Posted by Jay Livingston
I can’t remember the blog where I came across these optical illusions (a sign that I'm reading too many blogs), but the link is here. Apparently these are well known even outside perception-biz circles – even the teenager-in-residence here had seen them – but they were new to me.
The two lettered squares, A and B, are actually the same shade of gray.Here’s another.
The “blue” tiles on the top face of the left cube are the same color as the “yellow” tiles in the top of the right cube.
It’s hard to believe – after all, seeing is believing. But you can go here and see these and other illusions of color, brightness, and form along with masks that block out everything but the relevant squares. Unfortunately, it happens instantly, and all you can do is toggle back and forth between the masked version and the fully unmasked version. So it’s not so convincing.
Better to do it gradually.
I copied the top illusion into Paint and started using the Eraser. After a bit of erasing the shading difference was only slightly diminished. (Yes, I know my eraser technique is sloppy, but I never keep inside the lines either when I do my coloring books.)
But after only a bit more erasing, the illusion became clear.
(It’s harder to do with the cubes because the target squares are so small that you have to do a lot of very careful erasing. When you do, you see that both the apparently yellow and blue squares become gray.)I’ve got to show this to my class on Monday, I thought.
“But what’s the sociological significance?” asked the voice on my right shoulder.
“To hell with significance,” said the voice on my left shoulder. “Just take a few minutes at the start of class – the time some people spend calling the roll – just to show them something interesting.”
Waste time with cool stuff, or teach sociology?
Then I realized that in fact there was a sociological message – contexts. Whatever intrinsic qualities things may have, we invest them with meaning (and color), and we derive that meaning (or color) from their contexts.
3 comments:
That is so neat! And you've come up with an excellent excuse to show it in a sociology class! I might have to show my students this, as well.
I'm seen my share of impressive illusions, but the lettered squares illusion is one of the best I've ever come across. Thanks for sharing! (Btw, if you don't want to erase, you can also confirm these illusions by using the eye-dropper in a paint application.)
That's excellent. I'll have to make sure I come up with something as innovative when I start teaching again. It's probably better than the endless working-in-a-supermarket metapors I used to use.
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