Apply Neuro-imaging Scans Comparing Role-playing Gamers to Non-gamers.
Look for any physical differences in portions of the brain between non-role-playing gamers, and those that have engaged in role-playing gaming for many years.
If any physical or activity changes noted before, during, or after monitoring role-playing game sessions while being scanned by Functional Magnetic Resonance Imaging (fMRI), Positron Emission Tomography (PET), and/or Voxel-based morphometry (VBM), (and other neuro-imaging technologies as appropriate) are these changes just correlative, or is there a causality from long-term engagement in role-playing games? DId people with these noted differences in brain structure already have these differences, and are just attracted to RPGs because of the differences, or did their long term use of RPGs slowly shape their brains?
If physical changes found, begin longitudinal long-term controlled studies using the same monitoring media.
Over time bring in people that have not ever engaged in role-playing gaming before, and have them participate in longitudinal, controlled, studies, to determine if noticeable changes to the brain are found over time, or not.
Looking not just for real-time neurological activity during game sessions, but also if any significant long term changes are indicated in brain brain activity patterns, or even physical changes in portions of the brain.