Optical illusions that will blow your mind. Illusions of visual perception

Remember Irish fairy tales about leprechauns guarding pots of gold where the rainbow “ends”?

It turns out that a rainbow exists only in our perception - in reality it does not exist.
This is why it is impossible to find the ends of the rainbow. And that’s why leprechauns are gold :)
Why is that? Welcome to the cat... Special greetings lora_in for your curiosity :)

Rainbow- atmospheric, optical and meteorological phenomenon, observed when the Sun (sometimes the Moon) illuminates many water drops (rain or fog). A rainbow looks like a multi-colored arc or circle made up of the colors of the spectrum (from the outer edge: red, orange, yellow, green, blue, indigo, violet). These are the seven colors that are customarily identified in the rainbow in Russian culture, but it should be borne in mind that in fact the spectrum is continuous, and its colors smoothly transition into each other through many intermediate shades.

The center of the circle described by a rainbow lies on a straight line passing through the observer and the Sun, moreover, when observing a rainbow (unlike a halo), the Sun is always behind the observer, and it is impossible to simultaneously see the Sun and the rainbow without the use of optical devices. For an observer on the ground, a rainbow usually looks like an arc, part of a circle, and the higher the observation point, the more complete it is (from a mountain or an airplane you can see a full circle). When the Sun rises above 42 degrees above the horizon, a rainbow is not visible from the Earth's surface.

And now the most interesting...

Incredibly, there is no color in the world around us. Color is just an illusion created by the brain and does not exist in physical reality.

Look around you. From birth you are surrounded by an illusion, “additional reality”, which is so familiar that, like air, it is completely invisible to us.

For example, a person shows a rainbow only to himself: its existence is connected with the peculiarities of human vision and depends on the conical photoreceptors in the eyes - for other living beings that do not have similar cones, a rainbow does not exist at all. So you're not just looking at a rainbow—you're creating one.

You can read more about the structure of the retina.

Let's give the floor to Erwin Schrödinger, Nobel laureate in physics, one of the creators of quantum mechanics, better known to the general public thanks to one cat: “If you ask a physicist what he understands yellow light to be, he will tell you that these are transverse electromagnetic waves, the length of which is approximately 590 nanometers (nm) ). If you ask him: “Where is the yellow?”, he will answer: “It’s not there at all in my picture, but when these vibrations hit the retina of a healthy eye, the person who owns that eye experiences a sensation of yellow.” "

However, the sensation of color cannot be explained within the framework of the objective picture of light waves that physicists have. Proof of this is visual illusions, colorful dreams with eyes closed and people who are able to see color with other senses.

Optical illusion

Visual illusions reveal some aspects of how vision works. If you look closely at a point in the center of a black and white image for 15 seconds, the picture takes on color.

Let's look at another illusion. In Russian it is called “running light green circle”, in English it sounds like “lilac hunter”. It is based on the Troxler effect.

What's unusual here? A moment later, in place of the disappearing purple spots, a green spot appears, moving in a circle. But in reality it doesn’t exist! Electromagnetic waves from the spectral range of 500-565 nanometers do not physically reach the retina of the human eye. This is as unusual as if we heard the melody of a song without any sound vibrations reaching the eardrum. And if you concentrate on the cross, the purple spots disappear completely.

Here's a still frame from the GIF above that captures the reality. Only the purple circles are physically present. There is no green in any of the frames. This is another confirmation of the non-physical nature of color. Moreover, when we see colored dreams, our eyes are generally closed.

Concentrate your gaze on the center of the picture. After some time, the blurry colored images will disappear and turn into a solid White background. The picture is not a gif. Here, on the contrary, electromagnetic waves responsible for colors enter our eyes, but we stop seeing colors.

If you look at the central tile of the cube at the top and on the side facing us, you can see that in the first case it has Brown color, and in the second - orange. This is our perception of reality. But the physical reality is that these two tiles are the same color.

Colored numbers

“I told my father: I realized that in order to write the letter “R”, all I have to do is first write “P” and then draw a line down from its loop. And I was so surprised that I could turn a yellow letter into an orange letter just by adding a line!” — wrote Patricia Lyn Duffy, writer and synesthetic.

In some people, irritation of one sense organ causes both sensations specific to it and sensations corresponding to another sense organ. This phenomenon is called synesthesia, which is translated from Greek as “shared feeling.” That is, a person can look at moving pictures and still hear sound. Or for it, each number or letter can have its own color, as in the picture below. Colored numbers are the most common type of synesthesia.

By the way, I wonder what Patricia will see if her orange “R” is written in light green ink? That is, it is not at all necessary that the color be associated with certain length electromagnetic wave.

Color can be generated by sound vibrations, and sound, for example, by a certain animation.

Nobel laureate in physics Richard Feynman said: “When I see equations, I see letters in color - I don’t know why.” He was also a synesthete. James Wannerton tastes words. New York tastes like it to him boiled egg , and London is like mashed potatoes

. And the other man, McAllister, sees the music. The areas responsible for hearing and vision react to sound. It is amazing that he has been blind since the age of 12: “When I hear music, colorful flashes appear before my eyes, it seems to me that I see even more beautiful colors than sighted people.” And to check whether people are lying and whether they are crazy, tests such as those in the figure below have been developed. There are a lot of fives and twos printed on the piece of paper. A common person

Looks for two for a relatively long time, for him all the numbers look the same. A synesthete does not need time to look at each number. He immediately sees the red pyramid formed by the twos.

Color phenomenon

We live in our own information reality. Color is just an illusion created by the brain and does not exist in physical reality. Depending on expectations, context, and mental models, the brain can arbitrarily change the colors of objects.

Which would be hard to imagine if color were a real physical phenomenon. Colors are definite shape

language. When we see one color, we see something vague, dependent, something like one word in a language. The interpretation of this “word” occurs if we place it in a “sentence” and its context. And electromagnetic waves are, apparently, entities presented to us in two forms: existential, as part of physical reality, and denotative, like ink spots on paper, formed into configurations that are meaningful to us, words that have meanings, as part of information reality.

By the way, even if the nature of color in our consciousness is revealed, the question arises: why are the colors exactly the way we see them? Is this due to our structure or was it, perhaps, somehow randomly chosen during evolution, just as these and not other letters for the alphabet were chosen by chance? What is it like to see the world in ultraviolet or gamma?

It also follows from this that our world, apparently, is not only colorless, but also silent. And to the question, can you hear the sound of a falling tree in the forest if no one is nearby, you can give an answer. No, I can't hear it. Physics is preserved. The tree falls, air vibrations spread. But the sound is born in the brain of the observer. Zen koan about"What does one hand clap sound like?

And one more thing - is Schrödinger's poor cat alive or dead? :)

We are accustomed to taking the world around us for granted, so we do not notice how our brain deceives its own masters.

The imperfection of our binocular vision, unconscious false judgments, psychological stereotypes and other distortions of worldview give rise to optical illusions. There are a huge number of them, but we tried to collect the most interesting, crazy and incredible of them for you.

At one time, this genre of graphics became so widespread that it even received its own name - impossibilism. Each of these figures seems quite real on paper, but simply cannot exist in the physical world.

Impossible trident Classic blivet – perhaps the most optical drawings from the “impossible figures” category. No matter how you try, you will not be able to determine where the middle prong originates.

Another shining example- impossible Penrose triangle.

It is in the form of a so-called “endless staircase”.

And also “The Impossible Elephant” by Roger Shepard.

Ames room

How does the Ames room work?

Movement Illusions

floating star

There are quite a few similar illusions of movement, that is, static images that appear to be moving. For example, the famous rotating circle.

Or yellow arrows on a pink background: when you look closely, they seem to sway back and forth.

Caution: This image may cause eye pain or dizziness in people with weak vestibular systems.

Honestly, this is a regular picture, not a GIF! Psychedelic spirals seem to drag you somewhere into a universe full of strangeness and wonder.

Changeling illusions

Two classic illusions-shifters: nurse/old woman and beauty/ugly.

A more highly artistic picture with a trick - when turned 90 degrees, the frog turns into a horse.

Other “double illusions” are more subtle.

Girl/old woman

Old people/Mexicans

Lovers/dolphins

The list of such dual pictures can be continued endlessly:

In the picture above, most people see the Indian's face first, and only then look to the left and see the silhouette in the fur coat. The image below is usually interpreted by everyone as a black cat, and only then does a mouse appear in its contours.

A very simple upside-down picture - something like this can be easily done with your own hands.

Illusions of color and contrast

Gray squares

This trick is possible due to the way our brain works. A shadow without sharp boundaries falls on square B. Thanks to the darker "surrounding" and the smooth shadow gradient, it appears to be significantly lighter than Square A.

Green spiral

Is the dress white and gold or blue and black?

The explanation of the dress phenomenon is very simple: as in the case of gray squares, everything depends on the imperfect chromatic adaptation of our visual organs. As you know, the human retina consists of two types of receptors: rods and cones. Rods capture light better, and cones capture color better. Each person has a different ratio of cones to rods, so the determination of the color and shape of an object is slightly different depending on the dominance of one or another type of receptor.

Those who saw the dress in white and gold noticed the brightly lit background and decided that the dress was in the shadows, which means White color should be darker than usual. If the dress seemed blue-black to you, it means that your eye first of all paid attention to the main color of the dress, which in this photo actually has a blue tint. Then your brain judged that the golden hue was black, lightened due to the sun's rays directed at the dress and the poor quality of the photo.

In reality the dress was blue with black lace.

And here’s another photo that baffled millions of users who couldn’t decide whether it was a wall in front of them or a lake.

Our vision can very easily deceive our brain with simple color illusions that surround us everywhere. Some of these illusions await you further.

How many colors are there in the picture?

Blue and green spirals are actually the same color - green. There is no blue color here.

The brown square in the center of the top edge and the “orange” square in the center of the front edge are the same color.

Look carefully at the board. What color are cells “A” and “B”? Does “A” seem to be black and “B” white? The correct answer is below.

Cells “B” and “A” are the same color. Gray.

Does the lower part of the figure seem lighter? Use your finger to cover the horizontal border between the top and bottom of the shape.

See chessboard with black and white cells? The gray halves of black and white cells are the same shade. Gray color is perceived either as black or as white.

The horse figures have the same color.

How many color shades are there, not counting white? 3? 4? In fact, there are only two - pink and green.

What color are the squares here? Only green and Pink colour.

Optical illusion

We look at the dot, and the gray stripe on the orange background becomes... blue.

In place of the disappearing purple spots, a green spot appears, moving in a circle. But in reality it doesn’t exist! And if you concentrate on the cross, the purple spots disappear.

If you look closely at a point in the center of a black and white image for 15 seconds, the picture takes on colors.

Look at the center of the black dot for 15 seconds. The image will turn into color.

Look at the 4 dots in the center of the picture for 30 seconds, then move your gaze to the ceiling and blink. What did you see?

At the intersections of all white stripes, with the exception of the intersection at which you fix your gaze this moment, small black spots are visible that are not really there.

Disappearance

If you look closely at the dot in the center for a few seconds, the gray background will disappear.

Concentrate your gaze on the center of the picture. After a while, the blurry color images will disappear and turn into a solid white background.

Does this cat go down or up the stairs?

Frog-horse

Just a piece of paper folded the right way

Do you see three pretty girls?
Now let's flip the image:

Which way is the window open?

Contrast simulation

Ames room

Dynamic brightness gradient

Four Circles Illusion

Color illusion. How many colors are there in the picture?

Illusion of color perception

Illusion of color perception. What color are squares "A" and "B"?

Illusion of color perception. Where is the dark die here, and where is the light one?

Illusion of color perception. The picture is black and white, but...

Illusion of color perception. The image is black and white, but...

The illusion of negative perception. What do you see in the picture?

Rice. I

in daylight they appear close to each other in brightness. At dusk, the poppy appears completely dark, and the cornflower appears lighter. IN art gallery At dusk, the colors gradually begin to disappear, first red, then yellow and green.

We can point out a number of cases when, when looking at colored objects, we also encounter visual errors or illusions.

Firstly, sometimes we mistakenly judge the color saturation of an object by the brightness of the background or by the color of other objects surrounding it. In this case, the patterns of brightness contrast also apply: the color brightens by dark background and darkens on light.

Great artist and scientist Leonardo da Vinci wrote: “Of colors of equal whiteness, the one that appears lighter will appear against a darker background, and the black will appear darker against a background of greater whiteness. And red will appear more fiery against a darker background, as well as all colors surrounded by their direct opposites.”

Secondly, there is a concept proper color or chromatic contrasts, when the color of the object we observe changes depending on the background we observe it against. We encounter illusions of color vision of this kind in the following types. The black circle shown in Fig. VII,

Rice. VII

seems slightly reddish against a green background, but when we cover this circle with thin transparent paper, the illusory red color becomes even more noticeable. Obviously, transparent paper creates the illusion of colored lighting and thereby enhances the effect. Likewise, a black circle on a red background will appear greenish, on a violet-blue background it will appear greenish-yellow, and on a blue background it will appear coppery. The same phenomenon of involuntary coloring of gray stripes can be observed through transparent paper in Fig. VIII.

Rice. VIII

It turns out that the color in which the black circle or gray stripe is painted is the so-called additional color to the background color. For each color there is another color, optical mixing with which gives an achromatic color (white or gray). Such colors are called mutually complementary. A circle or stripe does not have to be black or gray, for example, a yellow stripe appears greenish on a red background, and orange on a green background; V in this case these three colors when mixed will produce white or gray.

It is noted that this illusory coloring black and gray objects occur in a color that is only approximately complementary, but does not coincide with it exactly.

The most obvious concept of optical color mixing can be obtained as follows. If the disk (Fig. IX)

Rice. IX

with sectors having such angles and colors as shown in the figure, put into rapid rotation, then due to fast alternation different excitations, the colors of the sectors will merge into a common gray tone. This illusion of color vision is explained by the inertia of vision and the fact that the sum of appropriately selected radiations of different spectral composition causes the sensation of white light.

Based on the fact that our organ of vision is most adapted to perceive white sunlight Well, such an illusion can be explained. If you look motionlessly at a red spot for several seconds, and then turn your gaze to white paper, then we will see a green spot on the paper. If we look at the yellow circle, we will see a blue one on paper, and vice versa.

Others related to color contrast color vision illusions. Let's give a few more examples.

Rice. X

The areas of the inner square on the left and the strip on the right are equal, but the perimeter of the strip is twice the perimeter of the square. Peering at this drawing, we see a stripe that is brighter than the inner square.

The phenomenon of psychological contrast can be explained the illusion of so-called flower trimming which is as follows. If you look at Fig. XI,

Rice. XI

then on it you can see a figure in the form of a green cross, then the middle circle appears greenish; if you focus on the yellow circles, then the central circle will appear yellowish.

Also interesting illusion of consistent color contrast, appearing after examining the upper part of Fig. XII.

Rice. XII.

If you look closely at the black circle at the top of the picture for several minutes, and then quickly move your gaze to the black circle below, then after a few seconds color images of all four spots surrounding the upper black circle will appear on a white background. What color will these spots appear?

Note here that when moving from one color of a given surface to another color of the same surface, we have its apparent brightness will also change. Consequently, the brightness contrast will also change if we, say, simultaneously change the brightness of the object and the background, or if we view the same object against a less bright and then against a brighter background. This is why brightness contrast is related to color contrast for our vision. The more the color of an object differs from the background color, the more visible the object is and the more clearly its outline and shape are visible.

There are many examples of the effects of color contrasts on the eye. Goethe, for example, writes: “The grass growing in the courtyard, paved with gray limestone, appears an infinitely beautiful green when the evening clouds cast a reddish, subtle reflection on the stones.” Additional color zari - green; this contrast green color mingling with green herbs, and gives an “infinitely beautiful green color”.

Goethe also describes the phenomenon of so-called colored shadows. “One of the most beautiful cases of colored shadows can be observed during the full moon. Candlelight and moonlight can be quite equal in intensity. Both shadows can be made to be of equal strength and clarity, so that both colors will be quite balanced. The screen is placed so that the light of the full moon falls directly on it, and the candle is placed somewhat to the side at the appropriate distance; Some transparent body is held in front of the screen. Then a double shadow appears, and the one that is cast by the moon and which is at the same time illuminated by the candle appears to have a pronounced reddish-dark color, and, conversely, the one that is cast by the candle but is illuminated moon - most beautiful blue color. Where both shadows meet and combine into one, the result is a black shadow.”.

The fact that some colors are perceived by us as "speakers", and others like "retreating", illustrated here in Fig. XIII.

Rice. XIII

Looking at the top figure in this figure, we tend to think that this is a truncated pyramid with its apex facing us.

Looking at the bottom figure, we are ready to imagine a tunnel with an exit hole in the distance. The “prominent” colors usually seem to be red-orange-yellow (or “warm”) colors, while the “receding” colors usually seem to be green-blue (or “cool”) colors. Saturated and light colors We usually seem closer to dark and unsaturated ones. Chromatic colors usually “come forward” against the background of gray colors.

It should be noted that many properties of the eye that cause the appearance of illusions of color vision, at the same time They also turn out to be very useful for our visual sensations., more fully reflecting objective reality.

That is why, for example, on signs and advertisements assembled from luminous gas-light tubes, words written with red glow tubes come closer to the observer and seem to hang in the air, while words written with green or blue glow tubes recede. However, it turns out that for some people illusion of varying distances different colors is the opposite, i.e., blue colors seem closer (in some people the illusion is not observed at all). Among the various explanations for this illusion, the following deserves attention. The visual line intersects the plane of the pupil not in its center, but somewhat to the side, that is, the lens is not strictly centered in relation to the visual line. Therefore, when the eye fixes some blue dot, then the image of the red dot adjacent to it will give on the retina famous circle light scattering, and this circle will not be concentric with the image of the fixed point, but slightly shifted towards the temporal or nasal part of the retina. This displacement in binocular vision creates the same impression that we get from the irritated places of the retinas equally distant from the axes of the eyes, if the red dot is actually closer or further than the blue one.

However color vision illusions have been much less fully studied by physiologists, and many cannot yet be explained satisfactorily, and some of the hypotheses expressed about them are not justified.