Related Experiment Video
Updated: Jun 3, 2026
06:53
Creating Virtual-hand and Virtual-face Illusions to Investigate Self-representation
Published on: March 1, 2017
The illusion of owning a third arm
Arvid Guterstam1, Valeria I Petkova, H Henrik Ehrsson
1Brain, Body and Self Laboratory, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden. arvid.guterstam@ki.se
Plos One
|March 9, 2011
Summary
Scientists created a "supernumerary hand illusion," making people feel they have an extra limb. This challenges our understanding of body perception and representation.
Area of Science:
- Neuroscience
- Body Perception
- Human Augmentation
Background:
- The human body's perceived structure is traditionally viewed as a fixed constraint.
- Understanding the malleability of body representation is crucial for fields like prosthetics and human-computer interaction.
Purpose of the Study:
- To investigate the conditions under which a perceptual illusion of a supernumerary limb can be induced.
- To explore the characteristics of this illusion and compare it to existing phenomena like the rubber hand illusion.
Main Methods:
- Participants experienced a rubber hand illusion, with physiological and questionnaire data collected.
- Controlled experiments identified the minimal conditions for eliciting the "supernumerary hand illusion".
Main Results:
- A perceptual illusion was created where a rubber hand was perceived as an additional limb.
- This illusion differed from the traditional rubber hand illusion, with less disownership of the real hand and a stronger sense of possessing two right hands.
- Physiological evidence (skin conductance) supported the subjective experience.
Conclusions:
- The body representation can be updated to incorporate an additional limb, challenging traditional views of anatomical constraints.
- Multisensory processes related to the real hand appear to be co-opted, leading to a duplicated sense of touch and ownership.
- This research opens new avenues for understanding and potentially altering body schema.
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