Among adolescents and adults, there appear to be at least four different personality traits that dispose individuals to rash or ill-advised action: sensation seeking, negative urgency, lack of planning, and lack of perseverance. The four are only moderately correlated and they appear to play different roles in dysfunction. It is important to determine whether the traits are present among preadolescents because of their possible influence on subsequent development. The authors developed assessments of the four traits for preadolescent children and found evidence supporting (a) the internal consistency of each trait measure, (b) the convergent and discriminant validity of the four measures using the multitrait, multimethod technique, and (c) the hypothesis that the different traits correlated with different dysfunctional behaviors as predicted by theory. Pending further validation efforts, it appears to be the case that researchers may be able to distinguish among different dispositions to rash action prior to adolescence. (Contains 2 notes and 3 tables.)