Multidimensional scaling of color similarity in bees

A multiple choice experiment with free flying bees trained to a color signal is described which allows for multidimensional scaling of color similarity. The choice proportions are analysed by metric (Torgerson 1958) and non-metric (Kruskal 1964a, b) multidimensional scaling. The light reflected from the twelve color signals used differed in spectral composition, intensity, and the proportion of white light. Only two scales are necessary to reconstruct the experimental data. The interpretation of the scale values by Helmholtz-coordinates, derived from the chromaticity diagram for bees, shows that the main perceptual parameters are hue and saturation (or blue/greenness and UV/blue-greenness, respectively). Brightness is ignored by the bees in this choice situation. The total color difference is related to the differences on the two perceptual parameters by the city-block metric (Minkowski exponentp=1).