Your eyes cheat your brain

June 22, 2009 · 46 comments

No matter how strongly you want to believe you are seeing blue and green spirals here, there is no blue color in this image. There is only green, red and orange. What you think is blue is actually green. You can check this through Photoshop or by zooming, if you need an affirmation. Your eyes cheat you.

Your eyes cheat your brain - The Green and The Blue Illusion

If you don’t believe your eyes, check this image enlarged:

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There are a lot of psychological tests based off of eye-tricks like this one, such as the Rorschach and inkblot tests, which are called thematic apperception tests, or TAT. These TATs are an abstract way to remove mental blocks in psychological patients and find underlying and subconscious issues. TATs are frequently used in psychological testing in depression counseling and bipolar treatment centers, and although this is not an official TAT, it does make one question one’s perception.

Discovered on Akiyoshi Kitaoka’s site

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{ 27 comments… read them below or add one }

ScottC June 22, 2009 at 9:04 pm

Except for those of us who are red-green color-blind… then it just looks gray.

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Spiderbait June 28, 2009 at 2:26 am

I'm red-green color-blind and I don't see it as gray. But I do see the red as more of a pink color (including what I thought people thought was the blue color) and I can see the green pretty clearly although it is darker than the one in the green spiral.

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Anonymous June 24, 2009 at 11:44 pm

It's such a good illusion I didn't believe it until I copied it into paint, used the color picker on a "blue" spot and spray-painted it into a "green" spot… and nothing happened!

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AndyMo June 25, 2009 at 12:34 am

I would think it's more accurate to say our brains are cheating our eyes! Isn't this caused by our brains' interpretation of the color? Or it is a mechanism in the eye that causes the illusion?

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CosmicChuck June 27, 2009 at 10:54 pm

The illusion is generated in the visual cortex, due to what color it's alternated with (orange or magenta). I opened it with Paint and verified that what appears blue is actually green. The closer to the center of the spiral you look, the bluer the green looks (from cyan to blue basically). However what appears green stays fairly constant in appearance. The illusion is created in the part of the visual cortex that processes color. The cones in the eyes are what actually detects color through a process of triangulation based on the frequency of light being reflected from what you are looking at (3 types of cones: red, green, blue).

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fishken July 30, 2009 at 5:00 pm

The trichromatic theory of color vision is one of 2. The dichromatic theory posits red-green, and blue-yellow receptors.

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Janne June 25, 2009 at 3:49 am

AndyMo: our eyes are not passive receptors; the initial stages of image processing such as color opponency split and contrast detection happens right in the retina. I’d say the eyes themselves have more than a little responsibility for this illusion.

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prove to urself June 25, 2009 at 3:50 am

Take a piece of paper and make a tiny hole so you can just see one color only at a time through it, you can prove to yourself they are really the same color ^^

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sorrow June 25, 2009 at 3:31 am

Lies, lies, lies!!!

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Matt June 27, 2009 at 12:10 am

Please give proper credit to Akiyoshi Kitaoka for his work.

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misc June 27, 2009 at 1:28 am

The bluer ones are OUTLINED in blue — that significantly affects what we see.

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Marcello June 27, 2009 at 5:14 am

Er, they're not.

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Jay June 27, 2009 at 5:27 am

It appears that way in this post because the image is being resized by the browser. Click on the image to see it in its original form, and you'll see that there are no outlines.

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jeremy June 27, 2009 at 7:44 am

thats fuckin burnt

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Doug June 27, 2009 at 9:25 am

It's only because the "green" and "blue", at least one of them, are outlined in different colors – look closely.

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pebkac June 27, 2009 at 11:18 am

I don’t know what browser you are using but there is no “outlining” in mine.
This is an optical illusion. Get over it.

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mbm June 27, 2009 at 5:54 pm

there is no outlining, load it into photoshop and zoom in.

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Dirk June 28, 2009 at 6:09 pm

I printed this image and the illusion still holds. But when I cut a "green" and "blue" section out and compared them side by side, they appear the same color. However, that same color is different than either the "green" or "blue" within the image. It is a darker green and a lighter blue. But again, when I take the cutout strip and place it next to the color in the image, it will match both the "green" and the "blue" whichever it is placed next to. Thanks for a great demonstration. (If our eye-brain interface can be fooled like this, it is no wonder how our ear-brain interface can be fooled by polictians.)

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Neil Kellett July 7, 2009 at 11:38 am

If you zoom in using an image editor, you can quite clearly see the colours are the same. Very weird!

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name? July 22, 2009 at 11:44 am

BAsta con poner los dedos en la pantalla y ver los trazos por separado.

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name? translated January 10, 2010 at 3:10 am

It is enough with putting the fingers in the screen and seeing the outlines separately.

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David April 23, 2010 at 5:09 pm

This is true for loose definitions of "Green". The blue color you see is what you'd probably call green, but on RGB it's 255 green, 150 blue. There's plenty of blue in there.

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engraved dog tags November 10, 2010 at 2:52 am

This is exactly what I have been looking for, with the MS TAG you get better clarity and don’t need to worry much about cleaning your lens all the time u need to shoot. I will come back to read more updates on this.

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Live Video January 8, 2011 at 12:27 pm

I would think it's more accurate to say our brains are cheating our eyes! Isn't this caused by our brains' interpretation of the color

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Fred Miller March 4, 2011 at 4:39 pm

Actually the first image is absolutely flawed. Yes the colors are the same but your image suggests a moiree effect which is not present. It happened in the digital imaging and web process. The colors may be the same but the over-all effect if misleading.

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Anthony June 15, 2011 at 11:17 pm

I’ve looked at this illusion on a couple of websites and both have a similar problem. Apparently, in 2009, most commenters remarked that the “blue” spirals and the “green” spirals were perfect matches. But now, in 2011, the image of the illusion is so full of anti-aliasing errors that these supposedly identical colours are in fact different. Try it yourself before you reflexively deny it. Copy the source file out to an editor and sample the “blues” and “greens” at a high magnification.
Could the web-host have reprocessed the image files to reduce the page size, unwittingly introducing errors?

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Caz August 17, 2011 at 9:03 pm

That’s not red. That’s purple.

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