Table 1 Study hypotheses

Primary

Mindfulness

Five Facet Mindfulness Questionnaire

1

Mindfulness will increase more for the mindfulness meditation (MM) group than for the sham meditation (SM) group from t₁ to t₄

Mixed ANOVA

Critical Thinking

Halpern Critical Thinking Assessment¹, Heuristic and Biases items²

2

Critical thinking will increase more for the MM group than for the SM group from t₁ to t₄ (a ^1,2 ) and this effect will be moderated by baseline endorsement of thinking dispositions (b ^1,2 )

Mixed ANOVA, ANCOVA

Thinking Dispositions

Actively Open-minded Thinking¹, Need for Cognition²

3

Endorsement of critical thinking dispositions will increase more for the MM group than for the SM group from t₁ to t₄ (a ^1,2 )

Mixed ANOVA

Executive Control

Sternberg Working Memory Task

4

Executive control will increase more for the MM group than for the SM group from t₁ to t₄ (a) and this increase will mediate the relationship between levels of mindfulness and critical thinking performance following the intervention (b)

Mixed ANOVA, SEM

Secondary

Wellbeing

Warwick-Edinburgh Mental Wellbeing Scale

5

Wellbeing will increase and negative affect will decrease more for the MM group than for the SM group from t₁ to t₄

Mixed ANOVA

Positive Affect and Negative Affect

Positive Affect and Negative Affect Schedule subscale

6

Positive affect will increase more for the MM group than for the SM group from t₁ to t₄ (a)

Mixed ANOVA

Real-world Outcomes

Real-world Outcomes Inventory

7

Negative real-world outcomes will decrease more for the MM group than for SM group from t₁ to t₄

Mixed ANOVA

Manipulation Checks

Meditation Quality

Practice Quality-Meditation

8

Meditation quality will be positively associated with increases in mindfulness (a), executive control (b) and critical thinking (c ^1,2 ) and meditation quantity (d), task enjoyment (e) and task difficulty (f) and it will be higher in the MM group and across time.

Correlation, Mixed ANOVA

Meditation Quantity

Total Minutes Spent Meditating

9

Meditation quantity will be positively associated with increases in mindfulness (a), executive control (b) and critical thinking (c ^1,2 ) and meditation quality (d), task enjoyment (e) and task difficulty (f) and will not differ across time or groups.

Correlation, Mixed ANOVA

Task Enjoyment

Technology Acceptance Model Questionnaire subscale

10

Task enjoyment will be positively associated with increases in mindfulness (a), executive control (b) and critical thinking (c 1,2) and meditation quality (d), meditation quantity (e) and task difficulty (f) and will not differ across time or groups.

Correlation, Mixed ANOVA

Task Difficulty

Technology Acceptance Model Questionnaire subscale

11

Task difficulty will be positively associated with increases in mindfulness (a), executive control (b) and critical thinking (c 1,2) and meditation quality (d), meditation quantity (e) and task difficulty (f) and will not differ across time or groups.

Correlation, Mixed ANOVA

Intervention Acceptability

Items from Kirkpatrick et al. [60]

12

Intervention acceptability will be positively associated with increases in mindfulness (a), executive control (b) and critical thinking (c ^1,2 ) and meditation quantity (d), task enjoyment (e) and task difficulty (f) and it will be higher in the MM group but will not differ across time.

Correlation, Mixed ANOVA

Attrition

No. of participants lost from baseline to t₄

13

Attrition will be negatively associated with meditation quality (a), meditation quantity (b), task enjoyment (c) and task difficulty (d) and will not differ across time or groups.

Correlation, Mixed ANOVA