Context-Dependent Placebo Hypoalgesia Through Observational Learning: The Role of Empathy in Virtual and Real-World Settings

This study examined how empathy and contextual factors influence observationally induced placebo analgesia in virtual and real-world settings. Forty-seven participants observed a human or avatar demonstrator receiving painful stimulation with or without a placebo treatment, then experienced identical stimulations themselves. Observation led to significant placebo hypoalgesia for both pain intensity and unpleasantness. Human demonstrators evoked greater cognitive empathy, while placebo treatments reduced affective and cognitive empathy across contexts. Analgesic effects were stronger in the real world after observing humans, but in VR contexts, avatars induced greater placebo effects. Placebo effects were modulated by individual and experimental factors, including trait empathy and demonstrator type, respectively. These findings highlight how digital context, embodiment, and participant characteristics interact to shape pain outcomes, informing design strategies for immersive digital therapeutics.