Inhibition in Prolonged Work Tasks

A new model is presented that explains reaction time fluctuations in prolonged work tasks. The model extends the so-called Poisson-Erlang model and can account for long-term trend effects in the reaction time curve. The model is consistent with Spearman's hy pothesis that inhibition increases during work and de creases during rest. Predictions concerning the long- term trend were tested against data from the Bourdon- Vos cancellation test. The long-term trend in the mean and in the variance was perfectly described by the model. A goodness-of-fit test comparing frequency distributions of observed reaction and simulated reac tion times was also supported by the model. Index terms: concentration, continuous work, distraction, in hibition, prolonged work, reaction time, response time.