Conclusion
The current study investigated the differential effects of a rather novel daily app-based dyadic mental practice with socio-emotional focus as compared to app-delivered mindfulness-based practice on immediate changes and longitudinal changes over 10 weeks of training in thought patterns and emotional well-being. Indeed, we found evidence for the efficacy of both low-dose mental training approaches in an immediate improvement in affect valence after daily practice. Interestingly, findings revealed clear differential phenomenological fingerprints of both practices. While it could partly be replicated that solitary mindfulness practices are more effective in reducing thought content on several dimensions, the novel partner-based Affect Dyad was more powerful in increasing positive and other-related thoughts; the latter being in line with the social nature of this intersubjective socio-emotional practice. Whereas traditional in-person programs are limited to room sizes and local availability of teachers, app-delivered interventions are accessible, cheap, and can be learned within a comparably short time frame. The global scalability of these interventions offers immense potential in promoting mental health through changing patterns of thought and affect. Further, the unique practice-specific phenomenological fingerprints in thought patterns may help inform the development of personalized mental training programs tailored to the need of specific populations. These findings suggest promising avenues for scalable evidence-based brief mental intervention programs to improve psychological well-being and mitigate increasing mental health conditions that have been exacerbated during the COVID-19 pandemic.