Experimental Induction of Micro- and Macrosomatognosia: A Virtual Hand Illusion Study

Although body size misperceptions are known to occur under various neurological and psychiatric conditions, their neurocognitive underpinnings not yet resolved. Accordingly, it would be beneficial have an experimental paradigm, by which aberrant could induced systematically investigated. Expanding upon the “Virtual Hand Illusion” (VHI), this study aimed design such a paradigm. Using body-motion tracking system, we translated participant's real hand position movements embodiable, but resizable virtual model that presented participants via head-mounted display. The hand's was then shrunk enlarged in five different conditions (i.e., −50%, −25%, 0%, +25% or +50% rescaling). Applying VHI derivate on n = 35 healthy participants, investigated (1) if experience Sense of Ownership (SoO) Agency (SoA) over significantly deviates from own hand, (2) size-deviant induction, change perception is also induced. Virtual embodiment explicitly implicitly assessed means self-report EDA analysis. Questionnaire results revealed stable SoA across all while SoO parametrically decreased according scaling factor either direction. perception, turn, adapted hand-scaling factor. In conclusion, present provides important step toward paradigm can induce investigate body-size misperceptions.