The rubber tool illusion reveals how body image modifies body schema

Area of Science:

• Neuroscience
• Cognitive Psychology
• Body Representation

Background:

• The rubber hand illusion and tool-use paradigms study body representation through multisensory integration.
• These methods are typically investigated separately, limiting understanding of their interplay.

Purpose of the Study:

• To introduce a novel paradigm combining tool-use and rubber hand illusion.
• To investigate if perceptual body representation changes can induce motor representation changes, and vice versa.

Main Methods:

• Participants engaged in a tool-use task with varying tool lengths.
• The rubber tool illusion was applied, with participants holding a tool while observing a rubber hand using an identical tool.
• Control experiments assessed the influence of prior tool use, embodiment, and tool length mismatch.

Main Results:

• Active use of a long tool led to an expanded motor representation of the forearm.
• Experiencing the rubber tool illusion with a length mismatch (short held, long observed) expanded forearm representation.
• These effects were dependent on prior tool use, embodiment, and tool length discrepancy.

Conclusions:

• Motor representation of forearm length, part of the body schema, is modulated by body image alterations.
• This research bridges the gap between tool-use and body illusion studies, revealing bidirectional influences on body representation.