Why optical illusions trick our brains

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

Optical illusions are created through color, contrast, shape, size, patterns and perspective and trick our brains. But how exactly does this happen? Why do straight lines appear oblique, and the same line segments are different in length? We will tell you in this article.

People have been familiar with optical illusions for millennia. The Romans made 3D mosaics to decorate their homes, the Greeks used perspective to build beautiful pantheons, and at least one stone figurine from the Paleolithic era depicts two different animals that can be seen depending on the point of view.

A lot can get lost on the way from your eyes to your brain. In most cases, this system works fine. Your eyes move rapidly and almost imperceptibly from side to side, delivering scattered pictures of what is happening to your brain. The brain organizes them, determines the context, putting the pieces of the puzzle into something that makes sense.

For example, you are standing on a street corner, cars are passing through a pedestrian crossing, and the traffic light is red. Pieces of information add up to the conclusion: now is not the best time to cross the street. Most of the time, this works great, but sometimes, even though your eyes are sending visual signals, the brain makes a mistake in trying to decipher them.

In particular, this is often the case when templates are involved. Our brains need them to process information faster, using less energy. But these same patterns can be misleading.

As you can see in the checkerboard illusion image, the brain doesn't like to change patterns. When small specks change the pattern of a single checkerboard square, the brain begins to interpret them as a large bulge in the center of the board.

Also, the brain is often mistaken about color. The same color may look different on different backgrounds. In the image below, both of the girl's eyes are the same color, but by changing the background, one appears blue.

The next optical illusion is the Cafe Wall Illusion.

Researchers at the University of Bristol discovered this illusion in 1970 thanks to a mosaic wall in a cafe, which is why it got its name.

The gray lines between the rows of black and white squares appear to be at an angle, but in reality they are parallel to each other. Confused by contrasting and closely spaced squares, your brain sees gray lines as part of a mosaic, above or below the squares. As a result, the illusion of a trapezoid is created.

Scientists suggest that the illusion is created due to the combined action of neural mechanisms of different levels: retinal neurons and visual cortex neurons.

The arrow illusion has a similar mechanism of action: the white lines are actually parallel, although they do not seem to be so. But here the brain is confused by the contrast of colors.

An optical illusion can also be created through perspective, such as a chessboard illusion.

Due to the fact that the brain is familiar with the laws of perspective, it seems to you that the distant blue line is longer than the green one in the foreground. In fact, they are the same length.

The next type of optical illusion is pictures in which two images can be found.

In this painting, the faces of Napoleon, his second wife Marie-Louise of Austria and their son are hidden in the void between the flowers. Such images are used to develop attention. Found faces?

Here is another double image called "My wife and mother-in-law."

It was invented by William Ely Hill in 1915 and published in the American satirical magazine Puck.

The brain can also complement pictures with color, as in the fox illusion.

If you look at the left side of the fox picture for a while, and then move your gaze to the right, it will turn from white to reddish. Scientists still do not know what such illusions are connected with.

Here's another illusion with color. Look at the woman's face for 30 seconds and then move your gaze to the white wall.

Unlike the fox illusion, in this case the brain inverts the colors - you see a projection of the face against a white background, which acts as a movie screen.

And here is a visual demonstration of how our brain processes visual information. In this incomprehensible mosaic of faces, you can easily recognize Bill and Hillary Clinton.

The brain creates an image from pieces of information received. Without this ability, we would not be able to drive or cross the road safely.

Now try reading the text in the picture below.

When you are just learning to read, you read each letter, but then the brain memorizes whole words, and while reading, you recognize them as a whole image, glancing over the first and last letters.

The final illusion is two colored cubes. Is the orange cube inside or outside?

Depending on your point of view, the orange cube can be inside the blue one or hover outside. This illusion operates at the expense of your perception of depth, and the interpretation of the picture depends on what your brain thinks to be correct.

As you can see, despite the fact that our brain does an excellent job of everyday tasks, in order to deceive it, it is enough to break the established pattern, use contrasting colors or the desired perspective.

How often do you think the brain is deceived in this way in real life?