All sensations can be characterized in terms of their properties. Moreover, the properties can be not only specific, but also common to all types of sensations. The main properties of sensations include:

quality,

intensity,

duration,

spatial localization,

absolute and relative sensation thresholds

Quality - this is a property that characterizes the basic information displayed by a given sensation, distinguishes it from other types of sensations and varies within a given type of sensation. For example, taste sensations provide information about certain chemical characteristics of an object: sweet or sour, bitter or salty. The sense of smell also provides information about the chemical characteristics of an object, but of a different kind: flower smell, almond smell, hydrogen sulfide smell, etc.

It should be noted that when speaking about the quality of sensations, they often mean the modality of the sensations, since it is the modality that reflects the main quality of the corresponding sensation.

Intensity sensation is its quantitative characteristic and depends on the strength of the current stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions. For example, when you have a runny nose, the intensity of perceived odors may be distorted.

Duration sensations are a temporary characteristic of the sensation that has arisen. It is also determined by the functional state of the sensory organ, but mainly by the time of action of the stimulus and its intensity. It should be noted that sensations have a so-called latent (hidden) period. When a stimulus acts on a sense organ, the sensation does not occur immediately, but after some time. The latent period of different types of sensations is not the same. For example, for tactile sensations it is 130 ms, for pain - 370 ms, and for taste - only 50 ms.

And finally, for the sensations characterized by spatial localization irritant. The analysis carried out by the receptors gives us information about the localization of the stimulus in space, that is, we can tell where the light comes from, the heat comes from, or what part of the body the stimulus affects.

The sensation begins to develop immediately after the birth of the child. Shortly after birth, the baby begins to respond to stimuli of all kinds. However, there are differences in the degree of maturity of individual feelings and in the stages of their development. Immediately after birth, the baby's skin sensitivity is more developed. When born, the baby trembles due to the difference in the mother’s body temperature and the air temperature. A newborn baby also reacts to touch, with the lips and the entire mouth area being the most sensitive. It is likely that a newborn can feel not only warmth and touch, but also pain. Already by the time of birth, the child’s taste sensitivity is quite highly developed. Newborn babies react differently to the introduction of a solution of quinine or sugar into their mouth. A few days after birth, the child distinguishes mother's milk from sweetened water, and the latter from plain water. From the moment of birth, the child’s olfactory sensitivity is already quite developed. A newborn baby determines by the smell of mother's milk whether the mother is in the room or not. If a child has been fed mother's milk for the first week, he will turn away from cow's milk only when he smells it. However, olfactory sensations not related to nutrition take quite a long time to develop. They are poorly developed in most children, even at four or five years of age. Vision and hearing go through a more complex path of development, which is explained by the complexity of the structure and organization of the functioning of these sense organs and their lower maturity at the time of birth. In the first days after birth, the baby does not respond to sounds, even very loud ones. This is explained by the fact that the newborn’s ear canal is filled with amniotic fluid, which resolves only after a few days. Usually the child begins to respond to sounds during the first week, sometimes this period lasts up to two to three weeks. The child's first reactions to sound are of the nature of general motor excitement: the child throws up his arms, moves his legs, and emits a loud cry. Sensitivity to sound is initially low, but increases in the first weeks of life. After two to three months, the child begins to perceive the direction of sound and turns his head towards the sound source. In the third or fourth month, some children begin to respond to singing and music. As for the development of speech hearing, the child first of all begins to respond to the intonation of speech. This is observed in the second month of life, when a gentle tone has a calming effect on the child. Then the child begins to perceive the rhythmic side of speech and the general sound pattern of words. However, the distinction of speech sounds occurs by the end of the first year of life. From this moment the development of speech hearing itself begins. First, the child develops the ability to distinguish vowels, and at a subsequent stage he begins to distinguish consonants. A child's vision develops most slowly. Absolute sensitivity to light in newborns is low, but increases markedly in the first days of life. From the moment visual sensations appear, the child reacts to light with various motor reactions. Color discrimination increases slowly. It has been established that a child distinguishes color already in the fifth month, after which he begins to show interest in all kinds of bright objects. The child, starting to sense light, at first cannot see objects. This is explained by the fact that the child’s eye movements are not coordinated: one eye may look in one direction, the other in the other, or may even be closed. The child begins to control eye movements only at the end of the second month of life. He begins to distinguish objects and faces only in the third month. From this moment, the long-term development of the perception of space, the shape of an object, its size and distance begins. In relation to all types of sensitivity, it should be noted that absolute sensitivity reaches a high level of development already in the first year of life. The ability to distinguish sensations develops somewhat more slowly. In a preschool child, this ability is developed incomparably less than in an adult. Rapid development of this ability is observed during school years. It should also be noted that the level of development of sensations varies from person to person. This is largely explained by human genetic characteristics. - More details on Referatwork.ru: http://referatwork.ru/psychology-2014/section-18.html

There are two types of sensitivity: absolute sensitivity and discrimination sensitivity. Absolute sensitivity refers to the ability of the senses to respond to the minimal, weakest influences of stimuli. Discrimination sensitivity or differential sensitivity is the ability to sense subtle differences between stimuli.

Lower absolute sensitivity threshold- the minimum strength of the stimulus, causing a barely noticeable sensation. This is the threshold for conscious recognition of the stimulus.

Upper absolute sensitivity threshold is called the maximum strength of the stimulus, at which a sensation adequate to the current stimulus still arises. A further increase in the strength of stimuli acting on our receptors causes only a painful sensation in them (for example, an extremely loud sound, a blinding light).

The value of absolute thresholds, both lower and upper, varies depending on various conditions: the nature of the person’s activity and age, the functional state of the receptor, the strength and duration of stimulation, etc.

The sensation does not arise immediately as soon as the desired stimulus begins to act. A certain amount of time passes between the onset of the stimulus and the onset of sensation. This is called the latent period. Latent (temporary) period of sensation- the time from the onset of the stimulus to the onset of sensation. During the latent period, the energy of the influencing stimuli is converted into nerve impulses, their passage through specific and nonspecific structures of the nervous system, switching from one level of the nervous system to another.

the law of constancy of the magnitude of the increment of the stimulus was established, independently of each other, by the French scientist P. Bouguer and the German scientist E. Weber and was called the Bouguer-Weber law. Bouguer-Weber law– a psychophysical law that expresses the constancy of the ratio of the increment in the magnitude of the stimulus, which gave rise to a barely noticeable change in the strength of the sensation to its original value:

Where: I- initial stimulus value, D I- its increment, TO - constant.

Another identified pattern of sensations is associated with the name of the German physicist G. Fechner (1801-1887). Due to partial blindness caused by observing the sun, he began to study sensations. The focus of his attention is the long-known fact of differences between sensations depending on what was the initial magnitude of the stimuli that caused them. G. Fechner drew attention to the fact that similar experiments were carried out a quarter of a century earlier by E. Weber, who introduced the concept of “barely noticeable differences between sensations.” It is not always the same for all types of sensations. This is how the idea of ​​sensation thresholds appeared, that is, the magnitude of the stimulus that causes or changes the sensation.

Investigating the relationship that exists between changes in the strength of stimuli affecting human senses and corresponding changes in the magnitude of sensations and, taking into account Weber’s experimental data, G. Fechner expressed the dependence of the intensity of sensations on the strength of the stimulus with the following formula:

where: S - intensity of sensation, J - strength of stimulus, K and C - constants.

According to this provision, which is called basic psychophysical law, the intensity of the sensation is proportional to the logarithm of the stimulus strength. In other words, as the strength of the stimulus increases in geometric progression, the intensity of the sensation increases in arithmetic progression. This relationship was called the Weber-Fechner law, and G. Fechner’s book “Fundamentals of Psychophysics” was of key importance for the development of psychology as an independent experimental science.

QUESTION 5 FEELING– direct sensory reflection of individual properties of an object. They make up: the sensory-perceptual level of mental reflection. At the sensory-perceptual level we are talking about those images that arise from the direct impact of objects and phenomena on the senses.

An image is the result of perception, therefore the properties of the image = the properties of the perceived object. It can be perceptual (actually, perception) and non-perceptual (imagination, memory, thinking)

1. An image whose object is in the field of perception, i.e. resulting from stimulation of our sensory systems - a perceptual image or image of perception. A prerequisite here is the activity of receptor systems, peripheral physiological processes (mental image (with eyes closed) is associated with central nervous system processes). Perceptual images are divided into:

By modality (visual, auditory, tactile);

For extraceptive/intraceptive, i.e. images of the external world/internal state (the latter are worse, because the sensory receptors are poorer) - this division arose late. Small children and animals do not differentiate these conditions!

On conscious/unconscious images (in perception and imagination, most images are unconscious)

The paradox of the perceptual image - different people see the same object differently (even one person at different periods of life). Why? Because the image is not passively perceived, but is actively constructed by the subject. It is not objects that perceive us, but we find them in the environment. Perceptual images, unlike non-perceptual ones, have a sensory basis. Properties of the perceptual image:

Reality - a person believes in the objective existence of the perceived object, images of perception live in real time and space;

Objectivity – images are projected outward, projected into the space of the external world;

Integrity/objectivity – perception not of the sum of multimodal sensations, but of a holistic object;

Polymodality is the organic unity of data from various senses.

Constancy - constancy - images of objects are constant and do not depend on the conditions of perception (lighting) and the properties of the subject himself (ex. his appearance), i.e. this is the independence of the properties of a familiar object from the conditions of its perception (in children it is impaired - they may be afraid of their father in the image of D. Moroz)

Significance - ex., looking at the spoon we already see its function, influencing social and individual experience.

An image whose object is outside the process of perception is a non-perceptual image - when, without seeing the object itself, we imagine it, i.e. we do not have a real image, but we have an image associated with the processes of imagination, memory, thinking (ex., the image of memory is a former percept). Non-perceptual images have a quasi-sensory nature.

- mental image: an image of imagination or memory, arises without the participation of peripheral nervous processes and is created by human experience or creativity; can be visual, auditory or any other sensory modality, as well as purely verbal.;

- synesthesia: accompaniment of perceptual sensations of one modality with pseudo-sensations of another modality (“assorted” feelings, color hearing, etc.); This interaction of sense organs(“color hearing”, for example). This is a formal definition, and the idea of ​​synesthesia is that once the sense organs did not differ from each other, which has indirect confirmation: temperature sensitivity is directly used to assess the human appearance (a person is warm, cold, light, etc.)

- body diagram: a person’s idea of ​​a certain system of activity that he controls, which also includes physical components that go beyond the body. Important components of this image are considered to be kinesthetic and temperature-tactile representations. The body diagram is included in the “I-image”, but the latter is broader;

- phantom images: part of the image of one’s own body that remains even despite the loss of the corresponding bodily organ (usually a limb);

- hallucinatory images: occur without an external stimulus, the subject is convinced of the reality of the external object, this is a projection of the subject’s internal image into the external world. Hallucinations differ from mental images in their clarity and detail. Their special case is hypnological images (on the verge of sleep and wakefulness);

- phosphenes: usually appear in the form of unsaturated spots or relatively stable patterned images. The term is also used to refer to dots or colored spots visible when the eye is inappropriately stimulated, for example by mechanical pressure or electrical current.

- eidetic images: common in 70% of children - this is the result of inertia of the visual system. The eidetic sees, but does not remember! disappearing image within minutes and even hours (Rykiel's experiments with the painting). According to Vygotsky, eidetism is widely represented among primitive peoples (it is the basis of topographic memory). In modern man, eidetism is destroyed by higher mental functions and social influence.

So, sensation is a mental reflection of the isolated properties of objects in the objective world, arising from their direct impact on the senses.

The occurrence of sensations is associated with special physiological processes involved in the reception and primary transformation of the effects of certain stimuli from the external and internal environment of the body. These devices are called analyzers(I.P. Pavlov). Each analyzer consists of three parts: first, the peripheral section (receptor), where the recoding of physical effects into nerve impulses occurs; secondly, afferent (from the Latin afferentis - bringing) nerve pathways, along which information encoded in the form of nerve impulses is transmitted to the central nervous system (in

7.1. Feeling

of all animals and humans - into the brain), and, thirdly, the center of the analyzer - a special area of ​​the cerebral cortex. As a result of processing the received information in the cortical section of the analyzer, sensations arise. The return signal, which implements the body's reaction to the stimulus, passes through the efferent (from the Latin efterentis - efferent) nerve pathways.

Living beings differ in the stimuli to which they respond and, accordingly, in the sensations they experience. There is evidence that birds navigate during long-distance flights using the Earth’s magnetic field and therefore must have some kind of “magnetic” sensation that is inexplicable to humans. Sharks are sensitive to electrical discharges coming from fish scales. Bats have a special ultrasonic analyzer with which they recognize obstacles encountered on their path. Insects see in a part of the color spectrum that is inaccessible to us. Human hearing detects a range of 15-20,000 Hz, while a dog can distinguish sounds of higher frequencies. The well-known circus act of “transmitting orders at a distance” from the trainer to the animal is based on this effect. The dog is trained to respond in a certain way to a whistle with a frequency of about 35,000 Hz. Spectators cannot hear the conditioned signal (producing such sounds is quite simple with the help of a slightly modified whistle), and it seems to them that the dog is performing tricks by magic, reading the owner’s thoughts. It is likely that, under certain conditions, a person can develop sensitivity to stimuli that are usually beyond the capabilities of sensory systems. An example is the experiment on the formation of “skin vision” conducted by A.N. Leontiev (see 7.1.4).

Different analyzers have unequal projections in the cerebral cortex. Maps were experimentally obtained that schematically show the location and size of the area of ​​the cortex, which provides an analysis of sensations coming from various areas of the body. One version of such a map is shown in Fig. 40. Note that different types of animals have significantly different “maps”.

Thus, in humans, the maximum area of ​​the cerebral cortex is occupied by the projection zones of the mouth, eyes and hands, which is determined by the leading role of vision, speech activity (it requires developed sensory sensitivity of the lips and tongue) and subtle hand movements for social life. In an animal for which another type of sensory is of greatest importance

The presence of highly specific analyzers, each of which is susceptible to only one specific type of stimulation, poses the problem of the relationship between the properties of sensations and the properties of objects in the external world. In other words, it is necessary to understand how accurately we can judge the real properties of stimuli based on our sensations?

I. Müller (1801-1858) put forward the hypothesis of “specific energies of the sense organs.” The essence of this hypothesis is that sensations do not reflect the real properties of the stimulus, but only signal the state of our analyzers. “What our sensations give us reflects, expresses the nature and state of our sense organs, nerves, and not the nature of what causes these sensations,” wrote Muller. He illustrated his idea with simple examples: if you hit the eyeball, a person will feel “sparks falling from the eyes,” i.e. will receive a subjective visual sensation. Similarly, if you lick a strip of metal through which a weak electric current is passed, you will experience a sour taste. One gets the impression that sensations are pure subjectivity, only incidentally connected with the objective world. The position of I. Muller at one time had a great influence on the interpretation of sensation phenomena. However, evolutionary reasoning leads us to the conclusion that we are dealing with a pseudo-problem.

7.1. Feeling

Even if in some cases we perceive the world not as it is, in fact, our sensations as a whole are adequate to the world, since they allow us to effectively navigate the environment. A deeper comprehension of the world is provided by another mental function - thinking, which consists in a generalized and mediated knowledge of reality (see Chapter 9).

The second question that arises when discussing the topic of sensation is the question of the “immediacy” of the action of the stimulus. Indeed, we not only receive sensations from stimuli that are in direct contact with the surface of our body (we touch, taste and smell), but we also see and hear what is located at a considerable distance from us. Ancient thinkers solved this problem by admitting that objects “emit” the finest etheric copies from themselves, which easily penetrate the eyes, ears, etc. At a new stage of development, science has, in essence, returned to a similar understanding, having found physical carriers of “distant” stimuli that make them “close.” For vision, such a stimulus will be light, for hearing - air vibrations, for smell - the smallest particles of matter suspended in a neutral environment. According to C. Sherrington, sensations are usually divided into contact(the stimulus itself acts on the perceiving organ, and an intermediary delivering information is not required) and distant(i.e., a special “agent” is needed to bring information to the sensory surface). Contact sensations are gustatory, olfactory, skin, kinesthetic (sensations of the position of individual parts of the body) and organic (hunger, thirst, etc.), distant - auditory and visual sensations.

However, there are other prerequisites for dividing sensations into distant and contact. They lie in the anatomical features of the structure of the corresponding sense organs. Obviously, contact sensations are phylogenetically more ancient than distant ones. The receptors of contact analyzers do not generally constitute integral sensory organs. For example, tactile sensitivity is provided by isolated skin receptor cells (the so-called Paccini body, Meissner body). The former respond to pressure, the latter - to vibration. Distant analyzers are complex ensembles that include both the receptors themselves, concentrated in a certain area of ​​the body, and additional “devices” that ensure maximum efficiency of sensation. As A.N. points out. Leontyev, at a certain stage of evolution, these ensembles acquire their own engine -

Chapter 7. Cognitive processes. Sensation and perception

with a special apparatus, they acquire motor capabilities that are quite autonomous from the rest of the body (propriomotor apparatus). The eye, for example, has extraocular muscles, ciliary muscles, etc. Thus, the impact on distant sensory organs presupposes a higher counter activity of the subject. It is not for nothing that A. Schopenhauer compared vision with feeling: “Vision can be considered as an imperfect, but distant sense of touch, which uses rays of light as long tentacles,” he wrote in his work “The World as Will and Idea.” Such emancipation of distant sense organs can undoubtedly be considered as an evolutionary breakthrough in the formation of sensory systems. Unlike contact ones, they do not react to an already existing situation, but actively anticipate it (P.K. Anokhin).

In addition to dividing into contact and distant ones, C. Sherrington also proposed classifying sensations according to the location of their corresponding receptors (according to receptive fields). In this case they differ by interoceptive sensations (from receptors located in the internal organs), proprioceptive(from receptors located in muscles, ligaments and tendons) and Exteroceptive(from receptors located on the outer surface of the body). In general, the classification of sensations is presented in Table. 13.

General characteristics of sensations. Main characteristics of analyzers.

Feeling - this is the simplest mental process, consisting of reflecting individual properties of objects and phenomena of the material world, as well as internal states of the body under the direct influence of stimuli on the corresponding receptors. Since sensations arise as a result of the action of a specific stimulus on the corresponding receptor, the classification of sensations is based on the properties of the stimuli that cause them and the receptors that are affected by these stimuli. According to the nature of the reflection and the location of the receptors, it is customary to divide sensations into three groups: 1) exteroceptive , reflecting the properties of objects and phenomena of the external environment and having receptors on the surface of the body; 2) interoceptive , having receptors located in the internal organs and tissues of the body and reflecting the state of the internal organs; 3) proprioceptive , the receptors of which are located in muscles and ligaments; they provide information about the movement and position of our body. The subclass of proprioception, which is sensitivity to movement, is also called kinesthesia, and the corresponding receptors are kinesthetic or kinesthetic. From the point of view of the data of modern science, the accepted division of sensations into external (exteroceptors) and internal (interoceptors) is not enough. Some types of sensations can be considered external-internal. These include temperature and pain, taste and vibration, muscle-articular and static-dynamic.

The sense organs receive, select, accumulate information and transmit it to the brain, which every second receives and processes this huge and inexhaustible flow. The result is an adequate reflection of the surrounding world and the state of the organism itself. On this basis, nerve impulses are formed that arrive to the executive organs responsible for regulating body temperature, the functioning of the digestive organs, organs of movement, endocrine glands, for adjusting the sense organs themselves, etc. And all this extremely complex work, consisting of many thousands of operations per second, is performed continuously.

Expedient and safe human activity is based on the constant receipt and analysis of information about the external environment and about one’s internal state for a timely adaptive response. All irritations acting on the body from the outside and arising within it are perceived by a person with the help of sensory organs, including the organs of vision, hearing, gravity, smell, taste, and touch. Analyzers receive information from the senses about the state and changes in the external and internal environment and process it.

Analyzers – functional sensory systems that provide qualitative and quantitative analysis of stimuli affecting the body. The structure of each analyzer can be divided into three sections:

peripheral section– receptors, most often located in the sensory organs, perceiving irritations and converting them into nerve impulses;

conductor department– nerve pathways along which nerve impulses are transmitted to the cerebral cortex;

central department(nerve centers) are sensitive areas in the cerebral cortex that transform the received irritation into a certain sensation.

The main characteristic of analyzers is sensitivity – the property of a living organism to perceive irritations caused by the action of stimuli from the external or internal environment. Sensitivity is characterized by the value threshold of sensation. There are absolute and differential sensation thresholds.

Absolute threshold of sensation- this is the minimum force of irritation at which a sensation occurs.

Differential (difference) sensation threshold- this is the minimum amount by which the stimulus must be increased in order to obtain a minimal change in sensation.

Each analyzer is characterized by the minimum duration of exposure to the stimulus required for the occurrence of sensation. The time from the onset of exposure to the appearance of sensation is called latent period. Its value for various analyzers ranges from 0.09 to 1.6 s.

In a simplified form, the analyzer circuits are presented in Table 1.

Characteristics of the visual analyzer.

A person receives more than 80% of all information about the external environment thanks to lighting through the visual analyzer. Under the influence of a flow of radiant energy, light and color sensations arise, the level of which depends on the brightness and illumination of the objects in question, objects, and surrounding surfaces. Visual analyzer , like any other analyzer, consists of three functional parts. The peripheral part in the visual analyzer is the most important of the sense organs - the organ of vision - eye. Eye consists of an almost spherical eyeball, extraocular muscles, eyelids, lacrimal apparatus

Characteristics of the auditory analyzer.

Hearing analyzer includes the ear, nerves and auditory centers located in the cerebral cortex Human ear is an organ of hearing in which the peripheral part of the auditory analyzer is located, containing mechanoreceptors that are sensitive to sounds, to gravity and to movement in space. Most ear structures designed to perceive, amplify and convert sound energy into electrical impulses, which, when entering the auditory areas of the brain, cause an auditory sensation.

Characteristics of the skin analyzer.

One of the most important functions skin is a receptor function. The skin contains a huge number of receptors that perceive various external irritations: pain, heat, cold, touch. On 1 cm 2 of skin there are approximately 200 pain, 20 cold, 5 heat and 25 pressure receptors, which represent the peripheral part of the skin analyzer. Painful sensations cause defensive reflexes, in particular the reflex of moving away from the stimulus. Pain sensitivity, being a signal, mobilizes the body to fight for self-preservation. Under the influence of a pain signal, the work of all body systems is restructured and its reactivity increases. Mechanical effects on the skin that do not cause pain are perceived tactile analyzer . Tactile sensitivity is an integral part of the sense of touch.

Kinesthetic analyzer.

Motor or kinesthetic analyzer is a physiological system that transmits and processes information from the receptors of the musculoskeletal system, and also participates in the organization and implementation of coordinated movements. Physical activity contributes to the adaptation of the human body to changes in the environment (climate, time zones, working conditions, etc.). Various types of movements are characterized by the dynamics of physiological processes, which, when optimized, ensure the best preservation of the body’s vital functions. Excessive mobilization functional activity that is not provided with the necessary level of coordination and activity of recovery processes during work and for a long time after its completion is characterized as hyperdynamia . This condition occurs with excessive sports or heavy physical labor, or with prolonged emotional stress. Hyperdynamia develops as a result of mobilization of the functions of the neuromuscular, cardiovascular, respiratory and other systems that is inadequate for the functional state of the body and can be accompanied by a number of painful symptoms. Low physical activity is the cause physical inactivity. This condition is characterized by a decrease in the activity of all organs, systems and a disorder of interconnection in the body, metabolism is disrupted, the reliability and stability of the human body decreases under significant functional loads and the influence of unfavorable environmental factors. Thus, all this allows us to talk about a person’s motor activity as a process that largely contributes to the preservation of his health and work activity.

Olfactory analyzer.

The type of sensitivity aimed at the perception of various odorous substances using an olfactory analyzer is called sense of smell. The sense of smell is of great importance in ensuring safety, since people with impaired sense of smell are more likely to be at risk of poisoning. Determined for many odorous substances threshold of perception , i.e. the minimum concentration of a substance that can cause a reaction in the olfactory organ.

The main characteristics of the olfactory organ are:

· absolute threshold of perception – the concentration of a substance at which a person perceives the odor, but does not recognize it (even for familiar odors);

· threshold recognition - the minimum concentration of a substance at which the smell is not only felt, but also recognized.

· by their nature called pleasant, unpleasant, bad, vague, disgusting, suffocating, etc.;

· by intensity they are divided into weak, moderate, pronounced, strong and very strong;

· by irritant effect – not irritating, slightly irritating, unbearable.

Changes in the sense of smell can occur as follows:

· hyposmia – decrease in the acuity of smell, while the threshold for odor perception increases;

· anosmia – loss of smell perception;

· hyperosmia And oxyosmia – heightened sense of smell, while the threshold for smell perception decreases.

Hyposmia can be complete or partial. Occupational hyposmia can be functional (adaptation to smell, fatigue of the olfactory organs), toxic (after inhalation of lead, mercury, chlorine, etc.), respiratory (after inhalation of dust), inflammatory, post-infectious, post-traumatic. Changes in the sense of smell can be of either peripheral or central origin, depending on which part of the olfactory analyzer is damaged.

Taste analyzer.

Taste - a sensation that occurs when stimuli act on specific receptors located in different parts of the tongue. Taste sensation consists of the perception of sour, salty, sweet and bitter; variations in taste result from a combination of the basic sensations listed. Different parts of the tongue have unequal sensitivity to taste substances: the tip of the tongue is more sensitive to sweet , edges of tongue - to sour , tip and edges - to salty and the root of the tongue is most sensitive to bitter . The mechanism of perception of flavoring substances is associated with specific chemical reactions at the border " substance - taste bud " It is assumed that each receptor contains highly sensitive protein substances that disintegrate when exposed to certain flavoring substances. Excitation from taste buds is transmitted to the central nervous system along specific pathways.

The main properties of sensations include:

quality,

intensity,

duration,

spatial localization,

absolute and relative thresholds of sensations.

All sensations can be characterized in terms of their properties. Moreover, the properties can be not only specific, but also common to all types of sensations. The main properties of sensations include: quality, intensity, duration and spatial localization, absolute and relative thresholds of sensations.

Quality- this is a property that characterizes the basic information displayed by a given sensation, distinguishes it from other types of sensations and varies within a given type of sensation. For example, taste sensations provide information about certain chemical characteristics of an object: sweet or sour, bitter or salty. The sense of smell also provides us with information about the chemical characteristics of an object, but of a different kind: flower smell, almond smell, hydrogen sulfide smell, etc.

Intensity of sensation- a quantitative characteristic and depends on the strength of the current stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions. For example, if you have a runny nose, the intensity of perceived odors may be distorted.

Duration of sensation- this is a temporary characteristic of the sensation that has arisen. It is also determined by the functional state of the sensory organ, but mainly by the time of action of the stimulus and its intensity. It should be noted that sensations have a so-called latent (hidden) period. When a stimulus acts on a sense organ, the sensation does not occur immediately, but after some time. The latent period of different types of sensations is not the same. For example, for tactile sensations it is 130 ms, for pain - 370 ms, and for taste - only 50 ms. The sensation does not appear simultaneously with the onset of the stimulus and does not disappear simultaneously with the cessation of its effect. The visual sensation has some inertia and does not disappear immediately after the cessation of the stimulus that caused it. The trace of the stimulus remains in the form of a consistent image. There are positive and negative sequential images.

Positive consistent image corresponds to the initial irritation, consists in maintaining a trace of irritation of the same quality as the actual stimulus.

Negative sequential image consists in the emergence of a quality of sensation opposite to the quality of the stimulus that acts. For example, light-darkness, heaviness-lightness, warmth-cold, etc. The emergence of negative sequential images is explained by a decrease in the sensitivity of a given receptor to a certain influence.

Spatial localization of the stimulus. The analysis carried out by receptors gives us information about the localization of the stimulus in space, i.e. we can tell where the light is coming from, where the heat is coming from, or what part of the body the stimulus is affecting.

Quantitative parameters the main characteristics of sensations, in other words, the degree of sensitivity. Human senses are amazingly fine-working devices.

There are two types of sensitivity:

absolute sensitivity - the ability to sense weak stimuli;

Distinction sensitivity is the ability to sense subtle differences between stimuli.

However, not every irritation causes a sensation. In order for a sensation to arise, the force of irritation must have a certain magnitude.

Absolute threshold of sensation - the minimum magnitude of the stimulus at which sensation first occurs. Stimuli whose strength lies below the absolute threshold of sensation do not produce sensations, but this does not mean that they do not have any effect on the body. Thus, studies by Russian physiologist G.V. Gershuni and his colleagues showed that sound stimulation below the threshold of sensation can cause changes in the electrical activity of the brain and dilation of the pupil. The zone of influence of stimuli that do not cause sensations was called by G.V. Gershuni the “subsensory area.”

The study of sensation thresholds began with the German physicist, psychologist and philosopher G.T. Fechner, who believed that the material and the ideal are two sides of a single whole. Therefore, he set out to find out where the border between the material and the ideal lies. Fechner approached this problem as a natural scientist. In his opinion, the process of creating a mental image can be represented by the following diagram:

Fechner Gustav Theodor (1801 -1887)- German physicist, philosopher and psychologist, founder of psychophysics. Fechner is the author of the programmatic work "Elements of Psychophysics" (I860). In this work, he put forward the idea of ​​​​creating a special science - psychophysics. In his opinion, the subject of this science should be the natural relationships between two types of phenomena - mental and physical - functionally interconnected. The idea he put forward had a significant impact on the development of experimental psychology, and the research he conducted in the field of sensations allowed him to substantiate several laws, including the basic psychophysical law. Fechner developed a number of methods for indirectly measuring sensation, in particular three classical methods for measuring thresholds. However, after studying sequential images caused by observing the sun, he partially lost his sight, which forced him to leave psychophysics and take up philosophy.

Irritation -» Excitement -» Sensation -» Judgment (physics) (physiology) (psychology) (logic)

The most important thing in Fechner's idea was that he was the first to include elementary sensations in the range of interests of psychology. Before Fechner, it was believed that the study of sensations, if anyone was interested in it, should be carried out by physiologists, doctors, even physicists, but not psychologists. This is too primitive for psychologists.

According to Fechner, the desired boundary passes where sensation begins, that is, the first mental process arises. Fechner called the magnitude of the stimulus at which sensation begins lower absolute threshold . To determine this threshold, Fechner developed methods that are actively used in our time. Fechner based his research methodology on two statements called the first and second paradigms of classical psychophysics.

Human sensory system is a measuring device that responds appropriately to physical stimuli.

Psychophysical characteristics in people are distributed according to a normal law, that is, they randomly differ from some average value, similar to anthropometric characteristics.

The paradigms are already outdated and to a certain extent contradict modern principles of mental research, but Fechner's research was innovative in its essence.

Today, researchers understand that it is impossible to isolate and experimentally study one, even the most primitive, mental system from the entire structure of the human psyche. In turn, the activation in the experiment of all mental systems from the lowest to the highest leads to a very wide variety of reactions of the subjects, which requires an individual approach to each subject.

Different analyzers have different sensitivities. We have already talked about the sensitivity of the eye. The sensitivity of our sense of smell is also very high. The threshold of one human olfactory cell for the corresponding odorous substances does not exceed eight molecules. It takes at least 25,000 times more molecules to produce the sensation of taste than to produce the sensation of smell.

The absolute sensitivity of the analyzer depends equally on both the lower and the upper threshold of sensation.

The magnitude of absolute thresholds , both lower and upper, varies depending on different conditions:

nature of activity,

person's age,

functional state of the receptor,

strength and duration of irritation, etc.

Sensitivity to difference. Relative or difference sensitivity - to changes in the stimulus. If we put a load weighing 100 grams on our hand, and then add another gram to this weight, then not a single person will be able to feel this increase. In order to feel an increase in weight, you need to add three to five grams.

To feel a minimal difference in the characteristics of the influencing stimulus, it is necessary to change the strength of its impact by a certain amount.

Discrimination threshold - the minimum difference between stimuli, which gives a barely noticeable difference in sensations.

The values ​​of constants for the sensation of change in various stimuli were calculated.

In 1760, the French physicist P. Bouguer, using the material of light sensations, established a very important fact regarding the value of discrimination thresholds: in order to feel a change in illumination, it is necessary to change the flow of light by a certain amount.

Later, in the first half of the 19th century. The German scientist M. Weber, studying the feeling of heaviness, came to the conclusion that when comparing objects and observing the differences between them, we perceive not the differences between the objects, but the ratio of the differences to the size of the compared objects.

MeaningconstantsWeberForvariousorgansfeelings

Feel	Constant value
1.Feeling a change in pitch
2.Feeling a change in light brightness
3.Feeling a change in the weight of objects
4. Feeling of sound volume changing
5. Feeling a change in pressure on the surface of the skin
6.Feeling a change in the taste of the saline solution

General concept of sensations and their functions. Physiological basis of sensations

A person’s primary contact with the outside world and his own body, which gives him initial information about the properties and conditions of the external and internal environment, occurs through sensations. Sensation is usually understood as psychophysical knowledge of individual properties of phenomena and objects of the objective world, i.e. the process of reflecting the direct impact of stimuli on the sense organs, irritating the latter. Sensation is a subjective (mental) experience arising as a result of this process strength, quality, localization and other characteristics of the impact on the senses

Functions of sensations:

Firstly, with the help of the senses, the human body receives in the form of sensations a variety of information about the state of the external and internal environment. As a result, an adequate reflection of the surrounding world and the state of the organism itself arises

Thirdly, sensations are not only the source of our knowledge about the world, but also our feelings and emotions

A person has a STRONG need to receive impressions of the world around him in the form of sensations

The doctrine of sensation states that objects and their properties are primary, while sensations are the result of the influence of matter on the sense organs. At the same time, sensations reflect the world as it exists.

There are other views on the nature of sensations. On the one hand, sensations are seen as the only reality. On the other hand, this is a concept for which sensations are only conventional signs, symbols of external influences.

a mechanical stimulus can cause a sensation of pressure, sound or light, depending on whether it acts on the skin, ear or eye. Based on these facts, I. Müller put forward the hypothesis of a specific energy of the sense organs. The essence of this hypothesis is that sensations do not reflect the real properties of the stimulus, but

They only signal the state of our analyzers. That is, according to this idea, sensation does not depend on the quality of the stimulus, but on the specific energy of the sensory organ that is affected by this stimulus. “What our sensations give us reflects the nature and state of our sense organs, nerves, and not the nature of what causes these sensations,” wrote I. Muller. The conclusion that I. Muller draws is that it is not

There are similarities between our sensations and objects in the external world. However, even if in some cases we perceive the world not as it really is, our sensations are generally adequate to the world, since they allow us to effectively navigate the environment.

So, sensations are subjective images of the objective world

sensation as a mental phenomenon in the absence of a response from the body or in its inadequacy is impossible. In this sense, a motionless eye is as blind as a motionless hand ceases to be an instrument of cognition. The physiological basis of sensation is the neurophysiological process occurring in the analyzer. Analyzer -

a term introduced by I.P. Pavlov to designate a functional unit responsible for receiving and analyzing sensory information of any one modality. The analyzer has three sections.

The first of them is a perceptive organ or receptor designed to convert the energy of stimulation into the process of nervous excitation. The second section is a conductor, consisting of afferent nerves and pathways through which impulses are transmitted to the overlying sections of the central nervous system.

The third is the central section, consisting of relay subcortical nuclei and projection sections of the cerebral cortex. For sensation to arise, coordinated activity of all three parts of the analyzer is necessary.

The impact of an irritant on the receptor causes irritation. The beginning of this irritation is expressed in the transformation of external energy into an internal process, which is produced by the receptor. From the receptor, this process reaches the nuclear part of the analyzer along the centripetal nerve. When excitation reaches the cortical cells of the analyzer, the body's response to irritation occurs. We perceive light, sound, taste or other qualities of stimuli

excitation, in turn, is transformed into a mental image - the result of the combined activity of all three parts of the analyzer. Therefore, we can say that sensation is the transformation of the energy of external stimulation into a fact of consciousness

Types of sensations and their characteristics

By modalities,

distinguish visual, auditory, tactile, olfactory, taste sensations, sensations of movement and balance

English physiologist C. Sherrington proposed classification of sensations based on the anatomical location of receptors and their functions. He identified three main classes of sensations: exteroceptive, proprioceptive and

interoceptive.

Exteroceptive sensations arise from the action of receptors located on the surface of the body. are the main group of sensations that connect a person with the external environment.

In turn, exteroceptive sensations are divided into contact and distant. Contact Feel

caused by the impact of an object on the senses. - touch and taste. Distant sensations reflect the qualities of objects located at some distance from the sense organs - hearing and vision

smell occupies an intermediate position between contact and distant sensations, since

sensations arise at a distance from the object, but at the same time, the molecules that characterize the smell of the object with which the olfactory receptor contacts belong to this object

Proprioceptive sensations reflect the movement and relative position of body parts thanks to the work of receptors located in muscles, tendons and joint capsules

Interoceptive (organic) sensations signal with the help of special receptors the occurrence of metabolic processes in the internal environment of the body. Receptors for these sensations are located on the walls of the stomach and intestines, the heart and circulatory system and other internal organs. Interoceptors perceive the main

way of action of chemical agents (for example, on the digestive tract). This is the most ancient and most elementary group of sensations. In addition, interoceptive sensations are among the least conscious forms of sensations and always retain their proximity to emotional states. It should also be noted that interoceptive sensations are often called organic.

there are sensations that cannot be associated with any specific modality. Such sensations are called intermodal. These include, for example, vibration sensitivity, which connects the motor sphere with the auditory sphere.

According to most researchers, the vibration sense is an intermediate, transitional form between tactile and auditory sensitivity

Genetic classification allows us to distinguish two types of sensitivity: protopathic (more primitive, affective, less differentiated and localized), which includes organic feelings (hunger, thirst, etc.) and epicritic (more finely differentiated, objectified and rational), which includes the basic

types of human sensations. Epicritic sensitivity is younger in genetic terms, and it controls protopathic sensitivity.

Visual sensations are caused by exposure of the eye to light. Waves of a certain length cause a person to feel a certain color. Thus, visual sensations are sensations of color. All colors are divided into two large groups: colors achromatic(white, black and gray) Andchromatic

auditory sensations are caused by mechanical influences associated with periodic changes in atmospheric pressure in the corresponding range. All sounds that a person perceives can be divided into two groups: musical(sounds of singing, musical instruments, etc.) and noises(all kinds of creaks, rustles, knocks, etc.). Auditory sensations vary in pitch, volume and timbre. Height depends on the vibration frequency of the sound wave

Volume) determined mainly amplitude of oscillations(intensity) of the sound wave, but also depends on the frequency. The unit for measuring sound volume is decibels. Timbre distinguishes from each other sounds of the same height and intensity produced by different sources. Timbre is spoken of as the “color” of sound. Differences in timbre between two sounds are determined by the variety of forms of sound vibration.

Taste - perception of the properties of stimuli acting on the receptors of the mouth in the form of taste sensations. There are four main varieties or modalities: sweet, salty, sour and bitter. In most cases, taste sensations are mixed with olfactory sensations. The variety of taste largely depends on

admixtures of olfactory sensations

Smell- a type of sensation that reflects the chemical properties of volatile substances (called odors). For humans, odors are signs of an infinite number of objects and phenomena. The so-called chemoreceppores. These include exteroceptors of taste and smell and numerous interoceptors of internal organs, sensitive to the concentration of carbon dioxide, oxygen, etc. In addition to chemoreceptors, other receptors of the oral mucosa can also play a role in the construction of olfactory sensations: tactile, pain, temperature. Currently, a scheme is used that includes four main

odor: aromatic, sour, burnt, putrid, the intensity of which is assessed on a conventional scale from 0 to 8. It should also be noted that the sensitivity of the olfactory and taste receptors increases during a state of hunger

Skin sensitivity, or touch - This is the most widely represented and distributed throughout the body type of sensation. Skin sensations belong to the contact type of sensations, that is, they arise when the receptor comes into direct contact with an object in the real world. This may cause sensations

four main types: sensations of touch (tactile), sensations of cold, warmth and pain

There are two types of touch: passive and active; monomanual and bimanual; direct, instrumental.

Active touch- the process of forming a tactile image of an object during its palpation

At passive touch - a tactile image of the contour of an object is formed as a result of its sequential movement relative to a stationary hand or fingers. Under these conditions, the image is formed on the basis of only tactile signals

Instrumental touch, carried out with the help of some auxiliary tool (instrument) and achieves great accuracy, even when the object being touched is hidden from view

Kinesthetic sensations are sensations of movement and position of one’s own body and its parts, as well as applied muscle efforts. Using these sensations as an example, we can confirm the fact that not all sensations are formed consciously. They provide coordination of movements, contribute to the assessment of direction, speed and distance to an object. They are formed automatically, outside the control of consciousness, and enter the brain

and regulate movements on a subconscious level

Thanks to kinesthetic sensations, a person can determine the position and movement of parts of his body even with his eyes closed. Impulses entering the central nervous system from proprioceptors, due to changes that occur during movement in the muscles, cause reflex reactions and play a significant role

role in muscle tone and coordination of movements. In combination with vision, touch and other sensations, kinesthetic sensations play a significant role in the development of our spatial perceptions and ideas.

In addition to muscles, receptors for kinesthetic sensations are also located in other sense organs. For example, the formation of sensations that help maintain and maintain balance occurs thanks to special balance receptors that are located in the inner ear. In this case we are talking about the so-called human vestibular system

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