A critical path generalization of the additive factor method: Analysis of a stroop task

Sternberg's additive factor method was generalized to apply to tasks involving both serial and concurrent processing, based on the critical path method of scheduling, and the effects on reaction time of factors prolonging separate processes in a task are discussed.

Abstract

Sternberg's additive factor method was generalized to apply to tasks involving both serial and concurrent processing. The generalization is based on the critical path method of scheduling. The effects on reaction time of factors prolonging separate processes in a task are discussed; in general these effects are interactions of a simple form. Reaction times can be used to deduce, in part, the schedule of the mental processes in a task, including their order of execution. Bounds on process durations can be derived. Often there are redundant equations so the method can be easily rejected if it does not apply. A dual task experiment by Greenwald was analyzed. In the task subjects were presented with two stimuli and made a response to each under high and low compatibility conditions. Two bottlenecks in processing were located: (a) Subjects make only one decision at a time, in accordance with single channel theory, although the high compatibility condition may be an exception; (b) there is a mental process which takes longer when the stimuli conflict. The decisions about the two stimuli probably change places in the schedula when compatibility is changed.