Best illusions of the year

By Phil Plait | June 5, 2011 7:00 am

I love optical illusions (see Related Posts at the bottom of this article for more), so I was happy to discover that every year, the Neural Correlate Society has a contest to find the best ones. This year’s Top 10 finalists have been announced.

My favorite (which I can’t embed here, sorry) is called "Grouping by contrast". You’d swear the spots are not the same color, but I cut two holes out of a piece of paper to block the background, and sure enough they are. It’s incredible. The illusion is a variation on the well-known chessboard contrast illusion and is similar to another illusion showing that how we see colors isn’t as straight-forward as you might think.

Another cool one is this:

Click play, and stare at the white dot in the center. You can easily see the dots changing color… until the dots appear to rotate. They suddenly seem to stop changing color, but in reality they still are. Rerun the video and look at the dots instead of the center, and you’ll see.

The best illusions are the ones where you’d swear it’s a trick. But that’s the whole point, isn’t it? So go to the list and check out the other finalists. And remember: seeing is not believing. You cannot always trust your eyes and brain to give you a good picture of reality.

As a skeptic, I find that knowledge comes in handy quite often.

Tip o’ the Escher staircase to slashdot.


Related posts:

- The blue and the green (one of my most popular blog posts of all time)
- This illusion will drive you mad
- Video illusions
- Why does the Moon look so huge on the horizon?

CATEGORIZED UNDER: Cool stuff, illusion
MORE ABOUT: optical illusion

Comments (20)

Links to this Post

  1. illusions - LATEST TECHNOLOGY – LATEST TECHNOLOGY | June 20, 2011
  1. serenity

    “You cannot always trust your eyes and brain to give you a good picture of reality. ”

    I’m quite fond of Neil deGrasse Tyson’s idea: optical illusions should be called “brain failures”.

    This will surely cause this post to show up in the moderation queue – oh well.
    http://www.youtube.com/watch?v=zfAzaDyae-k#t=4m46s

  2. RaginKagin

    You’re a skeptic?

  3. Messier Tidy Upper

    @ ^ RaginKagin : Are you skeptical about that? ;-)

    @ serenity : Nah, “brain failures” refer to something else. I should know. But then we all have our moments some of us just have more moments than others. ;-)

    The term ‘Optical illusions’ works fine for me. :-)

  4. That’s not an illusion, it’s some dots that change colour and then rotate, however you look at it. Am I missing something obvious? [Edit - I just realised you're not suggesting the rotation is an illusion - I got it now]

  5. Pepijn

    Actually this one doesn’t work that well on me. I can still clearly see the spots change colour while staring at the white dot in the centre.

  6. Steve

    Ugh! Thanks for the headache to start my day!!

  7. The contrast one works for me. Very fun to look at that one :-)

    But the one you embedded doesn’t really. The first time I watched it I already had a hard time focusing on the white dot and once the rotation started I really looked at the dots directly – and when I watched it again I still saw the color changes.

    The reason why that happened is that I usually look at the experiment without reading what I SHOULD see. Because I find that with optical illusions I get into confirmation bias when I know what’s supposed to happen.

    (again: contrast one totally worked for me, rotating colorchanging dots didn’t) :-)

  8. DrFlimmer

    Or to say it with Obi Wan Kenobi:

    Your eyes can deceive you, don’t trust them.

  9. Fritriac

    Sorry, doesn’t work for me …

    /I’m a Jedi now?

  10. Bigfoot

    Fun post; I love optical illusions and took the time to go through them all (sad that I cannot perceive the fish bone indentation in the flesh, though).

    I still find this to be the most effective still image illusion ever:

    http://www.sapdesignguild.org/resources/optical_illusions/images/brain_shadow.jpg

    The contract illusion in this ordinary still image is EXTREMELY effective. Squares A and B are identical shades in this image!

  11. abadidea

    A lot of these don’t work for me. The red dot on the face, I can clear-as-day see the morphing behind it whether it’s still or moving. The orange triangle thing over the red balls, I don’t see the “broken 3D”, I just see a lot of 2D elements. The Venetian Mask, I just see a guy wearing a weird mask, I absolutely do not see any two people kissing. I also don’t get what the Dobby/Harry one is supposed to be showing, although it sure is cute.

    On a second viewing I got the “rotating rings: fixed or sliding?” one at the end, and the “red dot in a ring of little gray lines” has me swearing that yes, the animation really does does fast forward occasionally. The one included in this post I saw earlier this year, and yes it works for me :)

    And one of them is Java or Quicktime or something, Missing Plugin.

  12. QuietDesperation

    A lot of these don’t work for me. The red dot on the face, I can clear-as-day see the morphing behind it whether it’s still or moving.

    Same here. Sometimes I wonder if some new illusions are only illusory for the people who created them. Or maybe because we know it’s doing that.

    The orange triangle thing over the red balls, I don’t see the “broken 3D”, I just see a lot of 2D elements.

    Is that what we’re supposed to see? Some of the descriptions were very badly written to the point of incoherence.

    The Venetian Mask, I just see a guy wearing a weird mask, I absolutely do not see any two people kissing.

    I can see both, but this seems more like “forcing the issue”. The mask structure makes you expect to see a face looking out, not two profiles. I *guess* that’s an illusion.

    “red dot in a ring of little gray lines” has me swearing that yes, the animation really does does fast forward occasionally.

    Don’t think I saw that. either. It looked like it was just putting a new ring of random lines.

    The contrast one with the four pulsing dots was the best, although the easiest to understand.

  13. Neil NZ

    Nope, the dots still keep changing colour no matter how I look at it.

  14. Theramansi
  15. Matt B.

    I wish I could view the other illusions, but the website keeps making my computer freeze up.

  16. Messier Tidy Upper

    Not usre if its an illusion exactly but compare the size of the Southern Cross constellatuion with Delphinus and Circinus for examples and guess which is smaller?

    The answer is surprising, well surprises me – and this always applies permanently not just when they’re near the horizon! ;-)

  17. @ ^ For comparison purposes :

    http://en.wikipedia.org/wiki/Circinus

    http://en.wikipedia.org/wiki/Delphinus

    & finally

    http://en.wikipedia.org/wiki/Southern_Cross

    The Southern Cross is the smallest as well as, arguably, most famous of all the 88 constellations. It ceratinly makes up in bright stars and other objects (Jewel Box cluster, Coal Sack nebula, Ruby Crucis, etc ..) for what it lacks in size & sure doesn’t look the smallest in the sky to me though! ;-)

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