This review examines longitudinal studies of changes in attentional control following mindfulness training. A total of 56 retreat studies, feasibility studies, and randomized controlled trials were identified. Outcome measures were broadly categorized based on whether they operated primarily via top-down mechanisms, involving goal-directed modulation of attention via endogenous information, or bottom-up mechanisms, involving attentional capture via exogenous cues. Although many feasibility and retreat studies provide promising evidence supporting gains in both top-down and bottom-up attention following mindfulness training, evidence from randomized controlled trials, especially those involving active control comparison groups, is more mixed. This review calls attention to the urgent need in our field of contemplative sciences for adopting the methodological rigor necessary for establishing the efficacy of mindfulness meditation as a cognitive rehabilitation tool. Although studies including wait-list control comparisons were fruitful in providing initial feasibility data and pre-post effect sizes, there is a pressing need to employ standards that have been heavily advocated in the broader cognitive and physical training literatures. Critically, inclusion of active comparison groups and explicit attention to reduction of demand characteristics are needed to disentangle the effects of placebo from treatment. Further, detailed protocols for mindfulness and control groups and examination of theoretically guided outcome variables with established metrics for reliability and validity are key ingredients in the systematic study of mindfulness meditation. Adoption of such methodological rigor will allow for causal claims supporting mindfulness training as an efficacious treatment modality for cognitive rehabilitation and enhancement.
How mindfulness training promotes positive emotions: Dismantling acceptance skills training in two randomized controlled trials.
