FURTHER ARGUMENT FOR THE EXISTENCE OF A PACEMAKER IN THE HUMAN INFORMATION-PROCESSING SYSTEM

To support the idea that temporal information processing may depend on an internal clock, Treisman et al. proposed a pacemaker model (Treism an, M., Faulkner, A., Naish, P.L.N., Brogan, D., 1990. The internal cl ock: Evidence for a temporal oscillator underlying time perception wit h some estimates of its characteristics frequency. Perception 19, 705- 743.) and a technique for interfering with it by introducing an extern al periodic phenomenon. Experimental results obtained by these authors on time estimation and production tasks support this model. In anothe r study, Treisman et al. established that the pacemaker also affects r eaction times (RT) (Treisman, M., Faulkner, A., Naish, P.L.N., 1992. O n the relation between time perception and the timing of motor action: Evidence for a temporal oscillator controlling the timing of movement . Quaterly Journal of Experimental Psychology 45A, 235-263.). In the p resent study, we addressed the question as to which information proces sing stage (Sanders, A.F., 1980. Stage analysis of reaction process, I n: Stelmach, G.E., Requin, J. (Eds.). Tutorials in motor behavior. Nor th-Holland, Amsterdam, pp. 331-354.) is affected by this internal cloc k. For this purpose, we used the Additive Factors Method (Sternberg, S ., 1969. The discovery of processing stages: Extension of Donder's met hod. In: Koster, W.G. (Ed.). Attention and Performance II. Acta Psycho logica 30, 276-315.). To vary sensorial processing time, we used two v isual stimulus intensities. Stimulus-response mapping was manipulated to enhance central processing time. To modify the duration of the moto r stages, the two responses could be given by two fingers on the same hand (right ring vs. middle finger) or by two fingers of the different hands (right ring vs. left middle finger). Intensity of the stimulus, stimulus-response mapping, and repertoire of responses were found to be additive.