The practice of mindfulness meditation has its roots in Eastern contemplative traditions and it is a core element of Buddhism (Hanh 1998). In this context, mindfulness has been defined as the quality of bearing in mind or bringing to mind; it is the state of recollecting, the state of remembering, the state of non-fading, the state of non-forgetting (Payutto 1995). In recent years Western psychology has developed a burgeoning interest in mindfulness, where it has been operationalized as a focus of one’s attention in a nonjudgmental or accepting way on the experience occurring in the present moment (Kabat-Zinn 1994) and as an awareness of present experience with acceptance (Germer 2005). In Western psychology, attention has been primarily focused on the integration of these multidimensional mindfulness concepts into psychotherapy treatments (e.g., mindfulness-based cognitive therapy [MBCT]; Segal et al. 2002) aimed at teaching patients a more mindful approach to reducing distress, preventing relapse, and enhancing quality of life.

A related focus for mindfulness researchers has been the development of self-report scales to assess the impact of engaging in mindfulness practices (e.g., Lau et al. 2006) and the general tendency to be mindful in daily life (e.g., Baer et al. 2004). Although state-like scales are essential for evaluating mindfulness-based interventions, given that mindfulness is an intrinsic human characteristic (Kabat-Zinn 1990, 2003) with substantive within and between person variation (Baer et al. 2004; Brown and Ryan 2003; Walach et al. 2006), measures that can assess the general propensity to be mindful are also valuable. This is particularly true in light of research suggesting trait mindfulness is strongly correlated with a variety of psychological constructs relevant to mental health and well-being (see Brown et al. 2007 for a review).

Two widely used scales that measure the general tendency to be mindful in daily life are the Kentucky Inventory of Mindfulness Skills (KIMS; Baer et al. 2004) and the Mindful Attention Awareness Scale (MAAS; Brown and Ryan 2003). In developing the KIMS, Baer et al. (2004) conceptualized mindfulness in terms of four behaviorally oriented factors: observing or attending to internal and external stimuli (Observe); describing and labeling phenomena non-judgmentally (Describe); acting with awareness in which undivided attention is focused on one thing at a time (Act with Awareness), and; accepting or allowing present moments or events to occur without judging them (Accept without Judgment). These four factors were derived primarily from dialectical behavior therapy (DBT; Linehan 1993) where clients are taught “what” (observing, describing, and participating) and “how” (taking a nonjudgmental stance, focusing on one thing in the moment, and being effective) mindfulness skills. Utilizing a more cognitive framework, Brown and Ryan (2003) operationally defined mindfulness as an open or receptive attention to and awareness of present events and experience; this is assessed through the MAAS by asking respondents to rate the frequency with which their day-to-day consciousness reflects this quality. The MAAS therefore taps a distinct type of attentional awareness that can be impacted by, but was not designed exclusively to assess meditation experience (Brown and Ryan 2003). Together the KIMS and MAAS represent a robust measure of the Western operationalization of mindfulness, capturing the components of attention/awareness, nonjudgment/acceptance, and present moment focus.

Both the KIMS and MAAS have evinced relationships with a variety of indicators of mental health and well-being (Baer et al. 2004; Brown and Ryan 2003; Brown et al. 2007). For example, the MAAS has demonstrated positive relationships with constructs such as optimism, positive affect, and vitality and inverse relationships with impulsiveness and unpleasant affect (Brown and Ryan 2003; study 1). Similarly, the KIMS has been associated with higher levels of emotional intelligence and self-compassion and lower levels of alexithymia and dissociation (Baer et al. 2006). In addition to these indicators of mental health and well-being constructs, several studies have examined the MAAS and KIMS as predictors of depression and satisfaction with life. The theoretical basis linking mindfulness to enhanced satisfaction with life and decreased depression is derived primarily from clinical intervention mindfulness research. Mindfulness training forms the foundation of treatments designed to enhance health and well-being (i.e., mindfulness-based stress reduction [MBSR]; Kabat-Zinn 1990) and prevent depressive relapse (i.e., MBCT; Segal et al. 2002), and the effectiveness of both treatments has been well supported (e.g., Baer 2003; Grossman et al. 2004).

At the trait level, Brown and colleagues (Brown et al. 2007; Brown and Ryan 2003, 2004) argue that the receptive attention to and awareness of present experience tapped by the MAAS is key to facilitating well-being and decreasing distress because this disposition adds clarity and vividness to current experience and a closer sensory contact with life. In support of their argument the MAAS has been shown to be a significant negative predictor of depression symptoms (Argus and Thompson 2008) and has exhibited robust positive correlations with life satisfaction (Brown and Ryan 2003; study 1; Johnson 2006). Similarly, Baer et al. (2004) posited that because the four KIMS components (Observe, Describe, Act with Awareness, and Accept without Judgment) were derived from empirically-informed mindfulness practices (i.e., DBT), each factor is conceptually associated with enhanced well-being and reduced psychiatric symptomology. Indeed, two KIMS factors (Describe and Act with Awareness) have evinced a significant positive relationship with life satisfaction (Baer et al. 2004; study 4) and the Describe, Act with Awareness, and Accept without Judgment factors have exhibited an inverse relationship with negative affect (McKee et al. 2007).

However, despite evidence of associations between mindfulness and theoretically relevant constructs such as satisfaction with life and depression, further research is needed to evaluate whether the general tendency to mindful in daily life offers unique explanatory power in the prediction of these variables relative to other well-established predictors. In support of its uniqueness, the MAAS has accounted for significant variance relative to positive and negative affect (Zvolensky et al. 2006), pain intensity (McCracken et al. 2007), and perfectionism (Argus and Thompson 2008) in the prediction of depression symptoms. Similarly, the MAAS maintains a significant negative correlation with depression after controlling for rumination (Brown and Ryan 2003; study 1; Johnson 2006). However, in the prediction of satisfaction with life, although the MAAS accounted for unique variance relative to social desirability (Johnson 2006), it did not relative to acceptance and meta-emotion (Mitmansgruber et al. 2009).

Although we were unable to locate any research supporting the incremental validity of the KIMS in predicting satisfaction with life or depression, the Accept without Judgment factor was a negative predictor of posttraumatic symptoms relative to negative affectivity and number of trauma types (Vujanovic et al. 2009). Also, when psychological well-being was regressed onto the Five Facet Mindfulness Questionnaire (FFMQ; Baer et al. 2006)—a measure composed of a number of items from the KIMS with similar factors (i.e., Observe, Describe, Act with Awareness, Non-Judging, and Non-Reactivity)—four out of five factors (not Observe) were significant predictors, demonstrating that each accounts for a significant portion of the variance not accounted for by the others.

To expand on the extant research, Zvolensky et al. (2006) suggested researchers investigate the incremental validity of various conceptualizations of mindfulness relative to self-appraisal and cognitive variables in the prediction of well-being and distress. Self-esteem is a well-established predictor of satisfaction with life (Diener and Diener 1995; Lucas et al. 1996) and is generally considered to reflect a trait-like evaluative component of the self-concept; a broader representation of the self that includes cognitive and behavioral aspects as well as evaluative and affective ones (Blascovich and Tomaka 1991). Self-esteem also evinces a strong positive relationship with mindfulness (Thompson and Waltz 2008) and there is substantial conceptual overlap between the two variables (Ryan and Brown 2003). Therefore, including self-esteem in addition to the facets of mindfulness as assessed by the KIMS and MAAS in the prediction of satisfaction with life can allow for an examination of the unique contributions of each predictor.

Similarly, negative cognition is a well-established predictor of depression (Hollon et al. 1986; Segal et al. 2006), and akin to mindfulness, can be conceptualized as an enduring trait (Zuroff et al. 1999). Negative cognitions about the self may reflect broader cognitive structures or enduring themes that can contribute to persistent vulnerability to depression (Hollon et al. 1996; Joormann and Siemer 2004). Several studies have found a robust inverse relationship between negative cognitions and mindfulness (Frewen et al. 2008; Ramel et al. 2004) indicating that these variables share variance. Moreover, in questioning the validity of current self-report measures of mindfulness (including the KIMS and MAAS), Rosch (2007) suggests that the facets tapped by these scales are not assessing mindfulness per se, but rather constructs such as “more versus less pathology” (p. 262). Thus, accounting for the variance in depressive cognitions (i.e., pathological thinking) prior to adding facets of mindfulness as assessed by the KIMS and MAAS in the prediction of depression can help to disentangle the unique contributions of each predictor.

To the extent that dispositional mindfulness—as measured by the MAAS and KIMS—reflects an enduring emotional and cognitive self-regulatory process, self-esteem and negative cognitions may share important associations with these measures. Additionally, given that a growing number of authors have begun to question the validity of mindfulness measures (Christopher et al. 2009; Grossman 2008; Rosch 2007) research that examines facets of mindfulness as predictors of well-being and depression relative to conceptually related variables is needed. Thus, the overall goal of this exploratory study was to examine the incremental validity of five components of mindfulness (i.e., four KIMS factors and MAAS) beyond other theoretically relevant predictors in terms of satisfaction with life and depression symptoms. To be considered a unique explanatory factor, each component of mindfulness would need to demonstrate unique predictive value beyond that accounted for by conceptually related variables (i.e., self-esteem for satisfaction with life and negative cognitions for depression symptoms).

Method

Participants

Participants were 365 (260 female, 105 male) undergraduate students recruited from a large, public university and a small, private college both located in Pacific Northwestern U.S. The mean age for participants was 21.70 years (SD = 5.82). The racial makeup of the sample was 67% (n = 246) White American, 16% (n = 59) Asian American, 3% (n = 11) African American, 2% (n = 7) Latino American, 1% (n = 3) Native American, 9% (n = 31) Multiracial, and 2% (n = 8) other.

Measures

Mindful Attention Awareness Scale (MAAS)

The MAAS is a 15-item questionnaire in which respondents indicate, on a 6-point Likert-type scale (1 = almost always to 6 = almost never), their level of awareness and attention to present events and experiences (Brown and Ryan 2003). The MAAS only includes statements that assess mindlessness (e.g., “I do jobs or tasks automatically, without being aware of what I am doing”). Brown and Ryan (2003) assert that mindlessness is more easily detected given that these types of thoughts and actions are more common than mindful ones. A mean rating score is calculated with higher scores indicating greater mindfulness. The MAAS shows a good range of internal consistency across a wide range of samples (α = .80–.87) and excellent test re-test reliability over a 1-month time period (r = .81). The MAAS also exhibits adequate convergent validity; as expected it correlates negatively with measures of anxiety and depression and positively with measures of positive affect and self-esteem (Brown and Ryan 2003).

Kentucky Inventory of Mindfulness Skills (KIMS)

The KIMS is a 39-item questionnaire in which respondents rate, on a 5-point Likert-type scale (1 = never or very rarely true to 5 = always or almost always true) their general tendency to be mindful in daily life (Baer et al. 2004). The KIMS was designed to measure four elements of mindfulness: Observe, Describe, Act with Awareness, and Accept without Judgment. Items include, “I notice when my moods begin to change” (Observe); “I’m good at finding words to describe my feelings” (Describe); “When I do things, my mind wanders off and I’m easily distracted” (Act with Awareness—reverse scored); and “I tell myself that I shouldn’t be feeling the way I’m feeling” (Accept without Judgment—reverse scored). Internal consistencies and test–retest correlations (over a 2 week period) range from .76 to .91 and .65 to .86, respectively, for the four subscales. Exploratory and confirmatory factor analyses supported the proposed four-factor structure, and expected correlations with a variety of other constructs were obtained (Baer et al. 2004).

Center for Epidemiological Studies Depression Scale (CES-D)

The CES-D is a 20-item questionnaire in which respondents rate, on a 4-point Likert-type scale (0 = rarely or none of the time (less than 1 day) to 3 = most all of the time (5–7 days) their depression symptoms over the past week (Radloff 1977). Of the 20 items, 4 are positive and are reverse scored. Sample items include, “I felt depressed” and “I had crying spells.” The CES-D has an alpha coefficient of .85 and expected correlations with a variety of other constructs were obtained (Radloff 1977).

Crandell Cognitions Inventory (CCI)

The CCI is a 45-item questionnaire in which respondents rate, on a 5-point Likert-type scale (1 = almost never to 5 = almost always) their depressive cognitions (Crandell and Chambless 1986). Only the 34 negatively worded items are scored, the 11 positively worded items are included as a buffer. The CCI was designed to measure Beck’s (1967) hypothesis that the thoughts of depressed individuals are characterized by negative distortions concerning themselves, the world, and the future. Sample items include, “I’m just a nobody” and “I’ll never be happy with myself.” The alpha coefficient of the CCI in a sample of depressed patients, psychiatric patients, and non-depressed controls was .95 (Crandell and Chambless 1986). Convergent validity was demonstrated by a strong correlation between the CCI and Dysfunctional Attitudes Scale (DAS; Weissman and Beck 1978).

Rosenberg Self-Esteem Scale (RSES)

The RSES is a 10-item questionnaire in which respondents rate, on a 4-point Likert scale (1 = strongly disagree to 4 = strongly agree) their general total level of self-esteem (Rosenberg 1965). The RSES consists of five positively worded and five negatively worded items (the negatively worded items are reverse scored). Sample items include, “I feel that I have a number of good qualities” (positive) and “I wish I could have more respect for myself” (negative). The alpha coefficient for the RSES is .86 (Hudson et al. 2000) and test re-test reliability over a 2-week interval was .85 (Silber and Tippett 1965).

Satisfaction with Life Scale (SWLS)

The SWLS is a 5-item measure that is widely used to represent the cognitive evaluation of subjective well-being (Diener et al. 1985). Sample items include, “In most ways my life is close to my ideal” and “The conditions of my life are excellent.” All items on the SWLS are scored on a 7-point Likert scale (1 = strongly disagree to 7 = strongly agree). The instrument’s internal consistency is adequate (α = .87; Diener et al. 1985) and the test–retest reliability over a 2-month interval is excellent (r = .82; Diener et al. 1985). The SWLS also demonstrates expected correlations with measures of psychological distress and self-esteem (Diener et al. 1985).

Procedure

Potential participants were recruited in undergraduate psychology courses at their institution. Participants completed all study materials in small groups at the time and date they selected when they signed up to participate in the study. All participants completed an informed consent, as well as all of the self-administered materials noted in the Measures section. University IRB approval was obtained prior to data collection.

Results

Analysis Strategy

To test the incremental validity of the KIMS and MAAS relative to self-esteem in the prediction of satisfaction with life and relative to negative cognitions in the prediction of depression symptoms, two hierarchical linear regression models were tested. In the model predicting satisfaction with life, self-esteem was entered at step 1, followed by the MAAS and the four KIMS factors (Observe, Describe, Act with Awareness, and Accept without Judgment) at step 2. In the model predicting depression symptoms, negative cognitions was entered at step 1, followed by the MAAS and the four KIMS factors at step 2. Self-esteem and negative cognitions were utilized as covariates in the prediction of satisfaction with life and depression symptoms, respectively, to ensure any observed effects for the components of mindfulness (as indexed by the MAAS and KIMS) were not due to shared variance with these other variables.

Descriptive Statistics and Zero-Order Relations among Variables

The means, standard deviations, and pattern of zero-order correlations between components of mindfulness and other predictor (covariates) and criterion variables are shown in Table 1. As expected, all components of mindfulness were positively associated with self-esteem: Observe (r = 0.12; p = .027), Describe (r = 0.34; p < .001), Act with Awareness (r = 0.26; p < .001), Accept without Judgment (r = 0.53; p < .001), and MAAS (r = 0.45; p < .001). Similarly, all components of mindfulness (with the exception of Observe) were inversely related to negative cognitions: Describe (r = −0.29; p < .001), Act with Awareness (r = −0.25; p < .001), Accept without Judgment (r = −0.49; p < .001), and MAAS (r = −0.48; p < .001). The components of mindfulness also demonstrated expected relationships with the criterion variables. All components of mindfulness were positively associated with satisfaction with life: Observe (r = 0.13; p = .015), Describe (r = 0.17; p = .001), Act with Awareness (r = 0.17; p = .001), Accept without Judgment (r = 0.38; p < .001), and MAAS (r = 0.31; p < .001). Similarly, all components of mindfulness (again with the exception of Observe) were negatively related to depression symptoms: Describe (r = −0.21; p < .001), Act with Awareness (r = −0.27; p < .001), Accept without Judgment (r = −0.50; p < .001), and MAAS (r = −0.43; p < .001).

Table 1 Descriptive data and zero-order correlations between components of mindfulness and relevant variables (n = 365)
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Components of Mindfulness in the Prediction of Satisfaction with Life and Depression Symptoms

The results of the hierarchical linear regression analyses are shown in Table 2; results are presented based on values at the final step. In the prediction of satisfaction with life, Observe (β = 0.10; p = .034) accounted for a significant amount of variance relative to self-esteem (β = 0.58; p < .001), whereas Describe (β = −0.08; p = .103), Act with Awareness (β = 0.01; p = .847), Accept without Judgment (β = 0.09; p = .091), and MAAS (β = 0.01; p = .813) did not. In the prediction of depression symptoms, Accept without Judgment (β = −0.11; p < .001) accounted for a significant amount of variance relative to negative cognitions (β = 0.74; p < .001), whereas Observe (β = 0.07; p = .093), Describe (β = 0.02; p = .613), Act with Awareness (β = −0.06; p = .103), and MAAS (β = −0.01; p = .814) did not.

Table 2 Hierarchical multiple regression analyses predicting depression symptoms and satisfaction with life from theoretically relevant variables and components of mindfulness (n = 365)
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Discussion

The purpose of the present study was to examine the incremental validity of components of mindfulness beyond other theoretically relevant predictors in terms of satisfaction with life and depression symptoms. Results revealed that only Observe accounted for a significant amount of variance relative to self-esteem in the prediction of satisfaction with life. This was surprising given that Observe evidenced a less robust correlation with well-being compared to the other mindfulness components (i.e., Describe, Act with Awareness, Accept without Judgment, and MAAS) in our study and in previous research as well (Baer et al. 2004, 2006, 2008). Baer et al. (2006) suggested Observe may be sensitive to changes with meditation experience that alter its relationships with other mindfulness components and with related variables, such that it becomes a clear component of mindfulness and related to other variables in expected directions as mindfulness skills develop. Baer et al. (2008) subsequently discovered among experienced meditators (but not among non-meditating college students or educated adults) that Observe is significantly correlated with psychological well-being, but not predictive of it relative to the other facets of the FFMQ (i.e., Describe, Act with Awareness, Non-Judging, and Non-Reactivity) in a sample composed of meditators and nonmeditators. In light of Baer et al.’s (2006, 2008) findings, the results in the present study were rather unexpected. Given that the other four components of mindfulness shared a greater degree of variance with self-esteem than Observe did (i.e., stronger correlations), perhaps when accounting for shared variance in the regression, these predictors no longer made unique contributions to the model. Additionally, there may have been unmeasured characteristics of this particular sample that accounted for these results. Ultimately, future research into the Observe component across different groups and in relation to other variables will help elucidate these conflicting results.

Regarding depression symptoms, only Accept without Judgment accounted for a significant amount of variance relative to negative cognitions. This result supports previous research in which Accept without Judgment was predictive of psychological distress relative to the other facets of the FFMQ (Baer et al. 2006) and posttraumatic symptoms relative to negative affectivity and number of trauma types (Vujanovic et al. 2009). Acceptance of present experience is inherent to most operationalizations of mindfulness (e.g., Germer 2005; Kabat-Zinn 1994) and it is a foundational element of many mindfulness-based interventions, including acceptance and commitment therapy (ACT; Hayes et al. 1999). ACT maintains that the fundamental problem in depression is excessive experiential avoidance (or a lack of acceptance), which is an unwillingness to remain in contact with particular private experiences coupled with attempts to escape or avoid these experiences (Hayes and Gifford 1997; Hayes et al. 1999). The Acceptance and Action Questionnaire (AAQ; Hayes et al. 2004) was developed to measure experiential avoidance, and in support of its incremental validity, Boelen and Reijntjes (2008) discovered the nine-item version of the AAQ remained significantly associated with depression after controlling for neuroticism and thought suppression. Taken together, these results reveal that acceptance of present experience is an important component of mindfulness, and may be central to the prevention and treatment of depression and its relapse.

Overall, when utilizing self-esteem and negative cognitions as covariates in the prediction of satisfaction with life and depression symptoms, respectively, the majority of mindfulness components were non-significant predictors. These results largely failed to replicate previous research in which all facets of the FFMQ (with the exception of Observe) were significant predictors of psychological well-being (Baer et al. 2008) and the MAAS accounted for significant variance relative to positive and negative affect (Zvolensky et al. 2006), pain intensity (McCracken et al. 2007), and perfectionism (Argus and Thompson 2008) in the prediction of depression symptoms. Several possible factors may have accounted for the results in the current study. First, we sought to build on the extant literature by including self-appraisal and cognitive covariates in the prediction of satisfaction with life and depression symptoms. Both covariates accounted for a substantial percentage of variance in each criterion variable—self-esteem accounted for 39% of satisfaction with life and negative cognitions accounted 65% of depression symptoms—providing a very stringent test of the incremental validity of the KIMS and MAAS. Second, although the KIMS was developed to assess four distinct mindfulness skills and the MAAS assesses a present-centered attention that does not appear to be captured by the KIMS (Baer et al. 2004), several strong correlations between these components of mindfulness (e.g., MAAS and Act with Awareness, r = .50), suggests that including all four KIMS factors and the MAAS as simultaneous predictors in the regression models may have been redundant. Third, given the pattern of statistically significant zero-order correlations between facets of mindfulness and the criterion variables, but non-significant regressions after accounting for covariates, it is also possible that self-esteem and negative cognitions may mediate the relationships between mindfulness and satisfaction with life and depression symptoms, respectively.

Nevertheless, these results suggest that the MAAS and most of the KIMS factors may not contribute unique variance in the prediction of satisfaction with life and depression symptoms. In light of the conceptual overlap between various components of mindfulness and theoretically related variables, these results further highlight the importance assessing the incremental validity of measures of mindfulness in addition to analyzing zero-order correlations. For example, in this study Observe evidenced the smallest zero-order correlation with satisfaction with life in comparison to the other KIMS factors and the MAAS; however, in the prediction of satisfaction with life, relative to self-esteem, only Observe maintained a significant relationship.

The results of this study must be interpreted with caution due to several limitations. First, the sample was composed of a relatively homogenous group of college students, thus generalizations beyond this population must be tentatively made. Although some research has supported transporting mindfulness measures into other cultures (Dekeyser et al. 2008), other studies suggest that Western operationalizations of mindfulness may not adequately capture different cultural conceptualizations of this construct (Christopher et al. 2009; Johnson 2006). Therefore, replication with more diverse (e.g., ethnicity, age, education) samples is needed to determine if these results are relevant to different groups. Second, a cross-sectional design was used to test the hypotheses in this study. Future research testing the validity of various operationalizations of mindfulness will benefit from more prospective designs across larger periods of time. Third, the correlational methods employed in this study preclude statements of causality regarding the relationships between mindfulness and theoretically relevant variables. A growing number of researchers have begun investigating the effects of experimentally induced mindful self-focus (e.g., Kuehner et al. 2009), and future studies may benefit by further examining corresponding effects on multiple components of mindfulness and related variables within the same analyses.

With these limitations in mind, we believe these findings have important implications. The recent integration of mindfulness into Western psychology has generated a great deal of enthusiasm, and the preliminary research results are encouraging. In this study we provided a stringent test of the incremental validity of the four KIMS factors and the MAAS. Although Observe was predictive of satisfaction with life and Accept without Judgment was predictive of depression symptoms, overall the findings in this study suggest that components of mindfulness may offer little in terms of predicting satisfaction with life and depression symptoms relative to well-established self-appraisal and cognitive predictor variables.