Best Visual Illusion of the Year: How a Curveball Works

curveball illusion
The winning visual illusion shows how a curveball works (it's animated, so you have to go to the page and stare at the dot on the right as the ball on the left moves).

( -- Visual illusions sometimes seem to have a magical element to them, but they're actually just the brain's way of interpreting reality. In an effort to promote public knowledge of cognitive research, as well as medical discoveries of sensory and cognitive experience, the Neural Correlate Society hosted its 5th annual "Best Visual Illusion of the Year" Contest last Sunday evening, May 10th, at the Philharmonic Center for the Arts in Naples, Florida. The Mind Science Foundation sponsored the event.

Visual artists and scientists from all around the world submitted novel visual illusions, and an international panel of judges narrowed them down to the top 10. At the Contest Gala in Naples, more than 1,000 voters chose the top three winners. Voters included members of the public, as well as researchers who had attended a conference that week held by the Vision Sciences Society. The winners are:

1st prize: "The Break of the Curveball" by Arthur Shapiro, Zhong-Lin Lu, Emily Knight and Robert Ennis (American University, Bucknell University, University of Southern California, Dartmouth College, and SUNY College of Optometry, USA)

2nd prize: "Color Dove Illusion" by Yuval Barkan and Hedva Spitzer (Tel-Aviv University, Israel)

3rd prize: "The Illusion of Sex" by Richard Russell (Harvard University, USA)

The three winning illusions, along with the top 10 finalist illusions, can be seen at

The top three winners received a "Guido" trophy, designed by the Italian sculptor Guido Moretti. Sunday's Contest Gala also included a magic performance by the world famous magician and escapologist James Randi (a.k.a. "The Amaz!ng Randi").

"The contest is a celebration of the ingenuity and creativity of the world's premier visual illusion research community," the contest's website explains. "Visual illusions are those perceptual experiences that do not match the physical reality. Our perception of the outside world is generated indirectly by brain mechanisms, and so all visual perception is illusory to some extent. The study of visual illusions is therefore of critical importance to the understanding of the basic mechanisms of sensory perception, as well as to cure many diseases of the visual system."

At the contest's website, visitors can send free e-cards with visual illusions, as well as view winning illusions from previous contests since 2005.

© 2009

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User comments

May 13, 2009
The winning illusion is awesome, one of the strongest I've ever seen, but the effect is much more pronounced (at least in my case) at settings of 0, 34, 9, then the default ones, if you position the cursor in the last box and keep adding and removing the '-' sign while watching the blue dot the ball will move in a perfect zigzag pattern.

Color is also nice but much weaker. The sex one is interesting but the explanation fails to take into account much more obvious effects then contrast, the right face is much darker which makes it's large volume much more apparent on a light background which makes it much more male-like, also male faces tend to be naturally darker around the eyes due to much more pronounced eyebrows in males.

May 14, 2009
The sex one is a good explanation for why women tend to use facial makeup more then men.

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