Information reduction in the analysis of sequential tasks.

This paper proposes a taxonomy of information-processing tasks. Information conserving, reducing, and creating operations are viewed as different methods of processing. The main concern of this paper is information reduction which, it is suggested, represents a kind of thinking in which the solution is in some way implicit in the problem, but in which the input information must be reflected in a reduced or condensed output. A number of tasks within the areas of concept identification and utilization are shown to have this character. If the tasks require complete representation of the stimulus in the response (condensation) the amount of information reduced is directly related to difficulty both during learning and in utilization of previously learned rules. If the tasks allow Ss to ignore information in the stimulus (gating) the direct relation between reduction and difficulty is found during learning but may not occur after the rule is learned. Most applications of information theory to psychology have been concerned with tasks which require information to be conserved between input and output. In the standard reaction-time task the 5 is supposed to effect an energy and location change, but must preserve all the information in the input for errorless performance (Bricker, 19SSa). Verbal-learning experiments add to these requirements the necessity for 5 to serve as a hold circuit and thus delay the response a specified period of time. In studies of the limits of discriminability S is required to preserve in so far as possible all 1 A portion of this paper is based upon a dissertation submitted to the University of