Have you ever seen this picture? What is the color of the dress in the picture? Are the colors about blue and black or white and gold? Recently, the dress in the picture was a hot issue among teenagers. After someone posted this picture on SNS, most users who saw the picture were in a state of confusion over the real colors of the dress. It is blue and black. The reason for the confusion about the color of the dress was the direction of seeing it. The quantity of light is changed depending on the direction of sight. Furthermore, the users having various views can see the same picture with a different view. In general, this visual confusion is called an optical illusion. Let's confuse ourselves more and more with the eyes.
What is an Optical Illusion?
An optical illusion is the illusory phenomenon owing to the sense of sight. More specifically, an optical illusion is the difference between objective characteristics like size, color, and shape and the characteristics that you see through the eyes. This gap between the real quality of objects and the quality through the eyes always exists. Therefore, the optical illusion that we can see is a case of having big gaps between them. It’s not because your eyes have some trouble seeing. It is just a natural phenomenon caused by light.
What Factor Causes the Optical Illusion?
When the light arrives at the retina through bending in the pupil, the retina cell makes different responses according to the wavelength of light. There are three kinds of cone cells in the retine: red (R), green (G), and blue (B). However, the three cone cells don’t respond identically to the same stimulations. If the cone cells get the same strength of stimulation continuously, the strength of the reactions turns weak. Besides, the sensory organ and the structure of human knowledge make the observation transform when a person sees the view through their eyes. Consequently, many kinds of factors can make the image change while recognizing the view with the eyes. As a result, there are lots of factors making an optical illusion.
Confuse Your Eyes!
- Fick illusion: Look at the picture with the two blocks. Which one do you think is longer than the other? The two blocks are the same length, but the Block B seems to be longer than A. This is because the eyes normally recognize the vertical as longer than the horizontal.
- Ebbinghaus illusion: Which circle is the bigger one? Right or Left? Measure the diameters of the circles with the ruler. In fact, the two circles are the same size. The middle circle seems bigger or smaller than the other because of the size of circles surrounding.
- Fraser optical illusion: Look at the circle that is shaped with the spiral in the middle. Focus on the circle. The part except the middle circle swirls with movement.
- How many people are in these three pictures? Find them!
Optical Illusions Play Hide and Seek in Your Life
- The Dokkaebi Road in Jeju Island: There is the mysterious road on Jeju Island. Before the road became famous, a couple stopped their car to take a picture during their honeymoon trip. After a while, they found out the car, while stalled, was moving on. After that, tourists crowded into Jeju to see the amazing phenomenon. In fact, the Dokkaebi Road is an uphill road which has a gradual gradient. Nevertheless, even with the slight grade of around three degrees, people see the road as a downhill road because of the surrounding environment. Therefore, Dokkaebi Road is a famous place on Jeju.
- The Trick Art museum: Trick art is a new genre of art created by the Japanese. Trick art has the feature in which the picture changes according to the position of the spectator. Moreover, trick art uses science principles like diffraction and reflection of light. For example, two boys who have the same heights stand on a picture of Trick art. After taking a picture, it seems that one boy is bigger than the other. As trick art utilizes the light, trick art is a kind of optical illusion.
Before this, you didn't know about optical illusions and you would have passed the picture, just seeing it while knowing the picture was funny. However, from now on, you can catch on optical illusion. Find the objects applying optical illusions in our lives. Seeing differently, like seeing a picture that has two different faces, can help you to have the direction for seeing variously.