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Amplifying the sensibility and spectrum of your senses, and even adding new senses altogether, in order to perceive the most information from the environment is a common theme in my futuristic setting, and it's achieved through genetic engineering (or cybernetics when you want something beyond the biological limits).

Supposing you were not born with it, and that biological sensory extension cannot be tuned to specific frequencies neither turned off, would perceiving all possible frequencies of the electromagnetic/acoustic spectrum, for example, end up making you virtually blind/deaf, and end up making you lose information if some frequencies obscure others? Or would your brain eventually make sense of all that information with time, with help of natural sensory adaptation?

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    $\begingroup$ One question per question is the requirement here. At a minimum modify this question to focus on either sight or hearing - with a list of points of interest for that sense, but don't put them as separate questions - and post a separate question for the other sense. $\endgroup$ Jul 25, 2022 at 23:04
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    $\begingroup$ Remember, the materials that the human eye/lens are made of only transmit light in a certain range of frequencies, also diffraction varies with wavelength, rendering only a narrow band of "colours" in-focus at any time. $\endgroup$ Jul 26, 2022 at 0:12
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    $\begingroup$ It feels like this can trivially be answered with "polychromatic people exist, as do Mantis shrimp (which can see 12 colors), Butterflies (pentachromats, widest animal visual range from 300-700nm, far UV to red), and some fish (UV to IR)... so there shouldn't be any significant issue with extending our sensitive range." But it'll be a tradeoff of colors against resolution (as increasing cell-density of one frequency requires reducing others) and focus (as different colors bend differently with the lens). So, animals already have close-to-optimal sight for their niche, kinda by definition. $\endgroup$ Jul 26, 2022 at 16:56
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    $\begingroup$ Then the eyes would fail to focus an image on a retina, they would function as simple pits, light sensitive and slightly direction-sensitive unable to resolve an image. $\endgroup$ Jul 26, 2022 at 18:21
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    $\begingroup$ Well, there would still be a lens to focus the light, so the light would still be diffracting. In fact, with non-dense gas on both sides of the dense lens, diffraction would be more significant. $\endgroup$ Jul 26, 2022 at 18:42

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Yes, you probably would need to regulate the range of frequencies you see at a time unless you upgrade the brain to process the extra information, but it depends on how your vision is organised. Animals that see a wide spectrum tend to see in low resolution or with limited visual processing.

Rods and cones in the human eye are connected in groups to neurons called retinal ganglion cells (RGCs). The signals from each group are effectively combined into one pixel, with the number of cells per RGC varying across the retina.

Lower resolution per colour

If your larger eye has more rods and cones but the same number of RGCs, it will have the same resolution as a standard eye but better night vision and less "noise" in low light conditions. This will cause no problems for the brain but you might have some trouble adding extra colours.

You could keep the eye at the same resolution but replace some of the cones (or groups of cones) with cones that sense other frequencies. Then you'd have normal monochrome vision combined with poorer than usual colour resolution, leading to situations where you can read small letters in black on white but not in orange on yellow, for example.

The brain might need some modification to recognise the extra cone types, but there are already people with 2 or even 4 cone types instead of the usual 3, so it might be able to adapt as it develops.

An alternate solution would be to keep the standard 3 cone types but have each cone express two different pigments - the usual one plus one IR or UV band. Then use filtering spectacles or nictating membranes when you want to see only "normal" colours or only the extended palette.

HD-ready brain

If you add extra RGCs as well as more rods and cones, the eye will have more resolution and/or more colour depth. In this case you will need to upgrade the brain's visual processing system to cope.

The brain is already very good at filtering out irrelevant information, but it will need to do something to process the extra data before that filtering can take place. The visual cortex will have to increase in processing power (and physical volume) or simply work more slowly, unless some extra filter can be added to decrease its workload.

If your genetic engineers understand the brain well enough they might be able to add an extra filtering system that chooses only a few sets of cones at a time, effectively changing your colour palette depending on what you want to see, or compresses the whole palette into a colour space the rest of the brain can process quickly. But if they can do that, they can probably give the existing visual system more power to do its own filtering.

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  • $\begingroup$ Orange text on a yellow background? I have all my rods and cones and that is still hard to read. Also, there are humans with tetrachromacy! en.wikipedia.org/wiki/Tetrachromacy $\endgroup$
    – PipperChip
    Jul 26, 2022 at 18:38
  • $\begingroup$ @PipperChip Fair enough, it would be harder still if you had fewer red or green cones. I did mention tetrachromacy in the answer, but not by name. $\endgroup$ Jul 27, 2022 at 9:02
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Different devices for different bands of frequencies

As shown here, there are different microphones for different ranges of frequencies. Snakes have different sensors for visible light and infrared radiation.

Multiple ears and eyes

For your species, you can add more than one pair of eyes for infrared, ultraviolet and other bands electromagnetic waves. Also you can add more than one pair of ears for subsonic, ultrasonic and other ranges of longitudinal mechanical waves.

Brain can receive and understand signals from multiple optic and auditory nerves.

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  • $\begingroup$ Having different eyes for different frequencies would allow the lenses (or equivalent) and other parts to be specialised as well, covering a bigger total range. $\endgroup$ Jul 26, 2022 at 12:34

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