The hierarchical structure of self-reported impulsivity

Abstract

The hierarchical structure of 95 self-reported impulsivity items, along with delay-discount rates for money, was examined. A large sample of college students participated in the study (N = 407). Items represented every previously proposed dimension of self-reported impulsivity. Exploratory PCA yielded at least 7 interpretable components: Prepared/Careful, Impetuous, Divertible, Thrill and Risk Seeking, Happy-Go-Lucky, Impatiently Pleasure Seeking, and Reserved. Discount rates loaded on Impatiently Pleasure Seeking, and correlated with the impulsiveness and venturesomeness scales from the I(7) (Eysenck, Pearson, Easting, & Allsopp, 1985). The hierarchical emergence of the components was explored, and we show how this hierarchical structure may help organize conflicting dimensions found in previous analyses. Finally, we argue that the discounting model (Ainslie, 1975) provides a qualitative framework for understanding the dimensions of impulsivity.

Figure 1

Delay-discounting curves indicating the present values of a smaller, sooner reward available at time S (thin curve) and a larger, later reward available at time L (thick curve). At sufficiently long delays to both rewards (i.e., to the left of the crossover at C) the larger reward is preferred. Between times C and S the smaller reward is preferred, and if given an opportunity to choose during this interval this person may impulsively choose the smaller reward.

Figure 2

Component emergence diagram for extractions up to 8 components. The numbering notation is level-component: For example, 2-1 represents the 1st (largest) component in the 2-component extraction. Box width corresponds to the proportion of variance accounted for. Arrow labels and thicknesses show correlations larger than .30 between the component scores at adjacent levels of extraction. The number of items with loadings over .30 whose highest loading was on the component is shown in brackets. Asterisks indicate components on which discount rates (k) loaded above .30.