Perception traps: how the senses distort reality

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2024-01-13 00:26

Why do we see optical illusions, hear the wrong words and taste the same products differently?

We may not believe other people's words, but if we manage to see, touch or taste something, doubts disappear. We are used to trusting our feelings and sensations, because this is the only channel of our connection with reality. Who deceives us every day.

How our sight deceives us

Our daily life is full of illusions. For example, every girl knows that black clothes make them slimmer, and light ones make them thicker, although the figure does not change. This illusion was discovered back in the 19th century by the physicist Hermann Helmholtz and was called irradiation illusion.

According to her, a white square on a dark background seems larger than a dark one - of the same size - on a white one.

And scientists have only recently figured out what is the matter. There are two main types of neurons in the visual system: ON neurons, sensitive to light things, and OFF neurons, sensitive to dark ones.

Turning off neurons respond linearly: the greater the contrast between light and dark, the more they are fired. On the other hand, including ones behave less predictably: at the same level of contrast, they react more strongly, highlighting light objects against a dark background.

This feature helped our distant ancestors survive by visually enlarging objects in low light. For example, at night a predator sneaks up on you, turning on neurons are activated and make its light skin more noticeable. At the same time, during the day, when dark objects are already clearly visible, there is no need to somehow select them, so the turning off neurons behave as expected: they transmit their real sizes.

There is another useful visual illusion that can be used in everyday life - the Delboeuf illusion. So, the inner circles in the image below are the same, but due to the outer circles, the left one seems smaller than the right one. The distance between the first and second circle causes the eye to misjudge the dimensions of the inner element.

This illusion can be useful, for example, if you are dieting. People often overestimate the amount of food needed to be satiated. On small plates, in accordance with Delboeuf's illusion, the same amount of food looks more solid. As a result, a person imposes less and does not overeat. And it really works.

You might think that vision illusions are a useful thing. Some yes, but not all. For example, the disappearance of Troxler. Try to concentrate on the black cross, and after a while the blurred spots will disappear.

This illusion is due to the structure of the eye. In humans, retinal capillaries are located in front of its receptors and obscure them.

The human eye moves all the time, therefore the only stationary objects are its structures, the very capillaries. To provide a holistic perception of the picture, without shaded areas, the brain turns on a compensation mechanism: if the gaze is fixed at one point, the fixed areas of the image are "cut out" - you simply stop seeing them.

This only works with small objects, because the capillaries are small by default and are located only on the periphery of the vision - they are not in the center of the eye. But in real life it can play a cruel joke. For example, if you are concentrating on some small object in the car, you may not notice the headlights of another car - they will simply “disappear”.

So, sight constantly deceives us, for good or not. Moreover, it affects other feelings as well, causing us to be wrong about the simplest things.

Why do we hear not what it really is

Sometimes we hear not at all what we are told. Our vision and hearing work in tandem, and if visual information contradicts sound information, the brain prefers what it receives through the eyes.

There is one interesting illusion that cannot be overcome even if you know what it is. This is the McGurk effect, a perceptual phenomenon that proves the relationship between hearing and vision.

In the video, the man utters the same "ba" sound, but first you see his lips move correctly - exactly the way to say "ba". And then the picture changes as if the man is saying fa, and you really start to hear that sound. At the same time, he himself does not change. Try to close your eyes and you will be convinced of it.

This works not only with individual sounds, but also with words. Such illusions can lead to quarrels and misunderstandings, or even more dire consequences. For example, if you confuse the sentences He’s got a boot and He’s gonna shoot.

There is another interesting sound illusion that is not related to vision and speech - the effect of an impending sound. If the sound rises, the person tends to believe that he is closer than if the volume decreases, although the location of the sound source does not change.

This feature is easily explained by the desire to survive: if something is approaching, it is better to assume that it is closer in order to have time to run away or hide.

How our taste buds trick us

Research shows that our sense of taste is also not the most reliable source of information.

So, wine connoisseurs were given the same drink to taste. In the first case, it was an ordinary white wine, and people indicated its characteristic notes. Red food coloring was then added to the same drink and given back to the subjects. This time, connoisseurs felt the notes typical of red wine, although the drink was the same.

Even the color of the dishes can affect the taste of food. The study demonstrated that when hot chocolate was served in a cream or orange cup, it tasted sweeter and more flavorful to participants than in a white or red bowl.

This works with any beverage: yellow cans enhance the flavor of lemon, blue soda is better thirst quencher than red soda, and pink soda seems sweeter.

If gustatory senses are so easily deceived, one might assume that tactile perception cannot be trusted either. And indeed it is.

How tactile sensations can fool us

The famous rubber hand experiment proves this. The man puts his hands on the table: he removes one behind the screen, and leaves the other in plain sight. Instead of a removed hand, a rubber limb is placed on the table in front of him.

Then the researcher simultaneously strokes the rubber hand and the real one hidden behind the screen with brushes. After some time, a person begins to feel that the rubber limb is his hand. And when the researcher hits her with a hammer, he gets very frightened.

What's especially interesting is that during this experience, the brain stops counting the hidden hand as its own. The scientists measured the temperature of the extremities during the experiment, and it turned out that the hand behind the screen was colder, while the visible hand and legs remained equally warm.

The visual image tricks the brain into slowing down the processing of information from the real hand. This proves that body sensation is closely related to vision and thinking.

Our perception of weight is also imperfect. Dark objects seem heavier to us than light ones. Scientists have tested this effect. It turned out that with the same weight and shape, a dark object appears to be 6.2% heavier than a light one. Consider this when choosing dumbbells.

Despite all the illusions and distortions, we are too used to trusting our senses to allow ourselves to doubt them. And this is correct, because we do not have and will not have other sources of information. Just remember that sometimes even our own senses can trick us.

The life hacker studied more than 300 scientific sources and found out why this happens and why we often rely not on common sense, but on myths or stereotypes that have stuck in our heads. In our book “The Pitfalls of Thinking. Why our brain plays with us and how to beat it”we analyze one misconception and give advice that will help outwit your brain.