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Study Reveals Pupil Response as Synesthesia Indicator

3/28/2026

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Summary

Story summary

The study finds that individuals with grapheme-color synesthesia show distinct pupil reactions when viewing gray numbers, perceiving colors.
In synesthetes, pupils constrict for brighter colors and dilate for darker ones, signaling involuntary perceptual experiences.
The findings imply that pupil size could serve as an objective measure for identifying synesthesia.
The research was published in eLife on March 6, 2026.

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Story summary

The study finds that individuals with grapheme-color synesthesia show distinct pupil reactions when viewing gray numbers, perceiving colors.
In synesthetes, pupils constrict for brighter colors and dilate for darker ones, signaling involuntary perceptual experiences.
The findings imply that pupil size could serve as an objective measure for identifying synesthesia.
The research was published in eLife on March 6, 2026.