Kinesthesis can make an invisible hand visible.

Area of Science:

• Neuroscience
• Cognitive Science
• Sensory Perception

Background:

• Action and vision are linked, with movements typically having predictable visual results.
• The brain's predictive processing of sensory information is crucial for perception.
• It remains unclear if actions can actively generate visual perceptions.

Purpose of the Study:

• To investigate if self-generated movements alone can create visual perceptions in complete darkness.
• To explore the role of multisensory integration in kinesthesis-induced visual sensations.
• To examine the relationship between these internally generated visual sensations and oculomotor control.

Main Methods:

• A deceptive experimental design was employed where participants moved their hands in front of covered eyes in darkness.
• Kinesthesis-induced visual sensations were compared between grapheme-color synesthetes and non-synesthetes.
• The vividness of visual sensations was correlated with participants' ability to track self-generated movements.

Main Results:

• Participants reported visual sensations of motion when waving their hands in darkness.
• Grapheme-color synesthetes experienced significantly stronger kinesthesis-induced visual sensations.
• The vividness of these internally generated visual sensations predicted tracking accuracy.

Conclusions:

• Self-generated movements are sufficient to evoke visual perceptions in the absence of external visual input.
• Multisensory interactions, particularly in synesthesia, play a role in generating these visual sensations.
• These kinesthesis-induced visual sensations function similarly to externally driven visual perceptions, highlighting predictive coding in the brain.