Invariant Features of Memory Capacity

Our purpose in these experiments was to study short-term (immediate) and long-term memory in the memorization of the same subject matter. By memory capacity is meant the number of units a person is able to reproduce in one repetition, or on an average in one repetition. In short-term reception and full reproduction of the material to be memorized, short-term memory capacity is commensurate with the number of units reproduced. Long-term memory capacity reflects the ability to accumulate as well as to retain information. When the material to be remembered exceeds the short-term memory capacity, the first reproduction is incomplete, and multiple presentation and repetition of the information are necessary for error-free and complete reproduction. In this case the memory capacity is equal to the number of units contained in the presented material divided by the number of repetitions.