Abstract:      According to the internalization and identification mechanism in the social influence theory, in the knowledge community, the community, as a whole, hopes that the capable knowledge provider can provide knowledge, that is, the inducing behavior is the knowledge providing behavior, and the knowledge providing behavior will be reflected as the community contribution of the provider. For knowledge providers with obvious community centrality, on the one hand, they need more community contributions to maintain their authority image; on the other hand, knowledge offering behavior is the embodiment of their core position in the community, that is to say, knowledge offering behavior is also beneficial to the provider. Since knowledge providers clearly know that community promotion behavior (knowledge provision) is not only beneficial to the overall interests of the community, but also to their own interests, they will realize their own value optimization while achieving community goals, therefore, knowledge providers will actively internalize community promotion behaviors.
     In the knowledge community, the knowledge providers with obvious community centrality show strong personality charm, which is shaped by community interaction. These communities are clearly knowledge-centric providers. They will value their relationships with other people. In order to obtain good interpersonal relationships, the knowledge provider will demonstrate the homogeneity of you and other members as much as possible. Simply put, the knowledge provider will actively recognize the community or advocate the behavior of other members, thereby providing knowledge-related information.
     That is to say, the centrality of community is reflected in the two aspects of "knowledge authority" and "personality charm". The centrality of community is measured by "community contribution" and "community interaction" respectively, and the internalization process of community contribution and the identification process of community interaction are used to stimulate the behavior of knowledge providers. Therefore, this paper proposes the hypothesis that H1: the community-centered position of knowledge providers has a positive impact on their knowledge-providing behavior.
    The existing research confirms that the economic reward is not complete to the knowledge provider behavior incentive. This paper argues that the spiritual satisfaction gained from "community centrality" is another important driving force for knowledge sharing. While payment for knowledge brings economic benefits to knowledge providers, it has been shown that only a small number of knowledge providers make a living from it, and the influence of price fades when the community is sufficiently attractive. For knowledge providers, the image of authority and personal charm created by community contribution and interaction is more important, which is the embodiment of the core status of their community. In other words, the centrality of community partially replaces the incentive effect of economic reward on knowledge provision. Therefore, this paper proposes hypothesis H2: the community-centricity of knowledge providers has a more pronounced effect on their knowledge-providing behavior than economic rewards. H3: There is a partial substitution effect between community centrality and economic rewards. The more obvious the community centrality is, the smaller the influence of economic reward on the behavior of knowledge providers. And vice versa.

    In this paper, by writing python crawler, data of knowledge products and community relations from May 16, 2016 solstice and May 13, 2018 were collected, and 4248 valid data were obtained after collation. In this paper, exploratory factor analysis and principal component analysis were used to measure the main explanatory variable of community centrality, and regression analysis was used to demonstrate the influence of community centrality on the behavior of knowledge provision, as well as the incentive substitution effect between community centrality and economic reward. The results show that: community centrality has obvious incentive effect on knowledge provider′s behavior; the incentive effect of community centrality on the supply behavior of knowledge providers is more obvious than the economic reward, and there is a limited substitution effect between them.

      The theoretical contributions of this paper mainly include three aspects: first, different from traditional communities, gathering for "things". This paper proposes the concept of "community centrality" of knowledge payment, and decomposes and measures it based on the two dimensions of "community contribution" and "community interaction". Secondly, based on social influence theory and incentive theory, this paper discusses the influencing factors and mechanism of knowledge provider′s behavior in the Internet environment, and confirms the effect of community centrality. Third, through crawling the historical micro-data of "Zhihu live" platform, we empirically tested the incentive intensity and substitution effect of community centrality and economic reward. 

Key words:  knowledge payment, community, knowledge provision, community centrality, motivational effect