This optical illusion will blow your mind!

By Seriously Science | November 13, 2013 7:00 am

Ok, maybe it won’t actually blow your mind, but it does make straight-moving balls seem wriggly, which is pretty awesome. If white circles on a black field are moved in straight lines and allowed to intersect, they (not surprisingly) appear to move in straight lines. However, if those lines are designed to avoid intersections, the balls appear to to wriggle instead. The scientists who discovered this don’t know why it’s true, but who cares — it’s wiggly!

(A) Collision condition. All dots are moving in random directions in straight trajectories, and the dots are allowed to collide with each other on their paths.

(B) No-collision condition with wriggling motion trajectory illusion. All dots are moving in random directions in straight trajectories without colliding with each other.

Wriggling motion trajectory illusion.

“In this paper, we report on a novel visual motion illusion. When hundreds of dots move in straight trajectories and random directions without colliding, the trajectories are perceived as wriggling rather than straight (Experiment 1). We examined the nature of this “wriggling motion trajectory illusion” via six separate experiments. The illusion was most pronounced when there were a large number of dots (Experiment 2). The illusion was independent of both the distance covered (Experiment 3) and the observer’s eye movements (Experiment 4) as well as the dot types (Experiment 5). We also showed that the proximity among the moving dots plays a role in the illusion (Experiment 6).”


NCBI ROFL: Hmm… I wonder if this illusion works on other body parts?
NCBI ROFL: Wobbling appearance of a face induced by doubled parts.
NCBI ROFL: No way. According to my tongue, that hole is definitely wider. (That’s what she said.)
NCBI ROFL: What the cluck? Chickens can see optical illusions, and imprint on them.

  • LennySkaviski

    I see wriggling trajectories in both conditions!

  • Idoru

    I don’t see it. Just looks like balls moving in straight lines.

  • Gagandeep

    Agreed with Idoru… Can’t see any difference either… just balls moving from point a to b

  • Ferdinand Marcos 2.0

    ouch my balls!

  • Dwayne J. Stephenson

    Really, three seconds? What, were they low on Youtube tape?

  • Marcy Rindler

    Yeahhhh they both look the same… Maybe if I had more than 3 seconds to watch it..?

  • whatgoeson

    Reminds me of a regular old snowstorm…no pattern, rhyme or reason to it. It just is. Enjoy it, for what it is.

  • ConcernedHistorian

    I don’t “see” a wiggle when I’m just glancing at it, but there is an impression that the circles are curving their trajectories. If I look closely; however, I can see they’re moving straight, and the mental part of the illusion is destroyed.

  • Morva Ádám

    I have no idea what’s going on, because this crap is so short.

  • Runns Wiff Phoxes

    Huh? I don’t see any illusion here. They’re all moving in straight lines.


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Seriously, Science?, formerly known as NCBI ROFL, is the brainchild of two prone-to-distraction biologists. We highlight the funniest, oddest, and just plain craziest research from the PubMed research database and beyond. Because nobody said serious science couldn't be silly!
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