ABSTRACT
Search is considered to be conducted by the operation of a strategy, chosen from various potential solutions of the task problem by a high-level “planner.” The planner takes into account task, situational, and instructional factors in its choice of strategy, and the major purpose of this chapter is to determine why the planner adopts a particular strategy in preference to others. The characteristics of the strategy are deduced from experimental data, being generally described as a model of the system. The characteristics of the planner can be deduced from the strategy; thus theoretical models of behavior are seen as intermediate stages in the understanding of behavior — the ultimate stage being a description of the parameters the planner considered in its decision between strategies. On the basis of findings by Egeth, Jonides, and Wall (1972), it was reasoned that the internal representation of the alphanumeric characters could be separated cognitively (partitioning) — a technique that allows in some instances for the rapid detection of targets of a different category to the background. The experiments were aimed at discovering the task variables determining whether the option to partition is taken up.
