history of major cognitive impairments or head trauma. At the beginning of each session, participants were asked about their alcohol and drug use over the past 12 hours and were given a breath alcohol test using an Alco Sensor IV (Intoximeters Inc., St. Louis, MO). If a participant reported using any drugs within the past 12 hours, had a breath alcohol level above 0.0%, reported feeling hung over or sleepy, or were unable to answer test questions, they were excluded from participation at that session and rescheduled.