A very cool optical/perceptual illusion

[Telecaster]

Came across this on Twitter today. I love such stuff…even when you know your eye/brain system is misperceiving the visual field—in this case, despite how we see them all the squares are genuinely square—you still can't correct it. Our mistakes are hardwired. This is IMO helpful in understanding the extent to which vision is a constructed thing.

Have a look: http://cory.albrecht.name/Checkerboard/

And here's a brief analysis of what's going on: http://www.slate.com/blogs/bad_astronomy/2015/01/08/optical_illusion_the_bulging_checkboard_illusion.html

I'm particularly intrigued by the idea that this illusion may be related to the "Moon looks bigger nearer the horizon" phenomenon.

-Dave-

[Eric Myrvaagnes]

Wow! That is amazing! I can't remember seeing any other optical illusion that was so stubbornly convincing.
Thanks for sharing it.

[Jeremy Roussak]

Fascinating.

Jeremy

[Jonathan Wienke]

Very cool. But unfortunately the linked article seems to be a long version of "I have no idea why this works, but it does."

[Manoli]

Very cool. But unfortunately the linked article seems to be a long version of "I have no idea why this works, but it does."

Don't think you'll find a simple 'this-is-how-it-works' answer.

If you follow through on the many links of this page and those in the original article, you'll find links to several pdf's exploring the 'why' in greater detail. Hope you're not in a hurry, this has been ongoing since , at least, 1960 (?) ...

Here are two links to start with: one, two

[Ray]

Here are two links to start with: one, two

Interesting! Looking at the examples in the article on Tilt Illusions I find that some of these illusions don't work for me, particularly Figures 23, 29, 30, 31, 32, 34, 35, 38, and 41.

Sometimes if I shift my gaze around, up and down from one figure to the next, I might get a fleeting impression of a horizontal line tilting clockwise in those examples mentioned above, but not when I stare directly at those particular figures. However, certain other examples in the same article do produce strong illusions.

[Manoli]

Interesting! Looking at the examples in the article on Tilt Illusions I find that some of these illusions don't work for me, particularly Figures 23, 29, 30, 31, 32, ...

Interesting indeed, Ray.
The first example you cite Fig23, for example, I do suffer from the illusion. Fig.24 more so. So I presume that the difference between our perceptions , is more in 'degree' rather than an absolute!

"Visual illusion includes the illusion of shape, lightness, color, motion, etc. " This is going to be mud-in-the-eye for the 'non-tech, only care what I see crowd' and I can see it leading to quite a few 'interesting' discussions ...

[AreBee]

It's the dots and lines that act to confuse the brain.

If you deliberately blur your vision so that the dots and lines are not perceived the squares are seen correctly.

A more effective alternative is to view the image rotated 45 degrees.

[NancyP]

I can attest to that. Glasses on - bulge effect. Glasses off - orthogonal "checkerboard". I am very nearsighted.

[Peter McLennan]

That image is preposterous.  I actually had to hold my little plastic ruler up to the screen to demonstrate that those lines aren't straight...

Oh, wait...

[shawnino]

Love this stuff... Escher's stuff too (particularly the impossible figures).
Inspires us for real-world image capture.
Thank you for posting it.

[kers]

It reminds me of some photographs were everything is straight but  still the building seems out of balance...

Then if you make it less straight it becomes better...