SOMA Validation RCT: Testing Structural Equivalence and Mechanistic Orthogonality of an Open-Source Mindfulness Stimulus Library

Condition(s) studied

Investigational drug(s) / intervention(s)

SOMA Audio-Guided Mental Training Exercise: A single 12-minute audio-guided exercise from the Standardized Open-source Mindfulness Architecture (SOMA) library. The SOMA library comprises 88 distinct assets organized around 16 sensory practice modules (formal and informal) paired with structurally equivalent active control scripts. All materials are equity-engineered to a Grade 5-6 reading level, deployable without a meditation teacher, and free under CC BY-NC-SA 4.0 (osf.io/m76cg).

Study summary

Background: Mindfulness research faces two structural problems. First, weak active control conditions make it impossible to isolate specific mechanisms from expectancy and non-specific effects. Second, most protocols systematically exclude low-socioeconomic status (SES) populations through design assumptions that presuppose high literacy, quiet private spaces, and familiarity with contemplative practice.

Objective: This study validates the Standardized Open-source Mindfulness Architecture (SOMA), the first modular, open-source stimulus library purpose-built to address both challenges simultaneously. SOMA comprises 88 distinct audio assets organized around 16 sensory practice modules, each paired with a structurally equivalent active control script engineered to induce analytically orthogonal cognitive processing.

Design: Pre-registered randomized controlled trial using a 2×2 mixed design (Condition \[Mindfulness vs. Active Control\] × Measure \[State Mindfulness Scale vs. Analytical Engagement Scale\]), with quota sampling to ensure equal representation of participants with and without a university-level degree (n = 180 per SES stratum).

Setting: Online, via Prolific Academic recruitment platform and Qualtrics survey software.

Participants: N = 360 English-proficient adults aged 18 years and older (or the applicable minimum age of majority in the participant's country of residence) without a current mental health diagnosis or treatment, and without a current meditation practice.

Intervention: Each participant listens to a single 12-minute audio-guided exercise. Participants are randomly assigned to either the Mindfulness condition or the Active Control condition, and within that condition to one of 16 practice scripts. Mindfulness scripts guide bottom-up experiential awareness; Active Control scripts guide top-down analytical processing of the same everyday activities.

Primary Outcomes: (1) Credibility and expectancy equivalence between conditions (H1: Two One-Sided Tests on Credibility and Expectancy Questionnaire composite, equivalence bounds d = ±0.40); (2) mechanistic double dissociation - higher state mindfulness in the Mindfulness condition and higher analytical engagement in the Active Control condition (H2: 2×2 mixed ANOVA, interaction term as primary criterion).

Exploratory Outcome: SES-related differential experiential accessibility (H3: independent-samples t-test plus equivalence test on Semantic Differential composite by SES group).

Eligibility

Primary outcome measure(s)

• Credibility/Expectancy Questionnaire (CEQ) composite score — Immediately after audio exposure (single time point)
  CEQ composite 3-item composite (Logic, Success, Recommendation) from the Credibility and Expectancy Questionnaire (Devilly \& Borkovec, 2000), each item rated on a 1-9 scale (1 = not at all, 9 = extremely). Composite score range: 1-9; higher scores indicate greater perceived credibility and expectancy. Primary outcome for H1 (structural equivalence).
• Mechanistic Double Dissociation: State Mindfulness Scale and Analytical Engagement Scale Interaction Score — Immediately after audio exposure (single time point)
  State Mindfulness Scale (SMS; Tanay \& Bernstein, 2013): 7 items rated 1-5 (1 = not at all, 5 = very well); range 1-5, higher scores indicate greater state mindfulness. Analytical Engagement Scale (AES; purpose-built for this study): 5 items rated 1-5 (1 = not at all, 5 = very much); range 1-5, higher scores indicate greater analytical engagement.

Trial sites (1)

More Institute for Human Development and Potential (IHDP), Singapore trials in Singapore

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