This research report explores the relationship between impulsivity and inhibitory control, using a stop-signal paradigm to measure inhibitory control. The study involved 136 undergraduate students who completed an impulsivity questionnaire and then participated in a stop-signal experiment. The experiment tested the hypothesis that impulsive individuals have difficulty inhibiting prepotent responses, leading to slower reaction times to stop signals. Participants performed a choice reaction time task and were asked to inhibit their responses when a stop signal was presented. The delay between the go and stop signals was adjusted to allow inhibition on 50% of the trials. Reaction times to the go signal did not vary with impulsivity, but estimated stop-signal reaction time was longer in more impulsive individuals, supporting the hypothesis. Impulsivity is a key construct in personality theory, childhood psychopathology, and adult psychopathology. The study found that individuals with ADHD had more difficulty inhibiting prepotent actions and that stimulant medication improved inhibitory control in these individuals. The stop-signal paradigm was used to measure inhibitory control, with the stop signal acting as a control signal that makes the prepotent response inappropriate. The study found that stop-signal reaction time increased with impulsivity, consistent with the hypothesis. The validity of the new method for measuring stop-signal reaction time was tested by comparing it with a conventional method. The results showed that the new method produced similar values to the conventional method, but with greater reliability. The study concludes that the new method is a valid and feasible way to measure inhibitory control, and that the modified stop-signal paradigm is a promising tool for future research on inhibitory control. The results also support the information processing approach to personality and psychopathology, which allows for understanding normal and abnormal personalities in terms of underlying cognitive processes.This research report explores the relationship between impulsivity and inhibitory control, using a stop-signal paradigm to measure inhibitory control. The study involved 136 undergraduate students who completed an impulsivity questionnaire and then participated in a stop-signal experiment. The experiment tested the hypothesis that impulsive individuals have difficulty inhibiting prepotent responses, leading to slower reaction times to stop signals. Participants performed a choice reaction time task and were asked to inhibit their responses when a stop signal was presented. The delay between the go and stop signals was adjusted to allow inhibition on 50% of the trials. Reaction times to the go signal did not vary with impulsivity, but estimated stop-signal reaction time was longer in more impulsive individuals, supporting the hypothesis. Impulsivity is a key construct in personality theory, childhood psychopathology, and adult psychopathology. The study found that individuals with ADHD had more difficulty inhibiting prepotent actions and that stimulant medication improved inhibitory control in these individuals. The stop-signal paradigm was used to measure inhibitory control, with the stop signal acting as a control signal that makes the prepotent response inappropriate. The study found that stop-signal reaction time increased with impulsivity, consistent with the hypothesis. The validity of the new method for measuring stop-signal reaction time was tested by comparing it with a conventional method. The results showed that the new method produced similar values to the conventional method, but with greater reliability. The study concludes that the new method is a valid and feasible way to measure inhibitory control, and that the modified stop-signal paradigm is a promising tool for future research on inhibitory control. The results also support the information processing approach to personality and psychopathology, which allows for understanding normal and abnormal personalities in terms of underlying cognitive processes.