5. Discussion and conclusions
5.1. Overall effects of two initiatives
As one of few intervention-based studies from an environmental collectivism perspective, this study tested two strategies, namely, economic incentive and social influence, in terms of their effects at facilitating public participation in practices of household waste source-separation. It was found that both of them could promote residential waste separation behavior, whereas the former seemed more effective than the latter. The reason might be that the establishment and individual introjection of social norms cannot be accomplished immediately, and the advantages of social interaction and mobilization might be allowed to shine over a longer period. Therefore, both the economic and sociological/social psychological logics seem applicable to solve the free-rider problem and, hence, prompt individual effort to engage in separating their daily garbage, corroborating earlier research (e.g., Boonrod et al., 2015; Iyer and Kashyap, 2007; Mickael, 2014; Yau, 2010). More importantly, an economic instrument can work more efficiently at an early stage of promoting waste separation based on the findings of this approximately six-month study. However, it is important to remember that cost accounting should be taken into account in the policy decision from a practical point of view. Although it is outside the scope of this article, we mention some important aspects for the sake of completion. For the direct economic cost, while recruitment of community volunteers is much cheaper than purchase of public service from private corporations (37.5 RMB/household month paid for ‘‘Huge”), the latter provides extra services such as solid waste transposition and disposal, which are not covered by social influence approach and can compensate a considerable share of official fiscal expenditure invested in garbage removal, landfill or incineration.
