NEW UPDATE: Completed trials may now upload and register supplementary documents (e.g. null results reports, populated pre-analysis plans, or post-trial results reports) in the Post Trial section under Reports, Papers, & Other Materials.
A randomised controlled trial to evaluate the effects of an online mindfulness intervention on critical thinking performance and dispositions
Last registered on September 14, 2015


Trial Information
General Information
A randomised controlled trial to evaluate the effects of an online mindfulness intervention on critical thinking performance and dispositions
Initial registration date
September 14, 2015
Last updated
September 14, 2015 12:36 PM EDT
Primary Investigator
National University of Ireland, Galway
Other Primary Investigator(s)
PI Affiliation
National University of Ireland, Galway
Additional Trial Information
On going
Start date
End date
Secondary IDs
Mindfulness is often described as a process consisting of two components: present-moment attentional focus coupled with non-reactive monitoring of one’s ongoing experience (Bishop et al., 2004). Despite its origins as a way of cultivating clarity of thought, among the collection of studies on mindfulness conducted in recent years few studies have been concerned with the link between mindfulness and thinking skills in typically developing individuals. Assessments that attempt to capture the thinking skills of people in real-world situations can be found in the body of literature focused on critical thinking (CT; Butler, 2012; Ku, 2009). CT is recognised as an important higher-order cognitive process which involves the ability to analyse and evaluate evidence and arguments without bias from experience and prior knowledge. The application of CT requires a non-automatic response to a problem situation in order to avoid heuristic and biased thinking (West, Toplak, & Stanovich, 2008). Such non-automatic, critical and reflective responses are generally regarded as involving deliberative processes, referred to as Type 2 processes by Dual-Processing theorists (Evans & Stanovich, 2013) and require the engagement of executive functioning i.e. inhibiting, updating, and switching between representations in working memory. While an emerging body of theoretical and empirical work has linked mindfulness with enhanced executive functioning (Chambers, Lo, & Allen, 2007; Josefsson & Broberg, 2011; Tang, Yang, Leve, & Harold, 2012; Teper & Inzlicht, 2013), little is known about the relationship between executive functioning and critical thinking (Sanz de Acedo Lizarraga, Sanz de Acedo Baquedano, & Villanueva, 2012). Furthermore, though mindfulness has been shown to facilitate certain types of higher-order cognition, including insight problem-solving (Ostafin & Kassman, 2012; Wen, Butler, & Koutstaal, 2013), moral reasoning and ethical decision-making (Cottone & Javier, 2007; Ruedy & Schweitzer, 2011; Shapiro, Jazaieri, & Goldin, 2012), the relationship between mindfulness and critical thinking has not been empirically investigated.
In light of these identified gaps in the literature and building on two previous studies carried out as part of the principal applicant’s PhD which suggested links between trait and state mindfulness, executive functioning and critical thinking, the current project seeks to investigate the relationship between regular mindfulness practice, executive functioning, and critical thinking skills and dispositions in the context of a randomized-controlled intervention delivered online using the Headspace app.
Registration Citation
Hogan, Michael and Chris Noone. 2015. "A randomised controlled trial to evaluate the effects of an online mindfulness intervention on critical thinking performance and dispositions." AEA RCT Registry. September 14. https://doi.org/10.1257/rct.756-3.0.
Former Citation
Hogan, Michael, Chris Noone and Chris Noone. 2015. "A randomised controlled trial to evaluate the effects of an online mindfulness intervention on critical thinking performance and dispositions." AEA RCT Registry. September 14. http://www.socialscienceregistry.org/trials/756/history/5241.
Sponsors & Partners

There are documents in this trial unavailable to the public. Use the button below to request access to this information.

Request Information
Experimental Details
Before the intervention begins, potential participants will be invited to take part in a screening to test for previous experiences of meditation and possible confounding pre-existing conditions such as learning difficulties, clinical mental health conditions (including use of the Modified Mini Screen, a validated brief self-report measure that rapidly assesses for present mood, anxiety, and psychotic-spectrum disorders) or use of certain medications/drugs (i.e. those that affect self-regulation and cognition including anti-depressants, anxiolytics and recreational drugs).
Intervention materials will be delivered via Headspace, a commercially available application which runs on all major smartphones, tablets and web browsers. The Headspace meditation scripts are designed by an individual with Buddhist monastic training who guides users through mindfulness meditations and key concepts related to mindfulness meditation using both audio and visual materials. In order to participate, individuals are required to have access to a smartphone or desktop computer with Internet access. Headspace makes meditating accessible by combining technology and simple techniques that are designed for new meditators. Participants can practice at any time of day wherever they prefer. Headspace offers straightforward, guided, bite-sized mindfulness training that is non-religious. We have signed guarantees with Headspace that participant data collected through Headspace will never be sold, distributed, or publicised (except anonymously in scientific publications with Headspace having no involvement in the conduct, analysis, or reporting of the research in any way).
Participants will be sent an email introducing Headspace and describing the sign-up process. To get started, participants are required to register on headspace.com using their name and email address. Each participant will be given a unique code providing free access to Headspace for the duration of the study. It is through the provision of these codes that randomisation will be achieved. This will be done automatically using an online process described below in Section 3. In this way, group allocation will be double-blinded. After registering, participants may begin meditating straight away.
The proposed intervention is 6-weeks in length. Participants will be encouraged to practice meditation daily for the course of the 6-weeks using materials from the Foundation Pack which includes 30 x 10 minute sessions introducing the concept and practice of mindfulness training. Guided throughout, each session gradually builds on the previous one.
Primary and secondary measures will be taken at baseline, at the end of the intervention and at 3 months following the end of the intervention. Manipulation checks will be carried out during weeks 2 and 4 of the intervention. In terms of primary outcome measures, we will assess critical thinking using the Halpern Critical Thinking Assessment (Halpern, 2010) and items from the Heuristics and Biases literature (West, Toplak, & Stanovich, 2008), mindfulness with the Five Factor Mindfulness Questionnaire (FFMQ; Baer et al., 2006), thinking dispositions with the Need for Cognition scale (Cacciopo & Petty, 1982) and the Actively Open Minded thinking scale (Stanovich & West, 1997) and executive function with the Sternberg working memory task (Sternberg, 1975) presented on Inquisit software (Draine, 2004; demo at www.millisecond.com/download/library/Sternberg/). Objective measures of meditation adherence (no. of sessions initiated and completed and no. of minutes spent meditating) will be gathered through the Headspace app. Secondary measures will assess effects on wellbeing in order to compare with previous studies employing Headspace. The Positive Affect and Negative Affect Schedule (Watson & Clark, 1994) and the Warwick-Edinburgh Mental Wellbeing Scale (Tennant et al., 2007) will be used. Manipulation checks will focus on mindfulness meditation quality and task expectations, enjoyment and difficulty. Participants will be asked to complete these measures directly following completion of a meditation exercise. Mindfulness meditation quality will be assessed using the 6 item Practice Quality- Mindfulness questionnaire (Del Re et al., 2013) while task expectations, enjoyment and difficulty will be assessed using the Health Information Technology Acceptance questionnaire (Kim & Park, 2012).
We intend to submit the protocol describing the rationale and procedure for this study to the open access journal BMC Psychology for peer review and publication. When data analysis is complete and the results are written up, we intend to submit our findings to the same journal. All stakeholders (e.g. participants, funding body) will then have full, free access to the protocol, results and peer reviews (as BMC Psychology employs open peer review).

Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Participants will be asked to complete baseline and outcome measures assessing critical thinking, working memory, thinking dispositions such as how much effort one tends to put into thinking and how open-minded one tends to be, mindfulness and wellbeing. These will be completed online, allowing participants to complete them at their convenience. Participants will have the option to save their progress and continue as long as they complete the measures within the same week.

o Halpern Critical Thinking Assessment (Halpern, 2010) – 60 minutes
Involves 25 real-world situations with closed and open questions based on these situations.

o Heuristics and Biases items (West, Toplak, & Stanovich, 2008) – 25 minutes
A series of standard items assessing cognitive biases

o Five Factor Mindfulness Questionnaire (FFMQ; Baer et al., 2006) – 15 minutes
A 39 item questionnaire assessing levels of dispositional mindfulness.

o Need for Cognition scale (Cacciopo & Petty, 1982) – 10 minutes
An 18 item scale assessing tendency to engage in cognitive effort.

o Actively Open Minded thinking scale (Stanovich & West, 1997) – 15 minutes
A 34 item scale assessing tendency to avoid bias, to search actively for evidence against views one already accepts and to weigh such counterevidence fairly.

o Sternberg working memory task (Sternberg, 1975) – 10 minutes
Involves memorising a series of letters and indicating, as quickly and accurately as possible, whether a probe was in this series or not.

o Positive Affect and Negative Affect Schedule (Watson & Clark, 1994) – 10 minutes
Assesses tendency to experience positive and negative emotion.

o Warwick-Edinburgh Mental Wellbeing Scale (Tennant et al., 2007) – 5 minutes
A 14 item scale which covers both hedonic and eudaimonic perspectives of wellbeing.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
This study will employ a randomised-controlled design with two arms. Participants recruited from the School of Psychology undergraduate population will be randomised into either a mindfulness mediation group (experimental condition) or a sham meditation group (control condition). Both groups will take part in a 6-week online/smartphone intervention.
Data will be primarily be analysed through a series of 3 x 2 (time x group) mixed ANOVAs for each outcome measure with mediation analyses conducted using Structural Equation Modelling to test whether executive function, meditation quality and adherence are mediators of any potential relationship between mindfulness and critical thinking. Correlations between manipulation check measures will also be examined as will their correlations with FFMQ change scores.
Experimental Design Details
Randomization Method
Participants will be randomly assigned unique codes which will give them access to either the mindfulness or sham meditation content through Headspace and will act as their unique, confidential identifier for all data collection. Randomisation will be done automatically by computer and the unique codes will be delivered by email automatically.
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
2 groups - mindfulness meditation and sham meditation
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
30 participants per condition
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
The statistical program G*Power was used to conduct power analysis in order to determine the appropriate sample size. Adhering to Cohen's (1988) guidelines for small (r= 0.1), medium (r= 0.3), and large (r= 0.5) effects, two-tailed alpha of .05 was assumed for all tests. With 2 groups, 6 measurements, an assumed correlation among repeated measures of 0.3 (typically low in such research; Weiner, Schinka, & Velicer, 2012) as well as a medium effect size (again typical in research on the cognitive effects of mindfulness; Chiesa et al., 2011) and a power of 0.8, the recommended sample size for mixed (repeated-measures and between factors) ANOVA was 56. As it is recommended that the sample size be a multiple of the number of measurements, a sample of 60 will be sought, 30 per group.
IRB Name
NUI Galway Research Ethics Committee
IRB Approval Date
IRB Approval Number
(15/ Sept/03)
Analysis Plan
Analysis Plan Documents
Hypotheses and Tests

MD5: 04d97c764292f5e78c231f6700bfcfd1

SHA1: 1c1411445559934cd3f1c713f1b2ae8e9d0871c0

Uploaded At: September 14, 2015

Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)