Eye Fixations and Cognitive Processes

A widely accepted view of the human information processing system is that most of the symbol manipulation takes place in a central processor, sometimes referred to as the active memory (Neisser, 1967), working memory (Newell & Simon, 1963), operational memory (Posner, 1967), or the immediate processor (Newell, 1973). This paper is concerned with the rapid mental operations of the central processor and how they are reflected by the pattern and duration of eye fixations during a task.involving visual input. We will examine the basic operators, parameters, and control structure of the central processor as it performs such tasks as the comparison of rotated figures (Shepard & Metzler, 1971), mental arithmetic (Parkman, 1971), sentence verification (Carpenter & Just, 1975), and memory scanning (Stemberg, 1969). These tasks generally take less than 5 or 10 set to complete, and can be decomposed into very rapid mental operations, often estimated to consume between 50 to 800 msec each. The goals of this paper are to demonstrate that the locus, duration, and sequence of the eye fixations can be closely tied to the activity of the central processor, and to exploit this relation in investigating the fine structure of the processor’s activity in a number of cognitive tasks. The primary proposal is that the eye fixates the referent of the symbol currently being processed if the referent is in view. That is, the fixation may reflect what is at the “top of the stack.” If several symbols are