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Subjects identified which of eight matrices were being presented or made a "none of the above" response. The response alternatives were matrices in which each cell was filled with a color coded geometric figure, but the stimulus elements, which were presented separately, filled only one cell at a time with other cells left blank. Thus, the subjects were required to use their immediate memory prior to making a response selection. Independent variables were (1) input speed, defined in terms of stimulus element presentation rate, and (2) stimulus complexity, defined in terms of matrix size. Subjects were given a large number of performance trials. Results showed that extensive practice reduces the time required to respond accurately to a set of stimulus elements; the more complex the stimuli, the smaller the reduction. Whenever the minimal response time was surpassed, both performance accuracy and the amount of information transmitted per minute fell to a degree that was disproportionately greater than increases in input speed relative to the minimal response time (channel capacity). Apparently, subjects tended to recirculate information in immediate memory even when overloaded. Response times related to performance accuracy indicated that when the number of stimulus elements in immediate memory exceeded seven, chances of a correct response were practically zero, with sharp decrements occurring when five stimulus elements were being handled.

This paper presents a quantitative description of the volume required to use common hand tools. The volume described, termed the "space envelope", is for the tool using hand of right-handed subjects. The data were collected on six individuals who had hands at or above the 95th percentile of the military population in length and breadth. The data were obtained by use of a photographic process employing time exposures for each action. This technique provided data comparable to that provided by movie techniques but at a lower cost. The implications of the data for maintenance requirements are also discussed.

Following formulation of a subjective value model and laboratory validation of some of its key assumptions, the model was applied to the airborne antisubmarine warfare situation by pooling judgments of experienced personnel selected from operational airborne-antisubmarine-warfare squadrons. When scaled, these judgments permitted structuring of three sets of airborne-antisubmarine-warfare problems which varied in terms of the perceived value of information provided to crews. The dependent variable was adequacy of performance on realistic exercises in a training simulator. Personnel who made the original subjective judgments and others as well were employed. The proportion of search area remaining per unit time decreased as a linear function of perceived information value as predicted. The subjective model accounted for approximately 90% of the observed between-group variance, thereby demonstrating its efficacy in a limited real-world situation.