Participants were 166 undergraduate students recruited from introductory psychology classes at the University of Minnesota who received either monetary compensation or course credit. Eighteen of these were excluded from analyses: eight because of incomplete questionnaire data, three due to equipment problems during collection, four due to excessive artifacts, and two who discontinued prior to the completion of testing. Thus, the final study sample consisted of 149 participants (58 male; age, M=20.57, SD=3.70).2 A subset of these (N = 89) overlapped with the sample tested in the ERN study by Hall et al. (2007), with the remainder (N = 60) selected using the same sampling strategy as in Hall et al. Individuals scoring in the lowest and highest quartiles of the distribution of scores on an abbreviated version of the Externalizing Spectrum Inventory (ESI; see below) were over-sampled in the selection process to enhance the representation of individuals extreme (low and high) in externalizing proneness. Of the 149 participants comprising the final sample, 57 scored as High and 40 scored as Low, with the remainder falling within the middle 50% of scores on the ESI.
