Suppose we are able to stimulate the whole matrix of cones of a human retina, targeting each cone individually¹. Normally we would project an image in the LMS color space onto the cones, in such a way that each sub-image of particular color channel would get to cones of corresponding type. As the eye moves, this image would be adjusted so as to create an illusion of real surrounding (similarly to a VR headset).

Suppose now we think up a new spectral sensitivity function $P(\lambda)$. We choose a subset of e.g. M cones to represent this type of sensitivity, making sure that this set is scattered enough around the M cones so as to avoid clumping the same color channel cones. And then we try to simulate tetrachromatic vision by replacing the M-channel sub-image in the projection by a special sub-image that an actual sensor with $P(\lambda)$ would capture.

Would this result in a sensation of a new color having appeared in the image, or would this be simply a lot of noise in the visual field?

¹The technology is not quite there, but on the way: see e.g. this answer.

  • $\begingroup$ I think your question would be better if you provided more background information — at a minimum adding links for things like "LMS color space" will make your question somewhat more accessible. In addition, the material about eye-tracking seems superfluous and to me distracts from the question. Finally, my (non-specialist) understanding is that people with tetrachromatic vision have been identified, which perhaps obviates your question? $\endgroup$
    – tyersome
    Commented Dec 23, 2019 at 21:18
  • $\begingroup$ @tyersome OK, I've added the link to LMS color space@Wikipedia. Regarding the existing human tetrachromats, no, this doesn't obviate the question: I still wonder whether the people who don't have corresponding phenotype are able to have tetrachromatic-like sensations, and whether the choice of the type-four cones makes it any different. Moreover, there might be some limitation in the brain, restricting, if not potential for tetrachromacy,then maybe for pentachromacy—or there might not be—which is what I'm also interested in.The eye-tracking material was a description of the thought experiment. $\endgroup$
    – Ruslan
    Commented Dec 23, 2019 at 21:27
  • $\begingroup$ I think the thought experiment contributes to this questions seeming too speculative (i.e. any answer would be primarily opinion and thus would not meet the criteria for this site). ——— Are really really interested in whether adults can adjust to new color inputs? If so, there are reports about people acquiring UV vision after cataract surgery. $\endgroup$
    – tyersome
    Commented Dec 23, 2019 at 22:06
  • $\begingroup$ @tyersome well, UV vision is not a new color: basically, just an extension of S cone sensitivity. Namely, those people see UV simply as violet, which isn't a new color (the same cones are stimulated by 370 nm light as by 400 nm). I'm not looking for opinions, but rather an answer from the position of modern neuroscience theories about how brain functions regarding the processing of the input signals from cone/rod cells. $\endgroup$
    – Ruslan
    Commented Dec 24, 2019 at 5:43
  • $\begingroup$ And finally, I'm interested in how color vision works from the POV of my thought experiment: e.g. whether the neurons connected to different cone types are predefined to particular color channels, or it's possible to repurpose them for a different sensitivity curve by some kind of modification, so as to get completely new colors and higher-dimensional color gamuts. $\endgroup$
    – Ruslan
    Commented Dec 24, 2019 at 5:45


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