Is that dress black and blue or white and gold? Are those hot dogs or legs? For centuries, optical illusions have boggled minds far and wide, especially in the age of the Internet. Our current understanding of how optical illusions work is different and far more specific than the level of understanding from the past, but at what point was the original explanation created, and how has it evolved into what we know today?
Do you see a young woman or an old man?
Historians have traced optical illusions back to the 5th century B.C. when multiple philosophers attempted to explain why our brains read images in ways that were not necessarily correct. Greek philosopher Epicharmus claimed that even if we fully comprehend what we are seeing, our senses do not scan the image properly, creating an optical illusion. Another philosopher named Protagoras countered with a different explanation, arguing that the environment tricked people’s minds instead of their bodies. His reasoning likely came from a common ancient Greek optical illusion: tile roofs. The roofs from this time period were built on a downward angle, but at a glance, they appeared horizontal due to the exactly perpendicular walls in a given structure. Aristotle, Plato, and other philosophers weighed in on optical illusions at the time, but the whirlwind of opinions created confusion on the subject.
It wasn’t until the 19th century that extensive research was done on the illusions. Psychologists Johannes Mueller and J.J. Oppel conducted extremely detailed studies and came up with twelve different theories as to why illusions occur. That same century, German physicist Hermann von Helmholtz suggested that optical illusions, specifically cognitive ones, tricked us because whatever we are seeing goes against what we think or know to be true about our environment. Distorting illusions, on the other hand, created deceptive impressions due to warped proportions or characteristics of an item in an image.
The “rabbit duck”, originally published in 1892, is thought to be one of the oldest optical illusions. Archaeologists have found evidence of this drawing in French caves from the Paleolithic period. Source.
Knowing what we know today, past scientists were not too far from the truth. Optical illusions have been split into several categories, with each category having its own specific explanation. Literal illusions fabricate when our senses or perception tell us something different than our logical thoughts. Today, we know that dreams, delusions, and memory losses are managed with the same neural tools that control our sensory organs, so it is no surprise that we can easily see something that isn’t there or miss something that is there. Physiological illusions occur due to extreme stimulation of one or a few specific factors. These include color, motion, and brightness. The high amount of stimulation results in a matching amount of neurons firing in our brains. This leads to an imbalance in the brain, which then causes an altered perception of an image. Finally, cognitive illusions have to do with an image or sensation going against your expectations of it, as theorized by Hemholtz. When an image provides gaps in information, the brain automatically attempts to fill them with what someone would guess or know to be true.
Perhaps the science behind optical illusions is easier to understand than the illusions themselves. Perhaps we will never have the ability to stop our minds from seeing images incorrectly, even while consciously recognizing the roadblocks our body faces. Until these simple things cease to override our senses, we can continue to enjoy humorous Twitter disputes about which way a woman is spinning while marveling at the incredible details that God put into us, His creations.
Do you have a favorite optical illusion from popular culture or the Internet? Any particular type of illusion you find particularly mind-boggling or interesting? Let us know in the comments!
All images are from Google unless otherwise noted.