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Personality and Individual Differences 39 (2005) 991–998

Individual differences in decision-making

Ingmar H.A. Franken *, Peter Muris

Department of Psychology, Erasmus University Rotterdam, Woudestein J5-43, P.O. Box 1738,

3000 DR Rotterdam, The Netherlands

Received 13 September 2004; accepted 4 April 2005

Available online 16 June 2005

Abstract

Behavioral decision-making as measured with a gambling task has been found to be impaired in severalpathological conditions such as brain lesions, addiction, and personality disorders. It is not known how

individual differences influence performance on behavioral decision-making. The goal of the present study

was to examine to what extent performance on behavioral measures of decision-making is predicted by self-

reported personality traits of sensitivity for punishment and reward, impulsivity, and decision-making

styles. For this goal, performance on the IOWA gambling task was related to the BIS/BAS questionnaire,

the Dickman Impulsivity Inventory, and the Adolescent Decision Making Questionnaire in a sample of stu-

dents (n = 44). The results showed that behavioral decision-making was to some extent predicted by indi-

vidual differences in sensitivity for reward and self-reported decision-making style. However, behavioraldecision-making was not predicted by impulsive personality traits.

� 2005 Elsevier Ltd. All rights reserved.

Keywords: Behavioral decision-making; Impulsivity; BIS; BAS; IOWA gambling task

1. Introduction

Behavioral decision-making research is concerned with how people make choices. Researchersin the fields of psychology and economics generally agree on the importance of two fundamental

0191-8869/$ - see front matter � 2005 Elsevier Ltd. All rights reserved.

doi:10.1016/j.paid.2005.04.004

* Corresponding author. Tel.: +31 10 408 9563; fax: +31 10 408 9009.

E-mail address: franken@fsw.eur.nl (I.H.A. Franken).

992 I.H.A. Franken, P. Muris / Personality and Individual Differences 39 (2005) 991–998

human motives, namely the desire to reduce pain/uncertainty and the desire to obtain pleasure(Bentham, 1948). In contrast to earlier theories that viewed decision-making as a rational choice,it is now known that human decision-making is rather based on hedonic motives than on rationalmotives (Cabanac, 1992). For example, risky sexual behaviors are rather the result of anticipationof short-term reward than based on long-term risk assessment. Recently, there have been numerousattempts to interpret clinical problems such as addictive behaviors, criminal behavior, and braindamage in terms of this reward-based decision theory. These attempts are founded on recent under-standings concerning the psychology and neuroscience of decision-making (Bechara, Damasio,Damasio, & Lee, 1999; Rahman, Sahakian, Cardinal, Rogers, & Robbins, 2001; Rogers et al.,1999). Bechara, Damasio, Damasio, and Anderson (1994) demonstrated that patients with frontallobe damage have problems with reward-based decision-making: they often pursue actions thatbring some kind of immediate reward, despite severe long-term consequences such as the loss of job,home, and family. These studies on neurological patients have direct implications for understand-ing several psychiatric disorders including drug addiction, impulse control disorders (such as gam-bling), sexual disorders (sexual offenders), psychopathy, bulimia and obesity. The patients with thesedisorders experience similar problems in reward-based decision-making (Cohen & Blum, 2002).Despite recent scientific progress in this field (Krawczyk, 2002; Rahman et al., 2001), sev-

eral issues certainly require more research attention. One of these issues is the relation betweenpersonality and decision-making. For example, it is unknown to what extent behavioral deci-sion-making, typically measured by the IOWA gambling task (Bechara et al., 1994), is influencedby higher-order personality traits. In the IOWA gambling task, subjects have to select cards fromfour decks that range in probability and magnitude of rewards and punishments. The decks thatprovide immediate larger gains also provide net losses in the longer run. Two candidate person-ality traits that may influence IOWA gambling task performance can be discerned: impulsivityand Behavioral Inhibition System/Behavioral Approach System (BIS/BAS) sensitivity. The firstcandidate, impulsivity, can be described as the inability to tolerate long delays to reinforcerpresentation, or a preference for smaller more immediate rewards over larger but more delayedrewards (Ainslie, 1975). A recent study by Crone, Vendel, and van der Molen (2003) showed thatdecision-making is modulated by individual differences in disinhibition, which is a key feature ofimpulsivity. More specifically, performance on the IOWA gambling task was found to be affectedby individual differences in cognitive disinhibition, as measured by a subscale of Zuckerman�sSensation Seeking Scale (Zuckerman, Eysenck, & Eysenck, 1978). In their discussion, the authorsconclude that their findings indicate that subjects who are bad performers on the IOWA gamblingtask can best be characterized as reward-prone rather than as future-insensitive. However, recentstudies among healthy subjects indicate that impulsivity (or cognitive disinhibition) and rewardsensitivity do not represent the same construct (Dawe & Loxton, 2004; Franken, Muris, & Rassin,2005; Quilty & Oakman, 2004). In addition, studies among brain damage patients have indi-cated that decision-making and impulsivity can manifest themselves independently (Mavaddat,Kirkpatrick, Rogers, & Sahakian, 2000).A second candidate that may influence IOWA gambling task performance is BIS/BAS sensitivity

(Carver & White, 1994). The BAS mediates reactions to appetitive stimuli (such as reward),whereas the BIS mediates reactions to aversive stimuli (Gray, 1987). In general, Gray�s neuropsy-chological theory of personality predicts that subjects with high BIS are most sensitive to signals ofpunishments, while subjects with high BAS are most sensitive to signals of reward. Because in the

I.H.A. Franken, P. Muris / Personality and Individual Differences 39 (2005) 991–998 993

IOWA gambling task both rewards (gains) and punishments (losses) are used, it can be hypothe-sized that BIS/BAS sensitivity mediates performance on the IOWA gambling task. Van Honk,Hermans, Putman, Montagne, and Schutter (2002) showed that non-clinical psychopaths whohad a combination of low BIS and high BAS performed worse on the IOWA gambling task thannon-psychopathic persons who displayed BIS/BAS scores in the normal range. Yet, it is unknownwhether BIS and BAS each have an independent influence on IOWA gambling task performance.The present study further examined the influence of a number of potentially relevant personal-

ity traits on behavioral decision-making. For this purpose, a group of students carried out theIOWA gambling task and completed a set of self-report questionnaires for measuring sensitivityfor punishment and reward (BIS/BAS), and impulsivity. It is hypothesized that high levels of self-reported BAS and low levels of self-reported BIS, but not self-reported impulsivity, are negativelyassociated with reward-based behavioral decision-making on the IOWA gambling task. In addi-tion, participants also completed a self-report scale for assessing their decision-making style. Inthis way, it became possible to study the connection between a self-report and a behavioral mea-sure of decision-making. To summarize, the aim of the present study was to investigate to whatextent performance on the IOWA gambling task is predicted by questionnaires that measure gen-eral personality traits (BIS/BAS and impulsivity) and self-reported decision-making styles. Inaddition to a correlational approach, we also used regression analysis in order to study the relativecontribution of each of these factors to behavioral decision-making.

2. Methods

2.1. Participants and procedure

A sample of 44 psychology students (eight males) volunteered to participate in the presentstudy. The mean age of the sample was 20.0 years (SD = 4.2). Prior to participation, all subjectsprovided written informed consent. Participants were asked to complete Dutch translations ofCarver and White�s (1994) BIS/BAS Scales, the Adolescent Decision Making Questionnaire(ADMQ; Tuinstra, van Sonderen, Groothoff, van den Heuvel, & Post, 2000), and the DickmanImpulsivity Inventory DII; (Dickman, 1990). Next, subjects completed the IOWA gambling task.A two-tailed t-test did not reveal differences between males and females on IOWA gambling taskperformance or on any of the self-report measures (all t�s < 1.8). Therefore, no separate analysesfor male and female participants were conducted.

2.2. Instruments

For the present study we used the computerized version of the IOWA gambling task (Bechara,Tranel, & Damasio, 2000) with a progressive schedule of increased delayed punishments. TheIOWA gambling task consists of 100 successive trials in which subjects are required to choosea card from one of four decks. The participants are instructed to try to gain as much money aspossible by drawing cards from one of four decks. The decisions to choose from the decksare motivated by reward and punishment schedules inherent in the task. Two of the decks(i.e., A 0 and B 0) are disadvantageous, producing immediate gains (large rewards) but these are

994 I.H.A. Franken, P. Muris / Personality and Individual Differences 39 (2005) 991–998

accompanied by larger losses in the long run (larger punishments). The C 0 and D 0 decks areadvantageous: here, gains are modest but more consistent and losses are smaller. We used thenet-score (advantageous decks–disadvantageous decks) as dependent variable. A higher scoremeans that a subject is more often choosing advantageous decks.The BIS/BAS Scales are presented as a self-report questionnaire that has been constructed to

assess individual differences in personality dimensions that reflect the sensitivity of two motiva-tional systems, the aversive and appetitive system (BIS and BAS; Carver & White, 1994; Gray,1987). The BIS/BAS Scales consist of 20 items that can be allocated to two primary scales: theBehavioral Inhibition System scale (BIS; 7 items) and the Behavioral Approach System scale(BAS; 13 items). The BAS can be divided into 3 subscales: Fun Seeking (4 items), RewardResponsiveness (5 items), and Drive (4 items). The Dutch version of the BIS/BAS Scales has beendescribed in previous studies (Franken, 2002; Franken et al., 2005). Cronbach�s alphas for variousscales were found to range from .61 to .79.The DII (Dickman, 1990) is a 23-item self-report measure that distinguishes two types of impul-

sivity: functional impulsivity (11 items) and dysfunctional impulsivity (12 items). The functionalimpulsivity scale contains items such as: ‘‘People have admired me because I can think quickly’’and ‘‘Most of the time, I can put my thoughts into words very rapidly’’. The dysfunctional impul-sivity scale contains items such as: ‘‘I often say and do things without considering the conse-quences’’ and ‘‘I often get into trouble because I don�t think before I act’’. There were someminor adaptations made in the Dutch translation by Claes, Vertommen, and Braspenning(2000). First, all negative expressions were positively reworded. Second, some typical Flemishexpressions were reworded for use in the Dutch population. The psychometric properties of theDutch DII are good for both subscales (Claes et al., 2000), with a Cronbach�s alpha of .77 forfunctional impulsivity and an alpha of .80 for dysfunctional impulsivity (see Franken et al., 2005).The ADMQ is a 22-item self-report questionnaire that measures decision-making styles. The

ADMQ consists of 4 scales: self-confidence (e.g., ‘‘I think that I am a good decision maker’’),avoidance (e.g., ‘‘I avoid making decisions’’), impulsiveness (e.g., ‘‘I tend to drift into decisionswithout thinking of them’’), and panic (e.g., ‘‘I panic if I have to make decisions quickly’’).The ADMQ has been shown to be a reliable and valid questionnaire for measuring decision-making styles (Tuinstra et al., 2000). Cronbach�s alphas vary between .59 and .72.

2.3. Data analysis

Pearson correlation coefficients were calculated to examine the relations between IOWA gam-bling task score and ratings of the self-report scales. In order to investigate the relative contribu-tion of the self-report scales to behavioral decision, the significant scales of the correlation analysiswere added as independent variables in a linear regression model with the total score on theIOWA gambling task being the dependent variable.

3. Results

The mean IOWA scores (SD) were �4.7 (5.4) for the first set of 20 cards, �.7 (4.1) for the sec-ond set, �3.9 (4.1) for the third set, �7.5 (5.0) for the fourth set, and �8.6 (4.5) for the fifth set.

Table 1

Pearson correlation coefficients among IOWA gambling task scores and various self-report scales

IOWA score 1 2 3 4 5 6 7 8 9

1. BIS .08

2. BAS Reward

Responsiveness

.32** .13

3. BAS Drive .11 .00 .19

4. BAS Fun Seeking �.02 �.24 .34** .13

5. DII Functional

impulsivity

.26* �.57** .25 .18 .42**

6. DII Dysfunctional

impulsivity

.01 �.22 .23 .33** .39** .38**

7. ADMQ avoidance �.22 .31** �.23 �.26* .03 �.45** �.26*8. ADMQ self-confidence .19 �.44** .04 .33** �.10 .41** �.04 �.55**9. ADMQ panic �.28* .63** .15 .05 .02 �.58** �.04 .48** �.53**10. ADMQ impulsiveness .00 �.20 .18 .12 .24 .44** .47** �.29* �.09 �.20Notes. N = 44.

BIS = Behavioral Inhibition System, BAS = Behavioral Approach System, DII = Dickman Impulsivity Inventory,

ADMQ = Adolescent Decision Making Questionnaire.* p < .10.** p < .05.

I.H.A. Franken, P. Muris / Personality and Individual Differences 39 (2005) 991–998 995

Correlations between all variables are displayed in Table 1. As can be seen, scores on the IOWAgambling task were significantly correlated with the BAS Reward Responsiveness scale, whereas atrend towards a significant correlation emerged between IOWA scores on the one hand, and DIIfunctional impulsivity and the panic scale of the ADMQ on the other hand. Furthermore, clear-cut inter-scale correlations were found among dysfunctional impulsivity, BAS Drive, and BASFun Seeking. In addition, functional impulsivity was correlated in a theoretically meaningfulway with all ADMQ scales.The linear regression model indicated that high performance on the IOWA gambling task was

associated with higher scores on the BAS Reward Responsiveness scale (standardized beta = .48;t = 3.4, p = .001) and panic decision-making style (standardized beta = �.41; t = �3.0; p = .005).The overall model explained a third part of the total variance of the IOWA gambling task perfor-mance [R2 = .32; F(2,39) = 8.6; p = .001].

4. Discussion

In the present study, we found indications that behavioral decision-making is predicted by indi-vidual differences in sensitivity for reward, and that behavioral decision-making was not predictedby impulsive personality traits. Furthermore, behavioral decision-making was found to be tosome extent correlated to self-reported decision-making style. More specifically, subjects whoscored high on a panic decision-making style appeared to be worse decision-makers as measuredwith a behavioral index. This study indicates that performance on the IOWA gambling task is notonly mediated by neurological or psychiatric disorders but is also, to some extent, significantlyinfluenced by individual differences in higher-order personality traits and decision-making style.

996 I.H.A. Franken, P. Muris / Personality and Individual Differences 39 (2005) 991–998

Good performance on the IOWA gambling task was found to be positively related to BAS, inparticular sensitivity to reward, but not to BIS. This finding is somewhat at odds with the resultsobtained by Van Honk et al. (2002), who found that subjects with a combination of high BAS andlow BIS (i.e., non-clinical psychopaths) performed significantly worse on the IOWA gambling taskthan persons with the combination of low BAS and high BIS (i.e., normal controls). However, be-cause of the design of their study, Van Honk et al. (2002) were not able to examine the relative con-tributions of BIS and BAS to IOWA task performance. In contrast, the present study sheds morelight on the relative contributions of these personality traits on behavioral decision-making.The current findings showed that performance on the IOWA gambling task is not related to

impulsivity. Although Gray (1970) used the term ‘‘impulsivity’’ to characterize the high BAS sen-sitivity trait, the present study demonstrates that impulsivity is quite different from reward sensi-tivity, and thus adds further evidence to the notion that reward sensitivity and impulsivity areallied but separate constructs (Dawe & Loxton, 2004; Franken et al., 2005; Quilty & Oakman,2004). Impulsivity appears to represent rash and spontaneous behavior and as such is distinctfrom reward sensitivity (Dawe & Loxton, 2004).There was little overlap between self-reported decision-making styles and a behavioral measure

of decision-making. Only the self-reported ‘‘panic style’’ of decision-making was found to be asignificant predictor of behavioral decision-making. Higher scores on panic style were associatedwith lower scores on the IOWA gambling task. This can be explained in three ways. First, it mayindicate that persons are less capable of rating their own decision-making processes. This fits withthe idea that persons have in general limited insight into their own motives for behavior (Berridge,2004; Berridge & Winkielman, 2003; Nisbett & Wilson, 1977; Winkielman & Berridge, 2003). Sec-ond, it might be that the IOWA gambling task taps a different construct than the ADMQ. Sur-prisingly, the one scale of the ADMQ that was actually related to performance on the IOWAgambling task was the panic scale. It has not been documented before that bad performanceon the IOWA gambling task is related to a panic style of decision-making, and so it may wellbe the case that sample characteristics (i.e., the use of young college students) account for thisfinding. Third and finally, several researchers (e.g., Epstein, 1979, 1980) have noted that in theactual assessment of human behavior, sampling error is quite large when behavior is only mea-sured in one specific context. Only the inclusion of various behavioral tasks would make itpossible to reliably assess individual differences in decision-making.It should be mentioned that our population performed rather poor on the IOWA task as com-

pared to subjects in previous studies. There may be two explanations for this difference in perfor-mance. It is known that high-educated subjects perform worse than low educated subjects on theIOWA task (Bowman & Turnbull, 2004; Evans, Kemish, & Turnbull, 2004). Furthermore, inmost other studies the ‘‘original’’ IOWA task has been used, the so-called ABCD-task. In con-trast, in the present study we used the A 0B 0C 0D 0 task. This A 0B 0C 0D 0 task is analogous to the ori-ginal task (ABCD). The only difference is a change in the frequency and/or magnitude of delayedpunishment relative to immediate reward. The change is such that the discrepancy between rewardand punishment in the disadvantageous decks (A 0 and B 0) is larger in the negative direction. Inaddition, the discrepancy between reward and punishment in the advantageous decks (C 0 andD 0) is larger in the positive direction (Bechara et al., 2000). This probably makes the current taskmore difficult than the original task. However, it is unlikely that the relatively poor performanceof our subjects on the IOWA task had a negative impact on our correlational findings.

I.H.A. Franken, P. Muris / Personality and Individual Differences 39 (2005) 991–998 997

To summarize, the present study showed that behavioral decision-making was to some extentpredicted by individual differences in sensitivity for reward but not by impulsive personality traits.Furthermore, behavioral decision-making appeared to be correlated to the self-reported ‘‘panicstyle’’ of decision-making.

Acknowledgement

This study was sponsored by NWO (Netherlands organization for scientific research).

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