Visual information processing of sequentially presented inputs: III. Further effects of list length and interstimulus interval values on sub-span storage and retrieval mechanisms

Two experiments were carried out, employing a computer-based cathode-ray tube display system, to study further the effects of sub-span Hst length, i.e., two, three, four, and five decimal digits, and relatively small interstimulus interval (ISI) values, i.e., 20, 40, 60, 80, and 100 msec, on visual information processing, storage, and retrieval mechanisms. The results of the first experiment confirmed the compttcated intenctions found in two earlier studies between Hst length and ISI values, but with much smaller ISI values than employed preriousfy. The results of the second experiment, in which unequal ISI values were employed within the same length input string, showed little effect resulting from this parameter, but it was suggested that a wider distribution of different ISI values within the same length input string would produce very strong effects.     

A Systems Dilemma

The current shift of interest, reflected in public policy, from the production of goods to the provision of services, has caused a major re-examination of the nature of the services the individual can expect from his society. This re-examination is producing a number of insights, some of them shocking. In particular, we are learning that many of the systems we have created to deliver services are, in the name of “progress” and “civilization,” contributing to the conditions of human distress they were designed to alleviate. Much has been written lately about how service systems of one kind or another subvert their announced goals—how a welfare system perpetuates poverty, or how the medical profession creates iatrogenic illness. There has not been very much written, however, about how several systems inadvertently combine in their day to day operations in such a way as to frustrate each others' activities, and how, in so doing, they destroy in varying degrees the lives of people, or render it difficult for them to improve their lives. We have all been much too tightly locked in our own niches by training, experience, and various types of private interest to see this kind of interlock. It comes into sharp perspective only when one studies the problems of a single person in terms of his total life space, his “ecology.” This paper represents an effort to describe one such situation in a family as viewed from a community health services program designed to approach human crises as ecological phenomena, and to explore and respond to them within this framework. We have found that the best way to organize our view of the environmental field people move in is according to the diverse systems which make it up, so we have labeled our theoretical base “ecological systems theory.” ( 1 ) What is of particular interest to the behavioral scientist in the situation described is that neither individual nor family diagnosis, nor the contributions of the larger systems (in this case a housing system and a system of medical care) will, if viewed separately, explain the state of the man in question. Only when the contributions of all of these systems are made clear, and their interrelationships explored, do the origins of the phenomena described begin to emerge.