The illusion of a “sense of body lightness” while walking: a preliminary exploratory study

TL;DR

This study introduces a new illusion where people feel lighter while walking when given specific visual feedback, which could help in medicine and virtual reality.

Contribution

The study introduces a novel illusion of body lightness during walking using subjectively preceding visual feedback.

Findings

Nine out of 30 participants felt a sense of body lightness with subjectively preceding feedback.

The illusion may be useful in medical rehabilitation and extended reality technologies.

The illusion is generated by manipulating the timing of visual feedback during treadmill walking.

Abstract

Illusions have historically been used in experimental psychology to reveal information about perceptual processes. A recent study reported that participants felt a sense of body heaviness when given slightly delayed (incongruent) visual feedback compared with the predicted somatosensory feedback. In this study, we reported a novel illusion of feeling a sense of body lightness while walking. There is consensus that an important factor in a body’s perceptual process is congruency between the senses. When our 30 participants experienced “subjectively preceding feedback” while walking on a treadmill, nine of them felt a sense of body lightness. In this report, we discussed how we were able to generate the subjectively preceding feedback, the mechanism that induces the illusion of a sense of body lightness, and the potential applications of this illusion. Although this study was just a preliminary and exploratory research, this new illusion has the potential to contribute not only to the medical and rehabilitation fields but also to extended reality technology and other interdisciplinary fields.

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