14 May 2010

It's optical illusion Friday

The great and powerful Richard Wiseman has been working overtime in keeping me thrilled with his illusions. Here's his latest, and he posted it with the question, "Does this move for you?"

Everything the man throws out there jumps all over the page for me and it never occurred to me that my experience of his illusions isn't universal. Well, it turns out they're not. According to the polls he runs on his blog, up to half of his audience can't see any movement in some of these illusions. While hardly a scientific finding, he's been able to see that these illusions are are not an either/ or proposition. In other words, predicting who'll be able to see them and who won't can't be predicted. So I'm going to throw a bunch of them up here and and you guys if they move for you. I picked these ones specifically because they move for me. If you click on them, they'll show up full-size in another window.

My obsession with these "animated" static images started with this one.

I've been sorting around for an answer for why this image moves so much and I found it. The National Academy of Science has a library of scholarly papers that deal with visual perception. The archives of the National Academy are an information geek's treasure trove. If that weren't enough, I found a great science blog called Neurophilosophy that talks about this stuff less formally.

Now, I've always known that human visual perception is a function of the way our brains are wired. True, it's our eyes that feed the visual stimulus to our brains, but it's our brains that knit the whole mess of stimuli into a coherent narrative. Therein lies the rub.

Human brains evolved to keep us alive as primates first and foremost so they use our eyes to look for patterns and novelty. Just as the T. Rex in Jurassic Park could only see movement, our eyes work in much the same way. Unlike a T. Rex though, we have a brain to oversee the proceedings. When an object stops moving, the visual perceptors in our retinas stop seeing the object and our brains take over. The actual cells receiving the stimulus take a break and the brain steps in and uses what it assumes to be true about a scene to fill in the blanks. Stare at a beige paint chip for long enough and you can see this retinal fading in real life. The minute the view changes though, the cells in the retina spring back into action and send new information to the brain.

Well it turns out that this rentinal fading may save energy, but it can be an evolutionary disadvantage too. If a predator is stalking you, it doesn't really go away when it stops moving. To compensate for retinal fading, our brains evolved an ability to to issue a wake up call to those napping retinal cells and that wake up call is called a microsaccade.

Microsaccades are rapid, imperceptible (the brain adjusts for them), jerking eye movements. Human eyes exhibit these microsaccades all the time and they allow us to perceive stationary objects, among other things. It's also these microsaccades that are making these images move. Sometimes, an image has the right combination of fine lines and contrasting colors to override the mechanism the brain uses to adjust for the microsaccades it triggered in the first place. The result is a static image that appears to move.

Pretty slick. So what's this have to do with designing interiors? Everything. Design plays with perception, not vision and understanding perception is the name of the game. When you know where the chinks in the armor of perception are, you can exploit them. Besides, this is fun.

Now back to my original question, who sees which of these images move?


  1. Some of them move for me some don't, some move more than others, some of them I can stop and start moving, and the last one is trippy! Of course I only got up a short while ago and my eyes are still pretty unfocused. :-)

  2. That last one is the best example of these microsaccade-induced movement illusions I've ever seen. Although the second one up there comes pretty close.

  3. I feel dizzy! My microsaccades must be off the chain b/c they ALL move for me! That last one is almost unbearable to look at for me - cool but unbearable.

    Wonder what that says about my perception of an interior space? Or maybe it explains why I hate purple and green together so much... ; )

  4. I feel the same way about the purple and green one. I think this is the third time I've run it on this blog. I'm obsessed with the thing despite the fact that I can barely stand to look at it for any period of time.

  5. In the first one, only the outer circle moves.. I wonder if it's supposed to be that way or if that's just the way that I see it. The rest all move. I love how trippy these things are, though it sort of gives me that feeling like just before you faint and your vision goes all wonky. (but in a fun way?)

  6. Paul, these need to be set to music, from the 70's perhaps? What's interesting is that while the art moves, folks can't look at it for too long. What's that about? Awareness of our awareness? a feedback loop?

  7. Nim: I don't think there's a right way to see any of these things. They're an interesting test to witness your brain in action as it hits a scrap of information it can't process. I notice that sometimes they work for me and sometimes they don't. I'm alert right now so they're all jumping all over the place, but if I look at them tonight before I go to bed I probably won't see all of them moving.

    Patrick: It has to be some kind of a feedback loop. Some people get nauseous from these things and that has to be some kind of a brain going haywire feedback loop.

  8. Whoa, these are taking me back to my college days...

    *clears throat*

  9. maybe that's the bottom line appeal to them for me too. They make me feel like I'm in the parking lot of a Dead show in 1983.

  10. Paul, thanks for the science behind all those movements!
    The last image really is the fastest moving, but the grey one makes me uneasy.
    My college years were in the 80's, so no associations here ;)

  11. #1 and #5 didn't move for me. It was weird, #3 didn't move the first couple of times I looked at it, but then it did start moving every time I looked at it after that!

  12. They move for me. That last one is a doozy.

  13. Bozena, Steph and Sharon: Thanks for chiming in. #5 reminds me of hamsters running around a track. Seriously, if you look at the solid color rings rather than the black and white spokes, a universe opens up. And you got it Sharon, that last one is the dooziest of the doozies.

  14. All of them move for me except the first one. And they start moving as soon as I look at them. Even the little image in one of the "link within' images is moving. Freaky!!

    Heehehhehe!! Yeah, what are you thinking -- a condo for ONLY $489,000?! ;-) Even if that's a great deal, you don't want to live in Toronto. That place is insane!!!


  15. I see some type of movement in all of them - but especially the last image.


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