Are Your Eyes Tricking You?

An illusion is an incorrect interpretation of a sensation; a misperception

Cameras Stereogram by Gene Levine
Source: Gene Levine

I’m sure you have seen optical illusions in the form of those neat pictures that look like a bunch of pixels until your eyes unfocus to reveal the true image. (See above image)

You may have seen magicians giving the illusion that they like to cut people in half like it’s not a big deal to do so. You’ve probably seen disappearing acts, various things being pulled out of hats, and other such illusions.

Here, I explore two of my favorite types of illusions: Sensational and Cognitive

Sensational Illusion

sensational illusion is one that is universal, and is common to all species.

A great example of a sensational illusion is that of the bi-shaded square/checker square. In this video, the viewer is shown two squares that appear to be of two different colors. However, when a line separates the two blocks, it becomes apparent that they are actually the exact same color. This mind is unable to handle chaos, so it established homeostasis in order to sort it out and make sense of everything.

Check out the video here:

Cognitive Illusion

cognitive illusion is an illusion that is based upon immediately previously perceived stimuli.

Cognitive illusion is aptly demonstrated in the video of the Rat-Man illusion. You may have seen this in school.

In this situation, the audience is first shown a sequence of animal drawings, ending with a drawing of a generic rat. Next, the audience is shown a series of human face drawings, ending with the same drawing as before. This time, however, the rat appeared to be an old man with glasses. WHY?

This happens because, when one is shown a sequence of animal drawings, the memory cell of the animal in your brain is in the closest proximity. This results in the rat appearing as a rat. When you are shown a sequence of faces, the human faces memory cell is in closest proximity. This results in the viewer seeing the old man. One is able to easily switch between the two, however, as there is no emotional attachment regarding seeing animals or faces. When one is aware of what the sequence will be, he can simply anticipate the image and ‘rewire’ his brain to send energy to a different memory cell. This enables him to see either a rat or a face, depending on preference. (Obviously, you are not aware of the aforementioned ‘rewiring’ actually taking place.)

What is your favorite type of illusion? Let me know in the comments below!

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  1. I love things like these, but I wonder how many are truly universal. I stumbled across this article a while ago and it points out that the trick where you make two lines of the same length look different by adding either > or < at the end isn't the given universal we thought it was. Now I wonder which ones could also be similarly disproven!

    (I also used to be pretty good at those Magic Eye things as a kid, but I just CAN'T get that one started. Maybe there's something about seeing it on a computer screen….)


    • I have a lot of trouble with the “Magic Eye” illusions, as well. It definitely seems like it would be much more difficult to make out on a screen, since the image is relayed to you differently than if you saw it in person.

      Thank you so much for the input!


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