The dress illusionIn 2015, a photo of a dress became viral all over the world because people could not agree on its colors. They were either seeing it white and gold or blue and black. The internet was firmly polarized into two camps: #blackandblue and #whiteandgold, both camps thinking the other is absolutely wrong. The dress illusion was so polarized because of our eye system.
The eye system’s roleThe first step is to understand that we are dealing with an optical illusion. Both camps are right because the colors of the dress are just interpreted by the brain under different conditions. Which color is coming to our eyes does not only depend on light, it also depends on our perception in context to its surrounding environment. This means that the color experience of everybody is different. Some people will see only what’s in front of them and others will be much more affected by the context. What is happening with the dress photo is that our eye is either discounting the blue from the photo so we are seeing white and gold, or discounting the gold which results in seeing a blue and black dress. The explanation behind why our eyes trick us comes from our brain’s assumption of light and how it illuminates the dress. In a study from the Journal of Vision, New York University Neuroscientist Pascal Wallisch, Ph.D. explains that people who see the dress white and gold assume that the dress is lighting by natural light. On the other hand, people who see the dress in black and blue assume that the dress is lighting by artificial light. “Shadows are blue, so we mentally subtract the blue light in order to view the image, which then appears in bright colors — gold and white” “However, artificial light tends to be yellowish, so if we see it brightened in this fashion, we factor out this color, leaving us with a dress that we see as a black and blue,” conclude Dr. Wallisch after surveying more than 13,000 people.
Types of optical illusions
1 – Literal Optical IllusionsLiteral optical illusions happen when the image we see is different from the images that actually make the object or when our eyes focus on specific areas of the image resulting in seeing something that is not actually there. In the following example, our eyes use the edges of the objects to understand what this object is which results in seeing a lot of legs on this elephant.
2 – Physiological Optical IllusionsThis type of illusion is caused when we experience excessive stimulation (brightness, color, flashes, dimension, movement, etc.) for a certain period of time. Take a look at the following image:
Because the eyes are overwhelmed by the contrasting stimulus, the brain is overstimulated and confused. This two-dimensional figure looks three-dimensional because the brain interprets it to be that way. By focusing on the image, the brain realizes what the eye is actually seeing. The three-dimensional image does not actually exist.