What is Perceptual and Imaginary Disorder?
Perception is a subjective mental reflection of objects and phenomena, it is made up of sensations, the formation of an image, and its supplement with imagination. There are the following groups of pathological changes in perception: illusions, hallucinations (true and pseudo-hallucinations), psychosensory disorders, agnosias. The phenomena of extrasensory perception and psychosensory disorders are special groups of disorders, including disorders of perception, imagination and consciousness. Psychosensory disorders include depersonalization and derealization. Pathological fantasy belongs to the pathology of imagination.
Background, norm and evolution
The process of perception consists of elementary sensations, which are synthesized into an image of an object or phenomenon, characterized by objectivity, that is, concreteness, integrity, constancy and categoricality, which is expressed in the ability to relate the perceived object to a certain class of objects. The main properties of perception are most fully described by the founder of gestalt psychology M. Wertheimer. He also described the meaning of the ratio of the perception of the figure and the background. The greatest contribution to the study of perception was made by psychophysics (Weber – Fechner – Stivens laws), who studied the relationship between the threshold of sensation and the strength of the stimulus, as well as the adaptation processes of perception. N. Helmholtz is considered to be the founder of research on the physiology of perception. The visual perception is highlighted, the cerebral reception of which is associated with the retina; auditory associated with the organ of Corti; olfactory – with olfactory epithelium; gustatory – taste cells; tactile – with skin receptors; kinesthetic – with receptors of muscles, tendons, joint capsules; vestibular – with semicircular canals; as well as painful, which can be associated with any receptors with a super-strong effect on them.
At the level of image formation, recoding occurs – the transfer of signs from one sensory system to another. These transfers are studied by the psychology of subjective semantics, the founder of which in our country was E.Yu. Artemieva. Transfers are noticeable because, for example, we can associate form with color, smell, tactile sensations – with taste or sound, and so on, such transfers are called non-verbal-non-verbal.
With the limitation of sensory stimuli – deprivation – even in mentally healthy individuals, after 24 hours, the following disorders are observed. First, there is fear, panic, decreased mood; then the perception of space, which seems large or small, changes, motor coordination is disturbed and the feeling of time changes (days stretch like years), the rhythm of sleep – wakefulness is transformed; then there are disturbances in thinking and body schema, and then illusions and hallucinations. With further deprivation, the formation of delirium and somatic disorders are possible. With artificial sensory deprivation, for example, in special deprivation baths, perception phenomena appear that resemble parapsychological ones. For example, a person may hear a door open in a car on a nearby street. In the course of evolution, man has lost some receptive systems, although it is possible that in a latent state they function at an unconscious level, these include magnetoreception, which is especially pronounced in fish and birds. Thanks to magnetoreception, orientation in the Earth’s magnetic field and return home after migration occurs. The main laws of perception are:
- The law of similarity, thanks to which similar objects are recognized among other objects.
- The law of proximity, according to which there is a critical distance between two objects, which allows them to be considered as a single object.
- The law of pregnancies (orderliness), thanks to which we establish order in any chaotic field of objects.
- The law of closeness and complementarity, thanks to which we can supplement the missing details of the object, as if “completing” the integral image.
- The law of symmetry and imitation, which makes it possible to identify stereotypical rhythms of object structures.
- The law of continuation, thanks to which we can trace the movement of an object in the field of movements of other objects.
One of the peculiarities of perception is that we distinguish beautiful and attractive (attractive) and ugly (aversive). In each of the sensory processes, there are such attractive and aversive stimuli, which are divided into: general biological – for example, everyone seems to taste sweet, and bitter – unpleasant; ethnogenetic – for example, some peoples have ethnic characteristics of the perception of a number of colors and tastes, in particular, pygmies react with nausea to the smell of toothpaste; and customized. General biological attractiveness – unattractiveness is associated with the importance of a number of stimuli for the survival of the species.
Distorted perception of the world (illusory) is also due to biological laws, for example, looking at an object placed in water, we see it as if broken at the level of the water surface, due to this, when grabbing an object from the water, it is fixed with a displacement forward, which is important for fishing (Poggendorf illusion). An object in a corner appears to be larger than an object farther from the corner (Danzio’s illusion). Thanks to this illusion, the “hide-in-the-corner behavior” that occurs in fear helps to scare away the predator, as visual perception increases the size of the object. When we see the moving clouds and the moon, it seems to us that the moon is moving, and the background is stable. This adaptation is also evolutionarily determined, since, as primates, we are adapted to the fact that in nature the figure moves more often against the background than the background in relation to the figure. The Mueller-Luer illusions are directly related to the perception of a person by a person: if the observed person’s arms are raised, he seems taller than the one with lowered shoulders, although the sizes of their bodies are the same.
In ontogenesis, the processes of perception are integrated (syncretic). In particular, the child easily associates various sensory processes and can easily translate the visual image into the auditory one; in addition, he is able to recreate the image with the help of his imagination even when he has disappeared from the field of perception. This phenomenon, called eidetism, persists among artists, writers and creative personalities. In the process of eidetic perception, semantic transfers easily arise, for example, when the artist Aivazovsky reproduced a storm he had seen earlier, he felt nauseous at the time of its pictorial reproduction. Eidetism can be activated in some pathological conditions, for example, in the early stages of delirium development.
Diagnosis of Perception and Imagination Disorders
Research methods of perception depend on the studied modalities. When studying visual perception, its acuity, color blindness are investigated, for example, this is how color blindness, perception of form, perspective, movement of an object, visual fields, as well as the perception of familiar and unfamiliar objects are revealed. In audiographic examination of hearing, the perception of pitch, loudness, timbre, as well as the direction of the signal is highlighted. In the study of olfactory and gustatory processes, the reaction to pheromones, gustatory avoidance and taste blindness are studied. The study of tactile sensitivity allows you to identify a reaction to temperature, pressure, anesthesia, paradoxical sensitivity, hypersensitivity.
The peculiarities of non-verbal-non-verbal transfers are studied by the methods of psychosemantics.