“Illusion is the first of all pleasures.” -Oscar Wilde
But despite what these images you’re looking at might seem to show, there’s nothing rolling at all here.
Nor is anything moving, nor is there a hint of animation in any of these. Yet, based on what your eyes show you, things appear to be bulging, spinning, or more generally, there appears to be motion.
If you look closely, you can definitely see that whatever small section your eyes have honed in on isn’t moving, but it’s the portion of the image in your peripheral vision that appears to move. And because of how our brains are wired, our attention automatically seeks that out; this is probably a good thing, evolutionarily, for when a predator is stalking you! But that same wiring is what makes these snakes, below, look like they’re rotating in your periphery, except for the one you’re looking directly at!
This optical illusion, above, is no joke; it was made by Akiyoshi Kitaoka, professor of psychology and a researcher of illusions. One of the great illusions he investigated, as illustrated above, is known as the Peripheral Drift Illusion. In a nutshell, our eyes can be tricked by simple changes in luminance, which is why the color-scheme for the rotating snakes was chosen to have a black, a dark color, white, and a light color in that particular sequence. Let’s take a look into Kitaoka’s investigations.
If you put one of these circles, shaded as-is, in your peripheral vision, the light-and-dark shading will make it appear to rotate. I can only see it rotating slowly, and the effect is far from pronounced. But one of the great things Kitaoka has discovered is a way to enhance this illusion. By creating the shading-order as follows: black/dark grey/white/light grey, the effect of the peripheral drift illusion becomes greatly magnified.
And by altering the length of the edges, the effect can be enhanced even further!
That’s what the “rotating snakes” illusion was based off of. But Akiyoshi Kitaoka doesn’t just investigate and study illusions and how they are perceived by our eyes, however. He also creates his own, and they are truly spectacular, and appear to trick our eyes in a variety of ways. Here are some of my favorites.
Clockwise and counterclockwise rotation, simply by using the altered-length trick.
A visual spiral, even though all the “edges” in this picture, above, are completely circular!
A central object that appears to move relative to the outer “background,” particularly pronounced if you scroll past it!
And a second with the same effect…
and a third!
Here’s one that appears to be blowing in the breeze, even though it’s just a stationary background.
And here’s one where you can see reddish dots at the corners between the tiles, even though the corners are all white!
I wouldn’t call it the evil eye, per se, but it sure does feel like it’s sucking me in!
Check out Akiyoshi’s home page for literally hundreds of these illusions, and I hope you enjoyed this weekend’s diversion! (Oh, and for those of you who get dizzy looking at objects like this, you’ll probably get dizzy. I probably should’ve told you earlier. Oh well.)