Cat Vision

by F.

Via Omni Brain, I came across this story on the BBC’s website about cat vision. The article purports to reprint “the first pictures from an extraordinary experiment which has probed what it is like to look through the eyes of another creature.” That other creature is a cat. The article suggests that the pictures on the bottom are what the cat is seeing. Those on the top are what we see—a human face. (I guess).

_471786_catimage1300.jpg

There’s a pretty big problem with this conclusion, as far as I can see: there’s very little reason to think it’s true and some reason to think it’s false.

Remember than human vision is “constructive.” For instance, the image on our retina in upside down. Imagine if a martian scientist did something like this cat experiment on us. He might report his findings in his equivalent of Nature: “I have found that human beings have a remarkable property—they see the world upside down. And yet they are still able to navigate around the environment. It is absolutely amazing that they can accomplish anything at all. But I hooked up electrodes to the thalamus of various ‘volunteers’ and was able to use a linear decoding technique to produce these images.” Imagine a graphic with upside down images in the sidebar. Martian readers gasp in astonishment as they try to imagine what that would be like.

Not only is the image on the retina upside down, we have two eyes the data from which is integrated by the brain. Yet we don’t see two fields of vision. And we have this thing called a blind spot, which of course we don’t notice—our brains fill in the gap, even though it’s constantly moving all over our visual field. There are more examples but you get the point. If you want more, read Hoffman’s book, cited below.

So, when Snowball looks through her beautiful green, snake-pupiled eyes, she sees—-What? I don’t know. But there’s little reason to think it’s that blob pictured above, because her little mind may be constructing the perceived object. I’m not saying she sees a face. I don’t know what Snowball is constructing. But I don’t see why she wouldn’t see more than a bunch of pixelated blobs. How useful would it be to see a blurry bunch of undifferentiated goo? If our brains are constructive—which they are—why wouldn’t hers be? At least moderately.

From my own experiments—which don’t involve cutting or power-tools—I’ve noticed that my cat can recognize objects from a fair distance. I’m not an expert on cat vision by any means, but I believe I read that cat’s can only see a few feet with any clarity. But my research subject, Bijli, can see birds up to 60 meters away. How do I know she sees birds and not just “moving blobs”? Because she makes her little bird-chirp noise. She does this when, and only when, she sees the things you and I call “birds.” So somehow she’s able to pick out birds. At least, that seems like a reasonable conclusion.

She can also see other cats from about 100 meters away. From our porch, she can see our neighbor’s porch, and when his cat is out, she knows it. I’m less confident of what she sees in this case than in the bird case because she doesn’t have an “I see a cat” noise. But she does hunch down, sit still, crane her neck forward, and stuff like that. She does the same thing when Poppy, the next door cat, is close to her—5 meters or so—and I think it’s reasonable to conclude that she can see 5 meters.

David Marr, a neurophysiologist, described it this way: “Vision is a process that produces from images of the external world a description that is useful to the viewer and not cluttered with irrelevant information….” Put another way, our vision is fundamentally constructive. “[W]e cannot dispense with construction,” Donald Hoffman says in Visual Intelligence. “Dispense with construction and you dispense with vision. Everything you experience by sight is your construction.”

Why wouldn’t Snowball’s little brain be doing the same thing? After all, cats are pretty amazing little fuzz-balls, as Christopher Smart so effectively conveyed in perhaps the best cat-poem ever. “For I Will Consider My Cat Jeoffry,” Smart wrote sometime between 1756 and 1763 while confined in an asylum,

For first he looks upon his forepaws to see if they are clean.
For secondly he kicks up behind to clear away there.
For thirdly he works it upon stretch with the forepaws extended.
For fourthly he sharpens his paws by wood.
For fifthly he washes himself.
For sixthly he rolls upon wash.
For seventhly he fleas himself, that he may not be interrupted upon the beat.
For eighthly he rubs himself against a post.
For ninthly he looks up for his instructions.
For tenthly he goes in quest of food.
For having consider’d God and himself he will consider his neighbour.
For if he meets another cat he will kiss her in kindness.

Cites: Marr, D. 1982. Vision. San Francisco: Freeman; Hoffman, D. D. 1998. Visual Intelligence. New York: Norton.

Advertisements