During the past decade, there has been a rapid increase in the number of published experiments on short-term memory. These have been stimulated by a clash between some investigators who regarded that form of memory as having distinct and peculiar qualities, and others who contended that the same principles apply both to short-term and to long-term memory. This latter group in particular wished to make use of the principle of associative interference, which has been established as of major importance in long-term memory. That is, much forgetting is due to the need to remember other things, rather than to deterioration of the desired memory itself. All parties now agree that an 'iconic' or 'pre-perceptual' storage exists, to which the principles of long-term memory do not apply. Once information has passed beyond this stage, however, it is clear that these principles do play a part even in short-term memory; but that there are nevertheless some major experimental differences between memory over short periods and over long periods.