Why is it that I am not able to read a book without moving my eyes if the entirety of the page is within my field of view? Why do I have to center my eyes on an object to observe it fully? And why is it that I am still able to view changes in surroundings in the edges of my field of vision despite there being supposedly no way to focus on them from that angle?
Is it due to our brain’s capacity to absorb a finite amount of visual information at a given moment or is it a physical flaw in the structure of our eyes?
This is what interests and distresses me about the mysteries of the human body. I once saw a video about capturing a person’s recollection of his memory of a video clip by scanning his brain activity. The result was really obscured and blurry, but it actually did resemble the clip, which was deeply disturbing. I would have never known my actual vision is vastly different from what my brain makes me perceive to be.
What you perceive is vastly different than a continuous filmstrip. Have you ever tried to watch unstabilized footage from a person jogging? Totally unwatchable! But your brain smooths it out better than the best steadicam. Tilt your head from side-to-side: what you perceive stays upright. And of course you know hat your eyes don’t smoothly pan from subject to subject but are constantly “saccading” around, but your brain processes that all away.
Visual processing is amazingly complex. Its also interesting that our other senses have different levels of processing. Our sense of smell is nothing compared to a dog’s, our sense of hearing is nothing compared to a whale’s, etc. A metaphor I heard once (don’t know how accurate it is) is that when a human walks into a kitchen they might smell that a stew is cooking. A dog would smell both the overall smell but would also smell the individual carrots, peas, chunks of meat, etc.
I think a useful way to think about it is that your perceptual brain isn’t in the business of making you see, or hear, or anything like that - it’s in the business of giving you an accurate-enough-to-be-useful idea of what’s around you. You see the world as being sharp and stable and consistent even though the literal visual signals going from your eyes to your brain aren’t… because the world is sharp and stable and consistent. Or at least it’s enough those things that it was useful for the brain to evolve to generate that specific perceptual experience. The signals coming from your eye are just (some of) the information the brain uses to generate that experience.