Between February and April 2005 a total of 195 subjects were recruited for participation from the Human Subject Research Pool at the State University of New York at Binghamton, U.S.A. The subject pool draws on mostly full time students currently in psychology courses who participate in research studies for course credit. No screening measures were placed on who could participate. All procedures were approved by the Human Subjects Research Review Committee at the State University of New York at Binghamton and all subjects gave informed consent. Participants attended group sessions (maximum = 10), where they were first provided with oral instructions followed by DNA sample collection. Participants then completed the delay discounting task followed by the self-report measures administered in random order. In addition to the oral instructions, the DDT task and other measures were accompanied by on-screen written instructions and experimenters were available throughout the sessions for questions. The sessions lasted approximately one hour. All data were collected via personal computers.
