How mindfulness training promotes positive emotions: Dismantling acceptance skills training in two randomized controlled trials

Abstract

Mindfulness meditation interventions-which train skills in monitoring present-moment experiences with a lens of acceptance-have shown promise for increasing positive emotions. Using a theory-based approach, we hypothesized that learning acceptance skills in mindfulness interventions helps people notice more positive experiences in daily life, and tested whether removing acceptance training from mindfulness interventions would eliminate intervention-related boosts in positive affect. In 2 randomized controlled trials (RCTs) of stressed community adults, mindfulness skills were dismantled into 2 structurally equivalent interventions: (a) training in both monitoring and acceptance (Monitor + Accept) and (b) training in monitoring only (Monitor Only) without acceptance training. Study 1 tested 8-week group-based Monitor + Accept and Monitor Only interventions compared with a no treatment control group. Study 2 tested 2-week smartphone-based Monitor + Accept and Monitor Only interventions compared with an active control training. In both studies, end-of-day and momentary positive affect and negative affect were measured in daily life for 3 days pre- and post-intervention using ambulatory assessments. As predicted, across 2 RCTs, Monitor + Accept training increased positive affect compared with both Monitor Only and control groups. In Study 1, this effect was observed in end-of-day positive affect. In Study 2, this effect was found in both end-of-day and momentary positive affect outcomes. In contrast, all active interventions in Studies 1 and 2 decreased negative affect. These studies provide the first experimental evidence that developing an orientation of acceptance toward present-moment experiences is a central mechanism of mindfulness interventions for boosting positive emotions in daily life. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Trial registration: ClinicalTrials.gov NCT02502227 NCT02433431.

Conflict of interest statement

We declare one potential conflict of interest, which has not influenced the authorship or content of this article: author Shinzen Young owns a portion of 01 Expert Systems, which will be releasing a modified and extended version of Study 2’s Monitor+Accept mindfulness intervention as a commercial app.

Figures

Figure 1.

A. Study 1 CONSORT flow chart. B. Study 2 CONSORT flow chart. Note: EMA = Ecological Momentary Assessment.

Figure 1.

A. Study 1 CONSORT flow chart. B. Study 2 CONSORT flow chart. Note: EMA = Ecological Momentary Assessment.

Figure 2.

A. Study 1 diary-assessed positive affect (overall) at baseline and post-intervention by study condition. B. Study 2 diary-assessed positive affect (overall) at baseline and post-intervention by study condition.

Figure 3.

Effect size estimates (Hedges’ g) and 95% Confidence Intervals in Studies 1 & 2 for primary intervention comparisons. Note: MA = Monitor + Accept. MO = Monitor Only. PA = Positive Affect. NA = Negative Affect. EMA = Ecological Momentary Assessment.