The primary dependent measures on this task are the stop and go times. On each trial, participants are presented with a go signal (symbol on the computer screen) and instructed press a certain key as quickly as possible. The go signal appears at 2-s intervals, and the individual’s RTs (go RTs) are recorded. On 25% of the trials, a tone (stop signal) is sounded after the presentation visual stimulus is presented, and participants are instructed to inhibit (stop) their go response on those trials. The delay from the onset of the go signal to the onset of the stop signal (stop-signal delay) is systematically adjusted in 50-ms increments. If the individual fails to stop, the stop-signal delay is decreased by 50 ms on the following stop-signal trial. If the individual successfully stops, the stop-signal delay is increased by 50 ms on the next trial. Trials continue to vary until the individual is able to inhibit (stop) his or her key press responses on approximately 50% of trials. Stop RT is computed by subtracting the average stop-signal delay at which the
