Hey there. Welcome to Life Noggin.
哈囉。歡迎來到 Life Noggin。
Which one of these orange circles do you think is bigger? Well, neither is. They're actually the same size.
Now stare at the dot inside this circle. Keep staring, and the circle seems to disappear. But it doesn't really.
Why do our brains lie to us? Well, sometimes it just takes shortcuts.
Let's take this first image for example—the Ebbinghaus illusion. Even though the right orange circle may look bigger, it's not. See?
Rather than taking the time and energy to think critically, your brain makes assumptions. It sees that the right circle looks bigger in context with all the other smaller circles and believes it's larger than the other orange circle. But when you look harder, you realize they're the same.
Now, have a look at this. This is known as the Snake Illusion. It might look like it's moving, but I promise it's not.
Scientists have found that tiny eye movements called saccades occur when you look at this image. Your brain mistakes these eye movements for motion in the image, activating the part of your brain that processes movement. Okay, I'm really dizzy now. Let's move on.
Okay, next up, I want you to stare at the bird on the screen. Just the bird. Keep staring. Now look at the cage. Did a red bird appear inside the cage?
That happens because some of the color-sensitive receptors in your retina adapt to the color green after focusing on it for so long. When you look at the white cage, your eye is still adapted to green. But since it isn't there, your eye gives you the same shape in the complementary color, red.
Okay, I'm gonna let this bird go because my dog is trying to kill it.
Our brains don't just trick us with optical illusions like these. When you were a kid, you might have played the game Bloody Mary. It's when you stare at yourself in the mirror in a dark room and call out Bloody Mary three times. Some people see horrible things in the mirror. Well, what's happening is something called the Troxler Effect.
Your brain focuses on the thing it deems most relevant. Whatever facial feature you're staring intently at, other parts of your face can become distorted or even replaced with more body parts. Some features can even disappear altogether.
How do I look now? Am I ready for my close-up?
This Troxler Effect is also why that blue circle you saw earlier disappeared when you stared at the red dot.
But what about magic tricks? Have a look at Zigzag Girl.
You might think that there's no way a person could contort themselves into a shape like that. But what about now? It's a lot more realistic.
When the boxes are painted, our brains don't see the person inside as one continuous object, so it gets confused. This is the Gestalt Principle of Continuity in action. Designs with lines that suddenly change direction are a lot harder to comprehend, and magicians use that to their advantage.
While all these brain and visual malfunctions are normal, some conditions can trick your brain even more. And psychiatric illnesses can result in auditory hallucinations, hearing voices or things that aren't there.
There's still so much we don't know about the brain, but studying its response to optical illusions could help scientists learn so much more about how it really functions.
Do you have a favorite optical illusion? Has there ever been a time that your brain has lied to you? Let us know in the comment section below.