The assessment of behavioural activation––the relationship between impulsivity and behavioural activation

Personality and Individual Differences 37 (2004) 429–442 www.elsevier.com/locate/paid

The assessment of behavioural activation––the relationship between impulsivity and behavioural activation Lena C. Quilty *, Jonathan M. Oakman Department of Psychology, University of Waterloo, 200 University Avenue West Waterloo, Ontario, Canada N2L 3G1 Received 6 March 2003; received in revised form 25 July 2003; accepted 15 September 2003 Available online 30 October 2003

Abstract Many theorists propose that two fundamental biological systems are responsible for emotional regulation: one appetitive and one aversive. GrayÕs behavioural approach or activation system (BAS) and behavioural inhibition system (BIS) in particular offer considerable promise in explaining a variety of normal and pathological behaviours. While revisions of GrayÕs theory continue to be made, the nature of the BAS remains unclear and controversial. Because Gray proposed that BIS and BAS activity underlie trait anxiety and impulsivity, respectively, many researchers use impulsivity measures to assess BAS activity. However, impulsivity is a multidimensional construct, and which components are relevant to the BAS is by no means clear. This investigation sought to determine whether impulsivity is an appropriate measure of behavioural activation, and if so, which components are related to BAS activity. Measures of BAS and impulsivity were administered to University of Waterloo undergraduates. A series of confirmatory factor analyses revealed that while a case may be made for the use of global impulsivity measures as indicators of BAS activity, these measures are better thought of as composites of separate, correlated constructs, which are not uniformly connected to the BAS. These findings have implications for the current understanding of the nature of the BAS. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Behavioural activation; Approach; Impulsivity; Individual differences; Psychometrics

1. Behavioural activation Considerable neuropsychological research has sought to elucidate the brain mechanisms of emotion in animals. The emerging consensus is that emotions are reactions to reinforcers, which *

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may be either positive or negative, and either conditioned or unconditioned. Further, it is generally agreed that there are specific neural circuits which underlie specific emotions. Most theorists posit that there are two or three basic neural circuits, each mediating a different motivation and emotion (e.g., Davidson, 1993; Gray, 1982; Lang, 1995). Based mainly on work using conditioning paradigms in animal models, Gray has proposed a motivational model involving two primary biological systems: the behavioural inhibition system (BIS), and the behavioural activation system (BAS; Gray, 1981, 1982, 1987a, 1987b). These systems reflect brain structures that influence individual sensitivity to reinforcers and control the experience of emotion, and that give rise to two consequent personality dimensions, anxiety and impulsivity. According to Gray, the behavioural inhibition system (BIS) responds to signals of punishment, nonreward and novelty by inhibiting ongoing behaviour, and increasing arousal and attention to environmental stimuli. This system is believed to underlie passive avoidance and the extinction of previously reinforced behaviour, and its activation results in the emotions of anxiety or frustration. Individual differences in the activity of this system are believed to underlie trait anxiety. The behavioural activation system (BAS; alternatively called the behavioural approach system), on the other hand, responds to signals of reward and the nonpunishment of previously punished behaviour by initiating goal-directed activity and increasing arousal. This system is believed to underlie approach and active avoidance, and results in the emotions of hope or relief. Individual differences in the activity of this system are believed to underlie trait impulsivity (Fowles, 1987; Gray, 1982). A recent revision of this theory by Gray and McNaughton (2000) describes several changes to these inputs and outputs of the BIS and BAS; however, the implications of this revision have yet to be tested, and the plethora of literature inspired by Gray is based on his earlier (1982) theory (Corr, 2002).

2. Assessing behavioural activation It has been repeatedly noted in the literature that while the nature of the behavioural inhibition system has been considerably elaborated, the behavioural activation system has received much less attention (e.g., Heubeck, Wilkinson, & Cologon, 1998). Both the physiological underpinnings and the physiological indices of the BAS are imprecise and debated (Fowles, 1988; Matthews & Gilliland, 1999). Furthermore, there appears to be little consensus regarding the primary or critical ways in which BAS sensitivity is manifested in behaviour, resulting in varied methods of measurement (e.g., Carver & White, 1994; Leone, Perugini, Bagozzi, Pierro, & Mannetti, 2001). It has been noted by a number of researchers that GrayÕs dimensions are assessed in a variety of ways, and that there has been minimal empirical study of the relations between these methods of measurement, or how the use of different measures can impact research (Corr, 2001; Diaz & Pickering, 1993; Heubeck et al., 1998; Leone et al., 2001). Research concerning the BAS typically assesses the BAS through self-report, using one of three principal types of measures: measures designed specifically to assess this dimension, measures of the personality dimensions of neuroticism and extraversion; and measures of impulsivity. These three approaches will be discussed in turn.

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2.1. Measures of behavioural activation Of the measures designed specifically to assess the behavioural activation system, two appear to be most commonly used by researchers and to have accumulated the most evidence for their construct validity. The first of these is the BAS Scales from the BIS/BAS Scales designed by Carver and White (1994). They used a ‘‘divergent strategy’’ in their construction of the BAS Scales, due to the lack of consensus in the literature regarding its nature. They found three factors in their instrument: Drive, the relentless pursuit of goals; Fun Seeking, the craving for and inclination to impetuously approach novel potential rewards; and Reward Responsiveness, the positive reaction to reward or its anticipation. These scales all loaded positively on a second order factor, and were related to extraversion, positive affect and positive temperament. Carver and White state that their instrument provides ‘‘a broader array of possibilities for assessing BAS sensitivity’’ (p. 326) than existing measures, and therefore likely captures the critical manifestation of BAS sensitivity, whatever it is eventually discovered to be. Heubeck et al. (1998), and Jorm et al. (1999) questioned the validity of Carver and WhiteÕs BAS Scales, noting principally the problematic correlations of Reward Responsiveness with neuroticism-related measures, and the loading of the other two BAS Scales on a ‘‘positive personality or affectivity’’ construct with extraversion and positive affect. The BAS Scales therefore do not uniformly exhibit the positive relations with both extraversion and neuroticism hypothesized by Gray (1970). Indeed, they may not assess a personality construct unique from other well-established personality constructs such as extraversion. Leone et al. (2001), on the other hand, argued that the debate surrounding the nature of the BAS justifies the development of a measure reflecting all possible manifestations of the BAS proposed in the literature. They further maintain that Carver and WhiteÕs focus on motivation and emotion rather than behaviour is likely to result in different relations to constructs than those of existing measures. The second main measure used to assess GrayÕs behavioural activation system is the Sensitivity to Reward Scale of the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ) developed by Torrubia, Avila, Molto, and Caseras (2001). Their Sensitivity to Reward (SR) Scale includes items assessing behavioural tendencies in situations in which individuals could do something to obtain varying specific rewards. Although Torrubia et al. acknowledged that individuals with a reactive BAS need not necessarily be motivated by all kinds of reward, the implied assumption of this scale is that BAS sensitivity should be related to various rewards. This approach produced a scale with heterogeneous, situationally specific items, which nevertheless reached acceptable levels of internal consistency and test–retest reliability, and produced a unidimensional factor structure. The SR scale has some accumulated evidence for its convergent and discriminant validity (Avila, 2001; Caseras, Torrubia, & Farre, 2001; Torrubia et al., 2001; Zuckerman, Joireman, Kraft, & Kuhlman, 1999). 2.2. Neuroticism and extraversion measures Eysenck and Eysenck (1994) maintained that extraversion and neuroticism repeatedly emerge as markedly important dimensions in reviews of the literature, accounting for much of the variation seen in personality research, with a third factor of psychoticism accounting for much of the remainder. Gray (1981, 1982, 1987a, 1987b), however, hypothesized that extraversion and

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neuroticism are in fact derivative factors, resulting from combinations of and differences between his two primary dimensions of BIS and BAS. The BIS and BAS therefore account for the same phenomena as extraversion and neuroticism, but consist of a simple rotation of these dimensions. Researchers following GrayÕs (1987c) statement therefore assess BAS by summing measures of extraversion and neuroticism. However, as early as 1970, Gray acknowledged that the BAS likely involves more extraversion than neuroticism, and thereby involves a rotation closer to 30° (rather than 45°; Gray, 1970). According to this view, BAS consists of twice extraversion, summed with neuroticism (Pickering, Corr, & Gray, 1999). Other researchers, however, cite Tellegen (1985), who equated his personality dimensions of positive and negative emotionality with Eysenck and EysenckÕs (1994) extraversion and neuroticism, and behavioural activation and inhibition, and therefore use extraversion and neuroticism as direct measures of BAS and BIS, respectively (Diaz & Pickering, 1993). Furthermore, other prominent researchers propose that extraversion is made up of reward sensitivity, which suggests that it is an apt index of behavioural activation (Depue & Collins, 1999). Carver and White (1994) stated that this practice is problematic, as Gray views extraversion as reflecting the balance between impulsivity and anxiety. In addition, while Eysenck originally conceived of extraversion as consisting of sociability and impulsivity, more recent operationalizations of his constructs associate impulsivity with psychoticism (e.g., Diaz & Pickering, 1993). Eysenck therefore conceives of extraversion as largely sociability, which ‘‘plays no obvious role in GrayÕs theoretical scheme’’ (Carver & White, 1994, p. 320). Recent research has suggested as well that extraversion is principally made up of social attention (Ashton, Kibeom, & Paunonen, 2002). 2.3. Impulsivity measures Finally, some researchers, citing the fact that Gray labelled the personality dimension resulting from BAS activation ‘‘impulsivity,’’ use measures of impulsivity to gauge BAS sensitivity (Carver & White, 1994). Some impulsivity scales have demonstrated predictive validity in studies of behavioural activation, suggesting that they may have some validity as indicators of behavioural activation (Torrubia et al., 2001). Torrubia et al. (2001) caution against equating BAS activity and impulsivity, lamenting that ‘‘researchers seem to give more importance to this label than to the description of behaviours depending on the BIS and the BAS’’ (p. 840). Indeed, impulsive behaviour could theoretically result from a lack of BIS sensitivity as well (Fowles, 1987), and the BAS is directly related to only one of the ‘‘types’’ of impulsivity outlined by Gray (1983). Investigations have repeatedly demonstrated that impulsivity should not be conceptualized as unidimensional at all, as there are a variety of constructs which appear to be related to and are often subsumed under the label of impulsivity (e.g., Moeller, Barratt, Dougherty, Schmitz, & Swann, 2001). It therefore appears unlikely that impulsivity is related to behavioural activation in a straightforward way.

3. Impulsivity The construct of impulsivity is similar to behavioural activation not only in phenotypic expression, but also in the issues surrounding its measurement. Numerous researchers have noted

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that there is no accepted definition or measure of impulsivity (e.g., Harmstead & Lester, 2000). Moeller et al. (2001) observed that impulsivity is inconsistently defined as behaviour without forethought, or as consisting of a number of more specific subtraits. These various definitions have led to a number of methods of measurement, predominantly including self-report questionnaires, behavioural laboratory measures, and event-related potentials. Swann, Bjork, Meiller, and Dougherty (2002) point out that the choice of impulsivity measure strongly influences the results found in research, and Carrillo-de-la-Pena, Otero, and Romero (1993) propose that this is the case because many studies are not circumspect in their choice of measures and treat impulsivity as a global, undifferentiated concept equally measured by different methods. The application of data reduction methods to measures of impulsivity reveal more than one factor, suggesting that impulsivity is likely best conceived of as a multidimensional construct. Harmstead and Lester (2000), for example, explored nine common impulsivity questionnaires, and found that eight factors accounted for much of their variance. Patton, Stanford, and Barratt (1995) noted laboratory, field and clinical research findings suggest that there are three main subtraits of impulsiveness: attentional impulsiveness, motor impulsiveness and, nonplanning impulsiveness. Eysenck and Eysenck (1978), in contrast, found two factors accounted for the traits included in popular impulsivity and sensation seeking measures: impulsiveness and venturesomeness, with the former being linked with psychoticism and the latter with extraversion. Eysenck and McGurk (1980) found that these subcomponents of impulsivity are indeed important to consider, as impulsiveness was more implicated in criminality than risk-taking and sensation seeking. Even these related or lower-level constructs have been found to be multifactorial; for example, sensation seeking has been related to thrill and adventure seeking, experience seeking, disinhibition and boredom susceptibility (Zuckerman, Eysenck, & Eysenck, 1978). Attempts to determine the factorial structure of impulsivity measures have been supplemented with efforts to locate impulsivity within a model of personality. These efforts have not led to any consensus, likely due to the related debate within personality research regarding the number and nature of higher-order personality dimensions (Whiteside & Lynam, 2001). Whiteside and Lynam (2001) carried out a comprehensive review of the measures used to assess impulsivity, and found they could be reduced to four factors: (lack of) Premeditation, Urgency, Sensation Seeking and (lack of) Perseverance. Premeditation and Perseverance were associated with conscientiousness, Sensation Seeking with extraversion, and Urgency with neuroticism. Whiteside and Lynam finally concluded that impulsivity is ‘‘an artificial umbrella term that actually encompasses four distinct facets of personality,’’ (p. 687) which can be connected to major personality models in meaningful ways.

4. The present study Close attention to operationalizations of GrayÕs constructs is clearly necessary in order to advance empirical work on GrayÕs theory. This study attempts to clarify the relation between behavioural activation and impulsivity, thereby adding to the current understanding of the nature of behavioural activation. It seems that measures of impulsivity may not provide an appropriate index of behavioural activation, despite GrayÕs use of this label for his dimension of personality and the past success of measures of impulsivity as measures of behavioural activation.

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Impulsivity appears to be a multidimensional construct, with widely varying conceptualizations and operationalizations. Which aspects of impulsivity, if any, are most appropriate to assess BAS sensitivity is by no means clear (Carver & White, 1994; Eysenck & Eysenck, 1977; Zuckerman, 1994). This study therefore chose four of the most common measures of behavioural activation––the BAS Scales, the Sensitivity to Reward Scale, a transformation of EysenckÕs extraversion and neuroticism, and an alternate measure of extraversion––to then be related to impulsivity. Whiteside and Lynam (2001) found impulsivity to be made up of four facets: urgency, premeditation, sensation seeking and perseverance. Urgency reflects a tendency to behave rashly in response to elevated negative affect and therefore seems unlikely to be related to BAS activation in a straightforward way. Premeditation is well-captured by attentional impulsiveness subscales of existing impulsivity measures, and sensation seeking by disinhibition, and perseverance by boredom susceptibility. These types of impulsivity are represented in two of the most popular measures of impulsivity-related behaviour, the Barratt Impulsiveness Scale and the Sensation Seeking Scale. In an effort to be comprehensive in our measurement of the facets of impulsivity, as well to allow for comparisons to and extensions of previous research, these two measures of impulsivity were related to behavioural activation, in an attempt to gain new insight into the nature of the BAS. It is hypothesized that global impulsivity measures will be found to be adequate indicators of the BAS, given their demonstrated predictive validity. However, it is further hypothesized that impulsivity measures will negatively impact models of the BAS, given the diverse concepts they represent, which are likely not uniformly related to the BAS. It seems likely that disinhibition, given its relationship to extraversion, will be related to the BAS; however, the relationship of premeditation and perseverance with the BAS is less clear, given their relationship to conscientiousness, a less affect-laden construct.

5. Method 5.1. Participants Participants were 218 students enrolled in an introductory psychology course at the University of Waterloo in Waterloo, Ontario. The sample was composed of 105 males (48.2%) and 113 females (51.8%), ranging in age from 17 to 29 years (M ¼ 19:4, SD ¼ 1:4). Participants received course credit for their participation. 5.2. Procedure Participants completed a battery of questionnaires in groups of one to ten, including the BIS/ BAS Scales (Carver & White, 1994), the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ; Torrubia et al., 2001), the Eysenck Personality Questionnaire-Revised (EPQ-R; Eysenck & Eysenck, 1994), the NEO Five Factor Inventory (NEO-FFI; Costa & McCrae, 1992), the Sensation Seeking Scale Form V (SSS-V; Zuckerman et al., 1978), and the Barratt Impulsivity Scale-11 (BIS-11; Patton et al., 1995).

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5.3. Measures of behavioural activation 5.3.1. BIS/BAS Scales The BIS/BAS Scales is a 20 item self-report questionnaire assessing individual reactivity to reward and punishment, should they occur (Carver & White, 1994). This instrument yields scores for four subscales: BIS, an apprehensiveness concerning and a reactivity to negative events; Drive, the relentless pursuit of goals; Fun Seeking, the craving for novel rewards and the inclination to impetuously approach such rewards; and Reward Responsiveness, the positive reaction to reward or its anticipation. The latter three subscales can be combined to yield an overall BAS score. Internal consistency estimates (coefficient alpha) for the subscales range from 0.66 for Fun Seeking to 0.76 for Drive, and eight week test–retest reliabilities ranged from 0.59 for Reward Responsiveness to 0.69 for Fun Seeking (Carver & White, 1994). The subscales demonstrated convergent and discriminant validity, and predicted the experience of anxiety and happiness in laboratory studies involving anticipation of punishment or reward. Researchers have largely found support for the BIS/BAS Scales as appropriate measures of GrayÕs constructs, although limitations exist, such as the varied nature of the BAS Scales and the limited coverage of the BIS Scale (Heubeck et al., 1998; Jorm et al., 1999; Leone et al., 2001). 5.3.2. Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ) The SPSRQ is a 48 item self-report questionnaire assessing individual sensitivity to reward and punishment (Torrubia et al., 2001). The sensitivity to punishment (SP) scale assesses passive avoidance in response to the possibility of punishment or novelty, and cognitions produced by the threat of punishment or failure. The Sensitivity to Reward (SR) Scale assesses proneness to approach a wide variety of different kinds of rewards. Internal consistency estimates (coefficient alpha) for the SP and SR subscales range from 0.75 for SR in females to 0.83 for SP in males, and three month test–retest reliabilities were 0.89 for SP and 0.87 for SR (Torrubia et al., 2001). This instrument has been used in a number of experimental studies and in different cultures, and accumulated evidence suggests that it reliably and validly reflects individual differences in GrayÕs dimensions (Avila, 2001; Brebner, 1998; Caseras et al., 2001; Zuckerman et al., 1999). 5.3.3. Eysenck Personality Questionnaire-Revised (EPQ-R) The EPQ-R (Eysenck & Eysenck, 1994) is a 100 item self-report questionnaire assessing extraversion (E), neuroticism (N) and psychoticism (P). The EPQ-R is the product of a number of scale revisions, which attempted to produce a scale assessing theoretically important, orthogonal, reliable personality dimensions. Internal consistency estimates (coefficient alpha) for the EPQ-R subscales range from 0.66 for psychoticism in males to 0.86 for neuroticism in both sexes, and one month test–retest reliabilities range from 0.71 for psychoticism to 0.92 for extraversion (Eysenck & Eysenck, 1994). 5.3.4. NEO Five Factor Inventory (NEO-FFI) The NEO-FFI is a 60 item self-report questionnaire assessing the five factor model of personality (Costa & McCrae, 1992). This instrument yields subscale scores for five dimensions of personality: neuroticism (N), extraversion (E), openness to experience (O), agreeableness (A), and conscientiousness (C). Internal consistency estimates (coefficient alpha) for the NEO-FFI

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subscales range from 0.68 for A to 0.86 for N. The NEO-FFI was developed by amassing the items from the longer NEO-PI-R with the highest positive loading on each factor (Costa & McCrae, 1992). Despite the fact that the NEO-FFI subscales have been found to intercorrelate and the extraversion and openness to experience factors to be somewhat weak (Egan, Deary, & Austin, 2000), this instrument has since been used in numerous investigations of personality (e.g., Scandel & Wlazelek, 1999; Whiteman, Bedford, Grant, Fowkes, & Deary, 2001). 5.4. Measures of impulsivity 5.4.1. Sensation Seeking Scale Form V (SSS-V) The SSS-V is a 40 item self-report questionnaire assessing sensation seeking (Zuckerman et al., 1978). This instrument yields subscale scores for four different dimensions related to impulsivity and sensation seeking: thrill and adventure seeking (TAS), experience seeking (ES), disinhibition (DIS), and boredom susceptibility (BS). Internal consistency estimates (coefficient alpha) for SSS-V subscales ranged from 0.56 for BS in American females to 0.82 for TAS in English males (Zuckerman et al., 1978). Researchers have found a robust four factor structure and considerable evidence of convergent and discriminant validity (e.g., Beauducel, Brocke, Strobel, & Strobel, 1999). 5.4.2. Barratt Impulsiveness Questionnaire (BIS-11) The BIS-11 is a 30 item self-report questionnaire assessing impulsivity (Patton et al., 1995). Factor analyses have demonstrated that the BIS-11 contains three factors: attentional impulsiveness, or inattention and cognitive instability; motor impulsiveness, or motor disinhibition and lack of perseverance; and nonplanning impulsiveness, or lack of self-control and intolerance of cognitive complexity. The BIS-11 total score was found to have adequate internal consistency, and Patton et al. cautioned that the factors are of principal use in the exploration of impulsiveness, and its link to pathology. The BIS-11 has been translated into a number of different languages, and used to explore behavioural phenomena such as risk-taking behaviour (e.g., Bayle et al., 2000; Stanford, Greve, Boudreaux, Mathias, & Brumbelow, 1996). 5.5. Statistical analyses The relation of impulsivity measures to measures of the behavioural activation system was evaluated using structural equation modeling (SEM). Model fit was evaluated using Amos 4.0 (Arbuckle & Wothke, 1999). Data missing on an item level were estimated using the participant scale or subscale mean. Due to the fact that 9% of participants had missing data from one or more subscales, means and intercepts were estimated using the algorithms provided by Amos 4.0. Many fit statistics are available for model evaluation. The chi-square that is commonly reported is the chi-square difference of the observed data from the data implied by the specified model. This chisquare test is limited in that its sensitivity to sample size entails that analyses with large data sets will generally produce a significant chi-square, even if the discrepancy of the observed data from the implied data is trivial. Many different solutions to this problem have been proposed, and thus many different fit indices are available. Perhaps the most common of these is the Goodness of Fit Index (GFI). Unfortunately, the GFI cannot be calculated for data sets with missing data.

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Instead, we used the comparable Tucker–Lewis coefficient (TLI) and Bentler Comparative Fit Index (CFI). The TLI and CFI are interpreted in similar ways to the GFI, with values >0.90 indicating good fit. Finally, in some contexts, we may want to compare fit across models that are not nested (meaning that one model is not simply a constrained version of the other). Such comparisons are complicated because the models may differ in complexity, and different fit indices make more or less severe adjustments for model complexity. We report the Akaike Information Criterion (AIC) and the Browne–Cudeck Criterion (BCC), which are most suited for the comparison of nonnested models. These measures are a function of both model complexity and goodness of fit; simple, well-fitting models will receive low scores, while complex, poorly fitting models will receive high scores. For the purposes of model comparisons, the model with the lower score is to be preferred. In the first set of analyses we report, SEM was used to establish whether impulsivity measures are appropriate indicators of a single, latent variable of BAS. In the second analysis we report, we correlated the subscales of the impulsivity measures with the single, latent variable of BAS.

6. Results 6.1. Impulsivity as an indicator of the behavioural activation system (BAS) An initial one-factor model of BAS was estimated, with the observed indicators of NEO-FFI Extraversion, BIS/BAS Scales BAS Scales Total, SPSRQ Sensitivity to Reward Scale, and a transformation of Extraversion and Neuroticism from the EPQ-R (2E+N). The fit of this model was good (chi-squared ¼ 23.159, df ¼ 2, p < 0:001; TLI ¼ 0.963; CFI ¼ 0.993; AIC ¼ 47.159; BCC ¼ 47.725). To examine whether global impulsivity measures are appropriate measures of the BAS, a one-factor model of BAS involving Impulsivity measures as indicators was then estimated, including the previous indicators of BAS as well as SSS-V Total Scale and BIS-11 Total Scale (see Fig. 1). The fit of this model was less good, although still strong (chi-squared ¼ 58.116, df ¼ 9,

e1

e2

e3

e4

e5

e6

2E+N

E

C&WBAS

SR

SSS

BIS-11

.74

.58

.61 .68

.42

.48

BAS

Fig. 1. Single factor model of the behavioural activation system. BAS ¼ Behavioural activation system; 2E + N ¼ EPQ-R Extraversion (X2) + Neuroticism; E ¼ NEO-FFI Extraversion; C and WBAS ¼ BIS/BAS Scales Total BAS Scale; SR ¼ SPSRQ Sensitivity to Reward; SSS ¼ SSS-V Total Scale; BIS-11 ¼ BIS-11 Total Scale.

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e1

e2

e3

e4

e5

e6

2E+N

E

SR

C&WBAS

SSS

BIS

.76

.61 .66

.59 .71

.61

IMPULSIVITY

BAS

.62

Fig. 2. Two-factor model of the behavioural activation system and impulsivity. BAS ¼ Behavioural activation system; 2E + N ¼ EPQ-R Extraversion (X2) + Neuroticism; E ¼ NEO-FFI Extraversion; C and WBAS ¼ BIS/BAS Scales Total BAS Scale; SR ¼ SPSRQ Sensitivity to Reward; SSS ¼ SSS-V Total Scale; BIS-11 ¼ BIS-11 Total Scale.

p < 0:001; TLI ¼ 0.973; CFI ¼ 0.988; AIC ¼ 94.116; BCC ¼ 95.316). Furthermore, the factor loadings of the two Impulsivity measures were lower than those of the BAS measures. A twofactor model was therefore formed, including the measures of BAS as indicators of the latent variable of BAS and the measures of Impulsivity as indicators of the latent variable of Impulsivity (see Fig. 2). The two latent variables were allowed to be correlated. The fit of this model was also good (chi-squared ¼ 39.174, df ¼ 8, p < 0:001; TLI ¼ 0.981; CFI ¼ 0.993; AIC ¼ 77.174; BCC ¼ 78.441). Statistical comparisons revealed that this two-factor model had significantly better fit than the single factor model (chi-squared ¼ 18.942, df ¼ 1, p < 0:01). In addition, the correlation between the constructs was found to be statistically different from unity (z ¼ 4:63, p < 0:01). Therefore, it appears that while a case may be made for the use of measures of impulsivity as indicators of BAS, these measures are better conceived of as indicators of a separate, correlated construct. 6.2. Correlations of BAS with impulsivity subscales To examine which facets of impulsivity are related to the BAS, we examined the correlations of each of the subscales of the SSS-V and BIS-11 with the latent variable of BAS. A one-factor model with the latent variable of BAS and the four previous indicators was formed, with correlations between this latent variable and the subscales of the SSS-V and the BIS-11 being estimated. The impulsivity subscales were allowed to be correlated with each other as well. The fit of this model was good (chi-squared ¼ 119.975, df ¼ 23, p < 0:001; TLI ¼ 0.959; CFI ¼ 0.986). The loadings of the indicators NEO-FFI Extraversion, BIS/BAS Scales BAS Scales Total, SPSRQ Sensitivity to Reward Scale, and a transformation of Extraversion and Neuroticism from the EPQ-R (2E+N) were 0.60, 0.68, 0.68 and 0.67, respectively. Of the impulsivity subscales, we found that the subscales of Thrill and Adventure Seeking, Disinhibition, Boredom Susceptibility, and Motor and Attentional Impulsivity were significantly correlated with BAS (see Table 1). This finding supports

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Table 1 Correlations between the latent variable and indicators of behavioural activation and the impulsivity subscales 2E + N E SR C&W TAS ES DIS BS ATTL MTR NON

BAS

2E + N

E

SR

C&W

TAS

ES

DIS

BS

ATTL

MTR

0.67 0.60 0.68 0.68 0.31 0.11 0.36 0.22 0.34 0.58 0.09

0.57 0.49 0.38 0.21 0.10 0.26 0.15 0.27 0.34 0.21

0.31 0.43 0.21 )0.07 0.13 )0.09 0.06 0.26 0.04

0.46 0.18 0.09 0.38 0.32 0.38 0.42 0.08

0.22 0.12 0.17 0.16 0.16 0.50 )0.06

0.40 0.33 0.11 0.15 0.18 0.11

0.38 0.20 0.22 0.24 0.16

0.46 0.32 0.33 0.29

0.27 0.32 0.23

0.49 0.45

0.27

BAS ¼ Latent behavioural activation system; 2E + N ¼ EPQ-R Extraversion (X2) + Neuroticism; E ¼ NEO-FFI Extraversion; SR ¼ SPSRQ Sensitivity to Reward; C and W ¼ BIS/BAS Scales Total BAS Scale; TAS ¼ SSS-V Thrill and Adventure Seeking Scale; ES ¼ SSS-V Experience Seeking Scale; DIS ¼ SSS-V Disinhibition Scale; BS ¼ SSS-V Boredom Susceptibility Scale; ATTL ¼ BIS-11 Attentional Impulsiveness; MOTOR ¼ BIS-11 Motor Impulsiveness; NON ¼ BIS-11 Nonplanning Impulsiveness. * p < 0:05. ** p < 0:01.

findings in the literature that maintain that impulsivity is indeed a multidimensional construct, the components of which are not uniformly connected to BAS. 7. Discussion This study was carried out in an attempt to clarify the nature of the behavioural activation system (BAS) through its relationship with impulsivity. Given that impulsivity measures have demonstrated predictive validity as indicators of behavioural activation, the first part of this study sought to determine if global measures of impulsivity are appropriate indicators of the BAS. The second part of this study acknowledged that impulsivity is believed to be better construed as involving a number of facets, and sought to examine the relationship between different facets of impulsivity and the BAS. We found that while a case may be made for the use of global measures of impulsivity as indicators of the BAS, impulsivity measures did decrease the overall fit of the model and were somewhat less strong indicators than other more accepted indicators of the BAS. Furthermore, a model which postulated that BAS and impulsivity are separate constructs had better fit, and revealed that the relationship between the two constructs is significantly different from unity. These results suggest that behavioural activation and impulsivity are certainly related, but that they are best conceived of as separate constructs. The strong relationship between these constructs, however, does imply that impulsivity can be important in the understanding of behavioural activation. Given that impulsivity is considered by many to represent a number of facets of behaviour, the subscales of two popular measures of impulsive behaviour were related to the BAS. Many of the impulsivity subscales were intercorrelated, confirming Whiteside and LynamÕs (2001) finding that

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impulsivity-related measures in fact assess only a limited number of distinct facets of personality. It was found that Thrill and Adventure Seeking, Disinhibition, Boredom Susceptibility, and Motor and Attentional Impulsivity were significantly correlated to the BAS. The subscales assess all of three of the four facets of impulsivity that Whiteside and Lynam found to be represented by the measures in the literature, excepting Urgency which does not encompass simple or direct BAS-driven impulsivity. This suggests that behavioural activation may then encompass a broad range of behaviour, of which impulsivity is only a portion, rather than vice versa. This view is in line with Barratt and PattonÕs (1983) position that impulsivity is a higher-order variable that is also a ‘‘part of a more inclusive class of action-oriented personality predispositions’’ (p. 89). Further research replicating this effect with other relevant and increasingly used measures, such as the Impulsive Sensation Seeking Scale (ImpSS) of the Zuckerman–Kuhlman Personality Questionnaire (Zuckerman, Kuhlman, Joireman, Teta, & Kraft, 1993), would bolster this finding. These findings highlight the importance of the use of specific questionnaires such as the BIS/ BAS Scales (Carver & White, 1994) or the SPSRQ (Torrubia et al., 2001) to measure the sensitivity of GrayÕs behavioural activation system. While the use of impulsivity measures may often be convenient or face-valid, these results suggest that their use as indicators of the behavioural activation system may be misleading. Impulsivity measures, whether global or multidimensional, appear to tap different variance than measures of behavioural activation. The association of impulsivity with the nonaffectively laden construct of constraint, for example, should call its simple relationship to behavioural activation into question (Depue & Collins, 1999). The use of measures carefully constructed to assess a sensitivity to reward as described by Gray (1982) are likely more advisable, given these findings. Diaz and Pickering (1993) note that the dimension of personality resulting from behavioural activation was labelled impulsivity in a rather off-hand manner. Although this label has some face validity, ‘‘the proliferation of studies relating behaviour to questionnaires seems somewhat premature when it has not first been clarified which questionnaires measure the desired aspects of personality best’’ (p. 299). The fact that different measures of behavioural activation result in different, confusing and occasionally contradictory findings in research implies that these measures are not evaluating the same construct. Not only does this lack of convergence seriously question the validity of these instruments, but also it prevents the accumulation of a sound body of knowledge or the advancement of theory. Until measurement problems are resolved, the construct of behavioural activation will remain undefined and poorly operationalized, and its relevance in understanding different behaviour unresolved. This study suggests that behavioural activation and impulsivity are related constructs, and that global or lower-order measures of impulsivity can be cautiously used legitimately as indicators of the BAS. It appears, however, that these constructs are distinct, with behavioural activation likely involving a larger class of approach and action-oriented constructs, best assessed by specialized measures. References Arbuckle, J. L., & Wothke, W. (1999). Amos 4.00 userÕs guide. Chicago, IL: Small Waters Corp. Ashton, M. C., Kibeom, L., & Paunonen, S. V. (2002). What is the central feature of extraversion?: social attention versus reward sensitivity. Journal of Personality and Social Psychology, 83, 245–251.

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