Human Use of Short Term Memory in Processing Information on a Console. Esd-tdr-64-620.

This report assumes that an operator's console constitutes a third form of memory in addition to that integral, to the human and that integral to the machine which is not directly accessible to the human. Questions are raised concerning the characteristic modes of human storage and retrieval of information from internal memory when such external memory is accessible. The report also introduces the concept of associative memory nets formed by cue-related images of external events. Information loss occurs when cues, originally capable of providing access to images, become insufficient to direct retrieval, in subsequent memory growth. A list processing experiment is described. The processing involves adding or removing sequentially presented "items" (alphanumeric characters) from a list of previously processed items. Two conditions are established in which items are 1) presented directly, or 2) computed from presented data. Storage structures characterizing internal human memory and external console memory in this task are postulated. A retrieval model implied by these structures is constructed to account for the effects of computation and learning upon the features of the experimentally obtained curves. Insufficient retrieval of required information from internal memory is assumed to necessitate external memory search. The effect of computation is to increase the probability of insufficient retrieval and hence the frequency of external search. Learning decreases this probability. The effects of inducing alternate forms of internal storage are studied and found generally to result in increased storage and retrieval times. Implications for console design are discussed.