The Best Illusions of the Year

On Monday evening I attended the Best Illusion of the Year Contest in Naples Florida. (I live tweeted it as well — that was far more of a challenge than I had expected. See @profsimons if you’re interested). The winning illusions always receive a lot of visibility online, so I thought I would draw your attention to two illusions that were not among the winners, but that were fantastic nonetheless. First, a little background.

The contest coincides with the annual Vision Sciences Society meeting, and it highlights 10 new visual illusions selected by a panel of expert vision scientists from a huge number of submissions (this year, more than 170 distinct entries). Each contestant has 5 minutes to try to wow the crowd of nearly 1000 spectators with the originality and spectacularity of their illusion. At the end of the presentations, audience members vote for their choice of the best illusion, and the top 3 vote-getters win cool sculptures (as in the past 2 years, skeptic and magician James Randi gave a mentalism demonstration while the votes were counted).

This year, there were at least 5 illusions that might have placed among the winners in previous years — it was a remarkably strong year, and most of the presentations were terrific. The winning illusion was a beautiful example of change blindness presented by Jordan Suchow, a graduate student at Harvard (co-created with George Alvarez, a Harvard Psychology Professor). He had presented the effect at last year’s Vision Sciences meeting, and I blogged about it then as well. The effect received a huge round of applause from the audience, including an incredulous shout of “no way” from the back of the room. Here’s the winning demo:

Now for a couple of illusions that didn’t win this year but could have. Peter Tse, one of the greatest living illusion-creators and a regular participant in the contest, presented an important illusion, one with a strong theoretical motivation. His illusion isn’t as dramatic or flashy as some of the other contestants, but it is elegant and theoretically important. His illusion was a novel variant of one created years ago by Stuart Anstis (another well-known vision scientist and illusion creator, who’s own presentation of his earlier illusion immediately followed Tse’s presentation at the contest. Anstis showed many effects in his presentation, and you can see his official contribution to the contest here.). Anstis originally showed that people mislocalize a flashed stimulus when it is presented against a rotating background. Anstis’s effect is driven by the way our visual system detects and processes moving and stationary stimuli.

Tse’s innovation was to show that you could induce the same sort of mislocalization using only your mind. He presented white dots rotating in one direction and black dots rotating in the opposite direction in the same display and flashed dots at 12 and 6 o’clock. Critically, if you focus attention on the black dots, you see the red dots slanted to the left (at 11 and 5 o’clock), and if you focus attention on the white dots, the displacement goes in the other direction. The finding shows that the way you focus attention affects where you perceive the dots to appear, even though the display itself is unchanging. In other words, the mislocalization effect shown by Anstis is not purely visual — it depends not just on your eyes, but on your mind. You can view Tse’s illusion here.

A second wonderful presentation came from Arthur Shapiro, another great illusion-maker and a multiple-year winner of the Best Illusion of the Year contest. He presented a dramatic enhancement of a classic demonstration, first documented by Albert Michotte. If you view two shapes, one moving left-to-right and the other moving right-to-left so that their paths cross, the motion is ambiguous. They either appear to pass over each other or to bounce off each other. Shapiro presented a version in which the shapes appeared to bounce when they stood out from the background (high contrast) but to pass through each other when they didn’t (low contrast). He then showed that you could get the bouncing effect even when it meant that the features had to swap locations. Finally, he showed that you perceive the items as passing through each other when viewed in the periphery but as bouncing when viewed at the center of your gaze. It was one of the most compelling examples of the illusion I’ve seen. You can view it here.

You can view all 10 of this year’s illusions at neuralcorrelate.com. You can also view all of the finalists from previous contests, including my entry from last year, The Monkey Business Illusion:

If you’re interested, you can see my presentation of the illusion (I wore a gorilla suit and showed some other cool stuff). I’d also encourage you to check out Art Shapiro’s website: He has developed some fantastic interactive illusions and his site allows you to try out a wide range of variations of his effects. Peter Tse’s site also has a lot of great illusions he has created over the past decade.

If you enjoy great illusions like these, please consider helping to support next year’s illusion contest by participating in our charity promotion! Just select the Neural Correlate Society as the charity you would like us to support.

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