is necessary to admit that visual illusion doesn’t have the same effect on some people who are under the influence of alcohol and narcotics. The initially given illusion was found out in the case of hollow mask of famous actor Charlie Chaplin. The inversion of reality and processing of visual information belong to the functioning properties of the brain of a healthy man. The study of principles of brain activity is a quite difficult field. There are no definitive explanations even to this date. What is more real – the perception of real-world view by the brain of scizophrene (without processing) or the visual information processed by the brain of a healthy man?
1.5.1 Constancy Perception
As a result of evolution, our sensory system has adapted to an adequate perception of objects and phenomena of the surrounding world [Arnheim, 1974], [Shiffman, 2008], [Abbasov, 2019]. In the process of perception, surrounding objects are characterized by some relatively stable physical properties. Perceptual stability when changing parameters of physical stimulation is called perception constancy.
Constant Perception of Lightness
The brightness of the surface of objects is characterized by the intensity of the light reflected by it, or luminosity. When the light intensity changes, the degree of lightness of a sheet of white paper practically does not change, despite the change in luminosity. It will also be perceived as white paper, but with less brightness.
Constancy Perception of Size
The tendency to perceive the size of objects unchanged relative to the observer (the size of the projection on the retina) is a consequence of the constancy of the perception of size. As follows from Figure 1.5.2, a person sitting at the end of the corridor is perceived to be the same size as the one sitting in the foreground, although the size of the retinal image on the retina is several times smaller [Website istockphoto, 2020]. If you place the images next to each other, you can visually detect the resizing of seated human figures.
Figure 1.5.2 Constancy perception of size.
Constancy of Perception of the Form
The shape of the object can also be perceived stably, regardless of the angle of view. This feature of the visual system is called the constancy of perception of the form. Familiar to us doors are perceived as rectangular shapes, despite the angle at which we look at them. However, their projection on the retina has a rectangular shape only if they are directly in front of the observer.
1.5.2 The Development of the Process of Perception
To analyze the perceptual abilities of a person, some studies of abilities in infants can be noted. At the age of one month, babies cannot distinguish small details; their vision can only be distinguished by relatively large objects. Visual acuity is weak, facial expressions are difficult to distinguish, they see mostly the external contours of the face. Infants find some forms more interesting than others; they are more inclined to look at forms similar to human faces. By three months, the sharpness improves; the baby can already decipher facial expressions, and he has much more social reactions. He recognizes something in the face of the mother; when viewing he prefers to look at the photo of the mother, and not at the photo of an unfamiliar woman.
The perception of depth begins to appear at about three months of age, but is finally formed only by six months. At the age of four months, the infant begins to reach for the nearest of the two objects, determining which one is located closer to it, thanks to the binocular disparity. Constancy of perception also begins to develop from the first months of life.
1.5.3 Perception after Surgery Insight
From medical practice it is known that a person born blind, after an operation to restore vision in adulthood, faces many problems due to the lack of spatial impressions about the outside world. The mature people were unable to distinguish even simple objects or forms [Gregory, 1970]. After a long workout, they learned to recognize the simplest of the visible objects. But many have not been able to learn this, so they returned to the previous life of a blind person. This process was accompanied by strong emotional experiences. However, active and intellectually developed people, on the contrary, after the epiphany, were fairly well adapted.
Most patients had some repetitive processes:
– at first they see an objectively unorganized visual world, since there are a lot of unknown objects;
– they highlight the shape and background;
– the majority of patients are able to fix their eyes and follow moving objects;
– they have no objectivity of perception, they cannot determine the nature of the differences between objects;
– they have the ability to assess the spatial distance of objects.
Vision is restored more quickly in people who are blind after birth than in those who are blind. An interesting observation of a 52-year-old patient who underwent an insight operation is given in [Gregory, 1970]. At first, he did not see anything except a vague outline, but after a few days he could already walk through the hospital, find out the time by the wall clock, and watch the movement of cars through the window. In the zoo, he could correctly name most animals. Identifying objects, he often used his tactile experience. He had a specific perception of distance; for example, he thought that he would be able to touch the ground with his feet, being at the window at a height of 12 meters.
Sitting in the restaurant, he took the crescent moon for the reflection of a piece of cake in the mirror. He accurately estimated the distance and size of objects if he knew them well by touch. But he never learned to read with his eyes, although he immediately and without much difficulty began to distinguish between capital letters and numbers. He studied these letters at a school for the blind, and he did not perceive lower case letters. Therefore, it can be noted that he used his past tactile experience very effectively, which often limited the development of his visual perception.
In the museum, he was shown a machine placed under a glass cap, and he could not recognize it, although he dreamed of seeing it. When he was to take off the cap, and he could feel it, he said: “Now that I felt it, I see it.” In general, he perceived the world as dark and vague, which greatly upset him. After the onset of depression, he ceased to live an active life and died three years later. As noted, in such cases, the development of depression is quite characteristic. The image of the world around him, based on tactile sensations, was not able to accommodate a huge mass of constantly incoming new sensory information. Perhaps this led to the development of information stress, to the destruction of the established picture of the world, and then to a prolonged depression.
Studies on the role of congenital or acquired in the process of perception were performed on animals. A newborn animal is reared for some time in the conditions of sensory isolation, in darkness or in the absence of structured visual stimulation, and then its perceptual abilities are evaluated. It was found that in small young animals raised in the dark shortly after birth there is a perception of depth. They are usually observed underdevelopment or degeneration of cortical neurons, which indicates a violation of the analyzer system. As a result,
