So, I was just lurking about the forum when a thought occurred to me. When I read text, I’m only capable of discerning its meaning if I am looking directly at it, in the part of my visual field which has the highest resolution. If I glance to the left or right, I am no longer able to tell what the words are saying. The further off center my field of vision becomes from the text, the less able I am to read, despite clearly being able to see in that part of my visual field. The dyslexia isn’t quite as profound when I divert my gaze up or down, however.
Go ahead, try it out. Choose a forum post which is fairly big wall of text, and try reading words that you aren’t directly looking at. See how far away you can look from a word before it becomes unintelligible without shifting your gaze. When you do this, it’s important that you not know what the words are before you try and read them, otherwise you will get false readings.
I’m not concerned that something is wrong with me, but this does serve as an intriguing look into the neurophysiology of reading comprehension. My best guess is that only the neurons in the very back of the occipital cortex relay information to Wernicke’s area for comprehension. Neurons deeper in, which receive input from the exterior rims of your peripheral vision, only relay information to the accessory visual processing centers which handle “what” and “where”. Can anyone comment on what exactly is going on?
Also, this might serve as a way of illustrating to a normal person what trying to read is like for a dyslexic.
I’m fairly certain this is because only the central area has sufficient resolution to tell the words apart.
I tested this by using a spreadsheet to get very large print words displayed in a random order to the side of the screen. With sufficiently large letters I was able to tell the words apart.
I am quite surprised by this. If I look even slightly to to the right of the ‘Microsoft Windows xp Professional’ graphic that acts as the screensaver on one of the monitors on my desk I can just about discern the ‘W’ in the largest word of the graphic (‘Windows’)
It doesn’t seem to be due to the lack of ‘sharpness’ or clarity. Or even focus. It does seem to be due to the fact that my brain is simply not capable of anywhere near the level of processing power for everything outside that small fuzzy circular area at the center.
It is neural in the sense that we don’t have a conscious loss of visual information in the periphery because it is filled in. Also, less brain real estate is dedicated to peripheral information. However, as Oukile says, this is mostly due to your retina. Cones are better at fine detail than rods for several reasons (smaller size, less noise in the wiring, etc.). The fovea is filled with only cones; while the periphery is mostly rods with a smattering of cones. Your brain does not get the peripheral information in high acuity because it is not given it by the retina.
I’m not sure about speech but I can dig up a link later if you want. As far as what vs. where, the “what” pathway goes to the temporal lobe from occipital and gets a large part of its information ultimately from the cones, and then mostly the red & green cones (parvocellular pathway). The “where” pathway goes to the parietal lobe and gets most of its input from rods (magnocellular pathway).
Just want to repeat this point. You can’t really trust how the phenomenon seems to be since your brain habitually tricks you into thinking you see everything clearly while it’s making up the details of everything except the center of your visual field by memory and extrapolation.
Huh. And all this time, I thought it was my glasses (and lack thereof in the peripheral vision.)
Also, I do think that the brain can’t handle it as well as, in my withdrawal, I’ve had really sharp peripheral vision at times, and it made me very sick.
This is interesting - even focusing just a few words across the page, I wasn’t able to read the poster’s name on each new post as I scrolled down.
And yet, the tiniest motion in your peripheral vision, even just a piece of paper waving in the breeze, sparks a DANGER - LARGE PREDATOR AT NINE O’CLOCK “jolt” in your brain.
There’s a fair amount of evidence that you can use peripheral vision to read if you have to – patients with central scotomas (blind spots) due to various ocular diseases can use peripheral vision to read so long as text is magnified to a great extent – that’s part of what the optometric / opthalmologic specialty of “low vision” is all about. However, as other people have said, acuity gets progressively poorer the farther you get from the foveal region, which is why magnification is so important for these patients.
