When it comes to processing hearing and visual signals, our brain has different capabilities.

While it seems to be able to execute a spectral analysis for sounds, so that when we hear the superposition of more tones we still recognize each of them individually, this ability is not present when it processes light seen through our eyes, and we end up seeing white instead of green, red and blue.

Should a man have such ability of separating the spectral components in a visual signal, could this be a competitive advantage for the bearer?

  • $\begingroup$ This should mostly be a disadvantage for several reasons. There are already enough answers discussing this, but I feel like the question needs some improvement. Could you give more details on your story/world? What kind of environment do you have in mind? What tasks are to be performed? Intelligent species? What kind of animal anyways? Does it develop naturally or is it something that for example humans would achieve through genetics? $\endgroup$
    – Raditz_35
    Jun 8, 2017 at 9:16
  • $\begingroup$ Great apes (including humans) already have one the best color vision systems among mammals. So the question is a competitive advange compared to what competitors? Insects? $\endgroup$
    – AlexP
    Jun 8, 2017 at 10:17
  • $\begingroup$ When we hear unrecognised mix of sounds we call it a noise. And noise could be different. Even though our eyes are trichromatic, eye has better resolution than hear. And yes, our vision do some spectral analysis since some of us could differentiate 'orange' and 'carrot' colors. Could you rephrase your question? What additional ability do you propose? $\endgroup$
    – ADS
    Jun 8, 2017 at 11:21
  • $\begingroup$ @ADS, if you play two cords on a guitar you recognize two different tones. If you cast two colored beams on the same spot, you only see one color. $\endgroup$
    – L.Dutch
    Jun 8, 2017 at 11:25
  • $\begingroup$ It's not correct. Trichromatic eye coud percieve about 10 millions colors. You could hear tone because of distance between two signals. Also you could see red and orange due to distance in spectre of two beams $\endgroup$
    – ADS
    Jun 8, 2017 at 11:36

3 Answers 3


For full spectrum analysis, we would need a completely different kind of eye.

The reason we can see color is because each of our three cone cells contain a different pigment, and each pigment responds to a different range of wavelengths. All animals on earth use basically the same system; some have more pigment types (butterflies have up to 16) but there is a fundamental limit to this system.

The wavelengths of visible colors do overlap (so there are no "invisible wavelengths" between the highest and lowest wavelengths we can perceive) but there are "dips" in sensitivity within the colors we can see; our range of blue perception lies fairly far away from our range of red and green perception, which is why colors on the blue end of the visual spectrum are harder to differentiate than shades of reds, yellows, and greens.

This does make sense from an evolutionary perspective; primates probably evolved trichromatic vision mainly to differentiate between a healthy branch and a dead one (pretty important if you're a monkey), so picking up subtle shades of yellow and green is more important than subtle differences in the color of the sky or sea.

Sound works completely differently; we can detect different pitches because of the spiral shape of the cochlea; every part of this organ responds to a slightly different pitch, making us capable of detecting differences in sounds more or less equally at any point within our full hearing range.

There would be some potential benefits for detecting color this way - basically the same as the advantages of just adding more colors, but a little better. We could detect subtle shades that reflect the health or species of prey or predators, or tree branches, fruits, and flowers, as the case may be. Butterflies and mantis shrimp have some of the best color vision around; butterflies use it to detect slight differences between flowers and mantis shrimp probably use it for hunting, although they may also use it for communication.

But it is unlikely for a full spectral analysis mechanism to evolve on Earth, even if it is technically superior than pigment-based vision, as it would require the eye to be completely rebuilt from scratch. Life on Earth has been using pigment-based vision since before multicellular life existed, and it works just fine for all practical purposes. If an organism does need to detect more colors, it's much more practical to just evolve a new visual pigment than to completely rebuild the entire concept of an eye from the ground up.


Yes, such ability would allow to see much more nuanced colors. However, competitive advantage would not be huge. It would allow predators to more easily pick prey which uses mimicry. However, mimicry should be able to adapt to full spectrum vision too.

From a scientific standpoint, human eyes are not capable by design to do spectral analysis. We can move from being trichromatic to tetrachromatic, and maybe even pentachromatic, but this is not the same as full spectrum analysis. By contrast, inner ear splits sound to different frequencies and can analyze full audio spectrum.


By virtue of the fact that we actually see is RGB and the brain merges it into one coherent signal to display a colour, I would expect the opposite is true. It would be a disadvantage to see the three colours separately. I can't think of any situation in which it would be an advantage.

  • $\begingroup$ easier to see poisonous plants/animals/gas $\endgroup$
    – Evi
    Jun 8, 2017 at 8:17
  • $\begingroup$ A spectrum analysis permits more detailed visual identification of objects but I don't see how it could detect it's chemical composition. You might see a normally invisible cloud of gas as a series of visible hues and, because of it's transparency, guess at it's density more accurately, but not be able to tell what it is. More importantly, this brings up the issue of seeing gasses as a problem. If you could see the atmosphere of the planet and various other invisible things like radio waves, etc. Then the visual noise make it almost impossible to sort out all the information. $\endgroup$
    – 2redshirt
    Jun 8, 2017 at 8:31
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    $\begingroup$ @2redshirt you are confusing “its” (pronoun) with “it's” (contraction for “it is”). $\endgroup$
    – JDługosz
    Jun 8, 2017 at 8:40

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