Impulsivity and inhibitory control

We report an experiment testing the hypothesis that impulsive behavior reflects a deficit in the ability to inhibit prepotent responses. Specifically, we examined whether impulsive people respond more slowly to signals to inhibit (stop signals) than non-impulsive people. In this experiment, 136 undergraduate students completed an impulsivity questionnaire and then participated in a stop-signal experiment, in which they performed a choice reaction time (go) task and were asked to inhibit their responses to the go task when they heard a stop signal. The delay between the go signal and the stop signal was determined by a tracking procedure designed to allow subjects to inhibits on 50% of the stop-signal trials. Reaction time to the go signal did not vary with impulsivity, but estimated stop-signal reaction time was longer in more impulsive subjects, consistent with the hypothesis and consistent with results from populations with pathological problems with impulse control.