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The perspective matters! Multisensory integration in ego-centric reference frames determines full-body ownership.

Petkova VI, Khoshnevis M, Ehrsson HH - Front Psychol (2011)

Bottom Line: Recent advances in experimental science have made it possible to investigate the perceptual processes involved in generating a sense of owning an entire body.Here we investigate the fundamental question of the reference frames used in the process of attributing an entire body to the self.This demonstrates that the multisensory integration processes producing the sense of corporeal self operates in an ego-centric reference frame.

View Article: PubMed Central - PubMed

Affiliation: Brain, Body and Self Laboratory, Department of Neuroscience, Karolinska Institutet Stockholm, Sweden.

ABSTRACT
Recent advances in experimental science have made it possible to investigate the perceptual processes involved in generating a sense of owning an entire body. This is achieved by full-body ownership illusions which make use of specific patterns of visual and somatic stimuli integration. Here we investigate the fundamental question of the reference frames used in the process of attributing an entire body to the self. We quantified the strength of the body-swap illusion in conditions where the participants were observing this artificial body from the perspective of the first or third person. Consistent results from subjective reports and physiological recordings show that the first person visual perspective is critical for the induction of this full-body ownership illusion. This demonstrates that the multisensory integration processes producing the sense of corporeal self operates in an ego-centric reference frame.

No MeSH data available.


Related in: MedlinePlus

Experimental set-up developed to induce the body-swap illusion without head-mounted displays and video-technology (experiment #3). (A–C) The experimental set-up and the participant's field of sight in the conditions in which the mannequin's body was viewed directly from the first person perspective. (D–F) The set-up developed to probe the full-body illusion when the mannequin's body was perceived from the third person perspective.
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Figure 2: Experimental set-up developed to induce the body-swap illusion without head-mounted displays and video-technology (experiment #3). (A–C) The experimental set-up and the participant's field of sight in the conditions in which the mannequin's body was viewed directly from the first person perspective. (D–F) The set-up developed to probe the full-body illusion when the mannequin's body was perceived from the third person perspective.

Mentions: Here, we created a new set-up that allowed the participants to experience the illusion of owning the mannequin's body without the use of HMDs and video-cameras. The set-up used for the first person visual perspective conditions was as follows: the participant was asked to lay on a bed tilted at 30° from the horizontal. The front half of the body of a shop mannequin was positioned on top of the participant so that the shoulders of the mannequin were resting on the shoulders of the participant and the feet of the mannequin were resting on a horizontal support positioned ∼50 cm above the feet of the participant. Thus, when the participant looked down as if to look at his body, he saw the body of the mannequin in a similar position to where he would expect his own body to be had he been to lying down horizontally (Figures 2A–C). The experimenter used two plastic rods to apply touches on the right lateral part of the abdomens of the mannequin and the participant, either in a synchronous manner (1PP Sync) or in an asynchronous mode (1PP Async). While this was going on, the experimenter was out of sight, hidden behind a curtain, to prevent the participants from seeing the experimenter's hand touching the participant's own abdomen. Thus, the only hand the participant saw was the experimenter's hand touching the abdomen of the mannequin. After 1 min of synchronous or asynchronous tactile stimulation, the experimenter used a knife to “cut” the mannequin's abdomen in a single movement lasting approximately 3 s. The SCRs associated with these threat events were registered and analyzed as explained above and in the previously published protocols (Petkova and Ehrsson, 2008).


The perspective matters! Multisensory integration in ego-centric reference frames determines full-body ownership.

Petkova VI, Khoshnevis M, Ehrsson HH - Front Psychol (2011)

Experimental set-up developed to induce the body-swap illusion without head-mounted displays and video-technology (experiment #3). (A–C) The experimental set-up and the participant's field of sight in the conditions in which the mannequin's body was viewed directly from the first person perspective. (D–F) The set-up developed to probe the full-body illusion when the mannequin's body was perceived from the third person perspective.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108400&req=5

Figure 2: Experimental set-up developed to induce the body-swap illusion without head-mounted displays and video-technology (experiment #3). (A–C) The experimental set-up and the participant's field of sight in the conditions in which the mannequin's body was viewed directly from the first person perspective. (D–F) The set-up developed to probe the full-body illusion when the mannequin's body was perceived from the third person perspective.
Mentions: Here, we created a new set-up that allowed the participants to experience the illusion of owning the mannequin's body without the use of HMDs and video-cameras. The set-up used for the first person visual perspective conditions was as follows: the participant was asked to lay on a bed tilted at 30° from the horizontal. The front half of the body of a shop mannequin was positioned on top of the participant so that the shoulders of the mannequin were resting on the shoulders of the participant and the feet of the mannequin were resting on a horizontal support positioned ∼50 cm above the feet of the participant. Thus, when the participant looked down as if to look at his body, he saw the body of the mannequin in a similar position to where he would expect his own body to be had he been to lying down horizontally (Figures 2A–C). The experimenter used two plastic rods to apply touches on the right lateral part of the abdomens of the mannequin and the participant, either in a synchronous manner (1PP Sync) or in an asynchronous mode (1PP Async). While this was going on, the experimenter was out of sight, hidden behind a curtain, to prevent the participants from seeing the experimenter's hand touching the participant's own abdomen. Thus, the only hand the participant saw was the experimenter's hand touching the abdomen of the mannequin. After 1 min of synchronous or asynchronous tactile stimulation, the experimenter used a knife to “cut” the mannequin's abdomen in a single movement lasting approximately 3 s. The SCRs associated with these threat events were registered and analyzed as explained above and in the previously published protocols (Petkova and Ehrsson, 2008).

Bottom Line: Recent advances in experimental science have made it possible to investigate the perceptual processes involved in generating a sense of owning an entire body.Here we investigate the fundamental question of the reference frames used in the process of attributing an entire body to the self.This demonstrates that the multisensory integration processes producing the sense of corporeal self operates in an ego-centric reference frame.

View Article: PubMed Central - PubMed

Affiliation: Brain, Body and Self Laboratory, Department of Neuroscience, Karolinska Institutet Stockholm, Sweden.

ABSTRACT
Recent advances in experimental science have made it possible to investigate the perceptual processes involved in generating a sense of owning an entire body. This is achieved by full-body ownership illusions which make use of specific patterns of visual and somatic stimuli integration. Here we investigate the fundamental question of the reference frames used in the process of attributing an entire body to the self. We quantified the strength of the body-swap illusion in conditions where the participants were observing this artificial body from the perspective of the first or third person. Consistent results from subjective reports and physiological recordings show that the first person visual perspective is critical for the induction of this full-body ownership illusion. This demonstrates that the multisensory integration processes producing the sense of corporeal self operates in an ego-centric reference frame.

No MeSH data available.


Related in: MedlinePlus