INHIBITION IN SPEED AND CONCENTRATION TESTS - THE POISSON INHIBITION MODEL

A new model is presented to account for the reaction time fluctuations in concentration tests. The model is a natural generalization of an e arlier model, the so-called Poisson-Erlang model, published by Pieters & van der Ven (1982). First, a description is given of the type of ta sks for which the model has been developed. Next, the new model, calle d the Poisson inhibition model, is described. Each reaction time is co nsidered as series of alternating processing times and distraction tim es. During processing, the transition rate from work to distraction is assumed to be constant. Therefore, the number of distractions has a P oisson distribution. During distraction, the transition rate from rest to work is inversely related to the level of inhibition. The model is a limiting case of a model in which inhibition is assumed to oscillat e between a lower and an upper limit. The present model is described i n such a way that computer simulations of the reaction times can be ma de. Furthermore, the moments of the reaction times are derived. At the end of the paper it is shown that a description of the actual time se ries in terms of the underlying inhibition process is in complete agre ement with Spearman's theory about the universal factors, which are th e general factor and the factors oscillation and perseveration. (C) 19 95 Academic Press, Inc.