The Measurement of Attention Capacity through Concurrent Task Performance with Individual Difficulty Levels and Shifting Priorities

Abstract

Some of the unsolved problems in the application of secondary task techniques include: (a) the evaluation of relative changes in performance in dual task situations; (b) the prediction of possible interactions between different tasks and their components; and (c) the extent of voluntary control of capacity allocation. The present paper describes a three-phase experiment in which an effort was made to attack these problems by a new methodological approach. The three successive phases included separate performance of the experimental tasks (one dimensional compensatory tracking and a digit processing, reaction time task) with adaptive adjustment of difficulty, simultaneous performance of the tasks with equal task priorities, and simultaneous performance with several manipulations of the two task priorities. The results have demonstrated the usefulness of the general methodological approach for the assessment of capacity limitations as well as for the evaluation of possible interactions between tasks. With regard to the allocation of capacity, the experimental results proved that, in general, subjects were able to adjust their allocation of capacity to the various changes in task priorities.