IMPULSIVITY AND INHIBITORY CONTROL

We report an experiment testing the hypothesis that impulsive behavior reflects a deficit in the ability to inhibit prepotent responses. Spe cifically, 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 questi onnaire and then participated in a stop-signal experiment, in which th ey performed a choice reaction time (go) task and were asked to inhibi t their responses to the go task when they heard a stop signal. The de lay between the go signal and the stop signal was determined by a trac king procedure designed to allow subjects to inhibits on 50% of the st op-signal trials. Reaction time to the go signal did not vary with imp ulsivity, but estimated stop-signal reaction time was longer in more i mpulsive subjects, consistent with the hypothesis and consistent with results from populations with pathological problems with impulse contr ol.