Muller-Lyer Ticket Window

The original Müller-Lyer illusion is an optical illusion consisting of nothing more than an arrow. When viewers are asked to place a mark on the figure at the mid-point, they invariably place it more towards the tail end. Another variation, we often blogged about consists of two arrow-like figures, one with both ends pointing in, and the other with both ends pointing out. When asked to judge the lengths of the two lines, which are often equal, viewers will typically claim that the line with outward pointing arrows is longer. One possible explanation is that one sees the lines as three-dimensional, such as the outgoing and ingoing corners of a room. Another possible explanation is that the line with arrows pointing outwards may simply appear longer because the arrows themselves extend past the line. The other explanation could be simply because outward pointing arrows subliminally suggest that the line is growing.

One of the red vertical lines is actually longer. Can you tell which one is it?
One of the red vertical lines is actually longer. Can you tell which one is it?

In the example above, we used exactly the same surrounding suggested. In the Ticket Window Example, both arrows represent outgoing and ingoing corners of a room. It’s almost obvious that the ingoing corner’s arrow is much longer than the other. But look what happens if we fade the background and leave the arrows untouched. Shamefully, this didn’t make any difference. The right arrow still looks larger then the left one:

But when we further fade the background to the point where it almost become invisible, and even more important – if we completely cut the pointing arrow heads, the results are outstanding. Not only did we get the solution we thought we would (resulting with both lines becoming equal), surprisingly we find out that the left arrow was in fact lengthier than the ingoing corner’s one!


32 Replies to “Muller-Lyer Ticket Window”

  1. this ill.apparantly explains why we can see optical illusions in the first place ,the arrow lines seem to move up and down when you look at one then the other,this then tells you how fast your mind processes information.rather slowly

    1. Just because anyone can draw it, doesn’t make it not “an” illusion. Anytime something appears a certain way, but is not, it is “an” illusion. Your lack of faith disturbs me.

  2. Cool illusion! I like your step-by-step explanation. That will definitely be useful for newcomers to this site! :-)
    And your fascination for illusions is also reflected in the explanation for this post! Great job!

  3. In the first pic, I knew that you were going to try to say the left line was longer. I looked at the first pic for a few minutes and I was 100% sure that there was no way you were going to be able to say the left line was longer! When I saw the second pic I said “See, The right line is longer”. Then I scrolled down to the 3rd pic and I felt like an idiot. You really broke down the explanation perfectly. This is my first time on this website and you already have me Hooked!!! Great Website!! I can’t wait to show my 3 daughters!

  4. That is craaazy!! I too had to get my ruler…and even now when I look at it its hard to believe! Makes you wonder how often you’ve seen something in the world that you were 100% convinced was a certain way but were actually wrong.

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