Optical Illusions

  By Landon G.

Can you see it?

Have you ever seen a picture that can be seen in two different ways? Look at the title for an example. Can you see it? Well if you cant it says optical and illusion. But whats really cool is that you cant see optical and illusion all at once. Try this, put your finger sideways in front of your face about 5 inches out. Then focus on your finger, then look at your finger but don't focus on the finger, focus on whats behind it. See you can't focus on both at the same time. That is a little idea of what we are going to talk about.

What is it?

A optical illusion is an experience of seeming to see something that does not exist or that is other than it appears. There are many optical illusions and many different kinds. For an example there's an illusion called an ambiguous illusion. When you look at an Ambiguous illusion your brain sees one image then it sees another then maybe even another after that. The illusion makes it where in one image there's two things to see.

Perceptual organization

To make sense of the world it is necessary to organize incoming sensations into information which is meaningful. Gestalt psychologist believe one way this is done is by perceiving individual sensory stimuli as a meaningful whole. Gestalt organization can be used to explain many illusions including the rabbit-duck illusion where the image as a whole switches back and forth from being a duck then being a rabbit and thats why in the figure ground illusion its reversible.

Tips and Tricks

An optical illusion is a way of tricking the brain to see something that may not be there.The human brain puts images together because it has learned to expect certain things. Sometimes the data gets confused.Many people really enjoy looking at an illusion. They seem to love being fooled in this way. Magicians use illusions all the time. In fact, magicians are sometimes referred to as illusionists.Some experiments that are being done show that some mammals and birds are fooled by illusions in much the same way as people are.One of the oldest known illusion related to touch was described by Aristotle more than 2,000 years ago. If you cross two adjacent fingers and then touch an object such as a pen, with both crossed fingertips at the same time it will feel as though you are touching two pens, not one.


The silverware and table cloth illusion is when you touch both, the silverware appears to be colder than the cloth. The fact is, however, they are both at room temperature. This is because metal conducts heat away from your finger more rapidly that cloth does.Some illusions can actually be dangerous. Our sense of equilibrium or balance is located in the inner ear but it works closely with our visual world. When the pilot of an aircraft is flying at night or in a cloud and has no visual reference points it is possible for the pilot to become disoriented. He or she cannot tell whether the plane is gaining or losing altitude, or turning left or right. This is called vertigo. It is an illusion, and pilots are trained to never rely on their sense of position but to respond entirely to the plane’s instruments.


  • You can think 3d. That can happen when your brain compares the moon's perceived size to the sizes of objects whose dimensions you already know.
  • Even the celestial bodies can play tricks with your senses. The moon illusion, as NASA calls it, occurs when the moon looks unusually big to your eyes but normal to the camera.
  • Some illusions occur when your mind shifts its focus between an ambiguous image's background and foreground. For instance, when you look at the Rubin's vase illusion, you may see a vase.
  • Unlike physiological illusions, cognitive optical illusions occur when the mind attempts to make sense of incoming information based on how you think reality should be.
  • Your retina has three types of cones, and each type is sensitive to red, green or blue/violet.., so many illusions are made of those colors to confuse.
  • Negative afterimages occur when you see a negative of the original image. Lighter parts of the image appear dark, and darker parts seem light.

Types of Illusions

Distorting illusions are the most common, these illusions offer distortions of size, length, or curvature. They were simple to discover and are easily repeatable. Many are physiological illusions, such as the Cafe Wall Illusion which exploits the early visual system encoding for edges. Other distortions, such as converging line illusions, are more difficult to place as physiological or cognitive as the depth-cue challenges they offer are not easily placed. All pictures that have perspective cues are in effect illusions. Visual judgments as to size are controlled by perspective or other depth-cues and can easily be wrongly set.

Cognitive illusions instead of demonstrating a physiological base they interact with different levels of perceptual processing, in-built assumptions or 'knowledge' are misdirected. Cognitive illusions are commonly divided into ambiguous illusions, distorting illusions, paradox illusions, or fiction illusions. They often exploit the predictive hypotheses of early visual processing. Stereograms are based on a cognitive visual illusion.

Paradox illusions offer objects that are paradoxical or impossible, such as the Penrose Triangle or Impossible Staircases seen, for example, in the work of M. C. Escher. The impossible triangle is an illusion dependent on a cognitive misunderstanding that adjacent edges must join. They occur as a byproduct of perceptual learning.

Fiction illusions are the perception of objects that are genuinely not there to all but a single observer, such as those induced by schizophrenia or hallucinogenic drugs.

Ambiguous illusions are pictures or objects that offer significant changes in appearance. Perception will 'switch' between the alternates as they are considered in turn as available data does not confirm a single view. The Necker cube is a well known example, the motion parallax due to movement is being misinterpreted, even in the face of other sensory data. Another popular is the Rubin Vase.

So are you interested in optical illusions? Well this article about optical illusions told you about many different kinds of illusions and how they work. I hope reading this has made your interest in optical illusions increase. You now know about distorting, cognitive, fiction ambiguous, and paradox illusions.

Works Cited

Ausbourne, Robert. Visible Magic: The Art of Optical Illusions. New York: Sterling, 2012. Print. Citation 4

Carter, Rita, Susan Aldridge, Martyn Page, Steve Parker, Christopher D. Frith, Uta Frith, and Melanie B. Shulman. The Human Brain Book. London: DK Pub., 2009. Print. Citation 1

Sarcone, Gianni A., and Marie J. Waeber. Big Book of Optical Illusions: Over 200 Original Deceptive Artworks & Brain-fooling Images. Hauppauge, NY: Barron's, 2006. Print. Citation 5

Smith, Katherine Joyce. Astounding Optical Illusions. New York: Sterling Pub., 1994. Print. Citation 2

Winston, Robert M. L. What Goes on in My Head? New York: DK, 2010. Print. Citation 3


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