The research report by Gordon D. Logan, Russell J. Schachar, and Rosemary Tannock investigates the relationship between impulsivity and inhibitory control in young adults. The study uses the stop-signal paradigm, a method that measures the ability to inhibit prepotent responses. Participants, 136 undergraduate students, completed an impulsivity questionnaire and participated in a stop-signal experiment where they performed a choice reaction time task and were asked to inhibit their responses when a stop signal was presented. The delay between the go signal and the stop signal was dynamically adjusted to ensure that subjects inhibited on 50% of the stop-signal trials. The results showed that while reaction times to the go signal did not vary with impulsivity, estimated stop-signal reaction times were longer in more impulsive subjects, supporting the hypothesis that impulsive behavior reflects a deficit in inhibitory control. The study also introduced a new method for estimating stop-signal reaction time, which is easier to compute and understand compared to previous methods. The validity of this new method was tested and found to be reliable, with high correlations between the new and conventional methods. The findings suggest that impulsive individuals have difficulty inhibiting prepotent responses not because their prepotent responses are exceptionally fast, but because their inhibitory responses are exceptionally slow. The study highlights the importance of the information processing approach in understanding personality and psychopathology, demonstrating its utility in linking normal and abnormal behaviors to underlying cognitive processes.The research report by Gordon D. Logan, Russell J. Schachar, and Rosemary Tannock investigates the relationship between impulsivity and inhibitory control in young adults. The study uses the stop-signal paradigm, a method that measures the ability to inhibit prepotent responses. Participants, 136 undergraduate students, completed an impulsivity questionnaire and participated in a stop-signal experiment where they performed a choice reaction time task and were asked to inhibit their responses when a stop signal was presented. The delay between the go signal and the stop signal was dynamically adjusted to ensure that subjects inhibited on 50% of the stop-signal trials. The results showed that while reaction times to the go signal did not vary with impulsivity, estimated stop-signal reaction times were longer in more impulsive subjects, supporting the hypothesis that impulsive behavior reflects a deficit in inhibitory control. The study also introduced a new method for estimating stop-signal reaction time, which is easier to compute and understand compared to previous methods. The validity of this new method was tested and found to be reliable, with high correlations between the new and conventional methods. The findings suggest that impulsive individuals have difficulty inhibiting prepotent responses not because their prepotent responses are exceptionally fast, but because their inhibitory responses are exceptionally slow. The study highlights the importance of the information processing approach in understanding personality and psychopathology, demonstrating its utility in linking normal and abnormal behaviors to underlying cognitive processes.