Factors Affecting Aggregated Search Coherence and Search Behavior

Aggregated search is the task of incorporating results from different search services, or verticals, into the web search results. Aggregated search coherence refers to the extent to which results from different sources focus on similar senses of a given query. Prior research investigated aggregated search coherence between images and web results. A user study showed that users are more likely to interact with the web results when the images are more consistent with the intended query-sense. We build upon this work and address three outstanding research questions about aggregated search coherence: (1) Does the same "spill-over" effect generalize to other verticals besides images? (2) Is the effect stronger when the vertical results include image thumbnails? and (3) What factors influence if and when a spill-over occurs from a user's perspective? We investigate these questions using a large-scale crowdsourcing study and a smaller-scale laboratory study. Results suggest that the spill-over effect occurs for some verticals (images, shopping, video), but not others (news), and that including thumbnails in the vertical results has little effect. Qualitative data from our laboratory study provides insights about participants' actions and thought-processes when faced with (in)coherent results.