Tuesday, September 21, 2010

Resemblence / Divergence

Prosopagnosia is a perceptual phenomenon in which a human tends to have difficulty recognizing other human faces. This definitely falls into the category of things that I was kind of amazed to learn about (as in, "you mean there's a WORD for that?!") as well as things that I thought "everyone" experienced until I learned otherwise.

In my case I am capable of learning to recognize my fellow apes once I'm very familiar with them, but when someone I see only casually or infrequently gets a haircut or something, I'm liable to not know who the heck they are unless they happen to tell me.

I also used to run into amusing situations when I worked at my last job, as there were some people I only EVER saw in the lab or manufacturing areas. Everyone in those areas was required to wear blue lab coats, and for some reason my brain ended up integrating "blue lab coat" into whatever algorithm it used to recognize those folks. Hence, if one of them randomly walked up to me in the grocery store, initially I would find myself going "gah, who IS this person?" and then finally having to just come out and ask them who the heck they were.

Oh yeah. And when I first saw "Star Wars" as a kid I knew I really LIKED it, but I could not for the life of me tell those two white guys (Han Solo and Luke Skywalker) apart...not until I figured out that their SHIRTS were generally a different color. Seriously. I also spent several years of my childhood under the impression that removing/replacing my glasses was an awesomely effective disguise, seeing as I CLEARLY looked like a completely different person based on whether I was wearing glasses or not.

But! Regardless of whatever issues I might have with HUMAN faces, apparently this doesn't carry over to feline faces. Because every cat I've ever seen looks different from every other cat I've seen, and this is almost always immediately obvious to me. (Any neuroscientists reading this want to take a crack at explaining this one, I'd be very curious to get your thoughts!)

Case in point: two of the three ex-feral littermates sharing my home happen to be blue mackerel tabbies. And I've noticed that a lot of humans persist in classifying cats based almost solely on their coat pattern/color. Several people have, upon seeing Coraline and Brodie, asked me "...but how do you tell them apart? They look like twins!"

Um...no they don't. Not to me at least. They're siblings (brother and sister) so there are certainly aspects they share in common. But they do NOT look anywhere near identical.

Heck, they're not even the exact same color (despite falling generally into the "blue tabby" designation). Brodie is a lighter/softer grey, whereas Cora is "higher contrast" and has some areas of lighter fur that range almost toward a brown-tan color. You can sort of see this in the picture below (in which the tabby siblings survey the new shelves I just put up in the spare bedroom recently):

These two kitties are also quite different in size, though admittedly that's a lot easier to perceive in person than it is in photographs. Cora is a little compact kitty with a "roundness" to her (which isn't anything to do with weight...she's only 7 lbs). She also has this rather unusual fur that isn't quite long enough to be "medium" but which is extremely fluffy and kind of sticks out rather than flopping over (if that makes any sense). Brodie, meanwhile, presently weighs 14 lbs and is much longer-bodied than Cora.

This picture (above, in black and white), with Brodie on the left and Cora on the right, shows some pretty dramatic differences in how their faces are shaped. First off, there's the ears: Brodie's are more triangular, whereas Cora's are more oval-shaped at the tips. Cora also has kind of a heart-shaped face, while Brodie has a pointier chin and overall a more triangular face (with a squarish jaw...he's got some Maine Coon in there somewhere I think, despite his very short, fine hair).

...and here we have a really clear view of their differing profiles. (And it's just the camera angle making Brodie, on the left, appear smaller than Cora, on the right...again, he's a lot bigger than she is IRL). Brodie has a rather long head and muzzle, almost to Oriental/Siamese proportions, whereas Cora has a shorter muzzle and a little vaguely up-turned nose. Again, very different-looking IMO.

Of course their personalities are also quite different -- you'd NEVER mistake them for the same cat if you actually knew them. But even on the level of "mere" appearance, to me there's just no question they're not identical by any stretch of the imagination. They're both beautiful, certainly, but not in the exact same ways!


  1. Thanks for a great blog! We have three cats (all from different litters) - among them two ginger tabbies (one of them female, which is very unusual). Visitors and friends also have a hard time telling them apart, although they are very different in coloring, shape and size. The male is much larger (obviously), with a softer fur and is lighter in color, and has much more white in him than the female, who is smaller, much darker and has a coarser fur.

    We use the following to teach our friends to tell them apart
    1. white feet & belly - Tom vs white chin only - Kitty
    2. green collar - Tom vs blue collar - Kitty
    size only works in comparison if they are near each other.

    And ours also like to knock things over - especially empty food bowls, if every other attempt at getting our attention fails

  2. That's interesting about the prosopagnosia. I don't have quite as much trouble as you describe, but the experience of not recognizing people out of context is certainly one I'm familiar with. I've gotten a bit better with faces in person since I went to a presentation by a facial recognition expert, who serves as an expert witness in identity fraud cases - he talked about the tiny details he uses, and I find them more helpful than the general impression I'd get just from looking normally. For example, if I can remember, Bob is the guy with the really pronounced nasal philtrum, and Joe has a small scar by his right eye, that's more helpful than actually trying to learn Bob and Joe's whole faces.

  3. intransigentia: Yeah, the "not recognizing people out of context" thing is probably the most prominent aspect of how I experience prosopagnosia. I've actually gotten a LOT better at face-recognition in general since I was a young child...it takes me fewer times seeing a person now to get a good sense of what they look like.

    I wonder if maybe I just ended up gradually working out how to do the sort of thing you learned about in the facial recognition presentation you referred to (which sounds like it would have been really interesting...I'd love to see something like that).

    But in any case, I think perhaps cats are easier for me to recognize partly because they're so much smaller than humans (meaning I can see all of them at once and get more of a "shape gestalt sense" when I look at them. They're also not generally wearing clothing and they don't change their hairstyles very often so those things wouldn't be serving as a distraction from the rest of what they look like.

  4. Connie: Welcome! And wow, yeah, I've also heard female ginger tabbies are rather rare. There's a good summary of why here on Sarah Hartwell's site...basically a girl cat has to inherit two copies of the gene in order to be orange, whereas a boy cat only has to inherit one. Your kitties sound lovely...do you have any pictures of them to link to?

    Cora and Brodie's brother/littermate, Shadow, is solid black (except for a small white spot on his lower belly; he also used to have one white whisker but it fell out and grew back black.). So nobody is liable to mix him up with any of the others.

    Their mother Coal (who is feral, extremely wily, and has so far proven impossible to trap for spaying) is also solid black and has had several litters including both black and tabby kittens, though she did have one solid grey boy (Radar, though this isn't the best picture of him) which was kind of unusual.

  5. Okay, I know now that this is real for me. Explanation: I told a friend that I was prosopagnosic for humans (to the extent of not recognizing my own mother if she changes her hairstyle, not being able to tell my brother apart from other tall fat guys with black hair and mustaches, etc.) and not for cats, and she told me this wasn't possible and that I was probably telling them apart based on markings or something. Which of course I wasn't. I just recognize cat faces far more easily than human ones.

  6. Amanda: Oh geez. Your comment reminds me of how, when I was little, I would get upset if my mom took off *her* glasses, because she looked like a completely different person to me, to the point where it was really disturbing. Similar reaction the one time my dad shaved off his mustache...THAT was incredibly weird, especially as his upper lip was really pale due to never getting any sun usually.

    All that aside, I don't see why it would be impossible for someone to be prosopagnosic for one species but not another. In my case I do think there's probably an element (as I noted in a previous comment) of finding cats easier to recognize because they aren't wearing clothing or changing hairstyles the way humans tend do, but there IS also definitely just something about their faces that my brain finds easier to deal with.

    ...and now I must go feed the feline foursome as Shadow is sitting behind me reminding me loudly and repeatedly that it's dinnertime!

  7. Hello Anne,

    here is a link to pictures of the two gingers.


    Kitty also sports 1 single black whisker, and one that is black on the bottom, and white on top.

    One of Tom's canines is also partially broken off - we only noticed at the general check-up at the vets. Apparently, it is quite common, and does not bother them at all.

  8. I once mentioned off-hand to a friend who got a degree in neuroscience how interesting it is that humans see face shapes in everything (for example, in wall electrical sockets, cars, etc) and she told me about how there's a specific part of our brains that makes us recognize faces. So perhaps there's also a part of our brains that helps us recognize between different humans, and that could be affected by Prosopagnosia.

    I think a lot of people who make "they look like twins" comments have never owned animals. I agree that they're pretty easy to tell apart once you spend a small amount of time with them. Your two sibling cats look similar to me, but based on that picture, they look quite different. If only because the male is clearly larger than the female.

  9. From what I learnt in my neuropsychology class (I'm a 2nd year psych major) the 'fusiform gyrus' is the part of the brain usually responsible for face recognition. It's also responsible for other kinds of specialized recognition - birdwatchers show activation in this area upon seeing birds, car afficianados upon seeing cars, etc. Some psychologists have said, based on this, that most people are 'face experts'. One quirk of this is that normal recognition is unaffected by flipping the thing upside down, but fusiform gyrus recognition is seriously affected by this. There are exceptions, though, if you commonly see the thing in multiple orientations - monkeys for example can easily recognize upside-down faces.

    There are two kinds of prosopagnosia. One kind is when the fusiform gyrus doesn't work, and this kind would also prevent highly specialized recognition of other visual images. People with this kind are actually *worse* at recognizing faces than most other things, because the faces get sent to a 'black hole' of recognition.

    The second kind, which I suspect you have, is where the fusiform gyrus works just fine, but doesn't deal with faces. Basically, your brain doesn't signal faces as important enough for specialized recognition, so they go through the regular recognition system. As a result, recognizing an individual face is about as easy as a non-geologist recognizing an individual rock. This type appears to be more common among autistic people, probably because autistics are generally less interested in social interaction. And it doesn't affect use of the fusiform gyrus for other kinds of specialized recognition, such as recognizing individual cats if that's important to you.

  10. Ettina: Wow, that's interesting re. the fusiform gyrus and different variants of prosopagnosia. The second variant does indeed sound like what I experience...it's actually really weird to me to even consider faces being "specially" recognizable.

    For me recognizing a human face is pretty much exactly like coming to recognize a specific rock or something (and of course this doesn't mean I'm saying "humans are exactly like rocks"!). I have to build up data about what makes a given face "that face" over time. And with cats I definitely have a special interest in them so maybe my brain has just optimized in a way that makes it easier for me to tell them apart. Very interesting to think about at any rate.

  11. Mariko: Randomly, I checked out your blog and your cats are adorable! :D

    And also funny you should mention electrical sockets because that's one of the first inanimate objects I learned to see as "face-like". But that didn't happen until I was sixteen years old, oddly enough.


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