Abstracting Main Ideas from Technical Prose: A Preliminary Study of Six Passages.

Abstract : The construction of the macrostructure, or abstracted main content, for a passage should be based on the semantic content of the passage together with the reader's general knowledge, but guided or influenced by superficial features such as what the initially mentioned information is. Passages were studied that varied in the familiarity of their content, and in their structure according to the macrostructure theory. One type of passage was based on a generalization followed by specific examples; a second type was based on a conclusion followed by a supporting argument. Each passage appeared in either a good version, in which the main idea was explicitly stated in the first sentence, and in a bad version with no explicit statement of the main idea. For each passage, the subjects provided reading times, ratings of the importance of individual passage sentences, and one-sentence statements of the main ideas which were analysed for differences in content. The results show that, in arriving at their statements of the main ideas, readers make use of both semantic and superficial properties of the passage. In particular, they can recognize highly thematic sentences even in unfamiliar material; they make very direct use of explicit statements of the main idea; if the main idea is not explicit, they can infer one if the passage material is familiar; and they can organize even an unfamiliar passage around alternative forms when the main idea is not explicit. An informal process model for the process of abstracting main ideas is presented that summarizes these results. (Author)