Cognitive Daily

Casual Fridays: Veiled illusion

This week’s Casual Friday study is the most complicated design we’ve done yet. However, in the spirit of Casual Fridays, it should still take only a minute or two of your time. It involves an incredibly clever visual illusion, and should be quite fun as well.

As usual, you have until 11:59 Eastern time on Wednesday, February 15, to reply. However, the study will close after 250 responses, so make sure you get your response in as soon as possible!

Click here to participate in the study!


  1. #1 Peter Hollo
    February 11, 2006

    Intriguing. The image in the test itself was so pale on my laptop screen that I had to push it right down (it’s very good at staying clear if you move around it horizontally, but look at it from below at a highly obtuse angle vertically and it gets darker) in order to see the image at all, and no illusion of motion was present.
    However, when you showed it “unveiled”, the illusion was clear and present.

    PS I’m glad to have got in on this one in time! Living in Australia means I sometimes completely miss out 🙁

  2. #2 David S.
    February 11, 2006

    Just wanted to note that, although I could not recall wihch direction either ring was moving, I did recall that they were moving in opposite directions. You may want to add a survey option to indicate this.

  3. #3 Dave Munger
    February 11, 2006

    Thanks, David —

    Unfortunately we already have 183 out of 250 responses, so we won’t be able to implement it this time. We mainly included the direction condition to make respondents really think about whether they saw motion, so hopefully it won’t matter that we didn’t include an option for your experience.

  4. #4 Michelle
    February 12, 2006

    The modified version didn’t appear to move to me, but the original appeared to be rotating at a good clip. I think it was the higher contrast?

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