The Influence of Prior Knowledge on Expert Readers' Main Idea Construction Strategies

THIS STUDY examined the influence of prior knowledge on the strategies used by expert readers to identify and state the main idea of a text when the main idea is not explicit. Expert readers from the fields of anthropology and chemistry read texts from familiar and unfamiliar content domains, and gave verbal reports of the strategies they used in constructing a statement of the main idea. From these verbal reports, the author identified three methods for constructing the main idea: automatic construction, the draft-and-revision strategy, and the topic/comment strategy. Two related strategies were also reported: forming an initial hypothesis and listing words, concepts, and ideas thought to be related to the main idea. Readers reported automatically constructing the main idea statement significantly more often when they had prior knowledge of the content domain of the text, whereas when they lacked such prior knowledge, they more often used the strategy of draft-and-revision. The initial hypothesis and listing strategies were used only in conjunction with at least one of the other strategies. The author hypothesizes that readers lacking knowledge of the content domain may have to resort to strategies rather than constructing the main idea automatically because of the difficulty of the construction task, and possibly also because of the allocation of working memory to other necessary comprehension processes. Thus, although sometimes automatic, expert readers' construction of a main idea is often a mediated, strategic task. The author suggests that instructional materials and instruction should be designed to acknowledge the difficulty of the construction task.