Lightness and Brightness and Other Confusions

involved. It is worth mentioning that other studies 5 have shown some variation
in the average unique-hue choices from the speakers of different languages,
but in every case the variation between observers speaking the same
language was substantially larger than the variation across languages. Unlike
the anomaloscopic matching variability, there is so far no satisfactory explanation
for the variability in unique hue choices. It seems that the deeper in the
brain we go, the more mysterious things become.
We should not be surprised to find such individual differences in perception.
Along with its sibling, natural selection, variation is a hallmark of living
things. A perceptual system need only be good enough to guide its owner to
perform tasks that will sustain its species in its ecological niche, The advantages
that primates gained by developing chromatic perception involved such
activities as identifying predators and prey in dappled forest environment and
spotting ripe fruit among the leaves, doing so in various phases of daylight
and in changing shadows. There is no special premium that attaches to accomplishing
these perceptual tasks with a high degree of precision or close
agreement among perceivers. Biological mechanisms are typically a pastiche
of earlier evolutionary endeavours. They are inherently rough, ready, and
variable. The colours that we experience can be understood as natural signs of
the filtered patterns of spectral power distributions in our environment. They
should not be regarded as simulacra of the physical world that they represent.
If we had all been born spectrally inverted, would this have made much difference
in our ability to find our way around?
Keeping all of this in mind, how are we to approach the study of colour as an
integral part of our human life-world? First of all, we shouldn’t take the deliverances
of the senses too literally. My daily experience teaches me that the
physical world is filled with coloured objects. It also teaches me that the earth
moves only when there are earthquakes, that the heavens turn every 24
hours, that rocks are solid through and through, and that if there were antipodeans,
they would walk with their feet above their heads. Second, we
shouldn’t suppose that all scientific studies should be reducible to physics and
chemistry. Geology, archaeology and botany are scientific studies and are
thoroughly informed by physics and chemistry. But they, like the study of
colour vision, fundamentally involve historical accident, so the phenomena
that fall under them cannot be explicable in terms of universal laws. Third,
most phenomena of human interest are inherently too complex to admit of
rigorous analysis. This does not mean that they are incapable of a degree of
mathematical analysis (this is why God gave us statistics) but that estimation
and qualitative understanding are inescapable if we are to understand what is
going on.
5
Webster, M. A. et al. (2002). Variations in Normal Color Vision. III. Unique Hues in
Indian and United States Observers. Journal of the Optical Society of America A 19
(10) 1951-1962.
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