Digital meditation at scale: a randomized citizen science trial comparing four meditation practices

INTERVENTION: The method of randomization was simple randomization. A randomized list of the numerals 1 through 5 was generated, with each numeral representing a study arm. Participants for each run were then randomly ordered and assigned according to this intervention randomization list Intervention 1: Mindful body scan meditation. 15‐minute daily guided body scan practice delivered via the Muse smartphone app for 28 days, in which attention is directed sequentially through regions of the body. Intervention 2: Loving‐kindness meditation. 15‐minute daily guided practice delivered via the Muse smartphone app for 28 days, cultivating compassion toward oneself and others through mental imagery. Intervention 3: Nondual meditation. 15‐minute daily guided practice delivered via the Muse smartphone app for 28 days, attenuating the separation between observer and observed through direct examination of conscious experience. Intervention 4: Mantra meditation. 15‐minute daily guided practice delivered via the Muse smartphone app for 28 days, repeating the mantra "Om" either aloud or silently. Active control: Classical music listening. 15‐minute daily listening to calming classical music delivered via the Muse smartphone app for 28 days. CONDITION: Psychological well‐being, cognitive function, and neurophysiological outcomes in non‐clinical adults ; Other PRIMARY OUTCOME: Cognitive control measured using the Stroop task at baseline and 4 weeks Compassion for others measured using the Dispositional Positive Emotion Scales, Compassion subscale (DPES) at baseline and 4 weeks Interoceptive awareness measured using the Brief Multidimensional Assessment of Interoceptive Awareness (MAIA), 8 subscales at baseline and 4 weeks Nondual Awareness measured using the Nondual Awareness Dimensional Assessment, state version at baseline and 4 weeks Overall well‐being measured using the Arizona Integrative Outcomes Scale (AIOS) at baseline and 4 weeks Pain measured using the Pain Numeric Rating Scale at baseline and 4 weeks Positive and negative affect measured using the Positive and Negative Affect Scale at baseline and 4 weeks Psychological flourshing measured using the 8‐item Flourishing Scale at baseline and 4 weeks Self‐compassion measured using the Self‐Compassion Scale Short Form (SCS‐SF) at baseline and 4 weeks Self‐transcendence measured using the Cloninger Self‐Transcendence Scale at baseline and 4 weeks Sleep quality measured using the Sleep Quality Scale at baseline and 4 weeks Working memory measured using the 2‐back task at baseline and 4 weeks INCLUSION CRITERIA: 1. English‐speaking adults aged 18 years or older 2. Owned or willing to purchase a Muse electroencephalography (EEG) headband 3. Willing to accept randomization to any study arm 4. Willing to refrain from initiating or changing other therapies during the study SECONDARY OUTCOME: Heart rate and heart rate variability measured using the Muse photoplethysmography (PPG), 8 indices (mean heart rate, standard deviation of normal‐to‐normal [SDNN], low frequency [LF], high frequency [HF], LF/HF, sample entropy, Poincaré standard deviation [SD]1/SD2, phase‐rectified signal averaging ‐ acceleration/deceleration capacity [PRSA AC/DC]) at baseline and 4 weeks Heartbeat‐evoked potentials measured using Muse EEG and PPG, frontal and temporoparietal amplitudes in early and late windows at baseline and 4 weeks Individual alpha frequency measured using the Muse EEG headband, alpha center of gravity (7‐13 Hz) at baseline and 4 weeks Resting EEG spectral power measured using the Muse EEG headband Welch's method across five frequency bands (delta, theta, alpha, beta, gamma) at baseline and 4 weeks Temporal alpha asymmetry measured using the Muse EEG headband, ln(right) minus ln(left) at TP9/TP10 at baseline and 4 weeks Theta/beta power ratio measured using the Muse EEG headband at baseline and 4 weeks