Casual Fridays: Visual Illusions

Today's Casual Fridays study involves visual illusions. We're exploring when and how you see illusions. You'll need QuickTime and a computer with the volume turned up to participate. These illusions are great fun, and we're excited to see if there are any differences in how they are perceived. We really can't tell you much more without spoiling the results, so why not just try it?

Click here to participate.

As usual, the study is brief -- just 4 questions, which should only take a minute of your time. You have until 11:59 p.m. Eastern time on Wednesday, October 18 to participate -- or until we have 500 responses, whichever comes first. Then don't forget to come back next Friday for our analysis of the results!

Do you have any comments on this week's study? Do you have any visual illusions you especially like? Let us know about them in the comments.

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I chose "not moving" for the second one, but it actually looked like it was bobbing up and down. I think I was influenced by the progress indicator at the bottom on the first one.

I chose 'not moving' for the second one both times, because to me it seemed more as though it was rotating in place, and that wasn't an option.

Alan,

You can wait until the movie is completely loaded, then watch. Unfortunately, there's no way for us to know whether a particular user has broadband, but for the most part, I'm not especially concerned. I'll explain that more when we get to the data analysis next week.

I'm with Davis, though it is almost three in the morning here...

I've seen illusions before, but never one that tries to prime the visual illusion with sound. Didn't seem to work with me (perhaps the first half of the year it isn't meant to?) Anyway, why should the two senses change the interpretation of each other?

I can imagine that sound might affect the illusion, but in this case I just didn't see anything moving (unlike a lot of the images on Akiyoshi's amazing page).
Disclaimer: I'm a musician, and possibly slightly more immune to simple musical cues for that reason? But nobody else seems much affected as yet in the comments.)

Interesting to hear these early responses to the experiment. Part of the concept was to pick relatively ambiguous illusions and then see if sound facilitated the perception of them. We've already got 270 participants, so if there's an effect, I'm fairly confident we'll see it.