promoting recycling economy and improving urban environmental sustainability. Waste separation, however, may end in failure due to the free-rider problem similarly existing in other pro-environmental collective actions. Along with the economic and sociological/social psychological logic respectively, this study tested the effects of economic incentive and social influence, which are theoretically considered as two general solutions to domestic waste separation dilemma. One hundred and eighty-eight residents in the three communities of Hangzhou, Zhejiang Province were assigned to a control group or one of two experimental scenarios, where they were encouraged to participate in waste separation activities through either the economic rewards given on their performance, or door-stepping campaigns aimed at constructing a supportive social environment. Six-month intervention effects were analyzed and showed that economic inducement was more effective than social mobilization in promoting waste separation. Further mediation tests indicated that self-efficacy partially mediated the effects of both strategies, while personal norms were positively associated with two treatments instead of behavior demonstration. In addition, the moderating effects of several socio-demographic factors on psychological mechanisms were also explored. The findings, limitations and implications for future research and policy are discussed in the concluding section.