Whether and how the administration of one retention test affects performance in a subsequent test on the same material is a question of practical and theoretical interest to educationalists and psychologists. Previous research suggests a number of conclusions which generalise across both materials and procedures. A systematic investigation is described concerning the recognition and free recall of long lists of unrelated words. Finally, a model of recognition and recall is presented which claims that both tasks employ knowledge about the occurrence of individual items in the acquisition list and knowledge about the organisational structure of that list. It is argued that the administration of a recall test affects only the first kind of inf...