With the emergence of the fields of social-affective and contemplative sciences researchers have started thinking about the challenge to integrate first-person subjective reports with the traditional third-person objective measurements of behavior, brain, and body. A good example for such an integrated approach is plasticity research based on mental training studies. Thus, recent findings have suggested that training of mental capacities such as attention, mindfulness, empathy and compassion is indeed effective and leads to changes in both subjective well-being as well as in brain functions, health, and behavior. As an example for plasticity research, I will introduce the ReSource Project, a large-scale interdisciplinary and multi-methodological one-year secular mental training program that aims at the cultivation of attention, interoceptive awareness, perspective taking on self and others, meta-cognition, compassion, empathy, and prosocial motivation. To achieve these goals, we assessed more than 90 measures in more than 200 subjects including subjective measures and a huge variety of objective data ranging from behavioral, functional and structural brain-, autonomic nervous system- to genetical and hormonal measures. I will present first results of this large-scale study relating to differential pattern of brain plasticity observed after empathy versus compassion versus cognitive perspective taking training respectively. Furthermore I will present training-module specific findings of stress-reduction (i.e. cortisol) and prosocial behavior. Finally, I will use examples of the ReSource Project to highlight challenges related to the appropriate integration of measures of first-person subjective experience and third-person measurements and discuss these in the context of plasticity research in the field of social neurosciences.