Five studies were conducted to investigate the relationship between short term memory (STM) and long term memory (LTM), and the relationship between STM and problem solving. In study I, the necessity of postulating separate learning processes for tasks which are traditionally classified as STM tasks as opposed to LTM tasks was investigated. Results indicate, for both Study I and Study II, that the same storage system is involved in learning a span series, requiring only one presentation and in learning a supra-span series, requiring multiple presentations. In Study III an investigation was made of the relationship between memory span and the retention of a sub-span series of numbers following a period of intervening activity. Results showed that large memory span subjects (Ss) show better recall after intervening activity than small span memory Ss. In Study IV two experiments were performed to determine whether memory capacity measured by a digit span (DS) test is the same memory capacity involved in solving syllogistic reasoning problems mentally. Conclusions bore out the above hypothesis, however, training in solving problems reduces the load that is placed on STM. Two experiments in Study V showed that memory capacity measured by a DS test is also involved in storing "Meaningful" English words when the words are stored verbatim. (Author/KJ)