Introduction
Experiential avoidance refers to attempts to alter the frequency, duration, or form of negatively evaluated private events such as thoughts, feelings, memories, and the contexts that engender them (e.g., Hayes et al.
1999,
1996). The unwillingness to remain in contact with particular negative internal-subjective experiences falls on the same continuum as psychological acceptance, with higher levels of experiential acceptance reflecting more willingness to experience and endure unwanted private events without judgment and defense (Hayes et al.
1996). As Hayes noted, experiential acceptance “involves experiencing events fully and without defense...and involves making contact with the automatic or direct stimulus functions of events, without acting on the basis solely of their derived verbal functions” (Hayes
1994, p. 30).
Experiential avoidance is not pathogenic by definition. However, chronically or excessively attempting to avoid negative subjective experiences is considered a core psychological vulnerability underlying the onset and/or maintenance of a variety of unfavorable psychosocial and health-related outcomes, ranging from substance abuse to suicide (e.g., Blackledge and Hayes
2001; Hayes et al.
1999). For instance, avoidance behavior in anxiety disorders is generally considered to maintain and exacerbate anxiety-related problems via the process of negative reinforcement, thereby generating a vicious self-perpetuating cycle (Barlow
2002).
Ironically, the generalized tendency to respond to one’s negative thoughts and unwanted emotional states in an avoidant fashion in an effort not to have them, often yields increased sympathetic activation, more intense negative emotions, and renders it more likely that unwanted emotional responses will occur again and more severely in the future (Gross and Levenson
1997; Hayes et al.
1996). Moreover, the habitual use of experiential avoidance may produce the situation wherein the solutions aimed at controlling or minimizing emotional responding become problems themselves (e.g., not being able to travel in agoraphobia). Parallel to the accumulation of evidence suggesting that the association between stressors and adjustment may occur
because of experiential avoidance (i.e. experimental avoidance is a mediator in predictions of distress), a variety of behavior therapy approaches that have incorporated interventions to decrease avoidance patterns have been developed. These include, among others, Dialectical Behavior Therapy (Linehan
1993), Mindfulness-Based Cognitive Therapy (Segal et al.
2001), and Acceptance and Commitment Therapy (ACT; Hayes et al.
1999).
In light of the growing recognition that experiential avoidance is important in psychological (mal)functioning, the Acceptance and Action Questionnaire (AAQ) was developed, a self report measure tapping various aspects of acceptance/willingness vs. experiential avoidance. Several versions of the AAQ that contain different numbers of items have emerged. For instance, a 16-item version has been developed and examined by Bond and Bunce (
2003), whereas Hayes and colleagues have developed and examined a shorter 9-item version (Hayes et al.
2004). Although it should be noted that the AAQ-II will become available in the near future, at present this latter shorter version is most commonly used in research on ACT (Hayes et al.
2006). The current study therefore focuses on the psychometric properties of this 9-item version.
Across different versions, the development of the AAQ was guided by key assumptions of ACT and its underlying theory of language and cognition, called Relational Frame Theory (RFT; Hayes et al.
2001). According to RFT, the core of human language and cognition is the learned and contextually controlled ability to arbitrarily relate events mutually and in combination, and to change the functions of specific events based on their relations to others. Importantly from a clinical point of view, the nature of human language may markedly increase the range of potential aversive events, because in most contexts symbolic behavior allows for the categorization of private events and people’s contact with them. For example, because negatively evaluated subjective feeling states such as anxiety can be recalled or predicted via language (Hayes et al.
2004), humans can start actively avoiding or suppressing negatively evaluated private events such as anxious thoughts.
In a recent series of studies, using different samples including over 2,400 people, Hayes et al. (
2004) showed that the 9 items of the AAQ constitute a single dimension of experiential avoidance, and that higher scores on the AAQ are positively linked with several indices of psychopathology and decreased quality of life. Other studies provided additional support for the ACT/RFT conception of experiential avoidance, and the AAQ as a valid tool to tap the phenomenon (for a review see Hayes et al.
2006). Moreover, a study examining the Spanish adaptation of the AAQ has provided preliminary evidence in favour of the reliability and concurrent validity of the measure in a different Western culture (Baracca Mairal
2004).
Notwithstanding the importance of research conducted with the AAQ to date, several issues warrant further study. First, although many studies used the AAQ to assess experiential avoidance (Hayes et al.
2006), few studies were specifically designed to evaluate its psychometric properties. Second, no studies have yet examined versions of the AAQ other than Spanish (Baracca Mairal
2004) or English (Hayes et al.
2004) ones. In light of the rapid expansion of research on ACT/RFT, it is important to further establish the psychometric properties of the AAQ and the cross-cultural generalizability of findings obtained thus far. The overarching aim of the studies presented in this paper was to provide information on the psychometric properties of the Dutch version of the AAQ. In so doing, three independent samples were examined that varied in age and clinical status.
In Study 1, a sample of bereaved adults was used to investigate the factor-structure, internal consistency, and short term temporal stability of the AAQ, as well as its associations with measures of psychopathology. Based on the findings of Hayes et al. (
2004), it was expected that a unitary model, with items of the AAQ forming a single dimension of experiential avoidance, would fit the data well and would display adequate internal consistency and test–retest reliability. With regard to concurrent validity, it was predicted that higher scores on the AAQ would be positively associated with symptoms of depression, anxiety, and complicated grief.
In Study 2, a sample of undergraduate students was used to further examine concurrent associations between scores on the AAQ and measures indexing several aspects of psychological functioning. Specifically, participants completed questionnaires tapping depression and anxiety, the frequency and perceived stressfulness of daily hassles, coping style, and dimensions of personality as distinguished in the five-factor model of personality (i.e., neuroticism, extraversion, agreeableness, openness, conscientiousness; McCrae and Costa
1999). It was again predicted that higher scores on the AAQ would be positively associated with depression and anxiety. With respect to the construct validity, it was predicted that scores on the AAQ would be more strongly related to the perceived stressfulness of daily hassles than their actual frequency. This expectation was based on the fact that experiential avoidance is conceptualized as a process that is more strongly associated with the subjective experience of life’s adversity than with the actual occurrence of adversity per se (cf. Hayes et al.
2006). Moreover, higher scores on the AAQ were expected to be inversely associated with adaptive coping strategies (e.g., active coping) and positively associated with maladaptive coping strategies (e.g., venting of emotions, cf. Carver et al.
1989). Finally, based on previous work (Bond and Bunce
2003; Kashdan et al.
2006), it was expected that experiential avoidance would be positively associated with neuroticism, a widely recognized unhealthy personality dimension. In addition, experiential avoidance was expected to be negatively associated with extraversion, agreeableness, and conscientiousness—all representing relatively healthy features of personality (cf. Costa and McCrae
1992; Durrett and Trull
2005)—and positively associated with openness, a dimension that has been found to be associated with psychological malfunctioning (Trull and Sher
1994).
In Study 3, psychometric properties of the AAQ were further investigated in a clinical sample. Participants completed measures of depression, anxiety, thought suppression, neuroticism, and coping. Experiential avoidance is conceptualized as a process encompassing negative evaluations of private experiences, as well as deliberate attempts to minimize these experiences (Hayes et al.
2006). Therefore, with respect to the construct validity, it was predicted that the AAQ would be significantly correlated with neuroticism, representing the broader tendency to think and feel negatively, as well as with thought suppression, representing one specific manifestation of experiential avoidance. However, experiential avoidance is considered a phenomenon that is associated with, but more inclusive than neuroticism and thought suppression. Hence, it was expected that the AAQ would continue to predict variance in depression and anxiety, when controlling for the shared variance with both constructs (cf. Hayes et al.
2004). Finally, as in Study 2, it was predicted that higher scores on the AAQ would be positively associated with psychopathology and with maladaptive coping strategies and inversely related with adaptive coping strategies.
The selection of the measures employed in the current studies was based on several considerations. First, because experiential avoidance is assumed to be implicated in a wide range of clinical problems and disorders, it was considered important to select measures tapping different relevant domains of psychological functioning. Second, it was deemed important to select measures that were short, easily administered, and well-validated in the Netherlands.
Discussion
The current studies examined the psychometric properties of the Dutch version of the 9-item AAQ, originally developed by Hayes et al. (
2004) to assess experiential avoidance as conceptualized within ACT (Hayes et al.
1999). Three studies were conducted with a total number of 559 participants, including a large group of bereaved individuals, a non-clinical sample of undergraduate students, and a clinical sample of adult outpatients.
In Study 1, CFA was used to examine the fit of a model in which the items of the AAQ constituted a unitary factor of experiential avoidance. Findings showed that, after a minor adjustment (i.e. allowing error-terms of two comparable items to be correlated) this model fitted the data well. Findings are consistent with those of Hayes et al. (
2004) and provide additional evidence that a common core process cuts through different aspects of experiential avoidance (e.g., negative evaluation of private events, inability to take action when faced with such events, high need for emotional and cognitive control). Yet, it is noteworthy that the item phrased “When I evaluate something negatively, I usually recognize that this is just a reaction, not an objective fact” did not load significantly on the experiential avoidance factor. Although this finding suggests that this item may not be a good indicator of experiential avoidance, it appears that the finding is specific to the sample examined (i.e., bereaved adults). In fact, in the study of Hayes et al. (
2004) this item showed a factor-loading of 0.56. At this point, it is difficult to offer a plausible explanation for this discrepancy. If future studies replicate the poor performance of this item, it should perhaps be removed from the AAQ.
The test–retest correlation found in Study 1 indicated that the total score of the AAQ was relatively stable across an average period of three weeks. This finding links up with earlier studies that have shown that the AAQ total score is reasonably stable across periods of 5 to 6 weeks (
r = 0.71; Barraca Mairal
2004) and 4 months (
r = 0.64; Hayes et al.
2004). However, the stability of the individual items was less satisfactory, with items 4 and 6 showing poor stability. Hence, it appears that experiential avoidance as a broad tendency is relatively stable, whereas specific manifestations of this inclination may vary considerably across time and across situations. This fits the notion that the multiple features of experiential avoidance are
situated actions rather than stable traits (Hayes et al.
2004).
The internal consistency of the AAQ was adequate in Study 1, but quite low in the other two samples examined (Study 2 in particular), and also lower relative to the original instrument (
α = 0.70; Hayes et al.
2004) and the Spanish version (
α = 0.74; Baracca Mairal
2004). Although the cause of this somewhat disappointing result among undergraduates is unclear, this finding is relevant for the discussion about the appropriateness of applying conventional psychometric criteria to the evaluation of measures of experiential avoidance. Specifically, as is noted by Hayes et al. (
2004), from the viewpoint of ACT/RFT, tendencies to engage in experiential avoidance are not seen as representing a stable, internally consistent underlying trait, but, instead, are situated actions that have many different behavioral features. In this context, these authors noted “the alpha level seems likely to remain an issue because the underlying theory [...] suggests that the psychological processes being measured necessarily will include events that can participate in other, more specific processes” (p. 572).
With regard to the validity of the AAQ, in all three studies the AAQ was found to be strongly linked with measures tapping different forms of psychopathology, including symptoms of anxiety, depression, and complicated grief. These findings link up with previous research that supported the concurrent validity of the AAQ (Barraca Mairal
2004; Hayes et al.
2004) and with the growing body of research that points to the importance of experiential avoidance in psychopathology (Hayes et al.
2006). For instance, comparable to the present findings, Hayes et al. (
2004) found the AAQ to be significantly associated with depression (with correlations ranging from 0.36 to 0.72) and anxiety (with correlations ranging from 0.35 to 0.58).
Study 3 showed that the AAQ was also significantly associated with related constructs of neuroticism and thought suppression. These findings replicate earlier work also showing linkages between experiential avoidance and these variables (e.g., Bond and Bunce
2003; Hayes et al.
2004; Kashdan et al.
2006). Importantly, associations of the AAQ with depression and anxiety remained significant after controlling for the shared variance of the AAQ with these related constructs. These findings attest to the incremental validity of the AAQ, by showing that this measure taps a phenomenon that goes beyond neuroticism and thought suppression alone.
Studies 2 and 3 yielded several other findings supporting the validity of the AAQ. First, the linkage with the perceived stressfulness of daily hassles was stronger (albeit not significantly so) than the linkage with the actual frequency of these stressors. Second, in addition to the expected positive association between the AAQ and neuroticism (cf. Bond and Bunce
2003; Kashdan et al.
2006), individuals scoring higher on the AAQ were lower in extraversion, agreeableness, and conscientiousness. Finally, across studies a significant negative association between the AAQ and the coping strategy “acceptance” was observed.
Several limitations of the current studies deserve mention. First, women were overrepresented in Study 1. Hence, it remains to be determined to what extent findings on the factor structure of the AAQ can be generalized to men. Since the sample consisted of bereaved individuals only, future studies examining the factor structure across different populations appear warranted. Second, it should be noted that the internal consistency of some assessment instruments was modest (e.g., several subscales of the COPE in Study 2). Third, the clinical sample used in Study 3 was relatively small. Limited statistical power may therefore account for some of the non-significant associations with indices of coping style. Another caveat is that this sample was heterogeneous with respect to diagnostic status. Although this might indicate generalizability of findings to broad clinical populations, future studies should examine to what extent the AAQ performs differently across diagnostic subgroups. Finally, ethnicity data were not registered in Studies 1 and 2, whereas all participants in Study 3 were Caucasian. Hence, it was not possible to examine if the differences in AAQ scores between different ethnic groups observed in the study of Hayes et al. (
2004) also existed in the current Dutch samples.
Notwithstanding these limitations, the current studies provide important information about the psychometric properties of the Dutch version of the AAQ. Overall, the results are in line with earlier studies that have examined the psychometric properties of the AAQ (Baracca Mairal
2004; Hayes et al.
2004). In addition, the findings add to the impressive body of work that has provided empirical support for the ACT/RFT model of experiential avoidance (Hayes et al.
2006). Importantly, the similarity between the present findings and studies using the Spanish version (Baracca Mairal
2004) and original English version (Hayes et al.
2004,
2006) suggests that the measure can reliably be applied across different Western cultures. However, further improvement of the 9-item AAQ seems warranted given some of its weaker psychometric properties (e.g., its moderate internal consistency), as well as the rapidly growing knowledge on the nature and importance of experiential avoidance. As noted by Hayes et al. (
2004), the 9-item AAQ is meant as a starting point for the development of more comprehensive and/or disorder-specific measures of experiential avoidance. Although the field is indeed likely to benefit from future scale development, the current studies suggest that, in its present form, the 9-item AAQ is a useful tool for the purpose that it was designed for, namely exploring experiential avoidance in large population-based studies.