Testing the monitor and acceptance theory: the role of training-induced changes in monitoring- and acceptance-related capacities after attention-based, socio-emotional, or socio-cognitive mental training in reducing cortisol stress reactivity.

Mindfulness-based interventions have become a popular means to reduce stress. However, the specific mechanisms driving observed stress reduction remain understudied. The Monitor and Acceptance Theory suggests that the cultivation of monitoring and acceptance skills are necessary moderators of practice-induced stress reduction. In the context of the ReSource Project, a large healthy adult sample underwent three 3-month mental training modules targeting either attentional (Presence module), socio-affective (Affect module) or socio-cognitive skills (Perspective module). In the current study, the development of a range of inter-individual differences in mindfulness-, interoception- and compassion-related traits - which mapped to either monitoring or acceptance categories - was tracked. The relationship of these training-induced changes with cortisol stress reactivity after the three distinct 3-month training modules was explored. We found that stress sensitivity was particularly modulated by a differential adaptivity of one cultivated attentional capacity - Attention regulation - which predicted higher cortisol reactivity after mere attention training (Presence) but was associated with lower stress-induced cortisol release after additional socio-affective and socio-cognitive practice (Affect and Perspective). However, this effect did not survive multiple comparisons correction, and analyses were limited by the sample size available. We conclude that our study provides preliminary support of the Monitor and Acceptance Theory, lending weight to the advantage of primary attentional increases in order to fully harness the beneficial effects of socio-affective training, ultimately leading to stress reduction. Although training-induced increases in acceptance were not directly shown to contribute to lowering cortisol stress reactivity, the data suggest an additional benefit of socio-affective and socio-cognitive training that is not directly captured within the current analyses. Our study corroborates the importance of going beyond the training of attention monitoring to foster stress resilience, and highlights that mental training relies on the co-development of several interacting processes to successfully attenuate stress. Further exploring the overarching concept of acceptance in future research may prove beneficial to the theoretical framework of MAT, and in understanding the processes by which stress reduction occurs.