Two and a half millennia after the elaboration of mindfulness within Buddhism, it should be possible to bring a considerable array of investigative methods to bear on questions posed in the previous chapter. These include what mindfulness is and how it affects the mind and body. For instance, if mindfulness is a distinct state of consciousness, it should be relatively straightforward to describe its characteristics in the same neurophysiological terms that have permitted differentiation of the various states of bodily and mental arousal associated with the different stages of sleep. Psychological science should be able to assist in the identification and measurement of experiences that characterize mindfulness, as well as clarifying what the consequences of the continued practice of mindfulness are likely to be.
Mindfulness & Brain changes
The history of electrophysiological investigation of meditative states is a long but frankly disappointing one. The research has been scattered, methodologically inconsistent and poorly controlled. When reviewers comment on findings specific to ‘mindfulness’, they may be using the term idiosyncratically rather than in a way that makes for reliable comparison between one study and another. A huge amount of electrophysiological research on meditation took place in the 1970s and 1980s because of the popularity and claims of transcendental meditation (TM). This is a mantra-based meditation that is usually accompanied by states of deep relaxation. Classifiers of meditation tend to put it firmly in the category of ‘concentrative’ practices (e.g. Goleman 1988) on the basis of its subjective qualities. There was a need to distinguish TM’s central effects from those of relaxation, and, despite counterclaims that it could not be associated with consistent findings (e.g., Pagano et al. 1976; Stigsby et al. 1981), it was widely associated with an increase in coherence on EEG recordings of frequencies in the alpha and theta ranges (e.g. Dilbeck and Bronson 1981; Gaylord et al. 1989). Such findings are not unique to TM, and Cloninger (2004) attributes changes of this kind to a state he terms ‘mindfulness’. Cloninger points out how, in distinction from the alpha domination of drowsiness and the increasing beta activity that comes with ordinary wakefulness, higher conscious states are associated with co-occurring multiple frequencies, as well as greater coherence on the EEG trace. His state of ‘mindfulness’ is characterised by slow alpha (7-9 Hz) with theta in frontal cortical areas alongside less beta activity than in ordinary wakefulness. He also links these to early studies of changes in cerebral blood flow that suggest that mindfulness meditation is associated with greater blood flow to all three surfaces of the frontal lobe and the thalamus. He suggests that the former is consistent with inner focusing of attention and the latter to widespread if non-specific cortical activity.
Certainly, the most striking physiological findings in meditation research come from studies of experienced practitioners, when differences between aficionados of different traditions become more apparent. Probably the most famous – and suggestive – study to be conducted was Kasamatsu and Hirai’s (1966) investigation of Soto Zen monks in Zazen meditation. As their meditation progressed, there was a tendency for alpha waves to increase in amplitude and then decrease in frequency, before theta waves appeared and grew in amplitude. The changes are more pronounced in monks of long experience (there was a subgroup with over 20 years’ experience in their sample). Some of the most experienced meditators were subjected to a further investigation in which their responses to 20 clicks repeated at 15-second intervals were recorded and analysed. The finding that they failed to respond to repeated clicks by habituation of automatic responses, such as momentary blocking of alpha frequencies, seemed to suggest this was a demonstration of how, as a result of their training, they reacted to each stimulus as if they were hearing it for the first time. The experiment appeared to be a scientific demonstration of the ‘beginner’s mind’ that is widely associated with mastery of Zen. (As noted in the previous chapter, this aspect of Zen is also reminiscent of mindful awareness.)
Tantalisingly, the study has never been satisfactorily repeated. An attempt to do so with TM meditators and yoga meditators of several years’ experience showed both to habituate in ways comparable to untrained controls (Becker and Shapiro 1981). Even Zen meditators of seven and a half years’ experience habituated – although, unlike the Soto monks, they meditated with their eyes closed! In reviewing the episode, Austin (1998) maintained that the monks in the original study were probably entering states of deep absorption that meant their brains were blocking the clicks, and any other external stimuli, at the subcortical level. However, Kasamatsu and Hirai’s original report includes descriptions of the Zen masters’ own experience during the investigation:
[They] reported to us that they had more clearly perceived each stimulus than in their ordinary waking state. In this state of mind one cannot be affected by either external or internal stimulus, nevertheless he is able to respond to it. He perceives the object, responds to it, and yet is never disturbed by it . . . . One Zen master described such a state of mind as that of noticing every person one sees on the street but of not looking back with emotional curiosity.(Kasamatsu and Hirai 1966: 593)
Until a true replication is carried out, it seems impossible either to interpret the findings definitively or judge how relevant they are to the long-term impacts of mindfulness meditation.
Recent work with eight subjects having extensive experience of an objectless Tibetan meditation, in which their only action was to open themselves to feelings of pure compassion, has produced distinctive findings of a different kind (Lutz et al. 2004). It has involved careful analysis of rhythmic activity at faster frequencies than have usually been studied in previous work – the gamma range is around 40 cycles per second. While resting, these meditators were found to have significantly greater gamma-band activity relative to slower activity than controls. This difference was greatly exacerbated during meditation periods. Examination of the power of the gamma activity, and the distances separating scalp electrode sites between which synchrony was evident, showed that both increased with the meditators’ experience. Such long-distance synchrony is usually interpreted as the consequence of transient functional reorganisation in the brain, as neurons start to operate as a synchronised assembly rather than independently of one another. The implication is that, with the accumulation of meditative experience, a capacity for this organisation to occur over greater and greater areas develops. Lutz et al. report that gamma activity of the magnitude they report has not been seen in any other non-pathological group, meditators or non-meditators, while conceding such fast frequencies have not always been analysed in other studies. All future physiological studies of meditation clearly need to do so. In relating this work to other studies, observations that the raised gamma activity was most evident at prefrontal cortex and the insula are likely to be relevant.
In moving to mindfulness meditation, there are probably only three studies demonstrating sufficient clarity about the subjects’ practice for them to be acceptable as studies of mindfulness rather than any other kind of practice. All are relatively recent. In the first, Dunn et al. (1999) set out to define electroencephalographic differences between relaxation, ‘concentration’ and ‘mindfulness’ meditations. Relaxation was equated with sitting comfortably with eyes closed; concentration was meditating while maintaining attention on the movements of the breath; mindfulness was allowing the attention to wander freely between events presenting to it, aiming to experience them clearly, and sometimes simultaneously labelling perceptions as ‘seeing’, ‘hearing’, feeling’, etc. Concentration sessions would always take place while seated; mindfulness was practised while sitting and while walking. The 10 student subjects learned the two techniques in sequence (concentration before mindfulness) over 10 weeks. They continued some practice in concentration as they were learning mindfulness, but sessions and homework were tailored so that, by the end of training and prior to the crucial EEG recording sessions, they had an equal exposure to each (around 30 hours). EEG recordings were then conducted in all three conditions – the students indicating the depth of their experience in response to regular verbal prompts throughout the recording periods.
Comparisons were made between the three conditions in examining the distribution of activity across the scalp in each of five frequency bands. The plots of differences in activity during concentration compared to mindfulness showed significantly greater activity during mindfulness of four kinds: delta (left occipito-parietal and bilateral prefrontal); theta (left frontal); alpha (bilateral occipito-parietal), and beta 1 (i.e., 13-25 Hz) (left frontal and bilateral occipito-parietal). The fifth condition examined, termed beta 2 (25-37 Hz) by Dunn and colleagues, fell within the slowest part of the gamma spectrum. The picture there was much more mixed. Concentration recordings showed more activity over the occipital pole bilaterally, whereas at the frontal poles, there was significantly greater activity on the left during mindfulness and significantly greater activity on the right during concentration. There were also scattered areas of significant activity differences in parietal and right temporal locations at this frequency – with greater activity during mindfulness each time.
Dunn and colleagues (1999) felt the consistency of the differences here to be impressive, even if the findings during the mindfulness periods were counterintuitive at first glance. (Changes in slow-wave activity and fast-wave activity are usually complementary, rather than conjoint as here.) They reasoned that ‘the brain is calm and relaxed, thereby producing more delta and theta waves, but is simultaneously awake and alert, thereby producing more alpha and beta 1 activity’, so that ‘the brain’s electrophysiological response . . . coincides with the meditator’s subjective report’. Dunn et al. believe their work is significant in resolving contradictions within the extensive literature on TM, where disparate and apparently contradictory findings all belong within the range of observations made within their study. This suggests that TM has had elements of both concentration and mindfulness, and they urge future researchers to study one or the other rather than continuing to confound the two. They also encourage others to continue to look at qualitative differences alongside quantitative measurements in future research.
The second notable study on mindfulness meditators was also a study on novice meditators. This time, mindfulness training was through participation in the full 8-week training of Jon Kabat-Zinn’s mindfulness-based stress reduction (MBSR). (Davidson et al. 2003) have undertaken a controlled study of the impact of an 8-week MBSR programme on brain activation. Here, ‘activation’ was assessed by computer analysis of electrical activity (brain electrical activity mapping), to monitor selectively the spectral power density of frequencies in the alpha range (8-13 Hz). This is inversely proportional to the activation, with alpha activity being seen on a standard EEG when activation is not present. In the frontal lobes of the brain, asymmetrical activation, favouring one side more than the other, is consistently associated with specific mental states in the neurophysiology literature. For instance, greater left-sided activation has been associated with positive emo-tion. It has also been associated with enhanced immune function (measured in terms of natural killer cell activity), the other para-meter in Davidson’s study.
The brain activation and immune function of volunteers was assessed prior to commencement of MBSR, on completion of the course, and a further four months later. Sample records were always taken immediately after standard procedures to induce temporarily a positive mood and a negative mood. Immune function was assessed through influenza antibody titres. Results from the 25 subjects were compared with those of 16 controls. They did not differ significantly at the outset. The MBSR students differed from controls post-course, and at 4-month follow-up, with respect to greater anterior left-right asymmetry during both positive and negative mood induction. Their antibody titre was also significantly greater at these time points. When the variation within the sample was examined, a strong positive correlation between asymmetric activation and raised antibody titre was found, suggesting that frontal activation was directly linked to the improved immune response. Analysis of the distribution of the asymmetric activity found this to be stronger close to the midline rather than in the prefrontal region, as had been predicted.
Rather than speculate on the implications for localisation, Davidson noted the failure of these students to demonstrate significant improvement in positive affect as a possible reason why they did not show prefrontal differences also to the expected extent. An interesting observation is contained in a different report on the study (Goleman 2003: 345). The participants agreed to keep a record of their practice during the training period. These were not disclosed to Jon Kabat-Zinn, the instructor and co-researcher, until the sessions were concluded to ensure he was blind to this. Analysis of the post-MBSR brain activation and immunity status showed no correlation whatever with the time spent in mindfulness practice out of the training sessions. It is difficult to interpret this without independent corroboration of how ‘mindful’ each subject became. As it stands, the study could suggest that differences in post-training results reflected some students’ greater capacity to switch into mindfulness during other tasks, rather than the impact of formal practice. Or it could support a contention that other variables, such as expectancy, are more important than practice of either kind in predicting outcome. Most of Davidson’s other work on asymmetries of frontal activation has benefited from the higher resolution of functional magnetic resonance imaging (MRI). It will be extremely interesting to see how closely the variations within the EEG results are replicated in a functional MRI version of this study.
The third study, also controlled, has also attracted a good deal of press attention. Unusually, it was an anatomical, rather than a physiological, study, in which a possible link between the thickness of brain cortex and meditation experience was examined. The subjects were teachers and students of ‘insight’ meditation, characterised as `mindful attention to internal and external stimuli’ (Lazar et al. 2005: 1894). They had all attended retreats as well as practising regularly, with a minimum of 2 and an average of 9 years’ experience. Because the subjects varied in the intensity of their practice, an additional measure to years of experience was used as an index of total meditative experience. This was respiration rate while sitting, which has been shown to decrease progressively with meditation experience in other studies. Measurements of cortical thickness for the 20 meditators were compared with 15 controls having no experience of meditation or yoga. The meditators’ cortices were consistently thicker in several areas, in either hemisphere, but not thicker than the controls’ cortices overall. Detailed com-parisons were undertaken in areas hypothesised to be more likely to demonstrate effects from the existing literature and from the meditation’s emphasis on sensory experience. These showed clear differences bilaterally in the prefrontal cortex (Brodmann areas 9 and 10) and around the right insula (including an area of auditory cortex). While differences in thickness were less clear across the groups at the right prefrontal cortex than the left, they were directly related to subjects’ age. The older the subject, the greater the in-subject difference, suggesting that meditation might not be adding to the thickness here so much as preventing a thinning process that otherwise occurred naturally with age.
The study’s other principal finding came from correlations between cortical thickness and meditation experience. Although these were not found in the prefrontal cortex, there was a part correlation with insular thickness after correcting for age, and a strong correlation only at an area of the inferior occipitotemporal visual cortex. Although the cross-sectional nature of the study compromises attempts to infer causality from these associations, it is being taken as evidence that meditative attention excites neuronal growth in brain areas likely to be activated in the course of meditation. No comparable studies have been conducted on practitioners from other meditative traditions. Assuming the findings can be replicated, it is unclear how specific they are to mindfulness meditation.
Measuring mindfulness with self-report questionnaires
Although at least seven questionnaires have been devised and undergone validation as measures of mindfulness, currently only three are published and properly in the public domain, with another being freely circulated. All attempt to provide some assessment of individuals’ mindfulness from their responses to a paper self-report form. They differ significantly in their range of use, content and output.
Mindful Attention and Awareness Scale (MAAS)
The Mindful Attention and Awareness Scale (MAAS) (Brown and Ryan 2003) is a 15-item self-report questionnaire that has been widely distributed. The questions concern capacity to maintain attention and withstand distraction and were progressively selected from a huge pool on the basis of their lack of ambiguity, acceptability and discrimination. None of the questions refer to or are influenced by particular techniques of enhancing attention or awareness, in line with the authors’ interest in exploring natural variation in ‘mindfulness’ irrespective of its origins. As it enquires about how well attention is maintained in some circumstances (e.g., while walking, eating or driving), and how far actions are under-taken automatically, it has high face and content validity for this construct. Responses to it yield a single score for capacity to maintain awareness. Scores have been shown to be greater among Zen meditators than non-meditating controls, but a study of medical patients designed to compare MAAS scores before and after MBSR training found no significant difference (Brown and Ryan 2003). This does not necessarily apply to other contexts, the authors proposing that the lack of change reflected unexpectedly high baseline scores that may be typical of this client group. (Personal communications from other oncology professionals do suggest that present moment awareness is spontaneously enhanced among terminally ill people.)
Although the MAAS has been criticised for a perceived failure to measure a capacity for acceptance or non-judgment alongside attention and awareness, this was a deliberate decision. When working with a larger pool of candidate items for the scale, Brown and his colleagues found the correlation between scores for items reporting acceptance and those reporting attention was extremely high, as was the trend for them to move up or down in tandem. They found acceptance could be reliably inferred from the score for attention and awareness and did not need separate consideration.
Toronto Mindfulness Scale (TMS)
The Toronto Mindfulness Scale (TMS) of Bishop et al. (2003) is quite different in nature and purpose. It set out to operationalise mindfulness as a state of mind reached through formal practice, so that apparent benefits following mindfulness-based interventions could be related directly to their psychological impact. Intended specifically for use with people suffering from emotional disorders, it was meant to check subjects’ ability to prevent cognitive elaboration of experience as well as to maintain continuity of attention. It is designed to be filled in shortly after a mindfulness meditation session, and items refer specifically to experiences while attempting to meditate. The TMS is a compact scale of 10 items, which refer to recent awareness of internal sensations or thoughts, and the degree of reactivity that was shown toward these. The items were selected from a larger pool of candidate items as those that best discriminated experienced meditators from people with little or no experience of meditation. Factor analysis has confirmed that the items load to a single construct and the scale is scored to produce a single figure that, as an expression of mindfulness achieved in situ, could be taken as a measure of adherence to the meditation method. As befits a state measure, scores have been shown to fluctuate from session to session, with an overall tendency to rise according to experience. The instrument is currently unique as a method of assessing the direct contribution of (meditative) mindfulness practice in attainment of psychological change.
Kentucky Inventory of Mindfulness Skills (KIMS)
The Kentucky Inventory of Mindfulness Skills (KIMS) (Baer et al. 2004) was conceived within a different tradition of mindfulness training. The ‘skills’ referred to are primarily those identified by Marcia Linehan within the mindfulness training module of dialectical behaviour therapy. Four constructs that are prominent in mindfulness coaching within this model – observing, accepting without judgement, describing, and acting with awareness – have guided the initial selection of items, with further adjustments designed to minimise overlap between the sub-scales for each. A 39-item questionnaire has resulted that assesses each of these in terms of everyday habits of mind. It can therefore be used to assess aptitudes prior to any training in mindfulness skills, as well as to assess changes once this has been undertaken.
Freiburg Mindfulness Inventory (FMI)
The Freiburg Mindfulness Inventory (FMI) (Buchheld et al. 2002) is another self-report measure that yields a single score, although its conceptual structure is relatively complex. Choice of its 30 items was guided by experienced vipassana meditators’ views of what mindfulness is. They were placed by the authors under four headings following a factor analysis: ‘present-moment disidentifying attention’; ‘non-judgemental, nonevaluative attitude toward self and others’; ‘openness to negative mind states’; and ‘process-orientated, insightful understanding’. The FMI is longer established than the other measures here, and the scope of its questions is broader than in any other instrument. The first of its factors is itself broad and, as its title suggests, actually embraces items that would usually be seen now as indicative of distinct facets of mindfulness. The acuity of awareness (as in ‘I sense my body, whether eating, cooking, cleaning or talking’) and non-reactivity (as in ‘I watch my feelings without becoming lost in them’) sit side by side within this factor. Unlike the other scales, the FMI deliberately includes features that are assumed to increase as a consequence of attaining greater ‘mindfulness’ rather than being components of it. (This accounts for most items under the scale’s other three subheadings.) The FMI has been shown to discriminate clearly between experienced and inexperienced meditators, but it may not recommend itself so easily to those researchers who would see the links between attentive processes and their consequences as a subject for further investigation, rather than as something that a measure of mindfulness should assess at the same time.
Some interrelationships and complementarities between these measures will be evident from these descriptions. Important questions arise about how far the scales do measure the same things, and, collectively, how well they reflect the semantic scope of ‘mindfulness’. Ruth Baer (2006) has investigated these questions by a comparative study of five questionnaires, in which they were jointly administered to a large sample of students. This allowed study of the intercorrelation of scores from the different instruments as routinely applied, as well as factor analysis of the pooled items from all the questionnaires. The questionnaires concerned were the FMI, MAAS and KIMS as well as two unpublished measures. These were a 12-item ‘Cognitive Affective Mindfulness Scale’ (CAMS), reportedly very similar in structure and scope to the KIMS, and a 10-item Mindfulness Questionnaire (MQ), developed for use with patients with psychosis, which reportedly emphasises reactivity to negative experiences. The Toronto Mindfulness Scale was not included in the published study. This has meant that the available item pool had a heavy weighting toward items from the KIMS and the CAMS, instruments that place the naming of experiences and acting with mindfulness on a par with aspects such as the immediacy of awareness or being accepting.
Factor analysis led to a five-factor solution, initially accounting for only 33 percent of the variance. (The low proportion of the total variance here may be partly explained by the lack of medi-tation experience among the sample.) This structure informed the selection of those items having the highest exclusive correlation with each of the five factors, to yield a new composite 39-item instrument, the Five Factors Mindfulness Questionnaire (FFMQ). These factors were observing, non-judging, non-reactivity, describing and acting mindfully. This is essentially the same structure as Baer’s own KIMS, with the addition of ‘non-reactivity’. There are no items from the KIMS in this non-reactivity subscale, which is indebted to the FMI and MQ for its questions about being untroubled and undistracted by negative experiences. However, inspection suggests that differences between this subscale and the non-judging one may reflect the use of terminology in the KIMS, which dominates the latter, rather than substance. Unlike the FMI, the KIMS tends to enquire about reactions to experiences in terms of making judgements following them, rather than about accepting them. Items from the MAAS retained within the FFMQ were weighted almost exclusively on the ‘acting mindfully’ factor, alongside some further items from the KIMS.
These details are mentioned because the history of this apparently comprehensive instrument’s development is important when appreciating areas of possible weakness. Baer (2006) has subsequently gone on to use the FFMQ in a much-needed study of experienced meditators. In an ambitious series of investigations, she has attempted to link meditative experience to measures of psychological functioning, and to facets of mindfulness, and to seek evidence for the mediation of any associations between meditation and psychological functioning by mindfulness. Her sample this time has included very experienced mindfulness practitioners – 19 percent having 10 years or more experience. However, although all of the facets assessed by the FFMQ correlate with at least some of the indices of positive psychological functioning that were used, the data linking meditation experience to aspects of mindfulness were quite unequivocal. Only observation and non-reactivity showed truly robust associations with meditation experience. Stratification of this sample according to their reported experience has permitted a preliminary analysis of how far attainments on either observation or non-reactivity correspond to meditative experience. It appears from this that observation steadily improves in quality from the start of training, whereas non-reactivity is a later development. There are, of course, inherent limitations to this kind of cross-sectional survey, which can be reduced by observing how a pre-identified set of practitioners change over time through a planned series of assessments.
It is worth commenting a little further here on the content validity of these measures – that is, whether they appear to measure what they are supposed to from the questions they ask – in the light of the examination of mindfulness. There are certainly kinds of experience that are mentioned there, and that are traditionally associated with mindfulness, that are encountered only in the FMI. These include feeling tranquil and being curious about what is happening (with respect to emotions and actions, if not sensations). The FMI is also the only instrument to mention some aspects of what Shapiro et al. (2006) would classify as ‘attitude’, such as ‘friendliness’. There are still other ways in which the content of the FMI differs from other instruments. It pays considerable attention to respondents’ relationship to their own thoughts through items such as `2. I know that I am not identical to my thoughts’. While this kind of item does not appear in any other instrument, even the FFMQ, it is a precise description of one of the two things Kabat-Zinn reports being most valued by his students (Salzberg and Kabat-Zinn 1997). Curiously, the other consequence that Kabat-Zinn reports as being most valued does not figure in any of the instruments! It is subtle and best expressed in his own words:
They have a new-found awareness of the special quality of breath that relates to a greater sensitivity and awareness of their whole body. Along with the breath comes a sense of greater appreciation for the miracle of having a body, even if the body has a disability. Each breath, each moment, is a miracle, and when you begin to experience that directly, it vitalizes the quality of your life.(Salzberg and Kabat-Zinn 1997: 141)
If the FMI’s 30 questions manage to tap a relatively broad range of practitioners’ experience, this may reflect both its origins in wide consultation with experienced meditators, and the relative unimportance of theory in determining its structure.
Baer’s most recent work, despite giving constructs such as ‘mindful action’ or ‘describing’ a generous opportunity to establish their place, seems to confirm instead that the two most measurable aspects of mindfulness using self-report scales correspond to maintaining an open, present awareness (observing) and an accepting attitude (non-reactivity). This is consistent with a ‘proposed operational definition’ devised by members of a well-established research group in Toronto (Bishop et al. 2004). Baer has been able to compare the scores on these two dimensions from the FFMQ across her sample of experienced meditators when it is stratified according to their experience. This indicates that the quality of observation grows progressively in the expected direction from early in a meditator’s practice, while there is usually no change in non-reactivity until an initial lag period has been completed (Baer 2006). The likelihood of such a difference should generate prospective studies, in which a cohort of starting students is followed up at regular intervals, as this is the only reliable way to obtain an accurate picture of the dynamic relationship between these factors.
Unfortunately, it remains unclear what the most sensitive way of measuring them may be. Among the traditionally published questionnaires, it is only the oldest instrument, the FMI, that contains many items that correspond to each of these factors. Within its own structure, however, they are not clearly distinguished. All of the items that have become indicators of ‘nonreactivity’ in Baer’s FFMQ come under ‘present-moment disidentifying attention’ in the FMI. The four items signaling ‘observing’ in the FFMQ are divided evenly between ‘present-moment disidentifying attention’ and ‘openness to negative mind states’ on the FMI. In summary, if it is slightly clearer what the questions need to be to tap these two dimensions of mindful experience, much work remains to devise an instrument whose internal structure is clearly preferable to any alternative.
Recent studies are producing some confirmation that, whatever else it is, mindfulness appears to represent a capacity that can be coached and that usually follows a developmental curve. In order to assess where somebody may be on such a trajectory, it is essential to have a reliable set of images not of mindfulness as a single capacity, but as something that may have distinct properties as someone acquires more experience with it. People belonging to either end of this spectrum may, operationally, appear to have very little in common, as the neurophysiological studies reviewed at the start of the chapteroperationalize seemed to suggest.
Understanding mindfulness through qualitative research
Two things are evident to date from efforts to research the impacts of mindfulness-based interventions, especially MBSR, by quantitative methods. One is that, for any study that links practice of MBSR to a given outcome, evidence will be needed that this apparent effect results from subjects becoming more mindful as a result of the MBSR intervention. Many of the early studies contained no ‘marker’ of mindfulness that would serve this purpose, while there has been a good deal of activity recently to introduce and validate scalar self-report measures that could have this function. However, attempts to objectify ‘mindfulness’ by reducing it to elements such as skills in receptivity, sustained attention, awareness of internal sensations, awareness of other sensations or thoughts, acting mindfully, being non-judgemental, and so forth only highlight a lack of consensus about what it is to be ‘mindful’ – as well as indicating possible limits imposed by a need to quantify the result.
In general, qualitative research can be helpful in several ways when scoping a (psychological) research area. Done well, it will, first of all, indicate the range of experiences that are likely to be encountered when investigating an area. Secondly, it will indicate how much variation in the findings arises through idiosyncrasy. Thirdly, it can help to account for such variation by its ability to contextualize the content of individuals’ reports in terms of life circumstances or other individual factors, permitting explanation. Fourth, by indicating elements that are common across individual accounts, but which may require redescription, it can help to shape a conceptual framework and thereby contribute to the theorisation of a topic. Individual studies are now being performed in order to understand the needs of, and likely impacts on, specific client groups when undertaking interventions like the MBSR programme (e.g. Mason and Hargreaves 2001). However, the continuing failure to utilise qualitative research methods in the articulation of mindfulness within psychology remains, in my view, mindless.
As an illustration of the potential of qualitative research, I shall draw on an exploratory study I conducted some years ago based on a single focus group with six people with an active mindfulness practice. The five women and one man all had significant personal experiences of mindfulness teaching and practice. The discussion was recorded by audio tape, and a full transcript made for subsequent analysis. The discussion was organised around four questions, discussed by the group in turn. At each stage, members were encouraged to illustrate their comments with personal experience. The four guiding questions were:
- What makes an experience mindful?
- How does practice of MBSR reduce `stress’?
- How does mindfulness develop over time?
- Are there any negative consequences of mindfulness practice?
It should be said the process of the group was, in itself, remarkable. Some members were known to others, but there was an impressive curiosity concerning all the contributions that were made. Occasionally, a member’s observations did not chime with others’ experience, but this would be noted with respect and interest and an absence of argument. Although the question sequence had been prepared beforehand, only the first question was explicitly asked in advance of the group taking it up for discussion. For the other three questions, the group moved seamlessly through the sequence, being advised when they had anticipated the next question, while continuing to contribute occasional observations on earlier questions as they went on reflecting during the session. At the end of the discussion, the members expressed considerable appreciation of what they had heard and learned from each other.
Another comment is essential. At the time of the study, I remained personally naive to the literature that is being quoted throughout this book, with the exception of three practice-focused books. There was no wish to box or categorise the findings according to prevalent theories of mindfulness, including those I have summarised from the traditional literature. Accordingly, at the time of the study, it was necessary to coin some neologisms to describe phenomena that were clearly salient but unnamed in the discussion, rather than borrow terms from other contexts. In summarising it here, I have also not changed any of the terminology that arose within those original analyses.
The transcript was subjected to more than one analysis. In the first, the questions were used to organise the members’ comments as responses to one or more of the questions – a thematic content analysis. The themes this identified were aggregated into larger themes when there was demonstrable overlap, before their relative salience was assessed through the frequency with which they appeared as verbal comments and the extent to which they stimulated affirmative comments from other group members. This has been written up in detail elsewhere (Mace 2006), but a brief summary follows, highlighting its implications for the present discussion.
Characteristics of Mindfulness
In addressing the first question, `What makes an experience mindful?’, all of the contributors retrospectively recognised continuity between experiences that had been part of mindfulness training, and others that had preceded these. The commonest example of this was yoga, but two of the participants with musical experience spoke with feeling and in detail about the performance and practice of (Western classical) music as a meditative and mindful practice. Another participant had experience of the Alexander technique and saw this as cultivating a mindful attitude through its emphasis on awareness. In discussion, the participants were encouraged to discriminate between the characteristics of a `mindful’ experience, and other kinds of meditative experience that, in their experience, were not truly mindful. This was a productive move, helped by the participants having a variety of other meditative experiences on which to draw. These were not investigated in detail, but half the group referred to prior experience with the mantra-based technique of TM. This helped the following distinctions to be drawn:
- Mindfulness as inclusive awareness. In comparison with TM, mindfulness meditation led to a sense of expanded awareness that embraced many domains – not only mental and physical sensations but the room in which meditation was taking place.
- Mindfulness as retaining a sense of self. The sense of self was not attenuated to the extent it had been for those who had participated in other meditations and experienced a loss of personal agency during them. There was not complete consensus on this point.
- Mindfulness specifically includes the body. One participant felt this was the crucial distinction between mindful meditation and other meditations (including TM); the others agreed.
Five more characteristics of mindfulness emerged as members thought about what, for them, made an experience ‘mindful’:
- single-minded attention to what was present to the exclusion of anything else
- an equanimity that accompanies this attention
- a suspension of attempts to control the experience, or letting be
- disidentification from thoughts – the sense that a thought can be changed and can be let go of was felt to be an especially helpful aspect of mindfulness practice
- being able to rely on spontaneous actions in everyday life.
Reducing stress with mindfulness
The thing members of this group most clearly shared had been experience of MBSR. And there was no doubting that they each found themselves better able to deal with stress in their personal lives. The topic was raised in the discussion in order to discover how they did this in practice. Participants referred to experiences of psychological stress, especially fear, even more than experience of somatic pain. A wide range of pain experiences were cited, from coping with dental pain to chronic pain. Removal of fear was emphasised in this context. In discussion of situations where an illness was potentially terminal, stress was identified most closely with the fears of not knowing what would happen and of dying. The specific techniques that members used to reduce stress when faced by situations reflected different aspects of mindfulness. A participant who had emphasised the value of realising that thoughts were just thoughts commented on the value of this in reducing stress. Under more extreme threats, there would be a reappraisal of priorities, which brought with it a determination to value each moment. The specific techniques used in straightforward circumstances, such as the dental chair, involved deliberate attention to the breath and to sensations in the body using the ‘body scan’ of MBSR. In facing unnerving situations with other people, a technique falling outside standard MBSR teaching was cited that instilled positive feelings in place of fear prior to meetings. Participants confirmed that their preparedness grew with continuing practice of mindfulness techniques.
Progressive effects of mindfulness
Like its application in the face of stress, other aspects of mindfulness might be expected to deepen with practice and cumulative experience. The discussion identified some that appeared only to emerge as the result of sustained practice. One group of these were closely interrelated, being ways in which the experience of mindfulness spread beyond its initial, intended scope. I called them aspects of the ‘permeation’ of mindfulness, a term used and appreciated during the group’s discussion. Permeation was seen in an infiltration of mindfulness across an increasing range of activities of daily living, but also in a progressive growth in the continuity of awareness throughout the day and in the increasing spontaneity of mindful experience, such that it arose more and more without deliberate intention.
The other emergent aspects of mindfulness to be reported were a new sensitivity to others (a sense of being more sensitively attuned to them, which was also increasingly recognised by those other people) and a range of positive feelings that participants appeared to experience more regularly. These feelings included an unshakeable sense of trust in life, a deepening (but light-hearted) compassion, and a sense of profound love. These were spoken about as if they were far from incidental, but were now core to the participants’ experience of mindfulness. At the same time, there was a sense that mindfulness could not and should not be about doing things, but was simply about being with life as it happened.
Negative consequences of mindfulness
In the final stage of the discussion, and only then, were comments about possible negative consequences of mindfulness practice invited. In response, participants either recounted experiences when they were new to formal mindfulness practice, or when they had meditated intensively in a retreat setting. The initial problems were in the form of discomfort and, more interestingly, of living with the guilt of failing to live up to their own resolutions and expectations. There was also an admission of intolerance of others who were unwilling to take up mindfulness practice when it seemed likely to help them. Subsequently, members volunteered some ambivalent feelings about becoming acquainted with more difficult aspects of their personality in the course of practice, and about calling a halt on cherished projects as a greater realism set in. However, the consequences of these realisations did not appear to have been sources of serious or lasting regret. Difficulties were consistently spoken of as a challenge that needed to be embraced with equanimity within further practice. Negative experiences from participation in intensive retreats were more acute. Two members described vivid perceptual alterations that had been short-lived – and apparently responsive to being made the object of mindful attention.
In keeping with good practice in qualitative research, I had abstained from detailed examination of relevant literature until coding and analysis of the transcript had been completed. Subsequent comparison of the group members’ reports with the current literature on the assessment of mindfulness indicated which aspects of their experience were most remarkable – at least in relation to the aspects of mindfulness that quantitative research had already highlighted.
Of the six qualities that prompted subjects to see an experience as ‘mindful’, both inclusiveness and single-mindedness are consistent with statements that mindful attention is non-selective and fully engaged. The qualities of ‘equanimity’ and ‘letting be’ appear to reflect the ‘acceptance’ or ‘non-reactivity’ that is now emerging as a constituent of mindful attention (Bishop et al. 2004; Brown and Ryan 2004). The remaining observations concerning `disidentification from thoughts’ and ‘spontaneous actions’ indicate areas that have also been recognised in some attempts to operationalise mindfulness, but not others. Disidentification from thoughts was being described in terms identical with its description in the FMI and the TMS, or indeed the concept of cognitive ‘decentering’ (Safran and Segal 1990) on which items of the latter were based. Spontaneous action is close to the skill of ‘acting mindfully’ that Linehan (1993a) emphasised and that was intentionally represented in the KIMS, CAMS and FFMQ (and probably, in practice, in the MAAS).
Many of the comparisons these participants made between other meditative experiences and mindful ones are also reflected in the literature on psychological mindfulness. Although group members spoke about mindful awareness as embracing all forms of experience, including awareness of external as well as internal objects, it will be clear from the descriptions provided previously that self-report measures differ considerably in the range of experience they enquire about. However, all of the mindfulness scales that were reviewed do include reference to awareness of body sensations. As these were the most ‘mindful’ kind of focus the group recognised when differentiating meditative experiences as mindful from their content, that emphasis seems sound.
The group’s members had little difficulty in responding to the invitation to differentiate between aspects of their experience that are quickly realisable (‘common’) and those that emerge with the passage of years (‘emergent’). Until the very recent questionnaire-based studies summarised above, the impact of previous practice on the experience of mindfulness has been relatively unexplored in questionnaire-based studies, despite the considerable evidence of its importance from the studies of neurophysiology and psychological functioning cited elsewhere in this chapter. When the existing scalar measures have been deliberately designed to differentiate between experienced and inexperienced practitioners, they have done this by identifying mindfulness skills that were expected to be common to all practitioners, but could become more developed with experience. The FMI is notable in attempting to do this, thereby including many items that have been interpreted as the consequences of mindful practice, rather than integral to mindfulness.
The FMI has several items on positive attitude to self (e.g., ‘I am friendly to myself when things go wrong’), while the MAAS, FMI and TMS have items corresponding to different aspects of what I have labelled ‘permeation’. All three invite observations on the range and continuity of attention, but only the FMI appears able to tap the spontaneity of mindful experience (e.g., ‘I experience moments of inner peace and ease, even when things get hectic and stressful’). `Attunement to others’ remains as a characteristic recognised by members of the focus group that does not feature in any of the principal mindfulness measures. (Among the scales, only the FMI makes any reference to other people. This is a single item which checks how far the respondent becomes impatient with others.) As one of the criticisms that have been made of mindfulness-based therapeutic approaches is their apparent neglect of personal relations (e.g., Horowitz 2002), this seems an omission of strategic as well as descriptive importance.
Apart from relating, it was the more emotional aspects of mindfulness, as experienced by this group, such as emergent love and compassion, that had least place in any of the scalar measures. Conversely, the FMI also includes elements that were not prominent in this group’s discussion, nor in the content of other scales. Examples include transience (‘I am aware how brief and fleeting my experience is’) and metacognition (‘I consider things from different perspectives’; ‘I pay attention to what’s behind my actions’). Interestingly, these items have been among those least able to find a stable place within that scale’s internal factor structure (Buchheld et al. 2002), suggesting either that, when they do occur, they are somewhat accidental and unnecessary aspects of mindfulness – or that they may themselves be emergent aspects, likely to be found with increasing experience, that were not picked up in this exploratory qualitative study.
In terms of the systematic study of mindfulness, this exercise, despite its many limitations, has at least one implication that cannot be ignored. This is that proper qualitative exploration of the range of the phenomenon under study needs to precede and to underpin attempts to derive validated scalar measures. This is good practice in other fields of psychological research: it is ironic just how much it has been ignored in investigations of this most introspective phenomenon.
In addition, more detailed coding was undertaken in order to explore the hidden structure of the conversation in more depth by techniques borrowed from grounded theory (Strauss and Corbin 1990; Charmaz 2001) in a finer grained, ‘bottom-up’ approach. This identified themes in the material irrespective of the questions that had guided the discussion. Units (nodes) of meaning were identified whenever the content of conversation could be labelled by a concept mentioned by one of the speakers, yielding 88 distinct nodes. Their semantic relationships were then explored with the assistance of a dedicated software program (NVivo 2.0) (Gibbs 2002), leading to their arrangement within a progressive, hierarchical structure. When nodes could not be completely subsumed under others, they would be grouped under more abstract, axial nodes within a tree structure. Progressive reiteration identified an implicit internal structure for the group’s conversation, orientated around three independent axial nodes near the top of the tree structure: mindfulness, illness, and self/identity. These subsumed every other theme.
By continuing the investigation to its logical conclusion, according to the rules of procedure of ‘grounded theory’ (Charmaz 2001), it was possible to identify a single, implicit construct lying at the apex of the conceptual hierarchy. All of the discussion’s content was in effect an elaboration of this central theory. The construct that emerged was ‘embodiment’.
Apart from its implications for future quantitative investigations, what does an exploratory study of this kind tell us? The first, thematic analysis is sufficient to indicate that more qualities were being identified with ‘mindfulness’ than the questionnaires had acknowledged. A single group discussion is unlikely to be exhaustive in this respect. A full study should subject groups of different participants drawn from the same population to the same process until a new group fails to produce any new themes. Only at this point, termed ‘saturation’, is it reasonable to conclude that the groups have provided an adequate exploration of the scope of ‘mindfulness’. It is possible that, by doing this, additional observations, such as metacognition and friendliness, which have been incorporated into items on the FMI, would be added to the pool. Or they may not come into the pool, even when saturation is reached, because they express a way of understanding mindfulness that is not represented here, with the possibility that there are irreducible differences between one population’s experience of mindfulness and another’s. (The plausibility of this is evident from the distinctiveness of Ellen Langer’s work. This presents a non-Buddhistic conception of `mindfulness’ that equates it exclusively with metacognitive skills such as seeing a problem from many sides (cf. Langer 1989). Even within the range of usage being considered in this book, Shapiro et al.’s (2006) formulation of mindfulness as the resultant of intention and attitude, as well as attention, would make consistent differences more likely, as both intention and attitude are likely to differ from one training system to another.)
If mindfulness has a particular flavour that is common to practitioners of, say, MBSR, but that is not shared by practitioners of, say, vipassana meditation, then the second, grounded theory, mode of analysis provides a way of articulating the difference in terms of the core focus of either practice. It remains to be seen whether the centrality of embodiment holds for all mindful practices, or whether it is characteristic of MBSR. The specifics of MBSR will be covered more fully in the next chapter, alongside some other widely used ways of bringing mindfulness into clinical practice. Since I inferred embodiment to be the central theory of the group’s discussion from these analytic procedures, nothing in my subsequent experience of MBSR has seemed inconsistent with its being the organising principle of that method.
The psychological impact of mindfulness
The need for a truly satisfactory measure of mindfulness is growing, now that tentative evidence is amassing to challenge Bishop’s (2002) observation that there is no objective evidence that mindfulness training has its effects because trainees’ mindfulness increases. Work seems likely to continue on its mediating role between mindfulness training and observed clinical effects, and into different psychological factors that change subsequent to mindfulness training. However, these risk being pressed into the service of explaining why mindfulness might have a particular effect through a particular process, rather than a more fundamental enquiry into the nature of the overall psychological change mindfulness might bring about. If the traditional theories examined have any basis, these effects are likely to be very wide-ranging, influencing many aspects of experience at the same time. One way in which this has been expressed, in both classical Buddhist literature and modern psychology, is in terms of mindfulness meditation reversing the mind’s conditioning.
A pioneering investigation of this was undertaken by Brown and Engler (1986) in the 1970s. The intention was to compare mental functioning as it was manifest in perceptual and cognitive processes by getting meditators to respond to the kind of projective psychological tests used in the analysis of personality and psychic conflict in the 1960s and 1970s. These were to include the famous Rorschach test, in which a series of 10 ink-blot s are presented with an invitation to give free associations to them. Brown and Engler used three subject groups: American meditators attending an intensive 3-month retreat, very experienced American meditators whose practice was rated by teachers as ‘deep’, and a group of Burmese meditators and their teachers. The latter were included as all were said to be in a recognised state of enlightenment. (They are a most interesting group, in that far from being monks, all the students were wives or mothers whose enlightenment experience came within 3 years of starting meditation and whose retreat experience was typically much less than that of the American ‘beginners’.) Before any analysis of their performance on projective testing, the sample was classified, not according to their background or known meditative experience, but by an assessment of their level of meditative attainment. For this, the following five stages of attainment were identified (consistent with previous theoretical studies by Brown): beginners, concentration (samadhi) group, insight group, advanced insight group, and masters (this last occupied by a single teacher from the South Asian sample). The classification of each student was made through a combination of consensus between at least two expert teachers, and the student’s answers to questions from a scale previously developed by the investigators (and now unobtainable), the Profile of Meditative Experience (POME). This inventory contained no fewer than 600 questions, apparently culled from classic manuals like the Visuddhimagga (Buddhaghosa 1999) as well as the training provided to contemporary teachers of meditation. These comprised signposts of people’s meditative attainment, allowing them to be placed in one of the above categories on the basis of their reported experiences.
The result was that the largest group, beginning students, divided into 15 who remained beginners after a 3-month retreat, 13 who were seen as attaining concentration but not insight, and only three who had attained the direct ‘insight’ necessary for admission to the third stage. These three were distinguished from their co-retreatants by having at least 5 years’ previous meditative experience. The other eight Americans who were invited to join the study by virtue of the recognised depth of their experience divided equally into the `insight’ and ‘advanced insight’ groups after assessment. The only member of the master’s group was from South Asia. All the other South Asian participants, despite the relative brevity of the experience of most, were categorised as having ‘advanced insight’ after assessment. Apart from raising important questions about the relative amenability of this meditative tradition to people from different cultures, the other nine Burmese participants made no active contribution to the study. Despite the labour that went into translating the POME into the participants’ home language, the authors felt the difficulties of `cross-cultural Rorschach interpretation precluded reporting of their test results.
This may appear to be an unfortunate decision, as the quite detailed reports provided on the performances of other participants are remarkable, with clearly discernible and apparently consistent differences according to group membership. The Rorschach tests of retreatants who remained in the beginners’ group did not meaningfully differ from the tests they had completed prior to the retreat. Those who entered the concentration group made responses that were notable for their ‘unproductivity and paucity of associative elaborations’. They complained that the investigators’ demands that they associate in an elaborative way would take their energy and require the reassembly of perceptual layers that had broken down. At the same time, they were acutely aware of the physical features of the ink-blot , seeing it as an ink-blot , and commenting on its shape, colour and textures. If they did respond to the invitation to elaborate with other images, these were reported as being very fluid and quickly changing, while the subject would be curious about the internal process through which this was happening.
The Rorschach tests from the ex-retreatants and invitees that made up the insight group were remarkable for their ‘increased productivity and richness of associative elaborations’, as if there was a freeing up of associative processes and the subjects’ imaginations. As these subjects talk freely and metaphorically about the blots’ characteristics and the emotional responses these induced, the authors note how the developing narratives were always very responsive to what can be seen, commenting on this as evidence of the subjects ‘enhanced reality attunement’. The narratives could have a very life-affirming content, while, when subjected to the interpretative techniques ordinarily used to rate the tests, showing evidence of personal psychological conflict over sexual or aggressive impulses.
The small ‘advanced insight’ group yielded three Rorschach tests that the authors found to be different again, yet very consistent. They are described as apparently more ordinary than the previous two groups at first sight. While they are productive as in the insight group, it is in a less divergent way, and this is combined with an attention to physical characteristics and perceived movement reminiscent of the concentration group’s responses. What marks them out, however, is a repeated tendency by three of the four subjects in this group to ‘perceive the ink blots as an interaction of form and energy or form and space’. This means that the ink-blot would be seen as energy or space rather than as ink, while the subjects were commenting about the perception having distinct but interrelated levels. Their comments about energy and space would relate to the form of the inkblots, but be elaborated in a discourse about their systemic relationships to other energic or spatial entities in a world where matter is seen as movement. The authors comment here too from a conventional psychological perspective on the subjects’ unusually undefended attitude to depictions of personal difficulties that would ordinarily be the source of much internal conflict.
The only Rorschach test from a ‘master’ was also the only one considered from an Asian subject. At no point did he talk about the ink blot as anything other than a projection of the mind. Furthermore, having no prior experience of the test, the master used the 10 ambiguous images to produce a cogent discourse on the Buddha’s teaching concerning the ending of human suffering that linked all of the images in the sequence in which they had been presented. Accordingly, the early cards portrayed different kinds of suffering, and midsequence ones the mental habits that perpetuate it, before the later cards became depictions of the process of liberation and its freeing consequences. Throughout, the master incorporated features of each blot in the choice of images for his narrative, being particularly sensitive to gradations of shading.
Projective tests have fallen into general disfavour as a means of psychological diagnosis. Their interpretative schemes have been very dependent on psychoanalytic theory, and their very ambiguity raises concerns about reliability when used in clinical testing. However, instruments such as the Rorschach blots, or the pictorial story stems used in the Thematic Apperception Test that Murray and Morgan developed in the 1930s, provide methods of eliciting projected mental contents in research contexts independent of any interpretative schema. If mindfulness has an impact on the organisation of perceptual experience, there seems no reason why instruments of this kind should not be used in further studies across other samples of Western meditators encompassing a broader range of experience and accomplishments.
All four kinds of study that have been examined here – physiological, questionnaire-based, qualitative, and projective – currently suffer from a similar problem. Inconsistencies in methods, sampling or both mean that none can yet claim to demonstrate what that methodology is likely to reveal about mindfulness when investigated under optimal conditions.
Our understanding of mindfulness can be assisted by scientific investigations in several ways. Attempts to link mindfulness with specific brain states should be helped by advances in the resolution of functional imaging techniques. They have been limited by a lack of clarity in the discrimination of different meditation-related subjective states. It is also evident from empirical studies that ‘mindfulness’ is not static. Its apparent characteristics reflect at least the length (and probably the intensity) of an individual’s practice. Further work is required to distinguish the psychological features that are intrinsic to mindfulness and those that represent its sequelae. There are reasons to suspect that `mindfulness’ is not necessarily a unitary phenomenon, even if progressive effects are taken into account. As there could be irreducible differences between one system of training and another, further qualitative investigations should be helpful. Attempts to devise scales that measure mindfulness have been hampered by the failure to take practitioners’ experience into account, as well as a collective reluctance to inform their design by exploratory qualitative studies into the range of relevant phenomena. More work on each of these apparently disparate frontiers is needed if the future scientific investigation of mindfulness is to be coherent and productive.
References and Further reading on Science of Mindfulness
1. Goleman, D. (1988) The Meditative Mind. New York: Putnam.
2. Stigsby, B., Rodenberg, J. and Moth, H. (1981) Electroencephalographic findings during mantra meditation (transcendental meditation). A controlled, quantitative study of experienced meditators. Electroence-phalography and Clinical Neurophysiology, 51, 434-42.
3. Pagano, R., Rose, R., Stivers, R. et al. (1976) Sleep during transcendental meditation. Science, 191, 308-10.
4. Dilbeck, M. and Bronson, E. (1981) Short-term longitudinal effects of the transcendental meditation technique on EEG power and coherence. International Journal of Neuroscience, 14, 147-51.
5. Gaylord, C., Orme-Johnson, D. and Travis, E. (1989) The effects of the transcendental meditation technique and progressive muscle relaxation on EEG coherence, stress reactivity and mental health in black adults. International Journal of Neuroscience, 46, 77-86.
6. Cloninger, C. (2004) Feeling Good: The Science of Well-Being. New York: Oxford University Press.
7. Kasamatsu, A. and Hirai, T. (1966) An electroencephalographic study on the Zen meditation (zazen). In Altered States of Consciousness (3rd edn) (originally published in Folio Psychiatrica and Neurologica Japonica (1966), 20, 315-36) (ed. C. Tart), San Francisco: HarperCollins, pp. 581-95.
8. Becker, D. and Shapiro, D. (1981) Physiological responses to clicks during Zen, yoga and TM meditation. Psychophysiology, 18, 694-9.
9. Austin, J. H. (1998) Zen and the Brain. Cambridge MA: MIT Press. Bach, P. and Hayes, S. H. (2002) The use of acceptance and commitment therapy to prevent the rehospitalisation of psychotic patients: a randomized controlled trial. Journal of Consulting and Clinical Psychology, 70, 1129-39.
10. Lutz, A., Greischar, L., Rawlings, N. et al. (2004) Long-term meditators self-induce high-amplitude gamma synchrony during mental practice. Proceedings of the National Academy of Sciences of the United States of America, 101, 16369-73.
11. Dunn, B., Hartigan, J. and Mikulas, W. (1999) Concentration and mind-fulness meditations: unique forms of consciousness? Applied Psychophysiology and Biofeedback, 24, 147-65.
12. Davidson, R., Kabat-Zinn, J., Schumacher, J. et al. (2003) Alterations in brain and immune function produced by mindfulness meditation. Psychosomatic Medicine, 65, 564-70.
13. Goleman, D. (1988) The Meditative Mind. New York: Putnam.
14. Lazar, S., Kerr, C., Wasserman, R. et al. (2005) Meditation experience is associated with increased cortical thickness. Neuroreport, 16, 1893-7.
15. Brown, K. and Ryan, R. (2003) The benefits of being present: mindfulness and its role in psychological well-being. Journal of Personality and Social Psychology, 84, 822-48.
16. Bishop, S., Lau, M., Shapiro, S. et al. (2004) Mindfulness: a proposed operational definition. Clinical Psychology: Science and Practice, 11, 230-41.
17. Baer, R. A., Smith, G. and Allen, K. (2004) Assessment of mindfulness by self-report: the Kentucky Inventory of Mindfulness Skills. Assessment, 11, 191-206.
18. Buchheld, N., Grossman, P. and Walach, H. (2002) Measuring mindfulness in insight meditation (vipassana) and meditation-based psychotherapy: the development of the Freiburg Mindfulness Inventory (FMI). Journal of Meditation and Meditation Research, 1, 11-34.
19. Baer, R. (2006) Meditation, mindfulness, and psychological functioning in a sample of experienced meditators. In 4th Annual International Conference on Mindfulness in Medicine, Health Care and Society. Worcester, MA.
20. Shapiro, S. L., Carlson, L. E., Astin, J. A. et al. (2006) Mechanisms of mindfulness. Journal of Clinical Psychology, 62, 373-86.
21. Salzberg, S. and Kabat-Zinn, J. (1997) Mindfulness as medicine. In Healing Emotions: Conversations with the Dalai Lama on Mindfulness, Emotions and Health (ed. D. Goleman), Boston, MA: Shambhala, pp. 107-44.
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23. Mace, C. (2006) Long-term impacts of mindfulness on psychological wellbeing: new findings from qualitative research. In Dimensions of Well-Being (ed. A. delle Fave), Milan: FrancoAngeli, pp. 255-69.
24. Brown, K. and Ryan, R. (2004) Perils and promise in defining and measuring mindfulness: observations from experience. Clinical Psychology: Science and Practice, 11, 242-8.
25. Linehan, M. M. (1993a) Cognitive-Behavioral Treatment of Borderline Personality Disorder. New York: Guilford.
26. Horowitz, M. (2002) Self- and relational observation. Journal of Psychotherapy Integration, 12, 115-27.
27. Buchheld, N., Grossman, P. and Walach, H. (2002) Measuring mindfulness in insight meditation (vipassana) and meditation-based psychotherapy: the development of the Freiburg Mindfulness Inventory (FMI). Journal of Meditation and Meditation Research, 1, 11-34.
28. Strauss, A. and Corbin, J. (1990) Basics of Qualitative Research: Grounded theory Procedures and Techniques. Newbury Park, CA: Sage.
29. Charmaz, K. (2001) Grounded theory: methodology and theory construction. In International Encyclopedia of the Social and Behavioural Sciences (eds N. Smeser and P. Baltes), Amsterdam: Pergamon, pp. 6396-9.
30. Gibbs, G. (2002) Qualitative Data Analysis: Explorations with NVivo. Buckingham: Open University Press.
31. Langer, S. (1989) Mindfulness. Cambridge, MA: Da Capo.
32. Shapiro, D. (1992a) Adverse effects of meditation: a preliminary study of long-term meditators. International Journal of Psychosomatics, 39, 62-6.
33. Brown, D. and Engler, J. (1986) The stages of mindfulness meditation: a validation study. In Transformations of Consciousness (Also in Journal of Transpersonal Psychology (1980), 12, 143-92) (eds K. Wilber, J. Engler and D. Brown). Boston, MA: Shambhala, pp. 161-91.34. Buddhaghosa, B. (1999) Vissudhimagga or the Path of Purification (trans. N. Thera). Seattle, WA: BPS Pariyatti Editions.