Is my "red" your "red"?: Evaluating structural correspondences between color similarity judgments using unsupervised alignment.
iScience March 21, 2025 Genji Kawakita, Ariel Zeleznikow-Johnston, Ken Takeda et al.
A new method based on optimal transport can align the similarity structures of color experiences between people without assuming which colors correspond. After collecting subjective similarity judgments for 93 colors, the method correctly aligned the color qualia structures of color-neurotypical participants at the group level, but could not align the structures of color-blind participants with those of color-neurotypical participants. This provides quantitative evidence that color-neurotypical people's experience of "red" is relationally equivalent to other color-neurotypical people's "red", but not to color-blind people's "red". The method can be applied across sensory modalities.