How does an optical illusion work? Sight is a complex process that involves our eyes sending raw information for our brain to interpret. This visual system takes many short cuts and makes edits to images before we’re even made aware of them. Optical illusions take advantage of these shortcuts and uses them to fool the brain.

How does an optical illusion work?

Brain confusion

• Our brain is clever yet blind, like a supercomputer. Just a clever blob.
• Our eyes inform our brain what we see to determine our requirements. The difficulty is that our eyes only know a few words to express what they perceive.
• Our brain might be confused by what our sight are saying.
• This can indicate that the brain perceives movement when it is stationary. Or you may “see” imaginary forms, colors, or tones.
• This image shows Square A and Square B:
• See differences between Square A and Square B? According to the Queensland Brain Institute, Square A seems lighter but is really darker than Square B. Here are both squares side by side:

A basic language

• Like a youngster just speaking a few words, our eyes and brain communicate simply. Usually, our brain can interpret what our eyes see.
• Your brain knows the color of an orange, the size of a chair, and how distant the door is because the eyes tell it.
• Your brain must “fill in the blanks” by guessing from basic visual signals. Because the door seems this huge and the light shines on it that way, my brain thinks the door is around one metre away, which is usually correct.

A guess incorrect

• But sometimes the brain guesses wrong.
• When our brain and sight speak basic language yet misinterpret it, optical illusions occur.Our eyes didn’t tell the brain something was moving, but it thinks it did.
• Because early and frequent movement detection was helpful in pre-historic times, our brains and eyes developed to be sensitive to movement. A tiny stir in the woods might signal a predator, so flee. Early movement detection may save your life!)

How and why?

• Many scientists have spent years studying optical illusions. However, we often don’t realize how our brain and eyes manufacture these illusions.
• We know our eyes send information to the brain on a lengthy, intricate path. That path is confusing early on. Other visual illusions can only be described by complex mechanisms later in that journey.
• Scientists usually know less about how “confusions” develop farther down the line.
• But who knows? You may be on the research team that breaks the code.