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Buddha's ear illusion

Buddha's ear
2026-10-26 add · 773 words

A bodily illusion in which one's own earlobe feels as if it has stretched and hangs down by tens of centimeters. It was reported by Kenri Kodaka and Yutaro Sato of Nagoya City University, and the name comes from the long-lobed ears of Buddha statues. Its distinguishing feature is that it can be induced without any apparatus: another person lightly pinches and pulls the earlobe while performing, below it, a pantomime of "stretching the invisible earlobe". Most illusions in which the body's shape feels altered have dealt with the hands or arms; this one showed that a large sense of deformation arises in a short time in the ear, a small part with little mobility.

How to induce it

The participant, in front of a mirror or the like, has the experimenter pinch their earlobe. Keeping hold of it and pulling gently downward, the experimenter uses the other hand to act out in the air a motion of pulling the continuation of the stretched earlobe further down. The participant, watching that hand, has to estimate the shape of their own ear relying only on the touch applied to the earlobe. When this combination of vision and touch continues for a few seconds, a sensation arises of the earlobe stretching by the amount of the hand movement seen.

In the study, the tactile side was divided into two kinds, "pinching" and "pulling", and the visual side into two conditions, the hand held still below the ear (Stayed) and the stretching motion acted out (Mimed), and four conditions in total were compared. An interaction was confirmed in which the sense of deformation was strongest in the condition combining the touch of actually pulling the earlobe with the sight of the stretching motion. Either one alone gives a weak effect, so both the visual performance and the tactile backing are needed.

Reported size of the effect

According to the paper, about 88% of participants reported a "stretched feeling" of +4 or more on a seven-point scale. More than half, moreover, said that the earlobe had dropped by 10 centimeters or more during roughly 10 seconds of stimulation, a figure far removed from the actual range of motion of the earlobe. The authors position this as pushing out the proprioceptive constraints that illusions of body ownership usually obey.

Headlines such as "stretched by 20 centimeters" appear in articles for general readers, but all of these are participants' subjective reports, and no physical deformation takes place. It is a phenomenon in which only the brain's map of the body is rewritten while the shape of the earlobe itself stays unchanged.

Development from the slime hand illusion

This illusion was proposed as an application to the ear region of the "slime hand illusion", which the same laboratory had worked on. The slime hand illusion is a phenomenon in which the hand feels stretched like taffy, and it belongs to a line of work dealing with a sense of "deformation" that cannot be explained by proprioceptive information such as joint angles and limb position alone. Unlike the rubber hand illusion, which prepares a fake body part and transfers ownership to it, its focus is on feeling one's own body change into an impossible shape.

The earlobe has no joints and almost no proprioceptive receptors. For that very reason, the brain has no choice but to estimate its shape from vision and touch, and it yields greatly when given contradictory information. The choice of the ear is directly tied to the size of this illusion's effect; the selection of a small, inconspicuous part is what underpins the result.

To verify

  • The number of participants in the paper published in i-Perception. The figure of 16 (mean age 21.3) is based on the 2023 presentation material of the Japanese Cognitive Science Society, and it has not been confirmed whether this is the same group of participants as in the experiment in the 2024 paper
  • The figures "about 88% at +4 or more" and "more than half at 10 centimeters or more" were obtained via search results from the text of the paper's page, and the original itself could not be consulted (journals.sagepub.com and PMC were unreachable from this session)
  • Its treatment at the Best Illusion of the Year Contest 2023. There are accounts that it was presented at the contest, but it has not been confirmed whether it won a prize or was only entered or exhibited
  • The source of the "20 centimeters" in headlines of articles for general readers. The paper says "10 centimeters or more", and the relation between the two is unclear

References

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