How do our eyes “lock on” to objects, keeping them in constant focus despite movement, to the point where un-focusing takes conscious effort?
In: Biology
Two things:
1. Our eyes are (arguably) a part of our brains. They’re the only visible part of our brains. The retina is made of brain tissue, and the whole structure grows out of the brain during embryonic development.
I’m only saying this to highlight how close the mechanisms of the eyes (which receive external stimuli) is to the mechanisms of the brain (which process this stimuli)
2. Many different parts of the brain have the function of processing visual stimuli. The occipital lobe (back of ur head) is the most important part in this respect, whose main job is to processes visual info, and so it has many specialised functions related to it. Functions such as color differentiation and motion perception.
So if ur looking at something in motion, parts of ur occipital brain is lighting up, because ur eyes are noticing differences in light, and ur brain is processing such differences as “movement.”
This whole process – 1. eye receives stimuli, – 2. Sends visual info to the brain 3. The back of ur brain (occipital) processes this info – is automatic, just like differentiating red from blue is an automatic process.
Therefore, keeping track of something in motion is less difficult than trying to not keep track of the same thing, because the first is automatic, the latter is conscious.
Hope this helps, let me know if u have any further qs!
Our evolutionary needs required us to be able to narrowly focus on specific objects at specific distances, be it a branch we’re jumping to grab, a predator hiding in the bushes, or a prey animal we’re hunting. We developed the ability to control our eyes independent of our head (birds, for example, lack this and move their heads to see, not their eyes). Our forward facing eyes increase the overlap of vision from each eye and are adapted to increase depth perception, to better understand distance and relative motion of the things we’re focusing on.
We have the ability to change the shape of the lens in our eyes which adjusts the beam of light we’re “seeing”, allowing us to track the image and keep in focus.
In short, our ancestors who lacked this focusing abilities missed the branch they were swinging for, didn’t see the tiger in the grass, and didn’t kill the food they needed to survive.
Your brain fixes everything.
Your eyes are actually constantly moving, jittering around a little bit and they never stop. You never notice, because your brain decides that it’s better to filter all that out.
Your brain also fixes things like the blind spot you have in each eye from where your optic nerves meet your eyeballs, your lack of color perception on the edges of your vision (it fills in the color it remembers seeing), motion of your head and such.
It does this because if it didn’t, your crap vision would have led to your ancestors getting eaten more frequently.
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