this post was submitted on 08 Aug 2023
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Think of sight kind of like hearing and sonar, but confined to a cone of detection that is almost 180 degrees wide, and maybe about 45 degrees up, and 45 degrees down. This field of vision is incredibly detailed at the center of focus, which is a spot around 6 degrees wide. Detail drops away rather quickly, the further away from your center of vision it gets. The visual information isn't missing, it's just not coming in at the same fidelity, like background conversation when you're listening to one person. You can get more information by shifting your gaze/focus as needed.
Imagine reading braille, but the pad of your finger is just a patch of skin in the middle of a large field of skin, like on your back. In order to read, you'd have to stick the entire page to your back, and then move that center of focus all over the page. You'd feel the braille all over your back and recognize it as such, but you'd only be reading that one spot. That's roughly what shifting your gaze is like.
Light is like loudness, in that too much of it hurts, and wipes out detail. When there is very little light, detail gets wiped out as well.
Think of the visible light spectrum like the notes of the musical scale, where the note F always sounds like an F, regardless of the octave. The colors do seem related to each other in a similar manner as musical notes; orange does look like it fits between red and yellow, the way that C sharp/D flat fits between C and D.
The "like background conversation if you are listening to one person"-part is what sells it to me!
The analogy works to a certain extent, with one lopsided difference between active listening and active viewing. With hearing, you could theoretically pay attention to one voice emanating from any direction, without repositioning yourself. You probably would turn towards the voice to optimize clarity, but it's not a requirement.
With active viewing, you have to point your eyes directly at the item of interest. That six degree area of visual focus corresponds with visual receptor cells densely packed in one spot on the retina called the macula. The density of cone receptors falls off the further away you get from the macula.
Think of following that one conversation in a crowd, but with a directional microphone. That would give some sense of the manual activity that goes along with vision, to maintain reliable and current information about the visual environment.
Yeah, you are absolutely right. Man, you have a way with words! :) I am able to hear and I still can feel your description!
Right on. Color description is the most challenging to describe; a person who is colorblind will sill struggle with understanding the description of hues that they cannot see the same way as someone with normal color vision. They can see the same light, but because they have only two (or mostly two plus very few of the third cone) types of color sensitive receptors, they're composing an image that cannot fill in the other colors, for lack of detection of qualitative information. Right now if I look at my messy kitchen island, I can see blues,greens. Reds pink, some purple, orange, browns and yellow on the various packages. If I use an app that simulates protan or deuteran colorblindness, the same view is reduced to blues yellows and browns. Everything that was red now looks brown. Green things look brown. Basically everything that isn't blue seems to reduce to browns and yellows.
I have normal color vision, with the usual three types of color receptors. There are a few people who are tetrachromats, and have an additional channel of color information to add to the mix. They still see within the visible light spectrum, but can distinguish colors more easily than I can. This fascinates me, because I'm convinced that I'm seeing everything. But that's no different from a color blind person making due with two instead of three types of receptor. Intellectually, I understand that four distinct qualitative receptors will report more color information to the brain than three will, but it's still a challenge. I think of the tetrachromats as seeing what see, but with a much more refined ability to distinguish between very similar colors.
I love this comment!
Thanks!