Statistical analysis of self-report data
A multilevel-model analysis of variance (mlmANOVA) was used to compare disgust ratings between GROUPs (CR, OLP, PV) and PICTURE CATEGORIES (Disgust, Neutral). MlmANOVAs offer several advantages over repeated-measures ANOVAs, such as dealing with missing values or when the number of repeats varies. Furthermore, mlmANOVAs explicitly model random effects due to the clustering (observations nested within a cluster (e.g., subjects), resulting in cluster-specific coefficients for the intercept and/or slope. For the current analyses, we defined subjects as the cluster variable and allowed the intercept to vary. The effects of GROUP (CR, OLP) and TIME (before vs. after the picture viewing) on expected/perceived effectiveness of the treatment were also examined using a multilevel-model ANOVA with subjects as the cluster variable (varying intercepts). We used the GAMLj package of JAMOVI (version: 2.3.21).Bonferroni-corrected t-tests were calculated for post-hoc analysis following significant main effects/interactions of the multilevel-model ANOVAs. A t-test was conducted to compare the plausibility of the treatment rationale between CR and OLP. We report Cohen’s d as an effect size measure.