Everything that we see in reality is perceived as given. Whether it's a rainbow after a rain, a child’s smile or a gradually turning blue sea in the distance. But as soon as we begin to observe the clouds changing their shape, and familiar images and objects appear from them ... At the same time, we rarely think about how it turns out and what operations take place in our brains. In science, such a phenomenon has received a corresponding definition - optical illusions of the eye. At such moments, we perceive one picture visually, and the brain protests and decrypts 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 for psychologists and artists. In a scientific definition, they are perceived as inadequate, distorted perception of objects, error, delusion. In ancient times, the reason for the illusion was considered the malfunctioning of the human visual system. Today, optical illusion is a deeper concept related to brain processes that help us to “decipher” and understand the surrounding reality. The principle of the human vision is explained by the reconstruction of the three-dimensional image of visible objects on the retina. Thanks to this, one can determine their size, depth and remoteness, the principle of perspective (parallelism and perpendicularity of lines). Eyes read information, and the brain processes it.
The illusion of eye deception can vary in several ways (size, color, perspective). Let's try to explain them.
Depth and size
The simplest and most common for human vision is a geometric illusion - a distortion in the perception of the size, length or depth of an 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 pattern changes: a slope or bend appears, the parallelism of the lines is lost. The farther the road goes, the more difficult it is to determine the distance of any part of it.
The Italian psychologist Mario Ponzo first spoke about this illusion for the eyes (with explanations, everything is as it should be) in 1913. The habitual reduction in the size of an object with its remoteness is a stereotype for human vision. But there are deliberate distortions of these perspectives that destroy the holistic image of the subject. When a staircase maintains parallelism of lines along its entire length, it becomes incomprehensible whether a person descends or rises. At the very grandfather, the building has a deliberate expansion down or up.
In terms of depth, there is the concept of disparity - the different positions of the 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 observed in 3D images, when three-dimensional images are created on flat objects (paper, asphalt, wall). Due to the correct arrangement of forms, 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, perception may vary. This is due to optical irradiation - the phenomenon of "flow" of light from brightly lit to dark areas of the image on the retina. This explains the loss of sensitivity to the distinction between red and orange colors and its increase in relation to blue and violet at dusk. In this regard, optical illusions may arise.
An important role is played by contrasts. Sometimes a person mistakenly judges the color saturation of an object against a faded background. Conversely, vivid contrast muffles the colors of nearby objects.
The illusion of color can also be observed in the shade, where brightness and saturation are also not manifested. In the art of art there is the concept of "colored shadow." In nature, it can be observed when a fiery sunset turns red the houses, the sea, which themselves have contrasting shades. This phenomenon can also be considered an illusion for the eyes.
Outlines
The next category is the illusion of perception of the contours, outlines of objects. In the scientific world, it is called the phenomenon of perceptual readiness. Sometimes what we see is not such, or has a double interpretation. Currently, in the visual arts, a fashion for the creation of dual images has appeared. Different people look at the same "encrypted" picture and read different symbols, silhouettes, information in it. A striking example of this in psychology is the Rorschach spot test. According to experts, visual perception is the same in this case, but the answer in the form of an interpretation depends on the characteristics of a 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.
Changeling
This kind of illusion for the eyes is also popular in art. Its trick is that in one position of the image the human brain reads one image, and in the opposite - another. The most famous changeling are the old princess and the duck-hare. In terms of perspective and color, there is no distortion, but perceptual readiness is present. But for the difference it is necessary to turn the picture. A similar example in reality can be observing the clouds. When the same shape from different positions (vertically, horizontally) can be associated with different objects.
Ames's room
An example of a 3D illusion for the eyes is Ames’s 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 floor. In fact, this room is trapezoidal. The far wall in it is located so that the right corner is obtuse (closer), and the left corner is sharp (further). The illusion is enhanced by chess cells on the floor. A person is visually perceived by a giant in the right corner, and a dwarf in the left corner. Of interest is the movement of a person in a room - a person who is growing rapidly or, conversely, shrinking.
Experts say that walls and ceilings are not necessary for such an illusion. Enough visible horizon, which only seems to be relative to the corresponding background. Ames’s room illusion is often used in movies to create the special effect of a giant dwarf.
Moving illusions
Another type of illusion for the eyes is a dynamic picture, or autokinetic movement. This phenomenon occurs when, when viewing a flat image, the figures on it begin to literally come to life. The effect is enhanced if a person alternately approaches / moves away from the picture, glances from right to left and vice versa. In this case, the distortion occurs due to a certain selection of color, circular arrangement, irregularity or “vector” forms.
Tracking Pictures
Probably, every person at least once had to deal with a visual effect when a portrait or image on a poster literally observes its movements around the room. The legendary Mona Lisa by Leonardo da Vinci, Dionysus Caravaggio, Kramskoi's Portrait of the Unknown or ordinary portrait photographs are vivid examples of this phenomenon.
Despite the mass of mystical stories surrounding this effect, there is nothing unusual in it. Scientists and psychologists, pondering how to make the “eye-tracking” illusion, have come up with a simple formula.
- The model’s face should look directly at the artist.
- The larger the canvas, the stronger the impression.
- The facial emotions of the model matter. Indifferent expression will not cause the observer to curiosity and fear of persecution.
With the correct arrangement of light and shadow, the portrait will acquire a three-dimensional projection, volume, and when moving it will seem that the eyes are watching from a picture of a person.