Disembodiment
Final Report Abstract
The representation of one’s own body has repeatedly been characterized as being dynamic and flexible, which is backed up by fascinating observations such as the rubber hand illusion. In the active version of this experimental setup, participants control the movements of a rubber hand and – given the right conditions – readily report feeling as if the hand was part of their body. These observations show that the body representation is expanded by quite literally incorporating external objects as a result of sensorimotor experience – a process that is called embodiment. A dynamic view, however, holds that body representations cannot only be expanded by embodying additional parts but that they can also be narrowed down by disembodying such parts later on. Current theoretical approaches are tailored to explaining only one side of the coin by capturing embodiment as resulting from multisensory integration. The converse process of disembodiment, by contrast, has not been addressed by either empirical or theoretical work. The project thus focused on the disembodiment of previously embodied entities. We used physical as well as virtual versions of the active rubber hand paradigm to study the interplay of initial embodiment and later disembodiment. After embodying a real or virtual hand, our participants underwent different experimental conditions to probe for the mechanics of disembodiment. As a main result, we observed gradual disembodiment whenever the embodiment was not continuously updated by new sensorimotor experiences. A newly embodied entity thus fades from the body representation if it does not receive continuous reinforcement. Moreover, if sensorimotor experiences actively contradicted the embodied representation then disembodiment occurred abruptly so that the embodied entity was immediately removed from the body representation. Our results further revealed boundary conditions that allow embodied entities to become integrated in body representations in either a stable or a flexible manner. These findings inform practical applications of embodiment that aim at promoting either stable or flexible body representations. These applications include clinical uses such as prosthetics where maximally stable embodiment is desirable as well as immersion in virtual environments, which often benefit from flexible adaptation.
Publications
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How to lose a hand: Sensory updating drives disembodiment. Psychonomic Bulletin & Review, 28(3), 827-833.
Pfister, Roland; Klaffehn, Annika L.; Kalckert, Andreas; Kunde, Wilfried & Dignath, David
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Instant disembodiment of virtual body parts. Attention, Perception, & Psychophysics, 84(8), 2725-2740.
Eck, Julia; Dignath, David; Kalckert, Andreas & Pfister, Roland
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Bound by Experience: Updating the Body Representation When Using Virtual Objects. Human Factors: The Journal of the Human Factors and Ergonomics Society, 67(2), 115-140.
Eck, Julia & Pfister, Roland
