Class Warfare Blog

October 4, 2019

More on the “Reality” of Our Senses

Filed under: Science — Steve Ruis @ 12:45 pm
Tags: , , ,

A recent magazine article in Quanta magazine addressed some fine points most of us are unaware of regarding our vision (Your Brain Chooses What to Let You See, <sub> Beneath our awareness, the brain lets certain kinds of stimuli automatically capture our attention by lowering the priority of the rest.).”

There are a number of fascinating limitations on our ability to “see,” that is to take in information through our eyes and process it. Consider these snippets from the article:

“Scientists have long known that our sensory processing must automatically screen out extraneous inputs — otherwise, we couldn’t experience the world as we do. When we look at our surroundings, for instance, our perceived field of view holds steady or moves smoothly with our gaze. But the eye is also constantly making small movements, or saccades; our visual system has to subtract that background jitter from what we see.

“Automatic suppressive types of mechanisms take place … through large swaths of the brain,” said Richard Krauzlis, a neuroscientist at the National Eye Institute at the National Institutes of Health in Maryland. “Basically all over the place.”

“And automatic background subtraction, it turns out, can also manifest in intriguing, unexpected ways. Take a counterintuitive finding that Tadin and his colleagues made in 2003: We’re good at perceiving the movements of small objects, but if those objects are simply made bigger, we find it much more difficult to detect their motion.”

What a lot of people don’t realize is that the sheer amount of information available to our senses would swamp any brain, supercomputer, quantum computer, you name it. So, we necessarily must dump a very high percentage of the information (bits and bytes) coming in because we have neither a way to store it nor process it. (Read the book The User Illusion by Tor Norretranders if you are interested in this topic.)

Apparently there are many, many mechanisms used to sort and prune away superfluous information. One of those is that our eyes actually have a very small cone of focus (<10°) in which our vision is sharp and detailed. Visual acuity declines by about 50% every 2.5° from the center up to 30°, at which point visual acuity declines more steeply. Consequently, our visual sense flits about, usually caused by something moving. Our attention brings the moving thing center stage where we can see it clearly. This is why TV screens in a bar or another room keep pulling on our attention. The flashing lights simulate things moving, so our eyes flick there . . . over and over and over.

The light entering our eyes, as I have mentioned, is taking 3-D information and projecting it upon a 2-D surface (the retina) losing the information from the 3rd dimension. Well, and the optics of the eye flip the images upside down and . . . and . . . well, suffice it to say, a fair amount of “post capture” video processing needs to occur.

I recommend the article to you if you are interested in how our senses do not (and really, cannot) detect “reality.” And, those who are alarmed at how much our senses fail to detect “reality,’ well, I think they doth protest too much.

Our senses can be trusted to be what they are. In that they are quite trustworthy . . . flawed but trustworthy. And just because we are not immediately aware of what is going on, that doesn’t prevent us from actually learning what is going on, so as to appreciate it for what it is and not just what we think it is.

 

Blog at WordPress.com.