On the time relations of mental processes: An examination of systems of processes in cascade.

This article examines the possibility that the components of an informationprocessing system all operate continuously, passing information from one to the next as it becomes available. A model called the cascade model is presented and it is shown to be compatible with the general form of the relation between time and accuracy in speed-accuracy trade-off experiments. In the model , experimentlLlmanipulations may have either or both of two effects on a processing level: They may alter the rate of response or the asymptotic quality pf the output. The effects of such manipulations on the output of a system of proessesare described. The model is then used to reexamine, the subtraction and additive factors methods for analyzing the composition of systems of processes. The examination of the additive factors method yields particularly interesting results. Among them is the finding that factors that affect the rates of two different processes would be expected to have additive effects on reaction times under the cascade model, whereas factors that both affect the rate of the same process would tend to interact, just as in the case in which the manipulations affect the durations of discrete stages. On the other hand, factors that affect asymptotic output tend to interact whether they affect the same or different processes. In light of this observation, the conclusions drawn from several studies about the locus of perceptual and attentional effects on processing are reexamined. Finally, an outline is presented of a new method for analyzing processes in cascade. The method extends the additive factors method to an analysis of the parameters of the function relating response time and accuracy.