Optical illusions for the eyes, or Obfuscation of sight

All that we see in reality, we take for granted. Whether it's a rainbow after the rain, a child's smile or a gradually shining sea in the distance. But we need to begin to observe the clouds that change form, and from them appear familiar images, objects ... In doing this, we rarely think about how this happens and what operations occur in our brain. In science, this phenomenon has received a corresponding definition - optical illusions of the eye. At such moments visually we perceive one picture, and the brain protests and decodes it differently. We will get acquainted with the most popular visual illusions and try to explain them.

general description

Illusions for the eyes have long been an object of curiosity of psychologists and artists. In scientific definition, they are perceived as inadequate, distorted perception of objects, error, error. In ancient times, the cause of illusion was considered to be the incorrect operation of the human visual system. Today, deception is a deeper concept related to brain processes that help us "decipher", to understand the surrounding reality. The principle of the work of human sight is explained by the re-creation of a three-dimensional image of visible objects on the retina of the eye. Due to this, it is possible to determine the size, depth and remoteness of them, the principle of perspective (parallelism and perpendicularity of the lines). Eyes read the information, and the brain processes it.

The illusion of cheating the eyes can differ in several parameters (size, color, perspective). Let's try to explain them.

Depth and size

The simplest and most familiar for human eyesight is the geometric illusion-distortion of the perception of the size, length or depth of the object of reality. In reality, this phenomenon can be observed by looking at the railway. Near the rails are parallel to each other, the sleepers are perpendicular to the rails. In the future, the picture changes: there is an inclination or bending, the lines are not parallel. The farther the road goes, the more difficult it is to determine the distance of any of its parts.

This illusion for the eyes (with explanations, everything as it should) was first told by the Italian psychologist Mario Ponzo in 1913. A habitual reduction in the size of an object with its remoteness is a stereotype for the human eye. But there are intentional distortions of these perspectives, which destroy the holistic image of the subject. When the staircase preserves the parallelism of the lines throughout the entire length, it becomes incomprehensible whether the person descends or rises. At the very grandfather the building has a purposeless extension downwards or upward.

With respect to depth, there is the notion of disparity - the different position of points on the retina of the left and right eyes. Due to this, the human eye perceives the object concave or convex. The illusion of this phenomenon can be seen in 3D-pictures, when on flat objects (a sheet of paper, asphalt, a wall), three-dimensional images are created. Thanks to the correct arrangement of shapes, shadows and light, the picture is mistakenly perceived by the brain as real.

Color and contrast

One of the most important properties of the human eye is the ability to distinguish colors. Depending on the illumination of objects, the perception may vary. This is due to optical irradiation - the phenomenon of "flow" of light from brightly illuminated to dark areas of the image on the retina of the eye. This explains the loss of sensitivity to the discrimination of red and orange colors and its increase in relation to blue and violet in the twilight of the day. In connection with this, optical illusions can arise.

An important role is played by contrasts. Sometimes a person mistakenly judges the saturation of the color of an object on a faded background. Conversely, a vivid contrast muffles the colors near the objects.

Illusion of color can be observed in the shade, where brightness and saturation also do not appear. In art, there is the notion of "color shadow". In nature, it can be observed when a fiery sunset colors the red of the house, the sea, which in themselves have contrasting hues. This phenomenon can also be considered an illusion for the eyes.

Contours

The next category is the illusion of perception of contours, outlines of objects. In the scientific world, it was called the phenomenon of perceptual readiness. Sometimes what we see is not so, or has a double interpretation. Now in the visual arts there was a fashion for creating dual images. Different people look at the same "encrypted" picture and read in it different symbols, silhouettes, information. A striking example of this in psychology is the test with Rorschach spots. According to experts, visual perception in this case is the same, but the answer in the form of interpretation depends on the characteristics of the person's personality. When assessing the qualities it is necessary to take into account the localization, level of form, content and originality / popularity of reading such illusions.

Inverters

This kind of illusion for the eyes is also popular in art. The trick is that in one position of the image the human brain reads one image, and in the opposite one, the other. The most famous changers are the princess-old lady and the duck-hare. In terms of perspective and color, there are no distortions, but perceptual readiness is present. But for the difference, you need to turn the picture. A similar example in reality can be the observation of clouds. When one and the same form from different positions (vertically, horizontally) can be associated with different objects.

Ames Room

An example of a 3D illusion for the eyes is the Ames room, invented in 1946. It is designed in such a way that when viewed from the front it seems like an ordinary room with parallel walls perpendicular to the ceiling and the floor. In fact, this room is trapezoid. The far wall in it is located so that the right corner is blunt (closer), and the left one is sharp (further). Illusion is enhanced by chess cells on the floor. A person in the right corner is visually perceived by a giant, and in the left - by a dwarf. Interest is the movement of a person around the room - a person rapidly growing or, conversely, decreasing.

Experts argue that for such an illusion, the presence of walls and ceiling is not necessary. There is enough visible horizon, which only seems so with respect to the corresponding background. The illusion of Ames's room is often used in movies to create a special effect of a giant dwarf.

Moving illusions

Another kind of illusion for the eyes is a dynamic picture, or autokinetic movement. This phenomenon occurs when, when considering a flat image, the figures on it begin to literally come to life. The effect increases if a person alternately approaches / moves away from the picture, spends a glance from right to left and vice versa. In this case, the distortion occurs because of a certain color selection, circular arrangement, irregularity or "vector" forms.

"Tracking" pictures

Probably every person had to face the visual effect at least once, when a portrait or an image on a poster literally watches him move around the room. The legendary "Mona Lisa" by Leonardo da Vinci, "Dionysus" by Caravaggio, "Portrait of the Unknown" by Kramskoy or the usual portrait photographs are vivid examples of this phenomenon.

Despite the mass of mystical stories that envelop this effect, there is nothing unusual in it. Scientists and psychologists, reflecting on how to make the illusion of "watching eyes", derived a simple formula.

• The face of the model should look directly at the artist.
• The bigger the canvas, the stronger the impression.
• Emotions of the face of the model matter. Indifferent expression will not cause the observer curiosity and fear of persecution.

With the correct location of light and shadow, the portrait will acquire a three-dimensional projection, the volume, and when you move it will appear that the eyes are being watched from the picture behind the person.