In educational contexts, tests not only assess what students know, they can also directly improve long-term retention of subject matter relative to restudying it. More importantly, the memorial advantage of testing is not limited to select information that was tested earlier. Research has shown that testing can serve as a versatile learning tool by enhancing the long-term retention of non-tested information that is conceptually related to previously tested information; stimulating the subsequent learning of new information; and permitting better transfer of learning to new knowledge domains. We further investigated the potential benefits of testing on learning by asking whether testing can also improve students\u27 learning and retention of the conceptual organization of study materials, and if so, whether processes involved in mentally organizing information during learning contribute to the memorial advantage of testing. In three experiments with categorized lists, we asked whether the testing effect in free recall is related to enhancements in organizational processing. In the first experiment, different groups of subjects studied a list either once or twice before a final criterial test or they studied the list once and took an initial recall test before the final test. Prior testing enhanced total recall of words and reduced false recall of extra-list intrusions relative to restudying. In addition, testing increased the number of categories accessed, the number of items recalled from within those categories, and improved category clustering. In two additional experiments, manipulating the organizational processing that occurred during initial study and test trials affected delayed recall and measures of output organization. Testing produced superior long-term retention when initial test conditions promoted the use of semantic relational information to guide episodic retrieval, and measures of category clustering and subjective organization were correlated with delayed recall. The results suggest that the benefit of testing in free recall learning arises, at least in part, because testing creates retrieval schemas based upon categorical knowledge and recollections of previous recall attempts that guide and facilitate episodic recall
