Click here to see the illusion
The above link is to a static (non-animated) image where the parts in your peripheral vision seem to rotate. The illusion works even if the colors are changed or the image is made black and white.
Can anyone provide an explanation of why this happens?
Thanks!
Wow, that’s a good one!
Wow, that’s trippy. The circle I’m focused on always stands still, and the ones around it rotate. Weeeeird.
Here is my guess:
When you stare at a black spot for a while, then at a white paper, you will see this spot even though it’s not there. It will fade after a while.
This works also with grey scales. If you look at the ring, a succession of fading spots will look like they move. This of course needs you to move your focus all the time, which you do. It doesn’t work anymore if you sort of fade out (not focussing on the picture anymore).
look at this similar thing that supports my theory.
Ouch.
It looks a bit like the Ouchi illusion, with a hint of von Bezold chromatic
assimilation.
For me, the “motion” stops if:
OK, instead of waiting for someone to call ‘cite’, Here I offer a link to a text about the Ouchi Illusion. It’s not wholly understood, but it’s vaguely similar.
Here’s a decent list of optical illusions.
This page attempts to explain the Ouchi illusion, but I don’t fully understand the explanation:
http://www.cfar.umd.edu/~fer/optical/movement1.html
I think T. Mehr is on to the crux of it – persistence of vision.
The four colours are nearly complimentary pairs, so as your eye moves slightly, the “burned-in” retinal image of each element appears to be an extention of the adjacent element.
To get a handle on this effect, think of a simpler design: Imagine staring fixedly at a white circle on a grey background. The burned-in image of a black circle will not be apparent until your eye moves a bit. If your eye moves slightly to the right, you will see a black crescent on the left-hand edge of the circle. The same effect holds with colours.
Going back to the illusion in the OP, you’ll notice that its individual elements are both chromatic and geometric inversions of other elements. You’ve got the black and white concave bits and the greeny/bluey convex bits. As your eye drifts, the “burned-in” images appear to extend the adjacent elements a bit further, and as you try to follow the apparent motion, it perpetuates the illusion.
Thanks Larry. Very nice explanation. Doesn’t stop my head from spinning, but at least I have an idea as to why.
Good one Larry.
Those are so cool. Will the effect be similar if printed out on paper, rather than on a computer screen? I’d like to pass those around…
I would think the effect would survive printing, but if the effect depends on the colors being complements of each other, an inaccurate color printer could destroy the effect, I guess.
A whole bunch of similar “anomalous motion illusions” are elsewhere on the same site that Popup linked.
For instance, http://www.ritsumei.ac.jp/~akitaoka/motion-e.html
They are all cool.
The illusions on this page are the most similar (in fact, a couple are almost identical):
http://www.ritsumei.ac.jp/~akitaoka/rotate-e.html
Also, based on these other examples, it appears that color complementarity is not as much of a factor as specific luminance patterns (black -> dark -> white -> light). In the original image, the blue is the “dark” color and the greenish is the “light”.
I don’t know if it’s relevant or not, but I have only one functional eye, and all I see with the working one is static circles. Are there any other monocular dopers out there who can provide input? Or at least some pirate jokes I haven’t heard yet.
Hmmm. Some of them don’t seem to “work” for me. I see that the descriptions include “inset sometimes appear to move”.
Do you have to stare at them for a period of time?
