Modification of memory storage processes

This paper reviews current findings and thinking concerning the nature and bases of “time-dependent” processes in memory storage. Considerable evidence indicates that memory storage can be enhanced or disrupted by treatments of various kinds (such as electrical stimulation and drugs) which influence brain functioning if the treatments are given to animals shortly after training. This evidence supports the view that there are two types of memory processes, short term memory and long term memory. The fixation of long term memory occurs over time following training. We conclude that the bulk of the evidence is consistent with a “dual-trace” hypothesis and that alternative interpretations of these findings are not well supported. We point out that these studies can only provide indirect evidence of memory processes since they are studies of the susceptibility of memory processes to facilitating and disrupting influences. The treatments can vary in their effectiveness. Several conceptual models of the relationship between short term and long term memory are presented and evaluated. We suggest that the evidence is most consistent with the hypothesis that short term memory processes are different from but essential for the development of long term memory. The final section of the paper reviews recent findings which provide some understanding of the neurobiological bases of the treatments which modify memory storage processes. We suggest that knowledge of the behavioral effects of treatments which influence memory considered together with knowledge of the effects at a neurobiological level may provide some clues to the biological bases of memory.