Users' Knowledge Use and Change during Information Searching Process: A Perspective of Vocabulary Usage

One of the key questions in studies of Search as Learning is how to represent and measure the intangible and invisible learning processes that occur during the search process. In this study, participants are presented with two tasks and asked to represent their current relevant knowledge in a mind map. Participants then perform the search tasks and modify the mind maps as they search. In this paper we report on the use of measurement of vocabulary that is added to or removed from the mind map as a proxy for knowledge change in the search process. Mind maps represent user's knowledge with content in the tree structure. We examined the effect of users' prior knowledge upon their query behaviors by comparing users' pre-search mind map vocabulary with their query terms; and investigate how the content pages users read during search affected their knowledge change during search by comparing pre- and post-search mind maps. Our results demonstrated that users' prior knowledge played an important role in their query formulation. More than 50% of query terms came from users' prior knowledge, which accounted for nearly 40% of pre-search mind map vocabulary. As the search process proceeded, users added new vocabulary to their mind maps, and about 1/3 of new vocabulary was present in and copied directly from content pages. This study shows how prior knowledge and search results contribute to users' learning during information searching, and can help us better understand how learning occurred in the information searching process.