Prior knowledge of the content of a passage should reduce the effort required to encode the passage and facilitate its recall. This paper presents such effects of prior knowledge upon comprehension and memory of simple technical prose. The basic procedure was to collect ratings of the amount of prior knowledge for individual passage sentences and individual subjects, and then to determine whether these familiarity ratings predicted study time and recall. In order to validate the rating method, and also to obtain data on prior knowledge of individual facts, subjects also completed an objective test of prior knowledge of the passage facts. Three different encoding-task conditions were used: a self-paced study task, a forced-pace study task, and an incidental-learning task. A cued-recall test followed each condition. In the self-paced task, readers studied unfamiliar material longer than familiar material, but recalled at the same level regardless of familiarity. In contrast, familiarity did predict recall in the forced-pace and incidental tasks. This task specificity is explained in terms of the subjects' encoding strategies. The basic effect of prior knowledge can be explained not only by the elaboration principle, but also by a representation-saving principle, which is presented in a simulation model that can account for the effects of familiarity on study time.We all have the strong intuition that a person should be able to learn and remember material better if the person has a lot of prior knowledge about the content of the material. This issue has great practical importance in understanding how people learn technical material from textbooks and how they use technical documents such as maintenance manuals. However, the experimental literature documenting the relationship between content familiarity and prose memory performance is sparse, and the available results are somewhat contradictory. There are few studies presenting direct evidence that, in a prose memory situation, prior knowledge of the subject matter facilitates study and memory for passage content. Chiesi, Spilich, and Voss (1979) and Spilich, Vesonder, Chiesi, and Voss (1979) found that subjects who were very familiar with the terminology, rules, and procedures of baseball recalled important facts about a baseball game better than did subjects who were relatively unfamiliar with baseball. Anderson (1981) found that subjects given prior knowledge about individuals learned new information about the individuals faster, but retrieved this information more slowly. Graesser, Hoffman, and Clark (1980) found a slight facilitative effect of prior knowledge on reading times, The order of authors was determined at random.
