The art (and science) of optical illusions

Visual trickery plays an important role in puzzles. It can be the clever rebus that challenges you to find the words each image represents, or a visual brain teaser that forces you to think outside the box.

But nowhere in the realm of puzzles is visual trickery more obvious or more disconcerting than in optical illusions. Some are simple, like the famous old woman/young woman image above (or this hilarious video version). But others are not only more complex, they’re absolutely mind-bending.

And if we’re talking mind-bending optical illusions, at some point, you have to mention the work of Akiyoshi Kitaoka.

[Akiyoshi Kitaoka’s “A Bulge,” featuring nothing but squares.]

Dr. Kitaoka is a professor of psychology at Ritsumeikan University in Kyoto, Japan, and he has extensively studied biology and psychology. He has quickly emerged as a modern master of optical illusions, utilizing not only shapes and color gradients to trick the eye, but also to simulate motion in a static image!

Two of the techniques frequently cited in his work with illusions are perceptual transparency and visual completion. Both rely heavily on how our brain and eye process the incredible amount of information we perceive every second of every day.

This is probably the most famous example of a visual completion illusion:

Basically, our brain employs mental shortcuts in order to simplify the information. For instance, visual completion (also known as filling-in) occurs when information unavailable to the eye is assumed to be there and mentally added by the brain.

Perceptual transparency, on the other hand, involves how we can perceive one surface behind another.

Check out this amazing photo from a published paper on perceptual transparency, entitled Zen Mountains:

[The mountains in the background look transparent,
even appearing to overlap each other in impossible ways.]

Dr. Kitaoka’s illusions utilize visual shortcuts and processes such like these, but his most famous creations involve a perceptual technique known as the Fraser-Wilcox Illusion, which involves using lighter and darker gradients of black and white in order to trick the eye into perceiving motion. Essentially, moving from dark to light gradually creates the illusion of motion.

Kitaoka’s work, however, maximizes this effect by employing contrasting color schemes in order to challenge the eye further.

Feast your eyes upon “Rotating Snakes,” Kitaoka’s most diabolical optical illusion:

[For the full effect, click the image and
scroll down for a full-screen version!]

By employing color as well, the rotation illusion is even more striking. In all honesty, I can’t look at it too long or my stomach starts to feel a little off-kilter!

Similarly, Kitaoka tricks the eye into perceiving waves rolling diagonally over this quilt-like sheet in “Primrose’s Field:”

As we understand more about the eye and how it perceives the visual stimuli it receives, as well as more about the brain and how it processes information, I suspect we’ll be able to craft even more convincing, mind-blowing, and unnerving examples of visual sleight of hand.

And undoubtedly, Akiyoshi Kitaoka will be leading the way.


Many thanks to Dr. Kitaoka for granting permission for me to feature three of his illusions in this post. You can check out more of his amazing work on his website, as well as some of his books on Amazon here!

Thanks for visiting PuzzleNation Blog today! You can share your pictures with us on Instagram, friend us on Facebook, check us out on TwitterPinterest, and Tumblr, and be sure to check out the growing library of PuzzleNation apps and games!

It’s Follow-Up Friday: That Dress edition

Welcome to Follow-Up Friday!

By this time, you know the drill. Follow-Up Friday is a chance for us to revisit the subjects of previous posts and bring the PuzzleNation audience up to speed on all things puzzly.

And today I’d like to return to the subject of optical illusions.

Yes, by popular demand, I’m talking about The Dress.

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[The original photo is in the middle. To the left, the photo has been color-corrected toward white and gold. To the right, the photo has been color-corrected toward black and blue.]

For those who haven’t heard — and wow, I’m sincerely amazed you haven’t by now — the above picture of a dress was uploaded to Tumblr not too long ago, and the Internet collectively lost its mind debating whether the dress was white and gold or black and blue.

Some people think that color blindness has something to do with the different opinions on the dress, but the answer is simpler than that.

I’ve written about optical illusions in the past, and this photo is another prime example. As for why people are seeing two different sets of colors, it’s all about visual context and how we interpret contrasting colors.

The photo is saturated with sunlight, which skews the color of the dress. But for some people, when their eye color-corrects to determine what they’re looking at, they discount the blue in the photo, and end up seeing white and gold. Other people discount the gold in the photo, and see blue and black.

(This was also one of those cases where actually tilting your laptop screen could significantly change how the colors looked, since changing the angle of your screen altered how the image interacts with whatever light sources are nearby.)

I’ll give you another example. Check out this image from Gizmodo:

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These green and blue spirals, contrasted against the pink and orange, appear to be different colors, but they are actually the exact same color. Our eyes are fooled into seeing them as different shades by the alternating stripes around them. (The “green” have orange contrast while the “blue” have pink.)

The differing interpretations of The Dress operate under the same principle.

Oh, and for the record, here’s the dress without the sunlight skewing the color scheme, as seen on Ellen DeGeneres’s show:

people-behind-the-dress-appear-on-ellen-02

So which camp were you in, fellow puzzlers? White and gold or black and blue?

Thanks for visiting PuzzleNation Blog today! You can share your pictures with us on Instagram, friend us on Facebook, check us out on TwitterPinterest, and Tumblr, and be sure to check out the growing library of PuzzleNation apps and games!

Follow-Up Friday: Optical Illusion edition!

Welcome to Follow-Up Friday!

By this time, you know the drill. Follow-Up Friday is a chance for us to revisit the subjects of previous posts and bring the PuzzleNation audience up to speed on all things puzzly.

And today, I’d like to return to the subject of optical illusions.

Puzzles for the eye, optical illusions challenge the viewer to shift perspectives and accept that seeing is not always believing. And whether it’s Ok Go!’s tricky music video or a carefully crafted LEGO illusion, they’re a favorite subject here at PuzzleNation Blog. I mean, heck, we’ve got entire boards on Pinterest dedicated to them!

So you can imagine my delight when I stumbled upon a CollegeHumor video that had some fun with a few classic optical illusions.

I present Optical Illusion Girlfriend:

Have a marvelous weekend, puzzlers and PuzzleNationers! Here’s hoping everything you see is what it seems. =)

Thanks for visiting PuzzleNation Blog today! You can share your pictures with us on Instagram, friend us on Facebook, check us out on TwitterPinterest, and Tumblr, and be sure to check out the growing library of PuzzleNation apps and games!

It’s Follow-Up Friday: Optical Illusion edition!

Welcome to Follow-Up Friday!

For those new to PuzzleNation Blog, Follow-Up Friday is a chance for us to revisit the subjects of previous posts and update the PuzzleNation audience on how these projects are doing and what these people have been up to in the meantime.

And today, I’d like to follow up on the subject of optical illusions with a marvelous new example for you.

I’ve written about optical illusions on several occasions, because they’re wonderful visual puzzles that play with our perceptions in clever, unexpected ways. We either see two images in one, or an object floating in space, or we’re simply misled by careful use of angles and lighting.

The band OK Go released their latest music video this week for the song The Writing’s On the Wall, and the video beautifully utilizes numerous optical illusions to create a mind-bending visual experience.

Check it out:

And this is not the band’s first foray into puzzly music video creation, since they took part in an elaborate Rube Goldberg machine for their song This Too Shall Pass:

Here’s hoping they unleash more puzzle-infused fun in their next video.

Thanks for visiting PuzzleNation Blog today! You can share your pictures with us on Instagram, friend us on Facebook, check us out on TwitterPinterest, and Tumblr, and be sure to check out the growing library of PuzzleNation apps and games!

Mindbending illusions!

There are puzzles to solve and mysteries to unravel… and then there are the mindboggling optical illusions that play with your perception.

Stationary things move, items big and small end up being the same size… it’s simultaneously fascinating and a little unnerving.

The folks as Gizmodo assembled a gallery of twenty optical illusions of all sorts, including several favorites of mine like the Fraser Spiral and a neat variation on the Necker Cube, and you should definitely check it out, if only to challenge your eyes and your brain in a different way today.