How many colors do you see?

[Uncle Erik]

I came across this optical illusion and writeup here. I think it's an excellent example of why the human mind really should not be trusted as an accurate measure of reality. This is too good not to share. Enjoy:

Quote:

Via my evil twin Richard Wiseman comes one of the best color optical illusions I have ever seen. The original was apparently posted on Buzzhunt: You see embedded spirals, right, of green, pinkish-orange, and blue? Incredibly, the green and the blue spirals are the same color. At first I thought Richard was pulling our collective legs, being a trickster of high magnitude. So I loaded the image in Photoshop and examined the two spirals. In the two squares displayed below, the one on the left is colored using the same color from the blue spiral, and on the right using the green spiral. Like I said, incredible! For pedantry sake, the RGB colors in both spirals are 0, 255, 150. So they are mostly green with a solid splash of blue. The reason they look different colors is because our brain judges the color of an object by comparing it to surrounding colors. In this case, the stripes are not continuous as they appear at first glance. The orange stripes don’t go through the "blue" spiral, and the magenta ones don’t go through the "green" one. Here’s a zoom to make this more clear: See? The orange stripes go through the "green" spiral but not the "blue" one. So without us even knowing it, our brains compare that spiral to the orange stripes, forcing it to think the spiral is green. The magenta stripes make the other part of the spiral look blue, even though they are exactly the same color. If you still don’t believe me, concentrate on the edges of the colored spirals. Where the green hits the magenta it looks bluer to me, and where the blue hits the orange it looks greener. Amazing. The overall pattern is a spiral shape because our brain likes to fill in missing bits to a pattern. Even though the stripes are not the same color all the way around the spiral , the overlapping spirals makes our brain think they are. The very fact that you have to examine the picture closely to figure out any of this at all shows just how easily we can be fooled. This is why I tell people over and over again: you cannot trust what you see even with your own eyes. Your eyes are not cameras faithfully taking pictures of absolute truth of all that surrounds you. They have filters, and your brain has to interpret the jangled mess it gets fed. Colors are not what they appear, shapes are not what they appear (that zoomed image above is square, believe it or not), objects are not what they appear.

 

[Rhinosaur]

Wow, that's incredible. Always loved optical illusions. I don't think I've ever seen one this good before though, great find.

Continuing on the spiral theme, staring at this for 20 seconds or so and then looking at your hand is an interesting experience. Don't blame me if you feel slightly nauseous mind.

Spiral aftereffect

 

[johnwmclean]

Very nice post Erik, and thankyou for sharing. I wonder how much of this translates to hearing, are we all just delusional?

 

[.Sup]

haha nice one Erik

 

[ph0rk]

The brain and the senses are amazing instruments - we just don't have the complete user manual.

 

[shellylh]

That is incredible and very scary. Nice find.

 

[uberburger101]

That was creepy. Good one.

 

[krmathis]

Really good one!

I actually had to copy and paste what I saw as green and blue color into a different image, then lo and behold they are indeed identical.

 

[ishmael]

And nobody faults themselves or other people for "falling for it"; it is recognized as just an interesting way that the brain works.

But when it comes to hearing it's a different story. Your system is never good enough, your hearing is never good enough, etc.