Putting claims about mindfulness meditation to the strongest test

Mindfulness meditation has become a mainstream technique in the toolkit of psychologists, but its efficacy in non-clinical settings is unclear. In our recent study published in BMC Psychology and registered in the ISRCTN registry, we carefully designed a methodologically robust study to test the effectiveness of mindfulness meditation on critical thinking.


It is fair to say that mindfulness meditation has become a mainstream technique in the toolkit of psychologists and others working in various settings across the world. It has made its way from clinical environments, such as the hospital or therapy room, to our schools, our workplaces and our universities. But what evidence is there for its usefulness in these different contexts?

Moving away from clinical environments has meant moving away from a reliance on clinical effects to justify the implementation of mindfulness meditation interventions. Now, mindfulness meditation is not only linked to decreased stress and relapse of mood disorders, it is also claimed that mindfulness meditation results in better relationships, more prosocial behaviour, higher job satisfaction, more focused attention, greater memory skills and improved critical thinking.

But, how strong is the evidence for these claims? Take the research on relationships and pro-social behaviour – a recent meta-analysis demonstrated that evidence for these benefits falls away when studies use stronger methods.

Mindfulness meditation and cognition

Many of the other claims regarding the benefits of mindfulness meditation relate to cognitive ability. These claims can be divided into those pertaining to lower-order cognitive functions, such as perception, attention and automatic responses (as Nobel laureate Daniel Kahneman would say, thinking fast), and higher-order thinking skills such as problem-solving, decision-making and, in general, critical thinking (or thinking slow).

Since mindfulness, as it is taught in Western psychology, relies heavily on cultivating acceptance, it may have a negative effect on the tendency to think critically.

We were particularly interested in the claims that mindfulness may benefit critical thinking for two reasons. One, critical thinking is a hugely important set of skills to cultivate in society so it is important that we understand whether interventions aimed at improving critical thinking work.

Second, there is a potential paradox within the claim that mindfulness may facilitate critical thinking. Since mindfulness, as it is taught in Western psychology, relies heavily on cultivating acceptance, it may have a negative effect on the tendency to think critically. Critical thinking fundamentally requires not accepting information without questioning it. Interestingly, a cross-sectional study we conducted showed both positive and negative effects of the tendency to be mindful on performance in a critical thinking task.

We followed this up with a lab-based experiment on the effects of a single guided mindfulness meditation in comparison to a guided sham meditation – something that sounded like mindfulness meditation but without the specific instructions on how to control your attention. In this experiment, there was no overall benefit of being randomised to the mindfulness meditation group. However, those in the mindfulness meditation group who were less disposed towards putting effort into critical thinking and those who were less open-minded did experience some improvement in critical thinking performance.

Testing effectiveness of mindfulness meditation on cognition

Our latest paper published in BMC Psychology describes the strongest test of claims regarding mindfulness and critical thinking thus far. Across 6 weeks, we tested tCollege studenthe effects of regular mindfulness meditation against the effects of engaging in a sham meditation – listening to a recording which was ostensibly a guided mindfulness meditation – among a sample of university students. We focused on students not just out of convenience but also because a report on the integration of meditation practices in to higher education had suggested doing so would improve critical thinking among students.

Ninety students were randomly assigned to either the mindfulness meditation group or the sham meditation group. Importantly, neither the students nor the researchers were aware of which group the participants were in, and the participants were under the impression that both conditions involved equally effective meditation techniques. In other words, the study was a randomised controlled trial with a double blind methodology which was also pre-registered.

We were able to achieve this rigour by partnering with Headspace, a company which produces the world’s most popular mindfulness mediation app. This allowed us to collect objective adherence data and meant that our method of delivering the guided meditations was ecologically valid, since apps are one of the most popular ways of learning to meditate. We even got Andy Puddicombe, co-founder of Headspace, to record our sham meditation script.

This allowed us to collect objective adherence data and meant that our method of delivering the guided meditations was ecologically valid, since apps are one of the most popular ways of learning to meditate.

The outcome measures of primary interest in this study were mindfulness, executive functioning, critical thinking and two dispositions towards critical thinking – actively open-minded thinking and need for cognition. According to theories in cognitive psychology which focus on fast and slow thinking, known as dual process theories, executive function is the mechanism through which responses generated through fast thinking are inhibited which allows slow thinking, such as critical thinking, to occur.

Our results did not support the claim that regular mindfulness meditation practice improves critical thinking. We found that both mindfulness meditation and sham meditation resulted in equal improvements in critical thinking over the course of the study. Therefore, there was no effect specific to the practice of mindfulness meditation. We believe that there are a number of possible explanations for this finding.

Our results did not support the claim that regular mindfulness meditation practice improves critical thinking.

It is likely that the improvement in both groups can be attributed to a mixture of demand characteristics (i.e. participants changing their responses in line with what they expect the study results to be) and a placebo effect. In relation to the mindfulness outcome measure, it is also possible that the mindfulness questionnaire we used is not sensitive enough to detect changes.

The psychometric properties of this and many other mindfulness questionnaires are questionable and it is probable that the best we can hope to measure with such questionnaires is “perceived mindfulness”. In general, there is a great need for improvement in the methodological quality of mindfulness research, particularly in terms of measurement and experimental control.

In summary, there have been many unsupported and unchallenged claims regarding the supposed benefits of mindfulness practice, as it is taught in Western psychology, and a big industry has been built on the shaky foundation of these claims. We have demonstrated that it is possible to identify these claims and apply rigorous research methods to determine whether they are supported or not. Mindfulness research must continue to use randomized control trials, double blinding, and objective measurements of adherence and outcomes of the intervention for claims regarding mindfulness practice to be taken seriously.

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If people have already learnt how to practice mindfulness meditation (before participating in this study), then I would expect those individuals could benefit from even sham meditation sessions (as they already know how to meditate without instructions). So, I would expect ceiling effects.


Relating to my earlier comment, the recent mindfulness randomized controlled trial (Published in ‘Lancet Public Health’) has controlled for baseline scores [ref:
Galante, J., et al. (2017). A mindfulness-based intervention to increase resilience to stress in university students (the Mindful Student Study): a pragmatic randomised controlled trial. The Lancet Public Health.]

James Godwin

Thanks for this. Valuable insights. I get loads of requests from businesses asking if the results of a mindfulness practice is measurable. They ask, what is the ROI. Very difficult to quantify.

Ted Meissner

The “sham” meditation, as noted in the paper itself, may be too close to “real” meditation. Having read the script for it, I concur — the sham wasn’t a sham at all, it was a mindfulness of breath meditation. There was also un-moderated progression of exercises in the “real” group, which I would expect served to offset gains as it was too much change during the limited time frame. So you had one group being able to really go deep with one practice, and another that was constantly changing.

Note that the authors have been very up-front about the known constraints of the study, but didn’t appear to consult with experienced mindfulness teachers (i.e., the people who could see additional problems with the study and suggest solutions prior to implementation). It’s like doing a cardiac study without any cardiac docs involved.


Why did this study use a control group that also engaged in meditation? I think a ‘health education class’ alternative would have been a better control group. In physical activity trials, they almost always use a wait-list control group – not sure why this standard has to be more stringent when it comes to mindfulness trials.

wayne pocklington

Firstly the author if the above seems to have a strange view on some of the concepts if meditation. Acceptance in regards to meditation means to accept the state or reality of things as they are in the moment so we are able to see and understand them more clearly. It has nothing to do with accepting any old nonsense someone tells us, thus hindering critical thinking. Secondly, I note that one study lasted six weeks and then looked for results in specific area. Six weeks is far to short a time to expect significant or any results. Maybe try doing a study of people who have practiced meditation for a year or more, every day.


That same line caught my attention as well. It seems to suggest that acceptance necessitates ascribing a truth value to a statement – i.e. ‘My acceptance implies it must be true’ without any further questioning. I would have thought it’s more like ‘I accept (thus overcoming automatic bias) the existence of multiple perspectives (the what is)’. This might trigger a decision to attempt a resolution using tools such as critical thinking.

I agree that involvement of experienced practitioners would help provide clarity to this pretty fundamental point.