The Butcher's Tongue Illusion

Area of Science:

• Neuroscience
• Psychology
• Somatosensation

Background:

• The Rubber Hand Illusion (RHI) demonstrates multisensory integration, typically involving the hand.
• The tongue is rarely viewed directly, making its role in such illusions less understood.

Purpose of the Study:

• To investigate if the RHI can be extended to the tongue.
• To explore the multisensory integration of visual, tactile, and proprioceptive information involving the tongue.

Main Methods:

• Two experiments adapted the RHI using a mirrored artificial tongue.
• Participants received tactile stimulation on their own tongue while observing the artificial tongue.
• Experiment 2 involved illuminating the artificial tongue with a laser pointer.

Main Results:

• Participants reported feeling touch on their tongue corresponding to visual stimulation of the artificial tongue (visual capture).
• A significant number reported tactile or thermal sensations on their own tongue when the artificial tongue was illuminated.

Conclusions:

• The RHI can be induced for the tongue, extending beyond the hand.
• This highlights the brain's ability to integrate multisensory information for body parts not typically seen directly.