<p><b>Mindfulness, which was derived from Buddhist philosophy and practice, is often defined as “paying attention in a particular way, on purpose, in the present moment, and nonjudgmentally“. The practice of secular mindfulness exercises has received substantial interest in psychology over the last decade and mindfulness-based practices are now widely implemented in clinical interventions. Previous research has identified stable individual differences in mindfulness which are present even in non-practitioners. My research builds on this body of work and explores (i) the current state and directions in the literature on trait mindfulness research; (ii) the relationship between trait mindfulness and established individual differences such as personality and reinforcement sensitivity; and (iii) the cross-cultural applicability of current mindfulness measures.</b></p>
<p> In the first study in this thesis, I used recent developments in bibliometric analysis to examine the development of the field of trait mindfulness, identifying important research areas in this line of work and patterns of cross-national collaboration. I found 1229 documents in the time span from 2005 to 2021 using a search in the Web of Science. Examining the complete corpus of literature that referenced trait mindfulness, I found that current research approaches focus more on clinically relevant outcomes than on potential predictors of mindfulness, which manifested in substantial clusters of themes around well-being and treatment. I also found substantively more articles published by authors working in Western countries than in the majority world. This indicates that research appears to be biased both towards clinical outcomes of mindfulness and skewed towards Western cultural contexts and concerns.</p>
<p>In my next study, I examined the replicability of the Five Facet Mindfulness Questionnaire (FFMQ) to explore whether the same five major dimensions of mindfulness emerge in a different sample 15 years later. The FFMQ contains five facets: Non-Judging (non-evaluation of thoughts and feelings), Non-Reacting (ability to not act on negative thoughts and emotions), Acting with Awareness (awareness of self in the moment), Describing (labelling and expressing experiences), and Observing (awareness of sensory experiences). Following the overall protocol of the original study and using a range of currently available mindfulness measures, I found that the facets of the FFMQ could largely be retrieved in this conceptual replication. In addition, new measures of “Western” mindfulness were empirically separable from measures based in Buddhist conceptualizations. This supports the use of multi-facetted mindfulness measures to capture self-reported mindfulness.</p>
<p> In the second part of my thesis, I focused on potential individual-level predictors of the facets of mindfulness. In Study 3, I joined two previously separated lines of research by jointly examining the relationship between mindfulness, reinforcement sensitivity, and personality. In contrast to previous studies, I found that the facets of mindfulness might be differentially related to supposed biological (reinforcement sensitivity) and cognitive (personality) individual differences while accounting for their overlap. Specifically, Neuroticism, which in past studies was related to Non-Judging and Non-Reacting, was only related to Non-Reacting. In turn, Non-Judging was predicted by behavioral inhibition, but Non-Reacting was not.</p>
<p>In Study 4, I moved from cross-sectional analyses to a 4-month longitudinal investigation, using recent advances in modelling to separate within and between-individual relationships. In contrast to the cross-sectional investigation, I found a more complex pattern of relationships, including potential feedback loops between individual differences and mindfulness. Specifically, I found that the expression of supposed biological differences in long-term orientation predicted individuals’ level of awareness, but in turn higher awareness also predicted greater long-term orientation. This provides a tentative mechanistic explanation of the link between Acting with Awareness and health-behaviors identified in previous studies.</p>
<p> In the third part of the thesis, I focus on the applicability of mindfulness measures across cultures. As indicated above, mindfulness emerged in Eastern contexts but is currently studied in Western societies. Hence, I test how well the FFMQ as the gold standard of mindfulness trait measures performs across cultures. To provide a toolkit for cross-cultural researchers, I present a synthesis of standards for cross-cultural comparisons and developed a proto-type of an R-package that implements various methodological advances and analytical tools. In the final study, I applied these tools to examine the suitability of the FFMQ for cross-cultural comparisons across 16 countries. Overall, I found that the FFMQ is substantially biased towards higher income and more individualistic contexts and shows substantial variation across cultures. This finding implies that the FFMQ might not be suitable in its current form for cross-cultural comparisons, possible due to cultural differences in the understanding of Acting with Awareness, which in an exploratory study is separated into awareness of mind and body. This indicates that additional research is necessary to ensure the cross-cultural comparability of mindfulness and to advance research.</p>
<p> In my general discussion, I explore both methodological and conceptual avenues for future research in trait mindfulness. Returning to questions of individual differences in mindfulness, I highlight how recent advances in network modelling might allow researchers to untangle the differences in between and within-individual relationships observed in this thesis. I present some evidence of the application of network models from research on personality, to highlight the usefulness of this technique for future research on mindfulness. Focusing on cultural differences in structure and functionality, I review various lines of research that indicate that mindfulness-like features may be found in various cultural contexts, but may be differently experienced and expressed, as indicated by my psychometric examination of the FFMQ. I outline how researchers taking a functionalist approach might link current mindfulness approaches with different philosophical and cultural approaches to enrich the nomological network and present initial evidence on these relationships.</p>
Observed correlations from cross-sectional individual differences research reflect both between-person and within-person correlations
