Playing With Spatial Frames: Altering the Body Matrix Through Multisensory Egocentric and Allocentric Body Illusions

The multifaceted nature of body experience, encompassing affective, cognitive, and perceptual components, plays a critical role in the development and persistence of conditions such as anorexia nervosa (AN). Recent research attempted to address such disturbance to improve therapeutical effectiveness, using mirror exposure (ME) and body-swapping (BS) techniques in immersive virtual reality (VR). Procedures from a third-person perspective—as mirror-like experiences—were primarily used to address bodily cognitive and affective components, whereas first-person ones—as BS—were used to correct distorted body perception. This study investigated the effect of spatial reference frame on body self-consciousness and body perception during BS. Data revealed two main findings: Even though embodiment was significantly enhanced when participants engaged with a virtual body from a first-person viewpoint, both egocentric and allocentric perspectives influenced body size estimation (BSE), suggesting that both spatial perspectives critically form and sustain body self-perception. We discussed predictive coding theory to explain spatial perspective influence on body experience, highlighting the potential therapeutic benefits of incorporating first and third-person perspectives on body illusions (BIs) for more effective interventions targeting body-related disturbances.