The role of Gray's impulsivity in anxiety-mediated differences in resistance to extinction

Choice behaviour and extinction learning were studied in a group of 108 und ergraduates classified according to the Sensitivity to Punishment and Sensi tivity to Reward scales (that measure Gray's anxiety and impulsivity dimens ions, respectively). The learning task consisted of continuous choosing bet ween two response alternatives: one was continuously reinforced with a smal l reward and the other was partially reinforced with a greater reward. Afte r 200 trials, one of the responses remained as in the previous phase, and t he other was never rewarded in order to attain extinction. The main aims of the study were: (i) to replicate Avila's finding of lesser resistance to e xtinction of subjects having high scores on the Sensitivity to Punishment s cale; (ii) to investigate whether impulsives (subjects having high scores o n the Sensitivity to Reward scale) chose more than non-impulsives the respo nse associated with a continuous, small reward; and (iii) to test, followin g the model of Patterson and Newman, whether impulsive subjects had a great resistance to extinction of responses highly associated with reward. Resul ts supported all three predictions. Discussion is based on the compatibilit y of the models of disinhibition of Gray and of Patterson and Newman. Copyr ight (C) 2000 John Wiley & Sons, Ltd.