I am a PhD student in medieval history, a theatre kid in remission, and an aspiring game designer. More than anything else, I see games as mechanisms which allow us to inhabit lives not our own. In every game I design, teach, and play, I seek out character and atmosphere above strategy or optimization.
As a result, I see sincerity and empathy as the greatest tool for getting more out of games (and life). And sincerity and empathy are best achieved through good props!
I am only slightly kidding. Though I am not a psychologist, I firmly believe in the theory of Enclothed Cognition emergent from that field. Originally proposed by Hajo Adam and Adam Galinsky in 2012, the theory claims that the clothes a person wears (or thinks they are wearing) impact their empathy, mental skills, and emotional state. Recent work by Coyne et al* has begun expanding this concept to the logical conclusion of wearing costumes in order to encourage a certain mindset and outlook. They focused primarily on young children, but as a veteran performer and patron of the Renaissance Festival I can at least annecdotally confirm that this theory works on adults as well. Nothing increases a participant's engagement with alternate worlds like a tangible, tactile expression of their place in that world.
To some extent, that tactility can be facilitated by the experience designer. I certainly have tried to do so. However, the majority of the responsibility for creating these alternate worlds lies with you. No mechanic or prop creates a more effective or inviting portal to another, better world, than a sincere friend willing to take the journey with you.
Therefore, I encourage you: when you play one of my games (or any game, for that matter), throw yourself fully into creating and feeling a new world together. It'll be good practice for when we do the same to the real world.
*Coyne, S. M., Rogers, A., Shawcroft, J., & Hurst, J. L. (2021). Dressing up with Disney and make-believe with Marvel: The impact of gendered costumes on gender typing, prosocial behavior, and perseverance during early childhood. Sex Roles, 85, 1–12.