What Do Cats See?(mydeals.com)
mydeals.com
What Do Cats See?
http://www.mydeals.com/blog/what-do-cats-see/post
25 comments
I suspect not. To do so would imply that cats are self-aware, which no one has been able to demonstrate.
Or that there is an evolutionary advantage to being able to escape other cats by moving slower than they can see.
The idea was that moving slowly implies that they recognized the other cat has the same limitations as itself.
I am beginning to find Hacker News very tedious when people down-vote posts that they disagree with which were made in good faith.
I am beginning to find Hacker News very tedious when people down-vote posts that they disagree with which were made in good faith.
Have you ever seen a pride of lions hunting? The teamwork and understanding involved there is way beyond that required to recognize that another animal might not notice if one moves slowly.
One very simple step is they recognize the concept of upwind and downwind, not to mention the concept of beaters, ambushers and the ability to dynamically change their strategy when circumstances change.
One very simple step is they recognize the concept of upwind and downwind, not to mention the concept of beaters, ambushers and the ability to dynamically change their strategy when circumstances change.
This article was substandard for HN. No real mention or explanation was made of the reflective layer behind the retina, this is the special feature that gives cats what amounts to night vision, however it is at a cost of resolution. But hey, VGA night vision is better than a 4K pitch black image.
I have noticed that the cats I know are selectively short sighted. A rival cat from a neighbouring area or a fox can be spotted at considerable distance, however, a 'loved human' has to be relatively close to be acknowledged. This could have been rendered in the images, having it so that 'humans see humans' and 'cats see cats' in otherwise identical scenes.
Cat view - as in a few inches from the ground would not have been that hard to do - how difficult is it to take a photo these days rather than just download something random from the internets?
Furthermore, a cat's eyesight is augmented by an array of whiskers. These can be moved forward and back and are there to work out what something in close quarters is doing or shaped like. The cat has this area covered by the whiskers and has no need to be able to focus there even though we expect them to when we wave something in front of their noses.
I have noticed that the cats I know are selectively short sighted. A rival cat from a neighbouring area or a fox can be spotted at considerable distance, however, a 'loved human' has to be relatively close to be acknowledged. This could have been rendered in the images, having it so that 'humans see humans' and 'cats see cats' in otherwise identical scenes.
Cat view - as in a few inches from the ground would not have been that hard to do - how difficult is it to take a photo these days rather than just download something random from the internets?
Furthermore, a cat's eyesight is augmented by an array of whiskers. These can be moved forward and back and are there to work out what something in close quarters is doing or shaped like. The cat has this area covered by the whiskers and has no need to be able to focus there even though we expect them to when we wave something in front of their noses.
I understand that cats have face blindness. To a human, another human looks very distinctive and unique as we have been crafted by evolution to notice the tiniest difference between faces. To a cat, we all look pretty much the same, it takes them a bit more effort to work out who is who.
Cats and other animals can see different spectrum, which is useful to their hunting. Noting that raptors can see infrared so actually 'see' the thermals they are flying in makes a whole lot of sense from an evolutionary standpoint.
Apropos of nothing, I find this a fascinating way of enhancing the link authority of a coupon site. Given algorithm changes at Google which punish sites for little original content, adding a blog like this to your coupon site ups content that allows you to organically rank higher.
Apropos of nothing, I find this a fascinating way of enhancing the link authority of a coupon site. Given algorithm changes at Google which punish sites for little original content, adding a blog like this to your coupon site ups content that allows you to organically rank higher.
I am not sure if I agree with the blurriness of cat-seen images. Human eyes are known to be pretty bad in terms of hardware. It is our brain that applies the wonderful image reconstruction that gives us the perception of crystal clear images. By scanning the neural pathways that transmit image data to a cat's brain, researchers have only establish the kind of signals that a cat's eye sends to its brain, not what a cat actually sees. It is entirely possible (and very likely) that the brain of cats sees something very different than what these images would have us believe.
I thought enhanced color vision developed for distinguishing plants. Primates eat lots of plants nad have been trichromatic. Cats and dogs are mostly meat eaters.
When a cat looks at a human he sees a servant.
Ran the link through Lynx and the results seemed more accurate:
[BED] [BED] [SCRATCHING POST] [BED] [POTTY] [BED] [BED] [BED]
[BED] [BED] [SCRATCHING POST] [BED] [POTTY] [BED] [BED] [BED]
Forget about cats,how can we be sure that all humans see the same colors?
How come all those cats are nearly 6ft tall?
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if I understand correctly they are short sighted so a good picture to add would be a macrophotography with a background to see where is their best vision in terms of depth of field no ?
The trouble with "simulations" like these is they ignore cognitive post-processing - much like visualizations of what it's like to look through a compound eye portraying it as like looking at a wall of TV sets.
The human images and the cat images are not comparable because the human images represent a subjective impression, rather than a prediction from visual capabilities like the cat images. For example, the human images are crisp right out to near the edges. This is simply inaccurate - you can only read text within a FOV of about 6 degrees.
The human images and the cat images are not comparable because the human images represent a subjective impression, rather than a prediction from visual capabilities like the cat images. For example, the human images are crisp right out to near the edges. This is simply inaccurate - you can only read text within a FOV of about 6 degrees.
I think these simulations are after post-processing. That us exactly why the human vision picture is sharp past 6 degrees from center - the picture portrays what we see after our brains stitch together a visual field.
The human image is after post-processing. But we do not (cannot?) know what post-processing cats apply! Their impression of their own visual field could be just as sharp as ours (and probably is).
I think this misses one of the keys aspects of cat vision, movement perception. You'd need video for that. I imagine they see something like a glowing trail around moving stuff. Depeding on light conditions my cat might ignore food/toy until it moves.
The photos miss that, but it is mentioned in the text:
The increase in rods also enhances their “refresh rate”, so that they can pick up movements much faster (very helpful when dealing with small animals that change direction very quickly during a chase)
Also: Interestingly, this also means that humans have the ability to see very slowly moving objects at speeds 10 times slower than cats (that is to say that we can see very slow things move that would not appear to be moving to a cat)
Which made me wonder why sneaking up on a cat chameleon-style doesn't work better.
The increase in rods also enhances their “refresh rate”, so that they can pick up movements much faster (very helpful when dealing with small animals that change direction very quickly during a chase)
Also: Interestingly, this also means that humans have the ability to see very slowly moving objects at speeds 10 times slower than cats (that is to say that we can see very slow things move that would not appear to be moving to a cat)
Which made me wonder why sneaking up on a cat chameleon-style doesn't work better.
You're not moving slowly enough, and cats can hear really well.
And they can probably smell you unless you're down wind.
I often have to shake my cat's biscuits before she'll eat them, even if she has just been eating them.
Hasn't anyone invented a "jiggling cat food bowl" yet?
She'd probably try to kill it
It also misses another key aspect of cat perception - the keener senses of smell and hearing. They are less visually-centric than humans.
You could say the same about dogs and many other animals.
You could say the same about dogs and many other animals.
For the video simulations you're suggesting, they would have to slow everything down for us to see the difference, which would kind of break the realism they showed until then.
Also, the glowing trail thing would be a great way only for creatures like us humans, with slowly refreshing visual brains to handle information coming from faster refreshing retinas. But I have to imagine cats have their brains appropriately tuned for the refresh rate if their retinas and see movements clearly, with great detail in the time dimension.
Also, the glowing trail thing would be a great way only for creatures like us humans, with slowly refreshing visual brains to handle information coming from faster refreshing retinas. But I have to imagine cats have their brains appropriately tuned for the refresh rate if their retinas and see movements clearly, with great detail in the time dimension.
[deleted]
I have seen my cat find a mouse in a camouflaged garden even when the mouse was not moving. Either this study is wrong or my cat is special.
I think you're missing a few possible scenarios.
First and foremost, cats have exceptional olfactory senses.
Second of all, the mouse was likely moving around before it noticed your cat approaching, at which point it froze. (By that time, it was of course too late.) Mice don't typically just sit in a garden, never moving.
First and foremost, cats have exceptional olfactory senses.
Second of all, the mouse was likely moving around before it noticed your cat approaching, at which point it froze. (By that time, it was of course too late.) Mice don't typically just sit in a garden, never moving.
Cats hear up to 60kHz. Those are super senses for us. Imagine what they can hear by small animals -- the movements of the very small things in and on mice, their breath...
The mouse wasn't moving that you could see. Consider that a mouse has a much higher heart rate; if you can pick one up (eg those rare occasions where you are able to rescue prey from the cat) they practically vibrate in your hand.
Also, another poster makes a good point about cats' hearing. Not only do cats hear in higher frequency ranges than we do thanks to their reduced size, they can angle their ears to 'focus' on a particular sound; being a sound engineer by profession, I desperately envy them this ability. I have simulated this using cardioid microphones while wearing headphones, and I would cheerfully sacrifice a good deal of social standing for a pair of working prehensile ears.
Also, another poster makes a good point about cats' hearing. Not only do cats hear in higher frequency ranges than we do thanks to their reduced size, they can angle their ears to 'focus' on a particular sound; being a sound engineer by profession, I desperately envy them this ability. I have simulated this using cardioid microphones while wearing headphones, and I would cheerfully sacrifice a good deal of social standing for a pair of working prehensile ears.
Mount the microphone/headphones in something like these? http://www.necomimi.com/
You might have to follow through on that "I would cheerfully sacrifice a good deal of social standing" part, though...
You might have to follow through on that "I would cheerfully sacrifice a good deal of social standing" part, though...
Those pointy ears are there for a reason - cats use more than sight to locate prey.
Their visual acuity isn't based on movement, like a Tyrannosaurus. If you look at a painting, you can still see it just fine even though it's not moving.
Michael Crichton invented T-Rex movement based vision for his books (attributed to contributions from frog DNA). The T-rex likely possesed incredibly powerful vision. http://en.wikipedia.org/wiki/Tyrannosaurus#Senses
And their top speed is estimated at only 25mph rather than 45mph? My whole life is a lie!
that's a blog just to get seo for a "deals" website. to flag or not to flag?
Prefer the Mail? http://www.dailymail.co.uk/sciencetech/article-2462559/Nicko...
Both the DailyMail and PopSci websites reference this "deals" website as the source. So while the site doesn't look like official news, from what I can tell it seems to be the proper source.
This SEO-looking site does credit Nikolai Lamm, who's also posted the content on his personal site, with no further attribution for the photos:
http://nickolaylamm.com/art-for-clients/what-do-cats-see/
I was surprised to find that the "Art for Clients" tag on his site contains a lot of content that's gone heavily viral recently (especially "The Average Man" photos, which were on HN a few days ago):
http://nickolaylamm.com/category/art-for-clients/
And all these professional news agencies, presumably with legal teams to back it up, attribute Nickolay Lamm as the source for all of those I checked.
From his "About Me":
> I blog for MyDeals.com, MyVoucherCodes.co.uk and StorageFront.com. Each blog post I make takes around 4 weeks to create.
http://nickolaylamm.com/about-me-2/
I smelled something fishy from the "mydeals.com" source from OP, and initially thought that the Daily Mail's attribution to that site was just sloppy and awful... but it all checks out. Huh.
http://nickolaylamm.com/art-for-clients/what-do-cats-see/
I was surprised to find that the "Art for Clients" tag on his site contains a lot of content that's gone heavily viral recently (especially "The Average Man" photos, which were on HN a few days ago):
http://nickolaylamm.com/category/art-for-clients/
And all these professional news agencies, presumably with legal teams to back it up, attribute Nickolay Lamm as the source for all of those I checked.
From his "About Me":
> I blog for MyDeals.com, MyVoucherCodes.co.uk and StorageFront.com. Each blog post I make takes around 4 weeks to create.
http://nickolaylamm.com/about-me-2/
I smelled something fishy from the "mydeals.com" source from OP, and initially thought that the Daily Mail's attribution to that site was just sloppy and awful... but it all checks out. Huh.
I found it on http://www.spiegel.de/, which linked back to the seo-website.
I think there is one fundamental flaw with simulating color seen by non humans or dichromat humans. I've seen this in all computer based simulators. They simply change the weight of some colors relatively to others.
But a dichromat with say, missing L cones will not simply mix green and red, he will experience "green" totally differently than a trichromat. What a trichromat call green is the result of the stimulation of both M and L cones. We cannot see the pure spectral green. We cannot subtract the L cones contributions to what we experience, and its is quite important. The dichromat won't have any L cones contribution, the physiological stimuli won't be the same. He sees the actual spectral green. A color we have never seen and that we cannot imagine.
Now there is an experiment to do : put a full page of bright red and stare at it for minutes. It will start to become orange-ish. This is your L cones getting tired. Now swiftly switch to a bright green full page (prepare it so you can switch with a key press). You will experience a purer green that you ever experienced, because this green will have less red component to it as your L cones are tired (the effect will last mere seconds and quickly fade into normal green). If you were able to completely remove your L cones, you would see what the dichromat sees.
But a dichromat with say, missing L cones will not simply mix green and red, he will experience "green" totally differently than a trichromat. What a trichromat call green is the result of the stimulation of both M and L cones. We cannot see the pure spectral green. We cannot subtract the L cones contributions to what we experience, and its is quite important. The dichromat won't have any L cones contribution, the physiological stimuli won't be the same. He sees the actual spectral green. A color we have never seen and that we cannot imagine.
Now there is an experiment to do : put a full page of bright red and stare at it for minutes. It will start to become orange-ish. This is your L cones getting tired. Now swiftly switch to a bright green full page (prepare it so you can switch with a key press). You will experience a purer green that you ever experienced, because this green will have less red component to it as your L cones are tired (the effect will last mere seconds and quickly fade into normal green). If you were able to completely remove your L cones, you would see what the dichromat sees.
For the lazy programmers who don't want to write some quick JS to simulate what a dichromat perceives as green:
http://ill.cc/colorz.html
click on the page, toggle between red & green with any keypress
http://ill.cc/colorz.html
click on the page, toggle between red & green with any keypress
If you're on a mobile device without a keyboard, I made an alternative version that changes on click rather than keypress:
http://jsbin.com/iPIrucU/1
http://jsbin.com/iPIrucU/1
Derp. I figured someone else would beat me to it. Press or click. It goes through 3 contrasting pairs (based on the wikipedia article):
http://jere.in/opponentprocess.html
http://jere.in/opponentprocess.html
Oh, wow, thas was an incredible experience, thanks!
In trying to explain it some way... the green was SO GREEN that it actually looked like it was flashing blue.
By the way, is there any other similar experiment I could try?
In trying to explain it some way... the green was SO GREEN that it actually looked like it was flashing blue.
By the way, is there any other similar experiment I could try?
For some definition of 'similar': http://www.scientificpsychic.com/graphics/
You might be interested in what is called opponent process theory of color vision.
I know I can google it, but is there a particular link you recommend to read up on it?
As it happens I was just researching it myself (it was briefly mentioned in a lecture on scientific visualization). I found this (have not read yet), what seems like a thorough and serious treatment of the subject.
http://www.handprint.com/HP/WCL/color2.html#heringtheory
http://www.handprint.com/HP/WCL/color2.html#heringtheory
that is very interesting, thank you! Could you link to some research/info or drop some terms so I can search myself?
I wrote up a little more detail about the sensitivity of the 3 "colors" of cones in your eye: https://news.ycombinator.com/item?id=4169772
mind white balance correction?
I second your analysis. Moreover the 'qualia' perceived by any creature is not yet well defined. The whole effort is human-centric, even us looking at this web site and seeing 2 versions for comparison. One more thing, is the choice of a city view, which is quite unnatural and a panorama create by humans for humans.
I'm routinely impressed that my cat uses a litter box with no problem that is almost completely dark at night. Not sure how she can see what she's doing, but it's cool!
I don't think she needs to see anything (although she probably does, at least dimly). Even humans should have no problem navigating around a familiar environment without relying on vision -- especially those humans accustomed to it, such as blind people. And cats get plenty of help from their other senses that are considerably keener than their human equivalents.
If someone would do the same for eagles instead of cats, that would be awesome.
Wouldn't the bokeh (~defocus kernel) shape be changed by the fact that cats have a differently shaped pupil?
Interesting nonetheless.
Interesting nonetheless.
It's an interesting trend to run a blog that drives attention to your startup. The posts are becoming less and less relevant to the company too.
Don't forget about the scientists who apparently took direct video output from a cat's brain - it looks like they have a facial pattern recognition similar to that of ours - what I mean is they look for the eyes/nose/mouth/etc and most likely see cat-like faces on other animals and humans (like we do when we think a dog is smiling). Interesting...
Scientists at Berkeley have actually recorded what cats see by scanning a vision pathway in their brain: http://www.berkeley.edu/news/media/releases/99legacy/10-15-1...
Here's a link to the video: http://www.youtube.com/watch?v=piyY-UtyDZw
Here's a link to the video: http://www.youtube.com/watch?v=piyY-UtyDZw
What Garrett Stanley and Yang Dan did in that work [1] is very cool, but it's a reconstruction. It is "what a cat sees" in the same sense that a false color image is "what a satellite sees". Essentially they regressed the activity of an ensemble of LGN neurons (visually responding neurons in the thalamus) with pixels on a camera to build a set of linear filters in space and in time. Then they used those filters to reconstruct the scenes based on the neural activity alone [2]. So it's what the cat sees in a kind of information-theoretic sense.
1. https://stanley.gatech.edu/publications/stanley_dan_1999.pdf
2. And actually on a reread this morning, it doesn't seem that they cross-validated their reconstructions. So perhaps their reconstructed movie frames are actually an overestimation. Regardless, there is no doubt that their technique works and it was a great starting point. Keep in mind: they did this in 1999!
1. https://stanley.gatech.edu/publications/stanley_dan_1999.pdf
2. And actually on a reread this morning, it doesn't seem that they cross-validated their reconstructions. So perhaps their reconstructed movie frames are actually an overestimation. Regardless, there is no doubt that their technique works and it was a great starting point. Keep in mind: they did this in 1999!
If this is really what our cats are seeing, no wonder they seem to be scared or annoyed by us sometimes. Also, no point of buying colorful toys since they can't appreciate the colors.
A neighbour's cat and my cat had a argument, no actual fighting - just lots of staring, yowling and that strange growling sound cats make. Nothing too questionable there, but then my cat did something rather strange - she started moving away by walking extremely slowly and I mean extremely slowly. I wondered what on earth she was up to but after reading this article I think it must have something to do with the fact that cats cannot seem to detect very slow motion. It appears that cats can move and position themselves in such a way that it may be undetectable (or nearly so) to another cat.
Of course there may be a completely different explanation, but I like this one.