Participants were healthy adults, ages 18 through 25, whose scores on the Brief Sensation-Seeking Scale (Hoyle, Stephenson, Palmgreen, Lorch, & Donohew, 2002) placed them in the top (HSSs; n = 20; 10 males, 10 females) and bottom (LSSs; n = 20; 10 males, 10 females) quartiles of population-based norms. Exclusion criteria included the presence of metal in or on the body, pregnancy, a prior neurological or psychiatric diagnosis, learning disability, a history of substance abuse or smoking, current use of central nervous system medications, left-handedness (Oldfield, 1971), and poor vision that could not be corrected. Pregnancy and drug use were assessed prior to sessions via urinalysis. Participants also completed the Big-Five Inventory (BFI; John & Srivastava, 1999), the UPPS (Urgency, Premeditation, Perseverance, and Sensation Seeking) Impulsivity Scale (Whiteside & Lynam, 2001), the Eysenck Personality Inventory (EPI; Eysenck & Eysenck, 1975), the Zuckerman Sensation-Seeking Scale (Form V; Zuckerman, 1994), and the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ; Zuckerman, Kuhlman, Joireman, Teta, & Kraft, 1993).
