Müller-Lyer Illusion Proof


This version of Müller-Lyer Illusion is presented with ruller in background, and shows that often impossible can be possible. I’m sure you’ve seen this illusion before in our “Relative Sizes Category“, but if you haven’t, you can now see for sure that both lines are of the same length (eventhough they don’t appear like that)!

  • Deb

    You need to move the ruler so it starts at zero, otherwise it first appears that the first line is 5 inches long instead of four.

  • Pandas

    kinda boring. but classic

  • Scott Wilton

    wow thats waky

  • Lil Noir

    first to post^^

  • Lil Noir

    first to post^^

    This is kinda old, so you’ve seen it many times before, but it’s really messing with your head.

  • Brad

    That is awesome! Very tricky!

  • koogco

    hehe the fact that it starts in 1 and not in 0 almost made me think there actually was difference =D
    but nice illustration (though i have tried to messure those before)

  • rose

    That is crap… you guys havent yet realized that the lines arent the same length on the ruler!!!

    The illusion can be done…just not like that…

  • Soulseeker

    very nice. it still looks odd even with the ruler though.

  • sam


  • Jackal

    that’s so wierd

  • me

    yeah, i can never see these types of illusion, unless i measure the. and ill even know that theyre the same, but i just cant……..ruler’s nice touch. coula used something more original though…

  • Chuzzlewit

    These are an example of why witnesses are so unreliable, as any cop will tell you. We see with the brain, not the eye. Which fact gave birth to Blake’s axiom that we must see through, not with the eye, if we are to know truth. These “relative sizes” go against that axiom and are the exception that proves the rule, precisely which makes them a true . . . illusion. Sherlock Holmes brain would simply eliminate the arrows and he’d see the true length of the lines. It’s a matter of the mind training the eye to see what’s really there. Not an easy thing to do: be truly and accurately observant. A fascinating encounter would have been one between the fictional Holmes and the late Great Slydini, who could make you see things that weren’t there and not see things that were.

    Of course, once one has seen the “trick”, all bets are off. The Müller-Lyer is an oldie that almost everyone has seen.

  • killer bees

    i saw this one in my psychology class, they just had 2 transparencys and moved them over each other to prove it there tho.

    still neat

  • hi

    this is very cool.

  • Ziddy

    I found this image fairly easy to comprehend, unlike most of the stuff on this site ;)

    What’s going on, is your eyes are looking at the distance between the two points of the arrows.
    What you need to do, is forget about the arrows and look and the length of the lines. You’ll be able to easier see, that they are infact the correct/equal length!

  • Anonymous

    on 10:14 AM

    You need to move the ruler so it starts at zero, otherwise it first appears that the first line is 5 inches long instead of four.

    um… they’re centimetres… perhaps that’s the real illusion for you deb? :+)

  • Stephen

    intererstingly, this illusion only works on people who were raised in carpented societies. That is, people who grew up looking at right angles and square rooms and buildings their whole lives. If you showed this to someone brought up in the fields with no real carpentry in their lives to speak of, they’d just be wondering why you’re confused…

  • Cornelius

    I sandwiched the line between 2 windows, then activated the browser window, and the right one shrank while the left one lengthened. Wow!!!

  • kacheek

    which two lines are meant to be the same?!?!
    soo lost!

  • m4rek

    I think that for rose (post #8), the illusion has worked a little too well?

  • Hi it’s a little old tbh but it is quite funny

  • Tess


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