Mind Stretch: Eye Benders

image by Akiyoshi Kitooka

Image by Akiyoshi Kitooka

In our last mind stretch, we contemplated the way that many world maps distort our understanding of the relative size of places we think we know. Today we’re going to consider the inadvisability of always believing what we see.

I recently came across some illustrations from a book called Eye Benders: The Science of Seeing and Believing, and they were enough to send me looking for more.

Clive Gifford’s book is shelved in the children’s section of our library, which seems fitting, as spending a few minutes contemplating the images is quite likely to have your eyes wide with child-like wonder. There are pictures of many different kinds: patterns that seem to move, perspective traps, drawings that begin as one thing and end as another. If you went through a visual-tricks phase as a child, you’ll probably recognize some old favorites, but it seems that there have been some interesting advances in the field over the years. There are also some good intro explanations for the brain science that makes these illusions happen.

Given my experience with migraines, I didn’t spend a lot of time looking at the pictures that can create the illusion of movement–I get enough excitement that way on my own. (The website of the lead image’s creator has a “if you feel sick looking at these, run away!” warning.) But I was grabbed by a couple of images regarding color and shade, and they just didn’t want to let go. Often with a visual trick, once you see how something is done, the effect is lessened. But these are impressively persistent. The cube developed by R. Beau Lotto is a great example.

_49520839_illusion_464

The “this will surprise you” part of the picture is that the center of the top gray section and the center of the bottom white section are exactly the same color. We don’t go for that idea because we’ve got loads of contextual info (all the light-and-shadow cues) to lead us to other conclusions, but it’s true nonetheless. The Lotto Lab website has an animation you can watch in quicktime here, but it’s at least possible to see it and wonder whether some digital shenanigans has been at work. If taking the author’s word for it isn’t your preferred route, you can cut two holes out of a piece of cardboard that you can lay over your screen, masking the context clues, and just stare at the middle of each section.

You can use that same high-tech solution to help you wrap your head around this next one, which for me is even harder to credit.

Image-14 (1)

The brown tile at the center of the top side and the orange tile at the center of the shaded front side of the cube are–you guessed it–the same color. Are you furrowing your brows? Shaking your head? This one was a beast to get out from under–I made a quick mask with some sloppy oversized holes, and the effect persisted–even a little bit of context around each square was enough to send my perception centers off on their goose chase. It wasn’t until I blocked out everything but the two squares that I could verify that the color is the same (and even then, there’s a tiny part of me saying, wait, isn’t the bottom one a tiny bit lighter?)

The last one I’ll share I first saw in the book Being Wrong, by Kathryn Schulz (chock-full of interesting stuff, some of which I feature here). Devised by Edward H. Adelson, it also hinges on the way we perceive and understand shadow.

Grey_square_optical_illusion

Adelson wants us to talk about square A and square B. Now, I don’t know what kind of a character Adelson is. When we say, “obviously, A is darker than B,” I don’t know if he’s the sort to cackle gleefully and exclaim, “that’s just where you’re wrong!” Maybe he’s more likely to respond quietly with, “you’d think that, wouldn’t you, but–no.” However he says it, the fact remains that A and B are the same shade exactly. In Being Wrong, Shulz comments on how persistent the illusion was for her–I think I remember her saying something about taking a pair of scissors, not to cut a careful mask that she could lay over the figure, but to cut out the two squares themselves and lay them side by side.

Same_color_illusion_proof2

This handy connecting bar helps us a little in our quest to see them as the same shade, but we won’t see them exactly the same until we’ve removed all context cues. Our visual processing system is fiercely determined to do the job it was trained to do, thank you very much.

There are lots of other interesting things to see in Eye Benders (more on Clive Gifford here). The most interesting thing for me isn’t so much what it gives me to look at as what it gives me to think about. If I can be so wrong about things that all of my training and experience tell me are slap-the-forehead obvious, then perhaps I’d be wise to be a little more contemplative, a little more humble, and willing to consider other ways to look at things in the larger world, beyond pictures.

Oh, and if I could figure out how to cut something out of cardboard that would help me get over the times when I’m not seeing things the way they really are, that would be cooler than all the pictures in Gifford’s book.

 

 

 

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