ABSTRACT
Memory has three operationally-distinct temporal phases: acquisition (learning) , storage (retention ) , and retrieval (usage) . It is reasonable to suppose that these operational phases also correspond to theoretical phases . Of course , there may be a number of interesting theoretical interactions between acquisition, storage , and retrieval proces ses. For example , the rate of forgetting for one event might be slower than the rate of forgetting for another because of differences in the extent or nature of the acquisition process in the two cases. Another frequently cited interaction is that the nature of the retrieval process, particularly for recall and possibly also for recognition, is such as to underestimate the level of memory, perhaps to a different extent at different retention intervals.
