Through the Language Glass: Why the World Looks Different in Other Languages

by Guy Deutscher

There are about six million cones in total in the retina, but the three types are not found in nearly equal numbers: there are relatively few short-wave (violet) cones, more than ten times as many middle-wave (green) cones, and even more long-wave cones. The far greater numbers of middle-wave and long-wave cones means that the eye is more efficient in absorbing light at the long-wave half of the spectrum (yellow and red) than at the short-wave half, so it takes lesser intensity of yellow light to be detected by the eye than blue or violet light. In fact, our day vision has a maximum sensitivity to light of 555 nm, at yellow-green. It is this idiosyncrasy of our anatomy that makes yellow appear brighter to us than blue or violet, rather than any inherent properties of the light itself, since blue light is not in itself less intense than yellow light.