The Dickman Impulsivity Inventory (DII) is a self report measure that distinguishes two types of impulsivity. Dysfunctional impulsivity is the tendency to act with less forethought than most people of equal ability when this tendency is a source of difficulty. Functional impulsivity, in contrast, is the tendency to act with relatively little forethought when such a style is optimal. The current study presents an exploratory factor analysis of the Dutch DII and describes the psychometric properties of the instrument. It further clarifies the nature of functional and dysfunctional impulsivity by examining the relation between these two traits and another self-report measure of impulsivity, namely the Eysenck Impulsiveness Questionnare (I7). Finally, we also provide data concerning the relationship with demographics.
Impulsivity has been described by a number of overlapping and sometimes contradictory definitions (McCown et al., 1993 and Webster and Jackson, 1997). These include “human behavior without adequate thought” (Smith, 1952), “behavior with no thought whatsoever” (English, 1928), “action of instinct without recourse to ego restraint” (Demont, 1933) and “swift action of mind without forethought of conscious judgement” (Hinslie & Shatzky, 1940). Impulsivity may also mean acting with minimal thought regarding future actions, or acting on thoughts that are not in the individual's or others' best interest (Anon, 1951). Attempts to describe the construct of impulsivity empirically are at least 40 years old and continue to this day. In the excellent book by Doob (1990), impulsiveness is defined as the absence of reflection between an environmental stimulus and an individual's response. According to this definition, the appropriateness of impulsiveness is largely a function of the demands of the situation at hand. Some stimuli, such as a car suddenly braking on a crowded freeway, may demand immediate behavior without deliberation. Lengthy reflection regarding all of the possible options may prove harmful or even fatal. On the other hand, many situations require careful reflection of all possible responses (McCown et al., 1993).
Recent work on the relationship between impulsivity and cognitive functioning, also suggest that the consequences of impulsivity are not always negative. For example, when the experimental task is very simple, high impulsives, rapid responding has little cost in errors (Dickman, 1985). And when the time available for making a decision is extremely brief, high impulsives are actually more accurate than low impulsives (Dickman & Meyer, 1988).
One question raised by these findings (Dickman, 1990) is whether the factor that causes people to respond quickly and inaccurately when this style of responding is a source of difficulty (dysfunctional impulsivity) is the same factor that causes people to respond quickly and inaccurately when this style is optimal (functional impulsivity). It could be that there is a general tendency to respond quickly and inaccurately that is sometimes a source of difficulty and sometimes beneficial. Or, it could be that there are two separate traits, one that results in rapid inaccurate performance in situations where this is optimal and the other that results in rapid, inaccurate performance in situations where this is nonoptimal.
To determine whether it was possible to discriminate within the self-report domain between functional and dysfunctional impulsivity, Dickman (1990) wrote a large number of items designed specifically to tap these two types of impulsivity and then factor-analysed subjects' responses to these items in order to see whether the two hypothesised factors would emerge. The item pool used in this factor analysis contained 17 items written to tap functional impulsivity and 23 items designed to tap dysfunctional impulsivity. There were also 23 filler items. The first two factors that emerged from this analysis clearly represented the two hypothesised components of impulsivity. The 11 items that loaded over 0.30 on factor 1 had all been written to tap functional impulsivity, whereas the 12 items that loaded over 0.30 on factor 2 had all been written to tap dysfunctional impulsivity. These 23 items (11 functional and 12 dysfunctional items) formed the Dickman Impulsivity Inventory, short version (DII-short).
The current research was carried out in an attempt to provide a Dutch translation of the DII-short and to explore the factor structure and scale properties of this questionnaire in a Dutch-speaking Belgian sample. We further examine the convergence between the DII and another well-known measurement of impulsivity, the Eysenck Impulsivity Questionnaire (Eysenck & Eysenck, 1978). Finally, we present data on the relationship with educational level, age and gender. Most studies (Eysenck, Pearson, Easting & Allsopp, 1985) have found a decline in impulsivity with age and show that men are equal or more impulsive than women (Eysenck et al., 1985; Luengo, Carrillo-De-La-Pena & Otero, 1991).
