Participants were recruited using advertisements placed in local and student newspapers and around the community. This approach has been effective in attracting responses from individuals who vary in EXT problems and disorders (Finn et al., 2002 ; 2009 (link)). The range of ads / flyers targeted “daring, rebellious, defiant individuals,” “carefree, adventurous individuals who have led exciting and impulsive lives,” “impulsive individuals,” “heavy drinkers wanted for psychological research,” persons with a “drinking problem,” persons who “got into a lot of trouble as a child,” persons “interested in psychological research,” “quiet, reflective and introspective persons,” and “social drinkers.”
Advertisement respondents were screened via telephone to determine whether they met basic study inclusion criteria. The study inclusion criteria were: being between the ages of 18 and 30, able to read and speak English, had at least a 6th grade education, had consumed alcohol on at least one occasion, and didn’t have a history of psychosis or head trauma. If they met the basic inclusion criteria, they were asked a series of screening questions about current and lifetime alcohol, drug, childhood conduct, and adult antisocial problems. Subjects were invited to participate in the study if they fell within the range of these EXT problems that were targeted for the sample composition. We screened to target a sample composed of 25% with relatively low EXT problems (no diagnosable alcohol dependence/abuse, marijuana/other drug dependence/abuse, no diagnosable conduct disorder, low adult antisocial behavior, no current binge drinking), 50% with moderate (moderate-low to moderate-high) levels of EXT problems, and 25% with very high levels of EXT problems (at least a lifetime diagnosis of Alcohol Dependence and Conduct Disorder). We targeted these segments based on the distributions of these EXT problems that we had in our earlier studies that employed a dimensional model of EXT problems (Bogg & Finn, 2010 (link); Finn et al., 2009 (link)). Lifetime alcohol, drug, nicotine, childhood conduct, and adult antisocial problems counts were ascertained with the SSAGA. Table 1 lists the mean lifetime problems with alcohol, marijuana, nicotine, other drugs, conduct problems and adult antisocial problems for the full sample and for the subsamples in the WM load and no Load conditions of the delay discounting task. As can be seen, the subsamples for the WM Load conditions are equivalent for all variables.