One of the research reports that I read this morning was Characterizing the Influence ofDomain Expertise on Web Search Behavior (link opens PDF) written by White, Dumais, and Teevan at Microsoft Research. They found that domain experts (domain referring to subject matter) conducted searches with more branchiness than non-experts.
Branchiness is defined as "the number of re-visits to previous pages in the session that were then followed by a forward motion to a previously unvisited page in the session."Furthermore, the search sessions of domain experts consistently include more pages, more queries, and more overall time.
The findings of White, Dumais, and Teevan were consistent with findings of previous researchers on the topic including Ingrid Hsieh-Yee who is cited by White, Dumais, and Teevan. In 1993 Ingrid Hsieh-Yee found that students used more of their own search terms and less of external suggestions when researching topics for which they had prior expert knowledge.
What's this mean for teachers and students?
It would be unfair to expect students to be "experts" before conducting a web search. However, it might be worth having students develop a bit more prior knowledge of a topic before turning them loose to search the web for information about that topic. This might be done through reading materials provided by the teacher. It might also be done through mastering some vocabulary terms before embarking on a search. Increased prior knowledge could lead students to have more branchiness is their search habits.