On the relationship between pain and body ownership: A systematic review of rubber hand illusion studies

Human senses enable an individual to describe and set boundaries for themselves in relation to the outside world while creating their own body representation. Given the dynamic nature of such a complex structure, integrations of external elements inside the own body schema are possible. Since the 90s, scientific research has highlighted this phenomenon through the Rubber Hand Illusion (RHI) paradigm. Over the years, the literature on the induction of RHI has highlighted distinct, and often contradictory, effects on pain modulation, sometimes underscoring its analgesic, hyperalgesic, or null influence on pain sensation. Given RHI's role in therapeutic settings, the current systematic review seeks to shed light on its effects on pain perception and the role of pain in inducing RHI. Following the PRISMA guidelines, we retrieved and included 29 papers in our work. Overall, the evidence suggests that the relationship between body ownership and pain is context-dependent. When the embodied hand was presented as healthy and multisensory stimulation was congruent, RHI was more often associated with analgesic effects. Conversely, when the embodied hand appeared injured, threatening, or sensitised, embodiment tended to increase pain sensitivity or unpleasantness. Null findings were also common, suggesting that ownership induction alone is insufficient to reliably modulate pain. Studies using painful or nociceptive stimulation showed that RHI can be induced not only by innocuous touch. These findings suggest that pain and ownership interact through multisensory, affective, motivational, and predictive mechanisms. Future studies should use larger samples, clearer measures of ownership, and clinical populations.