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It's Surprisingly Hard To Notice When Moving Objects Change
An anonymous reader writes "Scientists at Harvard have found that people are remarkably bad at noticing when moving objects change in brightness, color, size, or shape. In a paper published yesterday (PDF) in Current Biology, the researchers present a new visual illusion that 'causes objects that had once been obviously dynamic to suddenly appear static.' The finding has implications for everything from video game design to the training of pilots."
Is that why my wife is always running around ?
Everything I write is lies, read between the lines.
It's Surprisingly Hard To Notice That It's Moving!
I think this was fairly well known (at least intuitively) by magicians. As long as you keep your hands moving, people can't tell what you are doing with them.
Our eyes are trained to do a whole lot of quick thinking and estimates before sending the raw data to our brain. This is one of the many reasons why simply hooking a camera up to the optic nerve doesn't quite produce the desired results - though our brains seem to be super-learning computers able to interact with almost any other kind of Input - Output, given enough time for trial and error.
I imagine our Eyes are trained to generalize the colour it sees and focus on the appearance of motion, because thats usually more important and relevant to survival, and our eyes are just like technology: Limited bandwidth.
You might call it a defect, I might think of it as evolutionary design.
IAAVN (I am a Visual Neuroscientist). It's a compelling illusion. I have not read the original paper, but will speculate nevertheless in true Slashdot fashion. The change that's perceived before the ring rotates is not so much due to the colors changing -- if you pay close attention -- but something that's called apparent motion. The classic example of apparent motion is the sequencing of lights around a movie marquis -- they appear to move, although the lights themselves are not actually moving. In the same way, the static ring has internal apparent motion as the colors change, because your brain is interpreting, for example, one dot turning yellow next to a dot that was previously yellow, as motion of a yellow dot, even though the underlying dots do not move. While apparent motion can be very strong, it is not the same as true motion.
Then, when the ring starts to rock back and forth, there is a true motion signal that swamps the apparent motion. If you pay attention to a given dot while holding your gaze still fixed at the central white point (not as hard as it sounds), you can clearly still see the colors changing.
So without having read the paper, I reserve some skepticism that they have not actually measured what they think they have. Change is still perceptible, but it would seem that real motion interferes with apparent motion.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
demonstration of how when the brain receives two different associated inputs and determines one is much more important than the other, how well it focuses you on just the important one.
In a predator-prey situation, prey are usually excellent at spotting movement. It's not surprising that when we see something start to move that's a bit dynamic, (like a tiger running through our view among the grass) how our brain "freezes" the image and allows us to process a more static interpretation of it while we track its movement through a visually very noisy environment.
Sort of along that line, after seeing that tiger race through the grass, you'd probably have completely missed the other three just standing there as the tiger you were tracking ran past them
I work for the Department of Redundancy Department.
Switching something when it is in the middle of fast movement is the basis of all kinds of slight of hand tricks. There's just a certain state where the mind identifies something just as a blurb of overlapping color, rather than anything processed meaningfully, and you can freely swap it with a similar item without any notice. Mix in basic misdirection, and you can fool almost anyone's expectations. It's also why you kind of have to learn to juggle by feel & pattern rather than just sight - because the hand really does have to be faster than the (mind's ability to process information from the) eye to keep up with the pattern.
Ryan Fenton
As a magician, I have known this for years. Dai Vernon, The Professor, explains that concept the scientists just discovered as a simplistic beautiful statement, "A larger action covers (or hides) a smaller action." Science finally catches up to the magicians.. Damn them. :-)
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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Unfortunately the video player had no indication that it was not loading at all (likely slashdoted), instead just sits static on the first frame. However, it took me about 30 seconds of staring at the static image wondering if my since of perception was so bad I -didn't see anything moving at all-
Turns out it is pretty bad, just not in the way I thought; I recommend going straight to the youtube versions linked on the article.
It's a pretty neat effect, sort of one of those things that become pretty obvious once you see it.
"Scientists at Harvard have found that people are remarkably bad at noticing when moving objects change in brightness, color, size, or shape..."
That may be because our eyes are exposed to so many different lighting conditions that our auto-white-balance is kicking in.
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As a former competitor at the world-level in first person shooters, perhaps my cortex has adapted differently, because when I stare at the dots in the center, I can always tell that the shape or hue or brightness are changing. I can tell when they change and how they change. I can see how in many ways this might be true for 99.99% of the population, but when you spend man-years staring at stationary dots in the center of a screen (crosshair) while "looking around" in-game waiting to notice single-pixel changes out of the ordinary, maybe you learn to notice it?
I'm surprised to report that this one doesn't affect me; I can definitely perceive that the dots change color, even when they're moving around.
Nebulo
Who only noticed a *diminished* sense of the colors changing? I could still see the colors changing, it just didn't seem to be nearly as much as before the dots started moving. My experience was as follows: 1) Ok, colors changing 2) dots moving and wow the changes stopped! 3) oh wait, no I'm seeing a few changes still....
Nice illusion indeed, and at least partially new. A while back, I combined two different illusions to make a single more effective illusion. I wonder if there's any connection with the one in the news article as they both seem to rely on the movement of peripheral vision confusing other aspects of change in peripheral vision:
http://www.skytopia.com/project/illusion/ipage-vb.html
The effect this one achieves is the disappearence of visual areas rather than 'merely' lessening the effect. Although mine is arguably more dramatic once it happens, it can be slightly tricky to see the effect immediately compared to the one in the news article.
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Nothing to see here move along
If enithin kan gow rong it whil. (Murfey)
Because in a primitive, hostile environment, the main thing is to see the enemy / victim coming. That's one of the reasons why people keep watching anything that moves above static parts. That it also changes color.. well.. big deal. Noticing it moving is much more important.
News Flash:
Humans find it difficult to notice things they are not looking at! Film at 11.
...that our brain is really great at recognizing objects despite changes in "brightness, color, size, or shape"?
bickerdyke
This is from 1999. http://www.youtube.com/watch?v=vJG698U2Mvo
Many of you might already know this, but this is the original.
It is even used in an add against cyclist(1) http://www.youtube.com/watch?v=Ahg6qcgoay4
A much more interesting one is to be seen at http://www.youtube.com/watch?v=W92tDI4RYCw Almost the same difference.
(1) You are to hit them and not miss them. At least that is what I get as message.
Don't fight for your country, if your country does not fight for you.
Decepticons have known this trick for aeons....
In the example videos, the changes are not random, they are a pattern that rotates around the group. (Watch the shape change and size change to see it most obviously, but it's there in the color/brightness ones as well.)
So when the group starts rotating, it is actually counter-balancing the individual item change. You're losing sight of the trees for the forest.
Example: a group of people are on a merry-go-round. Each one is holding paper with a symbol on it facing up. They start passing their papers around counter-clockwise. So each person's "symbol" is changing. You see it happening easily. Then the merry-go-round itself starts rotating, which counter-balances the rotation of the moving symbols. Even if you quickly reverse the merry-go-round motion every so often, as they do in their examples, you will see the 'overall pattern' seem stationary, followed by VERY QUICK movement, followed by stationary.
A better example would have each individual item's changes be completely random, not following an overarching rotating pattern.
Another non-functioning site was "uncertainty.microsoft.com."
The purpose of that site was not known.
The reef squid has the ability to quickly change colors and patterns on it's body, and seems to signal other squids in this fashion (as well as for camouflage). I wonder if they would be fooled by this illusion or if their neural optics are wired very differently than ours. It would be challenging to try to create an objective test that you could do with them.
I won't necessarily claim to be one here, since anyone can claim anything on the internet. But I wonder how well experienced MTI analysts (http://en.wikipedia.org/wiki/Moving_target_indication) would perform against these videos. Quite literally, it is the job of an MTI analyst to distinguish coherent from non-coherent changes across a vast number of moving dots displaying all sorts of crazy behaviors.
Additionally, I would prefer to see this experiment run under different conditions, such as having the videos begin with dots in apparent motion for many seconds, then having them stop moving. I do think the results of the experiment are damaged by having the motion segment (3 secs) be significantly shorter than the non-motion segment (5 secs) and always happening after the eyes and brain have adjusted to the lack of apparent motion.
I think another big problem with the videos provided is that the motion segment alters direction 9 times (counting first and last) within a short window -- this may not result in the human mind having difficulty seeing change in moving objects, but a difficulty in adjusting the perspective of the total scene to something observing rapid fluxuation in velocity. (I.E. The circle constantly rotates back and forth, preventing the brain from "getting used to" the scene, whereas when the dots are stationary and only changing in specific property, they remain in this configuration for a much longer period of time).
It's a interesting topic, but research could have focused more on overall configuration of how viewers were presented with the experiment. There isn't enough information present to draw an accurate conclusion from these observed results.
It seems to me that this is a fairly simple illusion: the frequent event is "more interesting" hence the brain focuses on that. Color change in this example is happening slower than rotation hence motion is favored instead of colors.
Maybe if our ancestors had fed on flocks of fast moving chameleons we would be better at this.
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I suspect that this is an optical illusion triggered because the brain is trying to match items by color and size. When color or size changes, the brain matches the wrong blob (which hasn't changed, or just happens to have changed to what the other one was, or to something closer to what the other one was than the other now is) to the original item.
I'd like to see a video with just the fixation point and one datapoint in the periphery. If we still lose track of shape and color changes then that will be harder to explain and more interesting.
I'd also like to see the same multi-blob video done with everything changing in the same way at the same time. I suspect the result would be the same as the one-blob video condition.
Not that this isn't a neat demo as is. I'm just hungry for some more conditions.
instead of making a video, couldn't they have made a flash thingie, so that you could change the parameters of the illusion too? maybe we could then tell at what rotation speed color change becomes hard to notice.
Wealth is the gift that keeps on giving.
The video directs the user to state at a stationary object (and even then it's not hard to notice some progression). If you actually look at the moving objects (you know, like the way people who aren't undergoing the Ludovico Technique normally look at stuff), it's quite easy to notice what's going on.
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"people are remarkably bad at noticing when moving objects change in brightness, color, size, or shape"
I think you left out an important qualifier:
people are remarkably bad at noticing when moving objects change in brightness, color, size, or shape IN THEIR PERIPHERAL VISION
If you look directly at any of the moving objects you can see any of them change in brightness, color, size, or shape. Your peripheral vision is not your focus for good reason, and of course its not going to track every single change like at the center of your focus of vision, its not supposed to and is better that it doesn't.
I'd like to see if there's a culture bias to this. Get someone from a very non-westernized culture and ask what they see. They're regularly not fooled by these kinds of "illusions":
Which line is longer:
>----------
Their eyes just aren't trained to see geometry the same way as westerners who are faced with tons of man-made things everyday.
"That which does not kill us makes us stranger." -Trevor Goodchild
When looking at the video I see all of the color changes, even when the ring is in motion. Then again, I am also one of those who can see the cycle rate of flourescent lights. Perhaps my eyes are hyper sensitive or have a higher bandwidth path to my brain than most people. I was in Vegas in November and saw the David Copperfield show and was in the front row. I was able to see the slight of hand that was being used to swap objects and figure out how he was doing the tricks. Made it somewhat boring for me, but my sisters enjoyed the show.
Next someone will publish a paper on how talking faster makes it more difficult to the listener to spot logical incongruencies.
- "They misunderestimated me."
If you ignore their instructions and stare at the ring while it is rotating you will notice that the colors change a lot slower while the ring is in motion than when it is static. When I look at the white dot I notice the surrounding change, it just seems a lot slower. Slower change is a lot harder to detect, especially when it's whirling past your vision.
A real test would involve changing the colors at the same speed whether the ring was moving or not.
two things I'd like to point out,
1) color-blind people don't see in black and white, they lack usually one of several photopigments and lack the ability to distinguish between a few colors that normal people can. red and green for example look the same to someone with RGCB. They can distinguish all the other colors, it's just that those two look identical.
2) sex linked has little to do with evolution in this case. you need one copy of the photopigment DNA to produce the pigment. Women have two X chromosomes. Sex-linked traits are traits expressed on the X chromosome. Men have only one copy, so if it's wrong, you lose out on something. The odds of a woman being shy on that allele on both of her X chromosomes is a lot smaller is all. Has nothing to do with the sex roles, that's just where that particular allele happens to be located. For example, a woman can have RGCB, but it's a lot rarer.
I work for the Department of Redundancy Department.
This trick now got some scientific proof :)
Coding etudes
Son, I told you now, stop it with the video games and get back to your damn homework!
Thanks for confirming what I said. Like you said, the only way you got busted is someone noticing something had changed from one observation to the next, because you knew how to be patient and move so slowly that no one ever saw you actually move -- am I right? Real sniping ain't no video game, and anyone who has knows that. I was a different type of cold warrior -- I worked signals, sources, stuff like that.
Why guess when you can know? Measure!
I remember some interview with an onLive tech representative talking about leveraging psychovisual properties. They could use these illusion videos as marketing materials!
bite my glorious golden ass.
I looked at the video , but i can see the dots changing color while they move ?
Is there something wrong with my eyes ?
Slipping shoelaces ?