Thesis title: Mechanisms of Mindfulness: integrating empirical findings and Buddhist perspectives
SUMMARY
Background. In our research project we set out to advance the understanding of (neuro)cognitive psychological mechanisms modulating the effects of mindfulness meditation, a meditation practice stemming from a 2500 years old Buddhist practice. While accumulating findings indicate positive outcomes of mindfulness practice on mind, body, and brain, still little is understood about how the practice of mindfulness brings about such effects. In response to
this gap in scientific understanding, we systematically reviewed the literature and empirically tested two candidate mechanisms. We looked at cognitive flexibility from a behavioral perspective, and at self-referential processing in brain activity patterns using EEG. Given the number of positive reports on the effects of mindfulness practice, our hypotheses were driven by existing literature evidencing that both notions play an important role in mental health. High levels of self-referential processing feature a vast majority of mental disorders, while the same holds for mental rigidity. Both cognitive flexibility and self-referential processing have been associated with mindfulness practice and seem therefore promising candidates for furthering generic mechanistic understanding of mindfulness meditation.
Study A: Cognitive flexibility. Objective changes related to the investment of attention and cognitive flexibility, and subjective changes in levels of mindfulness (FFMQ; Baer et al. 2008) and well-being (PFI; Joseph and Maltby, 2014), were assessed following a six days’s intensive mindfulness. We expected improvements on both objective and subjective measures relative to the control group. We anticipated that the use of a novel range of behavioral tasks implemented as mobile applications would make a useful methodological contribution to the field as well. Significant differences were found between the meditation and the control group in self-reported mindfulness, and well-being. In contrast, performance on behavioral measures- simple reaction time, sustained attention (MOT), task switching, inhibition of automatic responses (Stroop) and visual foraging - did not improve relative to the control group. Since most cognitive behavioral tasks are susceptible to practice effect (Goldberg, Harvey, Wesnes, Snyder, and Schneider, 2015), this indicates that observed improvements in the experimental group were the result of practice effect.
Study B: Systematic review of self-processing and mindfulness. Empirical findings in mindfulness research were systematically reviewed, focusing on studies that examined the relationship of mindfulness practice with (neuro) cognitive and psychological self-processing. Our findings suggested associations of mindfulness meditation (state), and dispositional mindfulness (trait) with self-referential processing, based on three consistent observations across disciplines: Mindfulness is associated with (1) a decreased reliance on verbalization during mindful awareness; (2) a more neutralized, less self-invested emotional processing, and (3) altered activity in the default mode network associated with self-referential processing. Our observations lend support to the operational framework of the self that was proposed by Farb et al. (2007), distinguishing an experiential mode of self (ES) and a narrative mode of self (NS) (Farb et al., 2007).
Study C: Self-referential processing. Using Electroencephalography (EEG), we measured brain activity before and after a six-day retreat, using an adaption of an established paradigm that evokes narrative and experiential self-processing (Herwig, 2010; Lutz et al. 2016). Selfreported measures assessing levels of mindfulness (FFMQ; Baer et al. 2008), positive affect (PFI; Joseph and Maltby, 2014), rumination and reflection (RRQ; Trapnell and Campbell,
1999), and interoceptive awareness (MAIA; Mehling et al. 2012) were also administered. EEG data were submitted to a multivariate pattern analysis though backwards decoding. This approach is relatively novel, as well as assessing pre to post retreat changes in self-referential processing through EEG. Our findings corroborate previous reports on dissociated neural patterns underlying the experiential and narrative mode of self, indicating the ability to volitionally engage in different mind states in our experimental group. Contrary to our expectations, we found less articulate dissociations between neural patterns in the THINK (narrative self) versus FEEL (experiential self) states following the retreat. Our findings further indicate that the resting mind was most affected by meditation. Participants may thus have developed increased aptitude to switch accurately between a default resting mind and the more meditative experiential mind state. Improved ability of switching between mind states suggests increased degrees of freedom as to what engages the mind. Further analysis should clarify the specific dynamics of the reported changes also in relation to self-report measures and relative to data obtained from the control group.
Discussion. While subjective measures showed expected significant changes following the retreat, changes in objective measures were not supportive of our hypotheses. Changes in habitual (self) processing may happen on a larger timescale than was provided by our experimental design. Therefore, such changes may not yet have been detectable immediately after the retreat. Following a recently proposed explanatory framework of mechanisms of meditation, based on Karl Friston’s Free Energy Principle, it is argued that influence of mindfulness meditation practice on habitual processing is directly related to cognitive flexibility and the ability to volitionary allocate attention. In addition, such changes may be evidenced by changed neural activity patterns corresponding to changed engagement patterns in the narrative and experiential mode of self. Further elaboration of the proposed explanatory framework is recommended. Future studies are encouraged to include such framework, as well as employing a combination of neuroimaging techniques, behavioral measures and phenomenological reports. And, ideally, employing a timeframe that allows for the consolidation of the hypothesized habitual changes.