The Blue and the Green

The entire universe in blog form
June 24 2009 10:34 AM

The Blue and the Green


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 Akiyoshi Kitaoka's incredible optical illusion website:

Advertisement

Blue green spiral illusion

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.

green and blue squares

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:

Blue green spirals zoom

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.

So the next time someone swears they saw Jesus, or a UFO, or a ghost, show them this picture. What you see in life is absolutely and provably not what you get.

Edit to add: if you like this illusion, then you might want to check out this audio illusion, and this one of a spinning woman's sillhouette which is one of my all-time favorites.

TODAY IN SLATE

Politics

Don’t Worry, Obama Isn’t Sending U.S. Troops to Fight ISIS

But the next president might. 

The Extraordinary Amicus Brief That Attempts to Explain the Wu-Tang Clan to the Supreme Court Justices

Amazon Is Officially a Gadget Company. Here Are Its Six New Devices.

The Human Need to Find Connections in Everything

It’s the source of creativity and delusions. It can harm us more than it helps us.

How Much Should You Loathe NFL Commissioner Roger Goodell?

Here are the facts.

Altered State

The Plight of the Pre-Legalization Marijuana Offender

What should happen to weed users and dealers busted before the stuff was legal?

Surprise! The Women Hired to Fix the NFL Think the NFL Is Just Great.

You Shouldn’t Spank Anyone but Your Consensual Sex Partner

Moneybox
Sept. 17 2014 5:10 PM The Most Awkward Scenario in Which a Man Can Hold a Door for a Woman
  News & Politics
Weigel
Sept. 18 2014 8:58 AM Does this Colorado Poll Show Latino Voters Bailing on the 2014 Election?
  Business
Business Insider
Sept. 17 2014 1:36 PM Nate Silver Versus Princeton Professor: Who Has the Right Models?
  Life
Food
Sept. 18 2014 9:34 AM How to Order Chinese Food First, stop thinking of it as “Chinese food.”
  Double X
The XX Factor
Sept. 17 2014 6:14 PM Today in Gender Gaps: Biking
  Slate Plus
Slate Fare
Sept. 17 2014 9:37 AM Is Slate Too Liberal?  A members-only open thread.
  Arts
Television
Sept. 18 2014 8:53 AM The Other Huxtable Effect Thirty years ago, The Cosby Show gave us one of TV’s great feminists.
  Technology
Future Tense
Sept. 17 2014 9:00 PM Amazon Is Now a Gadget Company
  Health & Science
Bad Astronomy
Sept. 18 2014 7:30 AM Red and Green Ghosts Haunt the Stormy Night
  Sports
Sports Nut
Sept. 17 2014 3:51 PM NFL Jerk Watch: Roger Goodell How much should you loathe the pro football commissioner?