It's Surprisingly Hard To Notice When Moving Objects Change 140
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 ? (Score:3, Funny)
Is that why my wife is always running around ?
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No, there's an even faster naked man behind her.
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It's an extension of Heisenberg's principle: It is possible to know how much weight a person is gaining, or how fast they are walking, but not both at once.
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+1 - Keep your vasectomy secret...and always use a condom!
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So you had a chance to have a long term relationship with someone and have a child together , even though you are sterile.
I don't see it. (Score:2)
It's Surprisingly Hard To Notice That It's Moving!
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Follow the link to the youtube video - they have the bandwidth!
News Flash (Score:2)
Humans find it difficult to notice things they are not looking at! Film at 11.
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I was thinking the same thing. For one, I COULD see the colors change but my peripheral vision is more developed than most(I can even see color with it).
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"I can even see color with it" ...is this supposed to be odd or something?
Re:News Flash (Score:4, Informative)
"I can even see color with it" ...is this supposed to be odd or something?
Yes, because only the cones [wikipedia.org] in the center of your eye are capable of perceiving color (the rods on the outside perceive only black and white.) Your brain senses everything in the periphery of your vision in black and white, but "fills in" best-guess colors from what your cones perceive directly in front of you.
I remember that from a psychology lecture only because a fellow classmate, like the parent poster, couldn't believe the color in his peripheral vision was an illusion. So, the professor drew an "X" in the middle of the chalkboard and asked him to stare at it without looking away. He then held up a colored note card directly in front of the "X" and asked him to name the color. (Of course, he named it correctly.)
The professor held up another note card, a bit further away from the X, and asked him to say what color that card was. And then he held up the next card, a bit further away from the X than the last one. And he kept holding the cards further and further towards the edge of his field of vision.
After about the fifth card, the kid was convinced that any card the professor held up was either a shade of gray, or the same color as the chalkboard. Once the note cards were in his peripheral vision, he couldn't tell what color they were, and couldn't tell that he couldn't tell what color they were. Great professor.
Re:News Flash (Score:5, Informative)
Uh, did you read the Wikipedia link you posted? "Cone cells are densely packed in the fovea, but gradually become sparser towards the periphery of the retina." They aren't located only in the fovea, but all across the retina. They're merely more densely packed in the fovea than towards the edge. What most likely happened to your classmate is cone bleaching [ucsd.edu]: the longer you stare at a particular image, the more the particular cones bleach their photoreceptors, and the harder it is to figure out the correct color. Depending on what color the chalkboard was, it's quite possible he simply had stared at it for too long.
The retina still perceives color at the edges, it just does so less effectively than if you focus on the center.
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VERY odd. Not as odd as a friend of mine who is color blind EXCEPT for certain places in his peripheral vision, but definitely only a few people share this trait.
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wait, is this really all they're tryin to prove? I'll admit, I pulled a non-RTFA, but shit, I've known for years that peripheral vision was not great at discerning detail. I've done degree tests, and while I can detect items slightly beyond the 180 degree plane, I have no clue what they are. If that's their point, this is first-year psychology shit. The center of human vision is accurate yet less sensitive to movement, and the peripherals are vice versa. That appears to be the way things should be, an objec
Re:News Flash (Score:5, Insightful)
In fact, just try to focus on one of the dots in the videos. Even if you know it's going to move, you know it's going to keep changing color and the dot is in your center of view you still might fall to the illusion (not to mention that other dots nearby also seem to be unchanging even though they're right next to the one you're trying to follow).
It's not about central vs. peripheral sight, it's about how motion and the perception of change interact.
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I don't normally bother to reply to these sort of posts, but: why on Earth did you think this comment was a good idea? You, by your own admission, didn't bother to read the article and clearly didn't understand what was being tested from the summary. What makes you feel qualified to criticise? Are you really so arrogant that you feel comfortable condemning something as "first year psychology shit" when you don't even know what it is, you haven't bothered to find out what's being studied, and the researchers
Slight of hand (Score:4, Interesting)
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.
Re:Slight of hand (Score:5, Interesting)
Sleights of Mind: What the Neuroscience of Magic Reveals about Our Everyday Deceptions by Stephen L. Macknick and Susana Martinez-Conde.
I saw this book at the Bucktown branch of the Chicago Public Library earlier today in the "New Non-fiction" section. I took it out but haven't had the chance to crack it yet. It looks like it speaks directly to your point.
This is from the blurb:
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It's actually slightly more complex than that; a Magician's task is to use body language, banter, props, etc to make people see one part of the picture while ignoring another part... and using humans' built in narrative creativity to fill in the hole (which is where you do the tricky stuff) with something from their own mind. Of course, moving your hands in *almost* predictable, common ways tends to fool most people into thinking that's exactly what you're doing.
The techniques used in parlour magic and st
This isn't all that new (Score:4, Interesting)
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.
Re:This isn't all that new (Score:4, Informative)
I call it evolutionary accident through a process of natural selection propagated by random mutations and favorable environmental factors to suppress competing alleles.
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If our ancestors had gone through millions of years avoiding ambushes by flying man-eating chameleons it might be different.
Re:This isn't all that new (Score:5, Informative)
(Essentially, the more light one cell receives, the more its neighboring cells are inhibited. At an edge between a light and a dark area, a "light" cell close to the edge will receive less inhibition than entirely bright-surrounded cells due to its "dark" neighbors and thus the light side of the edge will be perceived as brighter. Conversely, the "dark" cells closest to the edge will receive stronger inhibition than other "dark" cells due to their "bright" neighbors, causing that side of the edge to appear darker.)
Different kind of change (Score:5, Informative)
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.
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On the other hand, the premise might be believable even if the experiment is flawed. Humans needed to detect motion above all else to survive earlier on in evolution, as something moving might have plans to eat one of us. We can see tiny movements where we can't see diddly staring right at the same thing motionless
Re:Different kind of change (Score:5, Insightful)
I think in this case, when the ring is static, each individual object is a unique entity. Changes matter.
When the ring is in motion, each individual object becomes part of the whole. It is now one ring and we ignore changes occuring to the ring.
This is entirely sensible because when an animal is in motion, we don't care about the muscles rippling, or the feathers ruffling, or the fur shimmering, or the shadows from trees dancing on it. Our survival depends on being able to watch the animal itself as a single unit. So we are hard wired to ignore the micro changes to a single object.
When the ring moves, all the tiny objects join to become a single ring we must track. When it's not moving, we see they are separate objects.
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I think the illusion in this is because it's a group of shapes, plus persistence of vision - just like any other animation. My brain tracks the common sizes/colours spinning aroubnd, not original entities.
If it was a single shape moving I could see the changes.
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IANAAVN and I too can't be arsed to read the paper either and of course I've only skimmed your response. Now for my speculation:
The classic gorilla in the room http://viscog.beckman.illinois.edu/grafs/demos/15.html [illinois.edu] experiment is a far better demonstration of how our perception is rubbish.
Farting around with dots and rings just isn't going to get you on the news.
There are tons of static optical illusions which even when you know how they work, still work. This is probably a dynamic optical illusion.
Perhaps
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The gorilla illusion is not the same. That's an illusion based on the limitations of our attention; it is not a change illusion.
Fair point about reading the paper. I've downloaded and done a quick first read-through. If you look at Figure 1, they show the results for the four different kinds of change they tested, hue, luminance, size, and shape. The first two are more readily interpreted as apparent motion when the changes are slow. Their results show that the first two illusions are more susceptible
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Bugger - I'm going to have to do some research! Time for some reading, its almost as though a /. story might become interesting.
Right - I cry foul almost immediatly (I've only watch the first vid):
Its common(ish) knowledge that the visual field is very narrow. The fovea centralis http://en.wikipedia.org/wiki/Fovea_centralis [wikipedia.org] only covers a very small area, and I'd be willing to bet (only a small amount) that causes the apparent lack of movement.
You are instructed to concentrate on the central dot and the ga
Re:Different kind of change (Score:5, Informative)
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Blimey - that's an answer from above!
Thanks for your response. Its rather more than you get on /. normally
Cheers
Jon
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To be honest your findings fit my personal point of view and surely has this a major bearing on for example road safety.
I've grabbed a copy of your paper and will have to do a proper digest of it - a quick read shows it to be potentially pretty important in many fields of safety.
Good suff.
Cheers
Jon
PS Its not my thing as such (I'm an IT bod) but it makes a damn good "news for nerds" story
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hi jon, i'm one of the authors of the paper. just thought i'd answer your question about the refresh rate. we used laptop screens that ran at 60 Hz, but the demo works even if you keep the dots motionless and lift up the screen and rock it back and forth. (you can try this yourself if you download the video.) the demo also works on a CRT at 120 Hz. so yes, it the refresh rate was considered and controlled for, and it doesn't seem to matter much. the motion in the youtube and vimeo videos are a bit jerky because they were converted to 30 fps.
Mod this up!!!
Hey Moderators, we have an actual author of one of the discussed stories replying to a direct question in a thread. I think this merits some "+1 Informative" points.
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Naah. He obviously has an agenda is thus biased :D
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Since you're one of the authors, I thought I'd chime in and share my experience. I'm partially color blind, and if you put certain reds, greens and/or grays next to each other I have a real hard time distinguishing what's what. I'm not sure how much that affected what I perceived when I watched these.
When I watched the first video with the vividly colored dots, and they started moving, I thought "Huh, I don't get it. I see the colors change. What's the big deal?" My wife, who was watching at the same time,
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>>we used laptop screens that ran at 60 Hz, but the demo works even if you keep the dots motionless and lift up the screen and rock it back and forth.
You know this doesn't change anything, right?
Think about it from the point of view from the retinal afterimages left on an observer - if the laptop is moving a dot 1 inch/second on its screen, it will leave 60 afterimages, each spaced 1/60th of an inch apart. If you move the laptop instead, the observer will also have 60 afterimages in the second, also 1
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The gorilla illusion isn't universal, either - I successfully counted 15 passes AND saw the gorilla (complete with chest-beating) on my first view. I would wager than a not-insignificant percentage of people could do the same. I would even posit that the set of people who are "immune" to the gorilla illusion would intersect somewhat with the set of people who have high skill at rhythm gaming - both require tracking lots of moving objects.
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Correct, it isn't universal but it is common for people to miss it.
You may have been lucky or you may be gifted - who knows but in this case (ie this discussion) we have two data points - I missed it and you didn't. Now even on /. that is not normally considered proof one way or the other.
Cheers
Jon
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I got to the video by following a link that said "gorilla", in the context of a discussion of optical illusions. Of course I saw the gorilla - I was expecting it. (Idea for a follow-up experiment: make a video without a gorilla, and convince people that there is one in there.)
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im having trouble seeing this illusion, i kinda understand what im supposed to see but im not getting that response that is described.
Could that be because im a professional gamer, Focusing on competing in Starcraft 2 at this point in time. When massive armies clash and they have to be microed everything is moving around and changing and requires exact placement and control, Could it be that i simply have become immune to this illusion of not noticing when something is moving?
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Or you are especially good at analyzing computer generated images.
I still hold that this is an optical illusion of some sort, possibly exacerbated by the presentation medium.
On the first vid are you able to see that the dots seem to stop flashing when rotating and you are absolutely concentrating on the central dot?
Cheers
Jon
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Personally, I didn't see a complete cessation of flashing/pulsating/shapeshifting, although it did seem to slow while the dots were rotating as a unit. I could definitely still sense that the dots were changing independently of the rotation, however.
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I agree, I can still see the colours change, when the ring starts moving.
However - to me the apparent speed of change is slowed significantly.
If I move my focus to one patch of the ring, that patch seems to change colour slowly, moving or not. Change the focus, and the previously calm area is now moving rapidly (in my peripheral vision),
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There'd be an evolutionary advantage to observing the properties of a moving object, so I'd be surprised if we have a lot of trouble with it. Observing the shockwaves in the fur of a moving
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That's exactly what I found as well. I tried to work out what was going on, and noticed that if I did fix my "peripheral attention" on a particular outer circle as it moved, I could detect its changes, and a little of those adjacent to it.
I think also what is happening is that, when rotation begins, many dots are traversing the *same area* of vision while your eye is keeping very still. So instead of the brain "intentionally silencing" change over motion, another possibility is simply that points are traver
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Mod this post up. IANAVN (I am not a Visual Neuroscientist) but I noticed the same thing. If I narrowed the focus to a specific section of the circle, even when it was moving, I could see the color , shading, or shape changes with no problem. I had a hard time focusing on the entire ring at the same time when moving.
Just as an aside, is this really news? Don't most of us recognize from everyday life that it takes more effort to focus on details of moving objects, the faster the objects are moving relati
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That's aliasing, and it's an entirely different thing all together.
incredible (Score:2)
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
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For [random deity]'s sake please stop the predator/prey bollocks.
For a large part of humanity, being lunched by a sabre toothed donkey has not been much of a worry for a very long time.
So why not couch your argument in terms that are relavent? Have a think and decide how long ago your ancestors would have worried about a tiger (rather than say being nobbled by the local feudal system or disease) and then decide what the "rate" of evolution is.
I'll grant you that the rate of evolutionary change is probably
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In biological time it's just a blink.
I don't think four generations is really enough for selection pressure to have much effect in this case.
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Predators are also frequently excellent at spotting movement. Which is why many prey animals' first instinct when they see a predator is to freeze completely still.
Humans, though, were both predators and prey.
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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 chromoso
Classic magician's trick. (Score:5, Interesting)
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
Damn Scientists (Score:4, Insightful)
Buffering... (Score:3)
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.
well... yeah (Score:3)
"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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Except that not noticing a circle changing to a star is not really explainable with auto white-balance. (Watch the last video in TFA)
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I wasn't trying to explain that.
But if you think about how things change shape when they move, it's not that surprising, don't wanna lose track of what you're chasing or running from.
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so why would there be a difference between when the things move vs. don't move? there are always a mix of colors and brightnesses.
When you're a monkey moving through the forest, things are passing by as you're moving in and out of pools of light. Your eyes are trying to adjust to it. That's what the test they showed seem to be testing anyway.. the background was changing luminance while multi colored things roamed about.
Not everybody.... (Score:1)
I'll bet Monk [imdb.com] doesn't have this problem!
Hmmm (Score:1)
Not for me (Score:1)
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
Am I the only one.... (Score:3)
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That's what I saw. I put it down to knowing what effect they were trying to produce.
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On a similar theme... (Score:2)
http://www.skytopia.com/project/illusion/ipage-vb.html [skytopia.com]
The effect this one achieves is the disappearence of visual areas rather than 'merely' lessening the effect. Although mine i
obligatory (Score:1)
Nothing to see here move along
Seems logical (Score:2)
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Did they also notice... (Score:2)
...that our brain is really great at recognizing objects despite changes in "brightness, color, size, or shape"?
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Counter-claim: Their examples are bad. (Score:2)
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 aro
How would squids see this? (Score:4, Interesting)
This is Relevant to Me (Score:2, Interesting)
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 vi
Depends on relative frequency of both events (Score:2)
Environmental Adaptation (Score:4, Funny)
I suspect... (Score:2)
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 ha
stupid scientists (Score:2)
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.
Re:stupid scientists (Score:5, Interesting)
hi, stupid scientist #1 here. (i'm one of the authors of the paper.) you're right, it would be nice to have a flash app that lets you change the speed of rotation. sadly, i programmed everything in MATLAB and I don't know flash. (and hey, didn't our overlord already pronounce flash dead?) on that note, if anyone knows flash and wants to program this up into an interactive demo, send me a message, i'm sure we could work something out.
but you're in luck, my friend. the demo works even if you pick up the screen and rock it back and forth, and i have a movie (link below) with no motion. you can loop the video and whirl the computer around all you'd like, at various speeds.
here's the movie [jwsu.ch].
as an aside, the first experiment in the paper in a speed manipulation. (spoiler alert.) the fast the ring rotates, the slower the dots seem to change.
I call shenanigans! (Score:2)
Not if you look at them... (Score:3)
"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.
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In order to look at a moving object with your center of vision, you need to track the object with your eyes. When you do that, it's not really moving anymore. So, the qualifier is implied.
Culture Bias? (Score:4, Interesting)
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.
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I see all.... (Score:1)
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
There was a SIGGRAPH talk on the same topic (Score:2)
isn't this how OnLive's compression works? (Score:2)
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Decepticons have known this trick for aeons....
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I looked at the video , but i can see the dots changing color while they move ?
Is there something wrong with my eyes ?