A discussion of two experiments with human verbal learning, and an explanation of the interference phenomena in terms of the EPAM (Elementary Perceiver and Memorizer) model. A model of an association memory, the EPAM, is a learning system, a computer simulation of human verbal learning processes. No stored information in this memory is ever physically destroyed. Yet the behavior which is normally called "forgetting" occurs because of a loss of access (temporary or permanent) to information stored in a growing net of associations. In this system, forgetting occurs as a direct consequence of normal learning processes (i.e., forgetting is the result of the interference of items later learned with items learned earlier) without the postulation of a separate mechanism.