As a way of searching information in the social context, social search has the characteristics of complexity and diversity, and it shows great differences from traditional Web search. In terms of the prior studies on social search behaviors, great challenges are inevitable and further explanations are still needed both from the systematic overview and the logical construction view. Activity Theory has a rich theoretical vocabulary which is open and extensible. It can help us synthetically analyze the basic elements such as user, system as well as information, and build an integrated conceptual system or theoretical framework from the perspective of Ontology. Therefore, this paper draws on Activity Theory lens to explore the structure and process of social search behavior.

This paper reviews the research progress of social search from the perspective of information behavior, the development process of Activity Theory and its main applications in the Library and Information Science domain. Based on these factors, the paper focuses on the analysis of element, system and hierarchy structures of social search behavior, as well as its cognition and task execution processes. From a static microcosmic point of view, firstly, social search behavior involves six elements, namely subject (searcher), object (question), community, tool (search platform), rule/norm, division of labor (role). Among them, subject, object and community are core elements, while tool, rule/norm and division of labor are mediated elements. By the interaction of these elements, the social search task is finally completed and the result (answers/information/knowledge) is generated. Secondly, the combination of three adjacent elements of social search behavior constitutes four closely linked subsystems, that is to say, sharing system, production system, communication system and collaboration system. Thirdly, social search behavior can be divided into search activities, search actions and search operations via a top down approach, which is respectively influenced by search motive, search goal and search conditions. In the social search context, these six elements, four subsystems and three hierarchies are indispensable and closely linked to each other. Thus, the examination on the social search behavior structure can help us better understand the nature and mechanism of social search intuitively and clearly. At the same time, it is significant to design the platforms and tools of social search, as well as human computer interaction. From a dynamic macroscopic point of view, in the first place, there exists a cognitive process of internalization and externalization between the subject and the object of social search behavior. In the second place, social search behavior can be decomposed into three task execution phases, including pre search (identifying, considering), in search (selecting, questioning, obtaining) and post search (judging, confirming). In order to facilitate the understanding of the task execution phases, this paper selects four types of social search behavior (social Q & A, social search engine, social tagging and social media), namely Zhihu, Weibo Search, Douban, WeChat, which are widely used in the current Chinese context, and takes the search task “Please List Classic Films that Reflect World War II” as an example for the search experience and comparison.

From a theoretical perspective, this paper deeply reveals the structure and process of social search behavior, establishes main categories of social search behavior research and further expands the scope of Activity Theory in the emerging context. From a practical perspective, the findings of this paper are beneficial for improving information literacy of social search users, information value analysis of social search, and design of social search system interface and human computer interaction. 7 figs. 3 tabs. 77 refs.