Optical illusions have gained significant popularity in recent times, intriguing people’s curiosity as they marvel at how these illusions deceive their minds.
Have you ever wondered what optical illusions are?
How do optical illusions work?
Are all optical illusions the same, or are there different types?
If you still haven’t found the answers to these questions, then we will help you explore the world of optical illusions.
Here you will get to know the science behind the art used to create the various kinds of optical illusions and how they affect your brain and eyes. So, let’s explore the magical world of optical illusions and learn the science behind these vision-frazzling images.
What are optical illusions?
Optical illusions can be defined as the images that our brains perceive differently than they are. In simple words, when our eyes send information to our brains that tricks us into seeing something different from reality, then the phenomenon of optical illusion occurs. Our brain fails to interpret the optical illusion correctly because of the deception created by the different patterns, light, and colors in the images.
Optical illusions are also known as visual percepts because they trick your brain into seeing something different from what is there. Our brain has different parts that influence it to make any decision, but the visual cortex of the brain is the part where the optical illusion forms that leads to the occurrence of visual percepts when the images you perceive are different from the objective reality.
What are the types of optical illusions?
In our daily lives, we see many kinds of optical illusions. However, all of these illusions can be broadly divided into three categories, which are:
- Literal Optical Illusions: This type of illusion occurs when two different images are compressed into one picture.
- Physiological Optical Illusions: This type of illusion overstimulates our brain with light, shapes, and colors, making it perceive something different than reality.
- Cognitive-Optical Illusions: This type of illusion is a kind of logical paradox that presents inherently contradictory information.
So, let’s look at these optical illusions in detail, with examples.
Literal Optical Illusions
The literal illusion can be found in the pictures where two images seamlessly look like one image. Under this type of optical illusion, our brain tries to interpret the image as one while the eyes send communication to the brain to analyze it as the two images. One of the best examples of the literal optical illusion image is the one where you can see a young lady from one perspective and an elderly woman from another one.
British cartoonist William Ely Hill adapted an optical illusion that first appeared on an 1888 German postcard and published it in a humor magazine in 1915 with the title “My Wife and My Mother-in-Law.”
The optical illusions of hidden objects are also a part of the literal optical illusions. A good example of an illusion from hidden objects is the inkblot on a plain piece of paper. Your brain can interpret the inkblot in many ways and can find many random yet complex visual objects inside the inkblot image.
Physiological Optical Illusions
Physiological Illusions occur when our eyes and brain process the light. This kind of illusion is quite complex as our eyes overstimulate the senses of the brain during the phenomena of physiological optical illusion.
Our eyes see too much light, change of patterns, movement of shapes, color, dimension, and size that it confuses our brain to see something else far from reality. A two-dimensional figure will look like a three-dimensional figure in physiological illusions. The main cause behind this is that our brain immediately interprets the image differently. Later when the brain realizes what the eye is seeing it deciphers that the image in question does not exist in nature. The mend-bending geometric illusions are apt examples of the physiological illusions are the mind-bending geometric illusions.
It has been observed that many physiological optical illusions were created by the scientists. The above image was created by Akiyoshi Kitaoka, a Professor of Psychology at Ritsumeikan University in Japan. This physiological illusion was created with the effect of peripheral drift illusion. The illusionary motion in the picture is generated due to the overuse of the brain’s senses as it becomes susceptible to movement. Our eyes perceive too much light, movement, and color, confusing the brain to see an image of the rotating spiral.
Cognitive Optical Illusions
The most complex illusions are the cognitive illusions. These are also the ones that are most researched by scientists and psychologists as these illusions affect our subconscious minds.
In simple words, cognitive optical illusions reveal what your brain captures and then interpret something that has not been explained in the image. An excellent example of cognitive optical illusion is the Müller-Lyer illusion where two lines of the same length appear to be of different lengths.
The above illusion was named after a German psychiatrist and sociologist, Franz Carl Müller-Lyer. This cognitive illusion occurs when we see two lines of the same length, but due to the use of different arrowheads on the ends, the lines appear to be of different lengths. Our eyes and brain perceive the line with the arrowheads pointing outward to be shorter than the line with the arrowheads pointing inward.
Another example of a cognitive illusion is the slimming stripes. In these cases, research has been done on this too and it has been found that clothes with vertical stripes tend to make the body look wider as compared to clothes with horizontal lines make the body look taller and slimmer. However, these are subject to one’s body shape.
How Does Optical Illusion Work? Know the Science Behind the Art
By now you must have understood the science behind the art of optical illusions. It’s the glitch created by our eyes into our brains. The conflict between what our eye sees and how our brain interprets it creates optical illusions. The brain perceives something that does not exist from the information sent by our eyes by looking at an image.
During the process of optical illusion, the brain interprets the image in such a way that changes the perception of the image or object lying in front of you. You may see the object moving when it is not as your brain wrongly interprets the information conveyed by your eyes. The scientific explanation behind this is that our vision forms an image when our visual cortex processes the information. After that, the sensory stimulation can happen from the bottom up or the top down.
Bottom-up Simulation: Under the bottom-up process, the information comes from external stimuli by the sight of the object and is then processed in your brain resulting in a visual experience of the object. So, the bottom-up simulation helps the brain to interpret what you see as it is in the image.
Top-down Simulation: Under the top-down process, the information comes from Internal stimuli. This means that by looking at something familiar, your sight generates an internal visual experience from the brain. The top-down simulation is mainly generated from your memory to fill gaps in your vision creating an expected image in front of you.
The different outputs of the bottom-up and top-down simulations may cause illusions. Our brain interprets the raw visual data from our eyes to create a clear and distinct image in our minds. This process requires filling in gaps in the visual information. The brain has evolved to do this accurately, even when the information is missing or distorted.