

Your Lying Eyes: The Illusions of Kokichi Sugihara - davidmathers
http://www.npr.org/blogs/krulwich/2011/01/19/133017843/your-lying-eyes-can-this-be-happening

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juiceandjuice
I did something similar 9 years ago when I decided to make a 3D model of
Escher's Belvedere:

<http://home.utah.edu/~u0386084/hsci_old/belvedere.gif>

<http://home.utah.edu/~u0386084/hsci_old/belvedere_side_1.jpg>

<http://home.utah.edu/~u0386084/hsci_old/belvederelg.jpg>

For those familiar, the software I used (called Alpha_1) was originally
written in 1980 as a testbed for the Oslo Algorithm, and basically a NURBS
toolkit. The Oslo Algorithm would later pave the way for 3D rendering and ray
tracing of NURBS as well as 3D CADD/CAM software.

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srean
This reminded me of a story about a course in MIT were the prof taught about
visual perception. Maybe other HN'ers will be able to fill in the details.
What was striking to me was how quickly the brain adapts to distortion in our
visual field.

The prof would make students catch a ball with prisms before their eyes which
shifted the image laterally. They would initially miss. But soon the students
would adapt, and find nothing wrong with what they saw. These chages
persisted. So when the prisms were removed, real world seemed shifted for a
few minutes and they had difficulty navigating. Same with inverting lenses.

But what struck me most was that near the beginning of the course he
demonstrated a curious case of visual adaptation and never mentioned it again
till the end of the semester. At the end of the semester he showed the class
that the student's brain had still not unlearned the distortion. Something
related to seeing colors. I do not remember clearly.

It will be great if some one can fills in the details. Particularly about the
semester long, persistent adaptation.

~~~
RodgerTheGreat
Could it have something to do with the McCollough effect?

<http://en.wikipedia.org/wiki/McCollough_effect>

~~~
jacobolus
Mark Fairchild’s book _Color Appearance Models_ has a nice couple of pages on
high-level adaptation effects. Try the example on the page after this link for
a demonstration of differing spatial frequency adaptation in each half of the
visual field.

[http://books.google.com/books?id=8_TxzK2B-5MC&pg=PA155&#...</a><p>There are
some animated gifs floating around the web that you can stare at for a few
minutes and then leave yourself with really weird perception of everything you
see moving around depending on its color and orientation, sometimes lasting
quite a long while.<p>Vision is fun!

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athom
Big Clue:

I didn't notice this until after the contraption was turned and he started
fiddling with the balls again, but if you watch closely, you can see that they
roll "up" different ramps at different rates: almost a second along the lower
right ramp, yet barely a half second along the upper left. This wouldn't
happen if the ramps were all the same length and incline, as they're meant to
appear.

Sometimes, you just need to know what to look for...

