seeing in colour

Now, not a lot of people know that. Primates are a select bunch of creatures. We see three basic colours. Most mammals only distinguish two.

Trichromacy is dependent on three types of photoreceptor cells in the retina that preferentially absorb lights at different wavelengths. These are known as cone cells and each type contains a particular kind of light-absorbing sensor protein. Short-wavelength-sensitive (S) cone cells are most sensitive to blue lights, medium-wavelength-sensitive (M) cone cells are most sensitive to green lights, and long-wavelength-sensitive (L) cones are most sensitive to red lights. When light strikes the retina and activates the cone cells, the brain compares the responses of the S, M, and L photoreceptors, and it is the brain's assessment of their relative levels of activation that we perceive as color.

An interesting recent set of experiments managed to give mice the ability to see in three colours rather than two. Scientist predicted that it would take several generations before the mice might begin to use the ability but, apparently, brain plasticity is such that almost immediately, they began to be able to use their new ability.

Previous experiments with the visual, olfactory (smell), and gustatory (taste) systems have suggested that introducing a new sensory receptor can expand the range of an animal's sensory perception, altering both its behavior and nerve activity, Jacobs noted that the new study is the first to demonstrate that these simple genetic changes can have even more profound effects. “By simply changing receptor proteins, not only can you extend the range of information that an animal might be able to sense, but if the nervous system has the plasticity we've seen in these mice, you can extract a new dimension of experience,” he explained.
“Our observation that the mouse brain can use this information to make spectral discriminations implies that alterations in receptor genes might be of immediate selective value not only because they expand the range or types of stimuli that can be detected but also because they permit a plastic nervous system to discriminate between new and existing stimuli,”

Is this related to the ability of human subject to 'see' by fitting sensory equipment and wiring it into their existing neurological system. I suspect so. It may have interesting implications for the philosophical debates on epistemology and perception.

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