Entertaining your Mind with Optical Illusions?
Optical illusions are pictures that use color, patterns, and light to trick the eyes and brain. When viewing an optical illusion, what the eyes see is interpreted by the brain, but the brain's interpretation does not match the true image. In fact, the brain sees something that is not really there. Optical illusions are fun to look at, but they also help scientists to learn how the brain works. Many optical illusions were created just to study how the brain processes visual information. There are three basic types of optical illusions: literal, physiological, and cognitive. Literal optical illusions form images that are unlike the objects that create them. The best way to understand a literal illusion is to look at one. An example of a literal illusion is the painting Bakery by Octavio Ocampo. In this painting, a woman sits in front of shelves full of bread in a bakery. However, the way the bread is arranged appears to form skulls. Another famous example of a literal optical illusion is the painting All Is Vanityby Charles Allan Gilbert in which a woman sitting at a vanity table looks like a skull when viewed from further away. Physiological illusions happen when excessive stimuli such as brightness, color, movement, or tilt, for example, cause the eyes or brain to see something that is not there. These illusions can also occur when stimuli compete. The Hermann grid illusion is a famous example of a physiological optical illusion. The Hermann grid is a white grid on a black background. When looking at it there appear to be gray dots at the intersections of the white lines, although in reality there are no gray dots. This is due to a physiological phenomenon called lateral inhibition which is when light and dark photoreceptors compete with each other and one part wants to become active and the other does not. This causes a perceptual illusion of gray dots on the grid. Cognitive illusions occur when the eye and brain make unintentional inferences. There are four types of cognitive illusions: ambiguous, distorting, paradox, and fictional. Ambiguous illusions offer two interpretations of a picture or object, but both can't be seen at the same time. A famous example of an ambiguous illusion is the Rubin vase, which either looks like a white vase or two face silhouettes facing each other. Distortions in length, size, and curves appear to be present in distorting illusions. A famous example of this type of illusion is the arrow illusion, otherwise known as the Mueller-Lyer illusion. In this illusion there are two lines that are the same size but one has the ends pointing in and one has ends pointing out; most people say that the line with the ends pointing in is longer. Paradox illusions are objects that are impossible in real life but look real in drawings, such as the Penrose stairs, which seem to go on forever without getting any higher. This illusion is due to the faulty belief that adjacent edges have to meet. The Penrose triangle is another example of a paradox illusion. Fictional illusions are only seen by a single person; they are actually hallucinations. They can be induced by alcohol or drugs, or by health conditions such as schizophrenia. Examples of fictional illusions are seeing double of one object or seeing something move when it really doesn't. Literal, physiological, and cognitive illusions all deceive the eyes and brain. People have been fascinated by optical illusions throughout history, and continue to be fascinated by them today. Paintings, books, and drawings of optical illusions have become famous because they are fun to look at; however, they also help scientists to discover how the brain works. Fun and science often go hand in hand. To learn more about optical illusions, please see the following links: Exploring Optical Illusions Types of Optical Illusions What You See Isn't Always What You Get! The Science of Light Optical Illusions Cognitive Illusions Gallery of Visual Illusions Different Optical Illusions Eye Popping Illusions Visual Illusion Illusion Optical Illusions for Teens Bio-Plasmics Optical Illusions Shedding Light When What You See IsNot What's There? Fun Visual Tricks & Optical Illusions 106 Visual Phenomena & Optical Illusions Rolling Uphill Can You Believe Your Eyes? Physiological Illusions Collection of Optical Illusions Seeing Swirling Snakes Arrows Optical Illusion Thaumatrope: An Optical Illusion Fun Optical Illusions 3D Illusions Pavement Drawings Using Illusions to Understand the Brain Optical Illusions Gallery What is an Optical Illusion Literal Optical Illusions The Hermann Grid
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