A MODEL AND DIAGNOSTIC MEASURES FOR RESPONSE-TIME SERIES ON TESTS OF CONCENTRATION - HISTORICAL BACKGROUND, CONCEPTUAL-FRAMEWORK, AND SOME APPLICATIONS

Based upon classical hypotheses about accumulating mental fatigue and distraction and its effect on response times, put forward in late 19th and early 20th century papers, a mathematical model is proposed for r esponse times on tests of speed and concentration. The model assumes t he random occurrence of very short distractions during information pro cessing. It explains fluctuation and the increasing trend in response times on successive equivalent task units and leads to some simple dia gnostic RT measures of speed and concentration as alternatives to the mean RT. A review is given of several experimental applications of the model, with subjects with and without concentration problems, using c ancellation and digit addition tasks. The results demonstrate the pote ntial usefulness of the model and the diagnostic measures derived from it. As predicted by the model, prolonged task performance yields an i ncreasing trend in RT mean and variance that can be strongly reduced b y giving very short resting periods very frequently, and to a lesser e xtent also by task alternation, but not by simply motivating the subje cts to concentrate. Some practical implications for the administration and scoring of tests of speed and concentration are discussed, as wel l as limitations of the present results and the complementary relation of our approach to popular ones such as ''stage analysis.'' (C) 1995 Academic Press, Inc.