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Intolerance of uncertainty and perceived threat
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Behaviour Research and Therapy 46 (2008) 28–38 www.elsevier.com/locate/brat
Intolerance of uncertainty and perceived threat Keith Bredemeier, Howard Berenbaum Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, USA Received 13 June 2007; received in revised form 25 September 2007; accepted 25 September 2007
Abstract The present study examined the relations between dimensions of intolerance of uncertainty (i.e., desire for predictability and uncertainty paralysis) and perceptions of threat (i.e., perceptions of the probabilities and costs of future undesirable outcomes) in a sample of 239 college students. Uncertainty paralysis was positively associated with both perceived probabilities and perceived costs for negative outcomes. Desire for predictability was positively associated with perceived costs for negative outcomes but was not associated with perceived probabilities for negative outcomes. When probability estimates for low base rate outcomes were examined separately, desire for predictability was negatively associated with perceived probabilities. Finally, perceived threat partially mediated the relations between dimensions of intolerance of uncertainty and worry. The results of the present study suggest mechanisms through which dimensions of intolerance of uncertainty might lead to excessive worry. Published by Elsevier Ltd. Keywords: Intolerance of uncertainty; Perceived threat; Probability estimates; Cost estimates
Introduction A significant body of research has shown that intolerance of uncertainty is associated with excessive worry in both clinical and nonclinical samples (e.g., Dugas, Freeston, & Ladouceur, 1997; Dugas, Gagnon, Ladouceur, & Freeston, 1998). In fact, research suggests that this association is specific to worry and is not accounted for by shared variance with other relevant constructs, such as perfectionism and intolerance of ambiguity (Buhr & Dugas, 2006; Dugas, Gosselin, & Ladouceur, 2001; Dugas, Marchand, & Ladouceur, 2005; Dugas, Schwartz, & Francis, 2004). Furthermore, there is growing evidence that this relationship is causal. More specifically, treatment research has shown that changes in intolerance of uncertainty generally precede changes in levels of worry (Dugas, Langlois, Rheaume, & Ladouceur, 1998). Also, de Bruin, Rassin, and Muris (2006) found that individual differences in intolerance of uncertainty predict state levels of worry following tasks intended to elicit feelings of uncertainty. Finally, experimental research has shown that efforts to manipulate intolerance of uncertainty lead to increases in worry (Ladouceur, Gosselin, & Dugas, 2000). Although a great deal of research has documented a link between intolerance of uncertainty and worry, surprisingly little research has been conducted to elucidate the specific mechanisms through which intolerance Corresponding author. Tel.: +1 217 333 9624; fax: +1 217 244 5876.
E-mail address: [email protected] (K. Bredemeier). 0005-7967/$ - see front matter Published by Elsevier Ltd. doi:10.1016/j.brat.2007.09.006
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of uncertainty leads to excessive worry. Dugas, Buhr, and Ladouceur (2004) have speculated that intolerance of uncertainty may lead to excessive worry in two different ways: (a) by leading to increased levels of positive beliefs about worry, negative problem orientation, and cognitive avoidance (all of which are positively associated with worry) and (b) by increasing perceived threat. In terms of perceived threat, Dugas, Buhr et al. (2004) have posited that high levels of intolerance for uncertainty may cause individuals to (a) overestimate the likelihood of negative outcomes (i.e., increase probability estimates) and (b) overestimate the consequences of negative outcomes (i.e., increase cost estimates). Given the growing evidence that both estimated probabilities of negative outcomes and estimated costs of negative outcomes are positively associated with levels of worry (Berenbaum, Thompson, & Pomerantz, 2007; Butler & Mathews, 1983; MacLeod, Williams, & Bekerian, 1991), it is important to examine whether intolerance of uncertainty is in fact associated with perceptions of threat. After all, Borkovec, Alcaine, and Behar (2004) have argued that ‘‘it is the perception of threat that initiates the anxiety process’’ (p. 81). Several studies (Berenbaum Bredemeier, & Thompson, in press; Buhr & Dugas, 2002; Carleton, Norton, & Asmundson, 2007) have reported factor analyses of the Intolerance of Uncertainty Scale (IUS; Buhr & Dugas, 2002), the most commonly used measure of intolerance of uncertainty. The results of these studies suggest that intolerance of uncertainty is a multidimensional construct. More specifically, Berenbaum et al. (in press) described four factors, as did Buhr and Dugas (2002). Carleton, Norton et al. (2007) utilized a combination of exploratory and confirmatory factor analysis to describe two factors in their proposed abbreviated version of the IUS. Importantly, two common factors emerged in all three studies. The dimension Berenbaum et al. (in press) labeled ‘desire for predictability’ closely aligned with the third factor described by Buhr and Dugas (2002). In addition, the seven items Berenbaum et al. (in press) used to compute the desire for predictability subscale score were the same seven items included in the Prospective Anxiety subscale of Carleton et al.’s abbreviated IUS. This dimension involves a strong preference to know what will happen in the future and is positively associated with conscientiousness and worry. The dimension Berenbaum et al. (in press) labeled ‘uncertainty paralysis’ closely aligned with the first factor described by Buhr and Dugas (2002). The uncertainty paralysis subscale also overlapped some, though not perfectly, with the Inhibitory Anxiety subscale of Carleton et al.’s abbreviated IUS. This dimension involves a tendency to be frozen into inaction by uncertainty and is negatively associated with both decisiveness and extraversion. Other subscales derived by Berenbaum et al. (in press) did not significantly overlap with factors/dimensions found in previous research. In summary, mounting evidence supports the idea that the original IUS has at least two stable and replicable dimensions (i.e., desire for predictability and uncertainty paralysis). Furthermore, Berenbaum et al. (in press) presented evidence to support the discriminant validity of these two dimensions/subscales. For this reason, we chose to use the desire for predictability and uncertainty paralysis subscales described by Berenbaum et al. (in press) in the present study. The purpose of the present study was to examine the relations between dimensions of intolerance of uncertainty and perceived threat. In contrast to Dugas and colleagues, we hypothesized a complex relationship between desire for predictability and probability estimates. Past research has shown that desire for predictability is a core component of the construct of intolerance for uncertainty and has the strongest associations with the core components of a similar construct known as need for cognitive closure (Berenbaum et al., in press). In turn, research suggests that individuals who are high in need for cognitive closure process and utilize information differently than do individuals who are low in need for cognitive closure. More specifically, Kruglanski and Webster (1996) have argued that people who are high in need for cognitive closure display ‘‘motivated closing of the mind.’’ In other words, these individuals exhibit two general tendencies: urgency (i.e., an inclination to attain closure or certainty as soon as possible) and permanence (i.e., an inclination to maintain closure or certainty for as long as possible). In fact, there is some evidence to suggest that similar tendencies are observed in individuals who are prone to worry. For example, Bensi and Giusberti (2007) have shown that individuals who are high in trait anxiety have an implicit goal of uncertainty reduction. More specifically, they found that individuals who are high in trait anxiety gather less evidence prior to making a decision. To the extent that individuals with high levels of desire for predictability are likely to exhibit ‘‘motivated closing of the mind,’’ they may be motivated to be more certain in their probability estimates (i.e., have estimates closer to 0% or 100%). More specifically, when a particular outcome seems unlikely to happen, individuals who are high in desire for predictability may report being more certain that it
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will not happen. On the other hand, when a particular outcome seems likely to happen, individuals who are high in desire for predictability may report being more certain that it will happen. In other words, we hypothesized that desire for predictability would be negatively associated with probability estimates for outcomes which are unlikely to occur (i.e., low base rate outcomes) and positively associated with probability estimates for outcomes which are likely to occur (i.e., high base rate outcomes), but not associated with probability estimates in general. Uncertainty paralysis, on the other hand, is associated with both depression and anxiety (Berenbaum et al., in press), both of which have been found to be positively associated with probability estimates for negative outcomes (e.g., Miranda & Mennin, 2007). Furthermore, uncertainty paralysis is negatively associated with decisiveness, suggesting that individuals who are high in uncertainty paralysis may exhibit a tendency to be ‘‘frozen into inaction’’ (Berenbaum et al., in press). In turn, this tendency might compromise an individual’s ability to prevent negative outcomes. Thus, we hypothesized that uncertainty paralysis would be positively associated with probability estimates for negative outcomes. There were two reasons to suspect that elevated levels of intolerance of uncertainty would be associated with cost estimates for negative outcomes. First, Dugas, Buhr et al. (2004) have argued that intolerance for uncertainty may contribute to overestimation of the consequences of negative outcomes. Second, past research has found that both intolerance of uncertainty and cost estimates are positively associated with worry (Berenbaum, Thompson, & Bredemeier, 2007; Butler & Mathews, 1983; Dugas et al., 1997). Whereas we expected desire for predictability and uncertainty paralysis to be differentially associated with probability estimates, we had no reason to hypothesize that they would be differentially associated with cost estimates. Finally, we hypothesized that perceptions of threat would mediate the link between intolerance of uncertainty and worry. However, we did not expect the sole means by which intolerance of uncertainty contributes to worry to be via perceived threat. The reason for this is that we believe that intolerance of uncertainty also contributes to worry in other ways, such as by moderating the impact of perceived threat on worry (Berenbaum, Thompson, & Bredemeier, 2007). It is also possible that intolerance of uncertainty contributes to worry independently of perceived threat. In fact, intolerance of uncertainty has been defined as ‘‘the excessive tendency of an individual to consider it unacceptable that a negative event may occur, however small the probability of its occurrence’’ (Dugas et al., 2001, p. 552). Dugas, Buhr et al. (2004) have argued that individuals who are high in intolerance of uncertainty find uncertain situations inherently distressing, and may even prefer a certain negative outcome over an uncertain one. In line with this argument, Koerner and Dugas (in press) found that negative attributions of ambiguous situations mediate the relationship between intolerance of uncertainty and worry. Consequently, we hypothesized that perceived threat would partially mediate the relationship between dimensions of intolerance of uncertainty and worry (i.e., it would contribute to worry both directly and via its impact on perceived threat). In summary, the present study tested the following hypotheses: (a) desire for predictability and uncertainty paralysis would both be associated with increased cost estimates for negative outcomes; (b) uncertainty paralysis would be associated with increased probability estimates for negative outcomes; (c) desire for predictability would be associated with decreased probability estimates for low base rate negative outcomes (but not associated with probability estimates for negative outcomes in general); and (d) perceived threat would partially mediate the relationship between dimensions of intolerance of uncertainty and worry. Method Participants and procedure Participants1 were 239 university students2 (58.8% female) between the ages of 18 and 23 (M ¼ 19.0; SD ¼ .9). Of those participants reporting their race/ethnicity, the majority (75.5%) reported being European American, 9.7% reported being Asian American, 5.1% reported being Latina/o, and 4.6% reported being 1 The participants in the present study were the same individuals who participated in Berenbaum et al. (in press) and Berenbaum, Thompson, and Bredemeier (2007, Study 2). 2 Due to missing data, the number of participants included in any given analysis ranged from 228 to 239.
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African American. Participants were tested in groups of 10 or fewer individuals. As part of their participation in a research project focusing on perceptions of threat, participants completed the questionnaires described below. Participants received partial credit toward a research participation requirement in exchange for their participation. Measures Intolerance of uncertainty Individual differences in intolerance of uncertainty were measured using the English version of the IUS (Buhr & Dugas, 2002). The IUS is composed of 27 items such as ‘‘Uncertainty makes me uneasy, anxious, or stressed,’’ and ‘‘When it’s time to act, uncertainty paralyses me.’’ In our analyses, we focused on the desire for predictability and uncertainty paralysis3 subscales described in Berenbaum et al. (in press). The desire for predictability subscale contains seven items indicating a strong preference to know what will happen in the future (e.g., ‘‘I always want to know what the future has in store for me,’’ ‘‘A small unforeseen event can spoil everything, even with the best of planning’’). The uncertainty paralysis subscale contains seven items indicating an inclination to be frozen into inaction in the face of uncertainty (e.g., ‘‘When it is time to act, uncertain paralyzes me,’’ ‘‘When I am uncertain I can’t go forward’’). These subscales have demonstrated both convergent and discriminant validity (Berenbaum et al., in press). In the present sample, a’s of the desire for predictability and uncertainty paralysis subscales were .84 and .83, respectively. Perceived threat To measure perceived threat, participants were asked to indicate ‘‘how likely’’ (0 ¼ not at all likely; 6 ¼ almost certain) it was that 39 negative outcomes (e.g., ‘‘your health deteriorating,’’ ‘‘making a mistake at work’’) were to occur, and ‘‘how bad’’ (0 ¼ not at all bad; 6 ¼ horrific) it would be if each of these outcomes were to occur. This strategy of measuring perceived threat has been used in past research (Butler & Mathews, 1983; MacLeod et al., 1991). The undesirable outcomes included in this instrument included several from each of the major sources of worry identified in past research (e.g., interpersonal, achievement, financial, and health). The average of the 39 ‘‘how likely’’ scores was used as a measure of participants’ probability estimates, and the average of the 39 ‘‘how bad’’ scores was used as a measure of participants’ cost estimates. In this sample, the a’s for probability and cost estimates were .95 and .94, respectively. In addition, we obtained an idiographic measure of participants’ probability and cost estimates. Participants were first asked to provide written descriptions of the five negative outcomes they worried about the most. After doing so, they were asked to indicate (a) how likely they thought it was for each of the outcomes to actually occur (1 ¼ extremely unlikely; 7 ¼ extremely likely) and (b) how upset they would be if each of the outcomes were to occur (1 ¼ not at all upset; 7 ¼ extremely upset). The average of the five ‘‘how likely’’ scores was used as a measure of participants’ probability estimates, and the average of the five ‘‘how bad’’ scores was used as a measure of participants’ cost estimates. In the present sample, the a’s for the probability and cost estimates were .67 and .65, respectively. As expected, the two measures of probability estimates were significantly correlated (r ¼ .36, po.01), as were the two measures of cost estimates (r ¼ .46, po.01). Consequently, we averaged across the standardized probability scores to compute a composite probability score, and across the standardized cost scores to compute a composite cost score.4 To test the hypothesis that desire for predictability would be negatively associated with probability estimates for low base rate negative outcomes, we computed the mean probability estimate for those 10 items on the nomothetic measure that had low probability estimates when averaging across all participants.5 We operationally defined low probability as an average probability score less than 2.0. Examples of outcome 3
Results were virtually identical when we used the Inhibitory Anxiety subscale described by Carleton, Norton et al. (2007) rather than the uncertainty paralysis subscale. 4 Results were virtually identical when scores on the idiographic and nomothetic measures were examined separately. 5 We also planned to select high probability items in order to test the hypothesis that desire for predictability would be positively associated with probability estimates for high base rate outcomes. However, none of the items on the nomothetic measure had a sample mean greater than or equal to 4.0.
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items, which met this criterion, include ‘‘Your house/apartment being robbed,’’ ‘‘Being in a natural disaster (e.g., tornado, earthquake, etc.),’’ and ‘‘Becoming seriously ill.’’ a for this new scale was .83 in the sample. Worry Worry was measured using both the Penn State Worry Questionnaire (PSWQ; Meyer, Miller, Metzger, & Borkovec, 1990) and the Worry Domains Questionnaire (WDQ; Tallis, Eysenck, & Mathews, 1992). Past research has indicated that the PSWQ has excellent test–retest reliability and good convergent and discriminant validity (Meyer et al., 1990; Nitschke, Heller, Imig, McDonald, & Miller, 2001). In the present sample, a for the PSWQ was .94. Individuals with high PSWQ scores were not rare; 52 participants had scores greater than 62 (which represents a proposed cutoff for pathological worry in unselected student samples; Behar, Alcaine, Zuellig, & Borkovec, 2003). Like the PSWQ, the WDQ has been found to have good psychometric properties (Stober, 1998). We prepared five new items regarding worry about school, since such worries were expected to be common in a sample of college students; these five items were written to resemble the work domain items in the original WDQ. Because the validity of the socio-political domain items is considered questionable, it was not included in this study. Thus, the WDQ was composed of 30 items (e.g., ‘‘I worry that I will lose close friends’’). In the present sample, a for the WDQ was .94. As expected, the PSWQ and WDQ were significantly correlated (r ¼ .58, po.01); consequently we averaged across the standardized PSWQ and WDQ scores to compute a composite worry score.6 Results Descriptive statistics for all of these variables, and correlations among them, can be found in Table 1. As described earlier, we hypothesized that uncertainty paralysis would be positively associated with probability estimates for negative outcomes. We also hypothesized that desire for predictability would not be associated with probability estimates for all negative outcomes. To test these hypotheses, we conducted a multiple regression analysis in which we simultaneously entered desire for predictability and uncertainty paralysis as predictors, and used composite probability estimates as the criterion variable. The results were consistent with our hypotheses and are displayed in Table 2. As can be seen in Table 2, higher levels of uncertainty paralysis were significantly associated with higher composite probability estimates, whereas desire for predictability was not associated with composite probability estimates. To test our hypothesis that desire for predictability would be negatively associated with probability estimates for low base rate outcomes, we conducted another multiple regression analysis in which we simultaneously entered desire for predictability and uncertainty paralysis as predictors, this time using probability estimates for low base rate outcomes as our criterion variable. The results were once again consistent with our hypotheses and are also displayed in Table 2. As can be seen in Table 2, desire for predictability was significantly negatively associated with probability estimates for low base rate outcomes. Uncertainty paralysis was still associated with probability estimates for low base rate outcomes in the same direction as they were when composite probability estimates scores were used as the criterion variable. To test whether dimensions of intolerance for uncertainty would be associated with cost estimates, we conducted a third multiple regression analysis in which we simultaneously entered desire for predictability and uncertainty paralysis as predictors, and used composite cost estimates for negative outcomes as the criterion variable. The results of this analysis are also displayed in Table 2. As can be seen in Table 2, both desire for predictability and uncertainty paralysis were positively associated with cost estimates. Having found that desire for predictability was associated with cost estimates, and that uncertainty paralysis was associated with both probability and cost estimates, we proceeded to examine the degree to which the relations between dimensions of intolerance of uncertainty and worry were mediated by perceived threat. Based on the recommendations of Preacher and Hayes (2004, under review), we used bootstrapping procedures7 (rather than traditional Sobel tests) to test (a) a simple mediation model examining direct and 6
Results were virtually identical when scores on the PSWQ and WDQ were examined separately. Additional information about procedures recommended by Preacher and Hayes, along with SPSS and SAS syntax for using these procedures, can be found at the following website: http://www.psych.ku.edu/preacher/. 7
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Table 1 Descriptive statistics and zero-order correlations for all variables IU DFP IU desire for predictability IU uncertainty paralysis Nomothetic probability Idiographic probability Low base rate probability Nomothetic cost Idiographic cost PSWQ WDQ
IU UP
Nomothetic probability
Idiographic probability
Low base rate probability
Idiographic cost
Nomothetic cost
PSWQ WDQ
– .53
–
.10
.32
–
.12
.19
.35
-.03
.16
.79
.16
.32 .22 .46 .44
.35 .23 .50 .61
.12 .10 .20 .44
.09 .18 .25 .41
– – .13 .08 .11 .19
– .46 .43 .38
– .42 .39
– .58
–
Mean
SD
2.49
.81
2.21
.79
2.45
.82
3.52
1.11
1.67
.80
3.84 5.77 3.10 2.54
.76 .95 .91 .77
Table 2 Dimensions of intolerance of uncertainty predicting probability and cost estimates
Desire for predictability Uncertainty paralysis Model a
Composite probability
Low base rate probability
Composite cost
ba
ba
ba
.04 .34
R2
.10
.15 .24
R2
.04
.17 .23
R2
.15
Standardized.
po.05. po.01.
indirect effects of desire for predictability on worry, treating cost estimates as a mediator8 and uncertainty paralysis as a covariate and (b) a multiple mediation model examining direct and indirect effects of uncertainty paralysis on worry, treating both probability and cost estimates as mediators, and desire for predictability as a covariate. The advantage of this approach is that tests of indirect effects are nonparametric. Also, this approach allows investigators to test multiple mediation models (i.e., models in which multiple hypothesized mediators are tested simultaneously). Using these procedures, indirect effects are estimated based upon data from the sample, and confidence intervals are estimated by resampling from the data in an iterative fashion. If these confidence intervals do not contain zero, one can reject the null hypotheses that there is no indirect effect of the predictor variable(s) on the criterion variable via the mediating variable(s) being tested. These procedures also simultaneously estimate direct effects of the predictor variable(s) on the criterion variable (i.e., effects that are not accounted for by indirect effects via hypothesized mediating variables). In cases in which there is a significant indirect effect, a nonsignificant direct effect suggests ‘‘full mediation’’, whereas a significant direct effect suggests ‘‘partial mediation.’’ The results from these procedures were consistent with our hypotheses and are displayed in Table 3. As can be seen in Table 3, zero was not included in any of the bias corrected confidence intervals for indirect effects, suggesting that relations between dimensions of intolerance of uncertainty and worry were mediated by 8
We did not test whether probability estimates mediate the relationship between desire for predictability and worry since desire for predictability and probability estimates were not positively correlated.
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Table 3 Tests of direct and indirect (mediated via perceived threat) associations between intolerance of uncertainty and worry
Desire for predictability Uncertainty Paralysis
Mediator
Indirect effecta
95% CIb
Direct effect
Cost estimates Probability estimates Cost estimates
.06 .10 .08
.01–.12 .05–.17 .03–.14
.19** .38**
*po.05; **po.01. a Sample estimate. b Bias corrected and accelerated; 5000 resamples.
perceived threat. More specifically, the relation between desire for predictability and worry was mediated by cost estimates, whereas the relation between uncertainty paralysis and worry was mediated by both probability and cost estimates. However, given that the b’s for the remaining contributions (i.e., direct effects) were statistically significant in each case, it seems that perceived threat did not fully mediate the relations between dimensions of intolerance of uncertainty and worry.
Discussion As hypothesized, the results of this study demonstrate that dimensions of intolerance of uncertainty are differentially associated with perceived threat. More specifically, we found that uncertainty paralysis was positively associated with both probability and cost estimates. In contrast, although desire for predictability was positively associated with cost estimates, it was associated with probability estimates in a more complex way. We found that desire for predictability was not associated with probability estimates for negative outcomes in general but was negatively associated with probability estimates for low base rate negative outcomes. The results of the present study provide further evidence for the discriminant validity of IUS subscales, and thus support the potential utility of using subscale scores rather than total scores when examining the relation between intolerance of uncertainty and worry. The results of the present study were consistent with our hypotheses about the relations between dimensions of intolerance of uncertainty and probability estimates for negative outcomes. More specifically, we hypothesized that desire for predictability would not be associated with probability estimates in general but would be negatively associated with probability estimates for low base rate negative outcomes. The fact that our data supported this hypothesis lends support to the notion that desire for predictability can be conceptualized as a motivational construct. More specifically, individuals who are high in desire for predictability may be motivated to feel more certain about what will happen in the future, and this will be reflected in their probability estimates for future outcomes. When individuals who are high in desire for predictability are inclined to believe that a particular outcome will not occur but are still not certain, they may be motivated to judge the outcome as less likely to occur in order to feel more certain about the future. Though the current study did not address the mechanism(s) through which this occurs, we speculate that this motivation may manifest in the form of (a) needing less information in order to feel certain about the future and/or (b) selectively seeking out and/or attending to information which supports one’s original inclination about whether a given outcome will occur. The results of the present study also supported our hypothesis that uncertainty paralysis would be positively associated with probability estimates for negative outcomes, which lends support to the notion that individuals who are prone to freeze in the face of uncertainty overestimate the likelihood of negative outcomes. One possible explanation for this finding is that uncertainty paralysis prevents individuals from taking action in order to prevent these outcomes from occurring, though again this hypothesis remains to be tested in future research. We also found that intolerance of uncertainty was positively associated with cost estimates for negative outcomes. More specifically, we found that both desire for predictability and uncertainty paralysis were
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positively associated with cost estimates. One possible explanation for these findings is that both desire for predictability and uncertainty paralysis may contribute to catastrophizing (Carleton, Sharpe, & Asmundson, 2007), which in turn has been found to be associated with excessive worry (e.g., Davey & Levy, 1998; Vasey & Borkovec, 1992). More specifically, individuals who are high in intolerance of uncertainty may be more motivated to think about the likelihood of potential consequences of negative outcomes, even when the likelihood of that outcome is low. It is also possible that intolerance of uncertainty may be positively associated with cost estimates for negative outcomes because individuals who are high in intolerance of uncertainty tend to interpret ambiguous outcomes as negative or threatening (Dugas et al., 2005). In line with this argument, Rassin and Muris (2005) have found that indecisiveness (which evidence suggests may be highly related to uncertainty paralysis; e.g., Berenbaum et al., in press) is associated with ‘‘worst case scenario reasoning.’’ Finally, the fact that desire for predictability was associated with cost estimates is not surprising, given that desire for predictability is the dimension of intolerance of uncertainty, which has been found to be most specific to worry (Berenbaum et al., in press), whereas high cost estimates seem to be specific to worry (compared with other forms of psychological distress; e.g., Berenbaum, Thompson, & Bredemeier, 2007). The results of the present study also supported our hypothesis that perceived threat would partially mediate the links between dimensions of intolerance of uncertainty and worry. This suggests that one important mechanism through which intolerance of uncertainty might contribute to worry is by leading to greater perceived threat. However, the fact that perceived threat did not fully mediate suggests that intolerance of uncertainty contributes to worry in other ways as well. Though there is some research examining other ways in which intolerance of uncertainty may contribute to worry (e.g., Berenbaum, Thompson, & Bredemeier, 2007; Koerner & Dugas, in press), it is clear that more research is needed on this topic. The results of the present study may have important implications for the treatment of anxiety disorders. Dugas and Robichaud (2007) have introduced a cognitive–behavioral treatment for generalized anxiety disorder, which specifically targets intolerance of uncertainty. More specifically, this treatment targets intolerance of uncertainty by (a) helping clients recognize that uncertainty is unavoidable, (b) helping clients to recognize how intolerance of uncertainty affects their behavior in their everyday lives, and (c) requiring clients to expose themselves to uncertainty-inducing situations. Existing research suggests that this treatment package is efficacious (e.g., Ladouceur, Dugas et al., 2000). The results of the present study lend support to the notion that targeting intolerance of uncertainty in therapy may be an effective way to reduce perceived threat (i.e., overestimations of both probability and costs for future negative outcomes). Furthermore, the results of the present study (as well as previous research examining the dimensionality of the construct of intolerance of uncertainty) lead us to posit that targeting the different dimensions of intolerance of uncertainty (i.e., uncertainty paralysis and desire for predictability) separately will enhance the efficacy of interventions aimed at reducing intolerance of uncertainty. More specifically, we propose that therapists could target high levels of desire for predictability by trying to foster acceptance of feelings of uncertainty. The relation between acceptance and change has recently become an important area of study in the development of interventions for psychological disorders (e.g., Hayes, Jacobsen, Follette, & Dougher, 1994). In fact, Roemer and Orsillo (2002) have introduced an acceptancebased treatment for generalized anxiety disorder, which uses mindfulness techniques to cultivate acceptance, and preliminary research suggests that this treatment is efficacious (Roemer & Orsillo, 2007). However, this treatment targets acceptance of ‘‘internal experiences’’ in a general sense, and does not specifically attempt to foster acceptance of uncertainty. Thus, in addition to therapists helping clients to recognize that uncertainty is unavoidable, therapists could help clients gain the necessary skills to be aware of feelings of uncertainty when they arise (as well as the negative thoughts and/or emotions that they habitually generate) and to cultivate an intentional attitude of acceptance toward these feelings. On the other hand, therapists could target high levels of uncertainty paralysis by promoting decisiveness and action rather than indecision and/or avoidance. More specifically, this might involve activities to help clients to acquire the necessary skills to act under conditions of uncertainty (e.g., problem-solving skills, assertiveness training), to identify and correct cognitive distortions which may contribute to indecision and/or avoidance, and to practice utilizing these skills in situations involving uncertainty. Thus, in addition to therapists encouraging clients to expose themselves to uncertainty-inducing situations, therapists could also help clients gain the necessary skills to take action in uncertain situations.
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The present study has some limitations that should be addressed in future research. First, since this study did not involve a clinical sample, it is difficult to say whether these results would generalize to individuals with anxiety disorders. However, given that results of past research suggests that normal and pathological worrying differ quantitatively rather than qualitatively (Ruscio, Borkovec, & Ruscio, 2001), we suspect that they probably will. Nevertheless, the findings of the present study should be replicated using clinical samples. Second, given the cross-sectional, correlational nature of the present study, it is impossible to draw conclusions about whether relations between dimensions of intolerance of uncertainty and perceived threat are causal. In fact, it is very possible that perceived threat may cause individuals to experience high levels of desire for predictability and/or uncertainty paralysis. It is also possible that the associations we found are driven by other variables associated with perceived threat that were not included. Thus, longitudinal and/or experimental research is needed to test whether intolerance of uncertainty causes individuals to overestimate the probability and/or costs of negative outcomes. Third, since none of the items in our nomothetic measure of perceived threat could be classified as high base rate negative outcomes, we were unable to test our hypothesis that desire for predictability would be positively associated with probability estimates for high base rate outcomes. Thus, additional research is needed to test the hypothesis that individuals who are high in desire for predictability overestimate the probability of high base rate outcomes. If future research supports this hypothesis, such findings could provide interesting insights into the nature of the outcomes about which individuals who are high in desire for predictability might worry about most. More specifically, this might suggest that individuals who are high in desire for predictability may worry more about high base rate negative outcomes (since they overestimate the likelihood that they will occur), but may be less inclined to worry about low base rate negative outcomes (since they underestimate the likelihood that they will occur). In conclusion, we found that intolerance of uncertainty is associated with perceived threat, and that perceived threat partially mediates the relationship between intolerance of uncertainty and worry. This finding provides preliminary support for the hypothesis set forth by Dugas, Buhr et al. (2004) that intolerance of uncertainty may contribute to worry by increasing perceived threat. Nevertheless, this relation appears to be more complex than Dugas and colleagues have speculated. More specifically, dimensions of intolerance of uncertainty (e.g., desire for predictability and uncertainty paralysis) were found to be differentially associated with probability and cost estimates for future negative outcomes. These findings provide further evidence that the construct of intolerance of uncertainty is multidimensional. Though it is clear that more research is needed to elucidate the mechanisms through which intolerance of uncertainty leads to excessive worry, the present study provides important clues as to how this might occur. Acknowledgments We would like to thank Sarah Sass, Edelyn Verona, and Naomi Sadeh for their helpful comments on earlier drafts of this paper. We would also like to thank Renee Thompson and Barrett Kern for their assistance with data preparation.
References Behar, E., Alcaine, O., Zuellig, A. R., & Borkovec, T. D. (2003). Screening for generalized anxiety disorder using the Penn State Worry Questionnaire: A receiver operating characteristic analysis. Journal of Behavior Therapy and Experimental Psychiatry, 34, 25–43. Bensi, L., & Giusberti, F. (2007). Trait anxiety and reasoning under uncertainty. Personality and Individual Differences, 43, 827–838. Berenbaum, H., Bredemeier, K., & Thompson, R. J. (in press). Intolerance of uncertainty: Exploring its dimensionality and associations with need for cognitive closure, psychopathology, and personality. Journal of Anxiety Disorders. Berenbaum, H., Thompson, R. J., & Bredemeier, K. (2007). Perceived threat: Exploring its association with worry and its hypothesized antecedents. Behaviour Research and Therapy, 45, 2473–2482. Berenbaum, H., Thompson, R. J., & Pomerantz, E. (2007). The relation between worrying and concerns: The importance of perceived probability and cost. Behaviour Research and Therapy, 45, 301–311. Borkovec, T. D., Alcaine, O. M., & Behar, E. (2004). Avoidance theory of worry and generalized anxiety disorder. In R. G. Heimberg, C. L. Turk, & D. S. Mennin (Eds.), Generalized anxiety disorder: Advances in research and practice (pp. 77–108). New York: Guilford. Buhr, K., & Dugas, M. J. (2002). The intolerance of uncertainty scale: Psychometric properties of the English version. Behaviour Research and Therapy, 40, 931–945.
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Behaviour Research and Therapy, 38, 933–941. MacLeod, A. K., Williams, J. M. G., & Bekerian, D. A. (1991). Worry is reasonable: The role of explanations in pessimism about future personal events. Journal of Abnormal Psychology, 100, 478–486. Meyer, T. J., Miller, M. L., Metzger, R. L., & Borkovec, T. D. (1990). Development and validation of the Penn State Worry Questionnaire. Behaviour Research and Therapy, 28, 487–495. Miranda, R., & Mennin, D. S. (2007). Depression, generalized anxiety disorder, and certainty in pessimistic predictions about the future. Cognitive Therapy and Research, 31, 71–82. Nitschke, J. B., Heller, W., Imig, J. C., McDonald, R. P., & Miller, G. A. (2001). Distinguishing dimensions of anxiety and depression. Cognitive Therapy and Research, 25, 1–22. Preacher, K. J., & Hayes, A. F. (2004). SPSS and SAS procedures for estimating indirect effects in simple mediation models. Behavior Research Methods, Instruments, & Computers, 36, 717–731. Preacher, K. J., & Hayes, A. F. (under review). Asymptotic and resampling strategies for assessing and comparing indirect effects in simple and multiple mediator models. Rassin, E., & Muris, P. (2005). Indecisiveness and the interpretation of ambiguous situations. Personality and Individual Differences, 39, 1285–1291. Roemer, L., & Orsillo, S. M. (2002). Expanding our conceptualization of and treatment for generalized anxiety disorder: Integrating mindfulness/acceptance-based approaches with existing cognitive–behavioral models. Clinical Psychology: Science and Practice, 9, 54–68. Roemer, L., & Orsillo, S. M. (2007). An open trial of an acceptance-based behavior therapy for generalized anxiety disorder. Behavior Therapy, 38, 72–85. Ruscio, A. M., Borkovec, T. D., & Ruscio, J. (2001). A taxometric investigation of the latent structure of worry. Journal of Abnormal Psychology, 110, 413–422.
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Stober, J. (1998). Worry, problem elaboration, and suppression of imagery: The role of concreteness. Behaviour Research and Therapy, 36, 751–756. Tallis, F., Eysenck, M. W., & Mathews, A. (1992). A questionnaire for the measurement of nonpathological worry. Personality and Individual Differences, 13, 161–168. Vasey, M. W., & Borkovec, T. D. (1992). A catastrophizing assessment of worrisome thoughts. Cognitive Therapy and Research, 16, 505–520.
Behaviour Research and Therapy 46 (2008) 28–38 www.elsevier.com/locate/brat
Intolerance of uncertainty and perceived threat Keith Bredemeier, Howard Berenbaum Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, USA Received 13 June 2007; received in revised form 25 September 2007; accepted 25 September 2007
Abstract The present study examined the relations between dimensions of intolerance of uncertainty (i.e., desire for predictability and uncertainty paralysis) and perceptions of threat (i.e., perceptions of the probabilities and costs of future undesirable outcomes) in a sample of 239 college students. Uncertainty paralysis was positively associated with both perceived probabilities and perceived costs for negative outcomes. Desire for predictability was positively associated with perceived costs for negative outcomes but was not associated with perceived probabilities for negative outcomes. When probability estimates for low base rate outcomes were examined separately, desire for predictability was negatively associated with perceived probabilities. Finally, perceived threat partially mediated the relations between dimensions of intolerance of uncertainty and worry. The results of the present study suggest mechanisms through which dimensions of intolerance of uncertainty might lead to excessive worry. Published by Elsevier Ltd. Keywords: Intolerance of uncertainty; Perceived threat; Probability estimates; Cost estimates
Introduction A significant body of research has shown that intolerance of uncertainty is associated with excessive worry in both clinical and nonclinical samples (e.g., Dugas, Freeston, & Ladouceur, 1997; Dugas, Gagnon, Ladouceur, & Freeston, 1998). In fact, research suggests that this association is specific to worry and is not accounted for by shared variance with other relevant constructs, such as perfectionism and intolerance of ambiguity (Buhr & Dugas, 2006; Dugas, Gosselin, & Ladouceur, 2001; Dugas, Marchand, & Ladouceur, 2005; Dugas, Schwartz, & Francis, 2004). Furthermore, there is growing evidence that this relationship is causal. More specifically, treatment research has shown that changes in intolerance of uncertainty generally precede changes in levels of worry (Dugas, Langlois, Rheaume, & Ladouceur, 1998). Also, de Bruin, Rassin, and Muris (2006) found that individual differences in intolerance of uncertainty predict state levels of worry following tasks intended to elicit feelings of uncertainty. Finally, experimental research has shown that efforts to manipulate intolerance of uncertainty lead to increases in worry (Ladouceur, Gosselin, & Dugas, 2000). Although a great deal of research has documented a link between intolerance of uncertainty and worry, surprisingly little research has been conducted to elucidate the specific mechanisms through which intolerance Corresponding author. Tel.: +1 217 333 9624; fax: +1 217 244 5876.
E-mail address: [email protected] (K. Bredemeier). 0005-7967/$ - see front matter Published by Elsevier Ltd. doi:10.1016/j.brat.2007.09.006
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of uncertainty leads to excessive worry. Dugas, Buhr, and Ladouceur (2004) have speculated that intolerance of uncertainty may lead to excessive worry in two different ways: (a) by leading to increased levels of positive beliefs about worry, negative problem orientation, and cognitive avoidance (all of which are positively associated with worry) and (b) by increasing perceived threat. In terms of perceived threat, Dugas, Buhr et al. (2004) have posited that high levels of intolerance for uncertainty may cause individuals to (a) overestimate the likelihood of negative outcomes (i.e., increase probability estimates) and (b) overestimate the consequences of negative outcomes (i.e., increase cost estimates). Given the growing evidence that both estimated probabilities of negative outcomes and estimated costs of negative outcomes are positively associated with levels of worry (Berenbaum, Thompson, & Pomerantz, 2007; Butler & Mathews, 1983; MacLeod, Williams, & Bekerian, 1991), it is important to examine whether intolerance of uncertainty is in fact associated with perceptions of threat. After all, Borkovec, Alcaine, and Behar (2004) have argued that ‘‘it is the perception of threat that initiates the anxiety process’’ (p. 81). Several studies (Berenbaum Bredemeier, & Thompson, in press; Buhr & Dugas, 2002; Carleton, Norton, & Asmundson, 2007) have reported factor analyses of the Intolerance of Uncertainty Scale (IUS; Buhr & Dugas, 2002), the most commonly used measure of intolerance of uncertainty. The results of these studies suggest that intolerance of uncertainty is a multidimensional construct. More specifically, Berenbaum et al. (in press) described four factors, as did Buhr and Dugas (2002). Carleton, Norton et al. (2007) utilized a combination of exploratory and confirmatory factor analysis to describe two factors in their proposed abbreviated version of the IUS. Importantly, two common factors emerged in all three studies. The dimension Berenbaum et al. (in press) labeled ‘desire for predictability’ closely aligned with the third factor described by Buhr and Dugas (2002). In addition, the seven items Berenbaum et al. (in press) used to compute the desire for predictability subscale score were the same seven items included in the Prospective Anxiety subscale of Carleton et al.’s abbreviated IUS. This dimension involves a strong preference to know what will happen in the future and is positively associated with conscientiousness and worry. The dimension Berenbaum et al. (in press) labeled ‘uncertainty paralysis’ closely aligned with the first factor described by Buhr and Dugas (2002). The uncertainty paralysis subscale also overlapped some, though not perfectly, with the Inhibitory Anxiety subscale of Carleton et al.’s abbreviated IUS. This dimension involves a tendency to be frozen into inaction by uncertainty and is negatively associated with both decisiveness and extraversion. Other subscales derived by Berenbaum et al. (in press) did not significantly overlap with factors/dimensions found in previous research. In summary, mounting evidence supports the idea that the original IUS has at least two stable and replicable dimensions (i.e., desire for predictability and uncertainty paralysis). Furthermore, Berenbaum et al. (in press) presented evidence to support the discriminant validity of these two dimensions/subscales. For this reason, we chose to use the desire for predictability and uncertainty paralysis subscales described by Berenbaum et al. (in press) in the present study. The purpose of the present study was to examine the relations between dimensions of intolerance of uncertainty and perceived threat. In contrast to Dugas and colleagues, we hypothesized a complex relationship between desire for predictability and probability estimates. Past research has shown that desire for predictability is a core component of the construct of intolerance for uncertainty and has the strongest associations with the core components of a similar construct known as need for cognitive closure (Berenbaum et al., in press). In turn, research suggests that individuals who are high in need for cognitive closure process and utilize information differently than do individuals who are low in need for cognitive closure. More specifically, Kruglanski and Webster (1996) have argued that people who are high in need for cognitive closure display ‘‘motivated closing of the mind.’’ In other words, these individuals exhibit two general tendencies: urgency (i.e., an inclination to attain closure or certainty as soon as possible) and permanence (i.e., an inclination to maintain closure or certainty for as long as possible). In fact, there is some evidence to suggest that similar tendencies are observed in individuals who are prone to worry. For example, Bensi and Giusberti (2007) have shown that individuals who are high in trait anxiety have an implicit goal of uncertainty reduction. More specifically, they found that individuals who are high in trait anxiety gather less evidence prior to making a decision. To the extent that individuals with high levels of desire for predictability are likely to exhibit ‘‘motivated closing of the mind,’’ they may be motivated to be more certain in their probability estimates (i.e., have estimates closer to 0% or 100%). More specifically, when a particular outcome seems unlikely to happen, individuals who are high in desire for predictability may report being more certain that it
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will not happen. On the other hand, when a particular outcome seems likely to happen, individuals who are high in desire for predictability may report being more certain that it will happen. In other words, we hypothesized that desire for predictability would be negatively associated with probability estimates for outcomes which are unlikely to occur (i.e., low base rate outcomes) and positively associated with probability estimates for outcomes which are likely to occur (i.e., high base rate outcomes), but not associated with probability estimates in general. Uncertainty paralysis, on the other hand, is associated with both depression and anxiety (Berenbaum et al., in press), both of which have been found to be positively associated with probability estimates for negative outcomes (e.g., Miranda & Mennin, 2007). Furthermore, uncertainty paralysis is negatively associated with decisiveness, suggesting that individuals who are high in uncertainty paralysis may exhibit a tendency to be ‘‘frozen into inaction’’ (Berenbaum et al., in press). In turn, this tendency might compromise an individual’s ability to prevent negative outcomes. Thus, we hypothesized that uncertainty paralysis would be positively associated with probability estimates for negative outcomes. There were two reasons to suspect that elevated levels of intolerance of uncertainty would be associated with cost estimates for negative outcomes. First, Dugas, Buhr et al. (2004) have argued that intolerance for uncertainty may contribute to overestimation of the consequences of negative outcomes. Second, past research has found that both intolerance of uncertainty and cost estimates are positively associated with worry (Berenbaum, Thompson, & Bredemeier, 2007; Butler & Mathews, 1983; Dugas et al., 1997). Whereas we expected desire for predictability and uncertainty paralysis to be differentially associated with probability estimates, we had no reason to hypothesize that they would be differentially associated with cost estimates. Finally, we hypothesized that perceptions of threat would mediate the link between intolerance of uncertainty and worry. However, we did not expect the sole means by which intolerance of uncertainty contributes to worry to be via perceived threat. The reason for this is that we believe that intolerance of uncertainty also contributes to worry in other ways, such as by moderating the impact of perceived threat on worry (Berenbaum, Thompson, & Bredemeier, 2007). It is also possible that intolerance of uncertainty contributes to worry independently of perceived threat. In fact, intolerance of uncertainty has been defined as ‘‘the excessive tendency of an individual to consider it unacceptable that a negative event may occur, however small the probability of its occurrence’’ (Dugas et al., 2001, p. 552). Dugas, Buhr et al. (2004) have argued that individuals who are high in intolerance of uncertainty find uncertain situations inherently distressing, and may even prefer a certain negative outcome over an uncertain one. In line with this argument, Koerner and Dugas (in press) found that negative attributions of ambiguous situations mediate the relationship between intolerance of uncertainty and worry. Consequently, we hypothesized that perceived threat would partially mediate the relationship between dimensions of intolerance of uncertainty and worry (i.e., it would contribute to worry both directly and via its impact on perceived threat). In summary, the present study tested the following hypotheses: (a) desire for predictability and uncertainty paralysis would both be associated with increased cost estimates for negative outcomes; (b) uncertainty paralysis would be associated with increased probability estimates for negative outcomes; (c) desire for predictability would be associated with decreased probability estimates for low base rate negative outcomes (but not associated with probability estimates for negative outcomes in general); and (d) perceived threat would partially mediate the relationship between dimensions of intolerance of uncertainty and worry. Method Participants and procedure Participants1 were 239 university students2 (58.8% female) between the ages of 18 and 23 (M ¼ 19.0; SD ¼ .9). Of those participants reporting their race/ethnicity, the majority (75.5%) reported being European American, 9.7% reported being Asian American, 5.1% reported being Latina/o, and 4.6% reported being 1 The participants in the present study were the same individuals who participated in Berenbaum et al. (in press) and Berenbaum, Thompson, and Bredemeier (2007, Study 2). 2 Due to missing data, the number of participants included in any given analysis ranged from 228 to 239.
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African American. Participants were tested in groups of 10 or fewer individuals. As part of their participation in a research project focusing on perceptions of threat, participants completed the questionnaires described below. Participants received partial credit toward a research participation requirement in exchange for their participation. Measures Intolerance of uncertainty Individual differences in intolerance of uncertainty were measured using the English version of the IUS (Buhr & Dugas, 2002). The IUS is composed of 27 items such as ‘‘Uncertainty makes me uneasy, anxious, or stressed,’’ and ‘‘When it’s time to act, uncertainty paralyses me.’’ In our analyses, we focused on the desire for predictability and uncertainty paralysis3 subscales described in Berenbaum et al. (in press). The desire for predictability subscale contains seven items indicating a strong preference to know what will happen in the future (e.g., ‘‘I always want to know what the future has in store for me,’’ ‘‘A small unforeseen event can spoil everything, even with the best of planning’’). The uncertainty paralysis subscale contains seven items indicating an inclination to be frozen into inaction in the face of uncertainty (e.g., ‘‘When it is time to act, uncertain paralyzes me,’’ ‘‘When I am uncertain I can’t go forward’’). These subscales have demonstrated both convergent and discriminant validity (Berenbaum et al., in press). In the present sample, a’s of the desire for predictability and uncertainty paralysis subscales were .84 and .83, respectively. Perceived threat To measure perceived threat, participants were asked to indicate ‘‘how likely’’ (0 ¼ not at all likely; 6 ¼ almost certain) it was that 39 negative outcomes (e.g., ‘‘your health deteriorating,’’ ‘‘making a mistake at work’’) were to occur, and ‘‘how bad’’ (0 ¼ not at all bad; 6 ¼ horrific) it would be if each of these outcomes were to occur. This strategy of measuring perceived threat has been used in past research (Butler & Mathews, 1983; MacLeod et al., 1991). The undesirable outcomes included in this instrument included several from each of the major sources of worry identified in past research (e.g., interpersonal, achievement, financial, and health). The average of the 39 ‘‘how likely’’ scores was used as a measure of participants’ probability estimates, and the average of the 39 ‘‘how bad’’ scores was used as a measure of participants’ cost estimates. In this sample, the a’s for probability and cost estimates were .95 and .94, respectively. In addition, we obtained an idiographic measure of participants’ probability and cost estimates. Participants were first asked to provide written descriptions of the five negative outcomes they worried about the most. After doing so, they were asked to indicate (a) how likely they thought it was for each of the outcomes to actually occur (1 ¼ extremely unlikely; 7 ¼ extremely likely) and (b) how upset they would be if each of the outcomes were to occur (1 ¼ not at all upset; 7 ¼ extremely upset). The average of the five ‘‘how likely’’ scores was used as a measure of participants’ probability estimates, and the average of the five ‘‘how bad’’ scores was used as a measure of participants’ cost estimates. In the present sample, the a’s for the probability and cost estimates were .67 and .65, respectively. As expected, the two measures of probability estimates were significantly correlated (r ¼ .36, po.01), as were the two measures of cost estimates (r ¼ .46, po.01). Consequently, we averaged across the standardized probability scores to compute a composite probability score, and across the standardized cost scores to compute a composite cost score.4 To test the hypothesis that desire for predictability would be negatively associated with probability estimates for low base rate negative outcomes, we computed the mean probability estimate for those 10 items on the nomothetic measure that had low probability estimates when averaging across all participants.5 We operationally defined low probability as an average probability score less than 2.0. Examples of outcome 3
Results were virtually identical when we used the Inhibitory Anxiety subscale described by Carleton, Norton et al. (2007) rather than the uncertainty paralysis subscale. 4 Results were virtually identical when scores on the idiographic and nomothetic measures were examined separately. 5 We also planned to select high probability items in order to test the hypothesis that desire for predictability would be positively associated with probability estimates for high base rate outcomes. However, none of the items on the nomothetic measure had a sample mean greater than or equal to 4.0.
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items, which met this criterion, include ‘‘Your house/apartment being robbed,’’ ‘‘Being in a natural disaster (e.g., tornado, earthquake, etc.),’’ and ‘‘Becoming seriously ill.’’ a for this new scale was .83 in the sample. Worry Worry was measured using both the Penn State Worry Questionnaire (PSWQ; Meyer, Miller, Metzger, & Borkovec, 1990) and the Worry Domains Questionnaire (WDQ; Tallis, Eysenck, & Mathews, 1992). Past research has indicated that the PSWQ has excellent test–retest reliability and good convergent and discriminant validity (Meyer et al., 1990; Nitschke, Heller, Imig, McDonald, & Miller, 2001). In the present sample, a for the PSWQ was .94. Individuals with high PSWQ scores were not rare; 52 participants had scores greater than 62 (which represents a proposed cutoff for pathological worry in unselected student samples; Behar, Alcaine, Zuellig, & Borkovec, 2003). Like the PSWQ, the WDQ has been found to have good psychometric properties (Stober, 1998). We prepared five new items regarding worry about school, since such worries were expected to be common in a sample of college students; these five items were written to resemble the work domain items in the original WDQ. Because the validity of the socio-political domain items is considered questionable, it was not included in this study. Thus, the WDQ was composed of 30 items (e.g., ‘‘I worry that I will lose close friends’’). In the present sample, a for the WDQ was .94. As expected, the PSWQ and WDQ were significantly correlated (r ¼ .58, po.01); consequently we averaged across the standardized PSWQ and WDQ scores to compute a composite worry score.6 Results Descriptive statistics for all of these variables, and correlations among them, can be found in Table 1. As described earlier, we hypothesized that uncertainty paralysis would be positively associated with probability estimates for negative outcomes. We also hypothesized that desire for predictability would not be associated with probability estimates for all negative outcomes. To test these hypotheses, we conducted a multiple regression analysis in which we simultaneously entered desire for predictability and uncertainty paralysis as predictors, and used composite probability estimates as the criterion variable. The results were consistent with our hypotheses and are displayed in Table 2. As can be seen in Table 2, higher levels of uncertainty paralysis were significantly associated with higher composite probability estimates, whereas desire for predictability was not associated with composite probability estimates. To test our hypothesis that desire for predictability would be negatively associated with probability estimates for low base rate outcomes, we conducted another multiple regression analysis in which we simultaneously entered desire for predictability and uncertainty paralysis as predictors, this time using probability estimates for low base rate outcomes as our criterion variable. The results were once again consistent with our hypotheses and are also displayed in Table 2. As can be seen in Table 2, desire for predictability was significantly negatively associated with probability estimates for low base rate outcomes. Uncertainty paralysis was still associated with probability estimates for low base rate outcomes in the same direction as they were when composite probability estimates scores were used as the criterion variable. To test whether dimensions of intolerance for uncertainty would be associated with cost estimates, we conducted a third multiple regression analysis in which we simultaneously entered desire for predictability and uncertainty paralysis as predictors, and used composite cost estimates for negative outcomes as the criterion variable. The results of this analysis are also displayed in Table 2. As can be seen in Table 2, both desire for predictability and uncertainty paralysis were positively associated with cost estimates. Having found that desire for predictability was associated with cost estimates, and that uncertainty paralysis was associated with both probability and cost estimates, we proceeded to examine the degree to which the relations between dimensions of intolerance of uncertainty and worry were mediated by perceived threat. Based on the recommendations of Preacher and Hayes (2004, under review), we used bootstrapping procedures7 (rather than traditional Sobel tests) to test (a) a simple mediation model examining direct and 6
Results were virtually identical when scores on the PSWQ and WDQ were examined separately. Additional information about procedures recommended by Preacher and Hayes, along with SPSS and SAS syntax for using these procedures, can be found at the following website: http://www.psych.ku.edu/preacher/. 7
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Table 1 Descriptive statistics and zero-order correlations for all variables IU DFP IU desire for predictability IU uncertainty paralysis Nomothetic probability Idiographic probability Low base rate probability Nomothetic cost Idiographic cost PSWQ WDQ
IU UP
Nomothetic probability
Idiographic probability
Low base rate probability
Idiographic cost
Nomothetic cost
PSWQ WDQ
– .53
–
.10
.32
–
.12
.19
.35
-.03
.16
.79
.16
.32 .22 .46 .44
.35 .23 .50 .61
.12 .10 .20 .44
.09 .18 .25 .41
– – .13 .08 .11 .19
– .46 .43 .38
– .42 .39
– .58
–
Mean
SD
2.49
.81
2.21
.79
2.45
.82
3.52
1.11
1.67
.80
3.84 5.77 3.10 2.54
.76 .95 .91 .77
Table 2 Dimensions of intolerance of uncertainty predicting probability and cost estimates
Desire for predictability Uncertainty paralysis Model a
Composite probability
Low base rate probability
Composite cost
ba
ba
ba
.04 .34
R2
.10
.15 .24
R2
.04
.17 .23
R2
.15
Standardized.
po.05. po.01.
indirect effects of desire for predictability on worry, treating cost estimates as a mediator8 and uncertainty paralysis as a covariate and (b) a multiple mediation model examining direct and indirect effects of uncertainty paralysis on worry, treating both probability and cost estimates as mediators, and desire for predictability as a covariate. The advantage of this approach is that tests of indirect effects are nonparametric. Also, this approach allows investigators to test multiple mediation models (i.e., models in which multiple hypothesized mediators are tested simultaneously). Using these procedures, indirect effects are estimated based upon data from the sample, and confidence intervals are estimated by resampling from the data in an iterative fashion. If these confidence intervals do not contain zero, one can reject the null hypotheses that there is no indirect effect of the predictor variable(s) on the criterion variable via the mediating variable(s) being tested. These procedures also simultaneously estimate direct effects of the predictor variable(s) on the criterion variable (i.e., effects that are not accounted for by indirect effects via hypothesized mediating variables). In cases in which there is a significant indirect effect, a nonsignificant direct effect suggests ‘‘full mediation’’, whereas a significant direct effect suggests ‘‘partial mediation.’’ The results from these procedures were consistent with our hypotheses and are displayed in Table 3. As can be seen in Table 3, zero was not included in any of the bias corrected confidence intervals for indirect effects, suggesting that relations between dimensions of intolerance of uncertainty and worry were mediated by 8
We did not test whether probability estimates mediate the relationship between desire for predictability and worry since desire for predictability and probability estimates were not positively correlated.
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Table 3 Tests of direct and indirect (mediated via perceived threat) associations between intolerance of uncertainty and worry
Desire for predictability Uncertainty Paralysis
Mediator
Indirect effecta
95% CIb
Direct effect
Cost estimates Probability estimates Cost estimates
.06 .10 .08
.01–.12 .05–.17 .03–.14
.19** .38**
*po.05; **po.01. a Sample estimate. b Bias corrected and accelerated; 5000 resamples.
perceived threat. More specifically, the relation between desire for predictability and worry was mediated by cost estimates, whereas the relation between uncertainty paralysis and worry was mediated by both probability and cost estimates. However, given that the b’s for the remaining contributions (i.e., direct effects) were statistically significant in each case, it seems that perceived threat did not fully mediate the relations between dimensions of intolerance of uncertainty and worry.
Discussion As hypothesized, the results of this study demonstrate that dimensions of intolerance of uncertainty are differentially associated with perceived threat. More specifically, we found that uncertainty paralysis was positively associated with both probability and cost estimates. In contrast, although desire for predictability was positively associated with cost estimates, it was associated with probability estimates in a more complex way. We found that desire for predictability was not associated with probability estimates for negative outcomes in general but was negatively associated with probability estimates for low base rate negative outcomes. The results of the present study provide further evidence for the discriminant validity of IUS subscales, and thus support the potential utility of using subscale scores rather than total scores when examining the relation between intolerance of uncertainty and worry. The results of the present study were consistent with our hypotheses about the relations between dimensions of intolerance of uncertainty and probability estimates for negative outcomes. More specifically, we hypothesized that desire for predictability would not be associated with probability estimates in general but would be negatively associated with probability estimates for low base rate negative outcomes. The fact that our data supported this hypothesis lends support to the notion that desire for predictability can be conceptualized as a motivational construct. More specifically, individuals who are high in desire for predictability may be motivated to feel more certain about what will happen in the future, and this will be reflected in their probability estimates for future outcomes. When individuals who are high in desire for predictability are inclined to believe that a particular outcome will not occur but are still not certain, they may be motivated to judge the outcome as less likely to occur in order to feel more certain about the future. Though the current study did not address the mechanism(s) through which this occurs, we speculate that this motivation may manifest in the form of (a) needing less information in order to feel certain about the future and/or (b) selectively seeking out and/or attending to information which supports one’s original inclination about whether a given outcome will occur. The results of the present study also supported our hypothesis that uncertainty paralysis would be positively associated with probability estimates for negative outcomes, which lends support to the notion that individuals who are prone to freeze in the face of uncertainty overestimate the likelihood of negative outcomes. One possible explanation for this finding is that uncertainty paralysis prevents individuals from taking action in order to prevent these outcomes from occurring, though again this hypothesis remains to be tested in future research. We also found that intolerance of uncertainty was positively associated with cost estimates for negative outcomes. More specifically, we found that both desire for predictability and uncertainty paralysis were
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positively associated with cost estimates. One possible explanation for these findings is that both desire for predictability and uncertainty paralysis may contribute to catastrophizing (Carleton, Sharpe, & Asmundson, 2007), which in turn has been found to be associated with excessive worry (e.g., Davey & Levy, 1998; Vasey & Borkovec, 1992). More specifically, individuals who are high in intolerance of uncertainty may be more motivated to think about the likelihood of potential consequences of negative outcomes, even when the likelihood of that outcome is low. It is also possible that intolerance of uncertainty may be positively associated with cost estimates for negative outcomes because individuals who are high in intolerance of uncertainty tend to interpret ambiguous outcomes as negative or threatening (Dugas et al., 2005). In line with this argument, Rassin and Muris (2005) have found that indecisiveness (which evidence suggests may be highly related to uncertainty paralysis; e.g., Berenbaum et al., in press) is associated with ‘‘worst case scenario reasoning.’’ Finally, the fact that desire for predictability was associated with cost estimates is not surprising, given that desire for predictability is the dimension of intolerance of uncertainty, which has been found to be most specific to worry (Berenbaum et al., in press), whereas high cost estimates seem to be specific to worry (compared with other forms of psychological distress; e.g., Berenbaum, Thompson, & Bredemeier, 2007). The results of the present study also supported our hypothesis that perceived threat would partially mediate the links between dimensions of intolerance of uncertainty and worry. This suggests that one important mechanism through which intolerance of uncertainty might contribute to worry is by leading to greater perceived threat. However, the fact that perceived threat did not fully mediate suggests that intolerance of uncertainty contributes to worry in other ways as well. Though there is some research examining other ways in which intolerance of uncertainty may contribute to worry (e.g., Berenbaum, Thompson, & Bredemeier, 2007; Koerner & Dugas, in press), it is clear that more research is needed on this topic. The results of the present study may have important implications for the treatment of anxiety disorders. Dugas and Robichaud (2007) have introduced a cognitive–behavioral treatment for generalized anxiety disorder, which specifically targets intolerance of uncertainty. More specifically, this treatment targets intolerance of uncertainty by (a) helping clients recognize that uncertainty is unavoidable, (b) helping clients to recognize how intolerance of uncertainty affects their behavior in their everyday lives, and (c) requiring clients to expose themselves to uncertainty-inducing situations. Existing research suggests that this treatment package is efficacious (e.g., Ladouceur, Dugas et al., 2000). The results of the present study lend support to the notion that targeting intolerance of uncertainty in therapy may be an effective way to reduce perceived threat (i.e., overestimations of both probability and costs for future negative outcomes). Furthermore, the results of the present study (as well as previous research examining the dimensionality of the construct of intolerance of uncertainty) lead us to posit that targeting the different dimensions of intolerance of uncertainty (i.e., uncertainty paralysis and desire for predictability) separately will enhance the efficacy of interventions aimed at reducing intolerance of uncertainty. More specifically, we propose that therapists could target high levels of desire for predictability by trying to foster acceptance of feelings of uncertainty. The relation between acceptance and change has recently become an important area of study in the development of interventions for psychological disorders (e.g., Hayes, Jacobsen, Follette, & Dougher, 1994). In fact, Roemer and Orsillo (2002) have introduced an acceptancebased treatment for generalized anxiety disorder, which uses mindfulness techniques to cultivate acceptance, and preliminary research suggests that this treatment is efficacious (Roemer & Orsillo, 2007). However, this treatment targets acceptance of ‘‘internal experiences’’ in a general sense, and does not specifically attempt to foster acceptance of uncertainty. Thus, in addition to therapists helping clients to recognize that uncertainty is unavoidable, therapists could help clients gain the necessary skills to be aware of feelings of uncertainty when they arise (as well as the negative thoughts and/or emotions that they habitually generate) and to cultivate an intentional attitude of acceptance toward these feelings. On the other hand, therapists could target high levels of uncertainty paralysis by promoting decisiveness and action rather than indecision and/or avoidance. More specifically, this might involve activities to help clients to acquire the necessary skills to act under conditions of uncertainty (e.g., problem-solving skills, assertiveness training), to identify and correct cognitive distortions which may contribute to indecision and/or avoidance, and to practice utilizing these skills in situations involving uncertainty. Thus, in addition to therapists encouraging clients to expose themselves to uncertainty-inducing situations, therapists could also help clients gain the necessary skills to take action in uncertain situations.
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The present study has some limitations that should be addressed in future research. First, since this study did not involve a clinical sample, it is difficult to say whether these results would generalize to individuals with anxiety disorders. However, given that results of past research suggests that normal and pathological worrying differ quantitatively rather than qualitatively (Ruscio, Borkovec, & Ruscio, 2001), we suspect that they probably will. Nevertheless, the findings of the present study should be replicated using clinical samples. Second, given the cross-sectional, correlational nature of the present study, it is impossible to draw conclusions about whether relations between dimensions of intolerance of uncertainty and perceived threat are causal. In fact, it is very possible that perceived threat may cause individuals to experience high levels of desire for predictability and/or uncertainty paralysis. It is also possible that the associations we found are driven by other variables associated with perceived threat that were not included. Thus, longitudinal and/or experimental research is needed to test whether intolerance of uncertainty causes individuals to overestimate the probability and/or costs of negative outcomes. Third, since none of the items in our nomothetic measure of perceived threat could be classified as high base rate negative outcomes, we were unable to test our hypothesis that desire for predictability would be positively associated with probability estimates for high base rate outcomes. Thus, additional research is needed to test the hypothesis that individuals who are high in desire for predictability overestimate the probability of high base rate outcomes. If future research supports this hypothesis, such findings could provide interesting insights into the nature of the outcomes about which individuals who are high in desire for predictability might worry about most. More specifically, this might suggest that individuals who are high in desire for predictability may worry more about high base rate negative outcomes (since they overestimate the likelihood that they will occur), but may be less inclined to worry about low base rate negative outcomes (since they underestimate the likelihood that they will occur). In conclusion, we found that intolerance of uncertainty is associated with perceived threat, and that perceived threat partially mediates the relationship between intolerance of uncertainty and worry. This finding provides preliminary support for the hypothesis set forth by Dugas, Buhr et al. (2004) that intolerance of uncertainty may contribute to worry by increasing perceived threat. Nevertheless, this relation appears to be more complex than Dugas and colleagues have speculated. More specifically, dimensions of intolerance of uncertainty (e.g., desire for predictability and uncertainty paralysis) were found to be differentially associated with probability and cost estimates for future negative outcomes. These findings provide further evidence that the construct of intolerance of uncertainty is multidimensional. Though it is clear that more research is needed to elucidate the mechanisms through which intolerance of uncertainty leads to excessive worry, the present study provides important clues as to how this might occur. Acknowledgments We would like to thank Sarah Sass, Edelyn Verona, and Naomi Sadeh for their helpful comments on earlier drafts of this paper. We would also like to thank Renee Thompson and Barrett Kern for their assistance with data preparation.
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