The concept of feeling. Physiological basis of sensation

Nature endowed every person with the ability to know the world in which he was born, and, in particular, the ability to feel and perceive the world around him - people, nature, culture, various objects and phenomena. The path to the knowledge of the environment and one's own states begins with sensations.

The meaning of feelings:

1. sensations allow a person to navigate in the world of sounds, smells, perceive colors, evaluate the weight and size of objects, determine the taste of a product, etc.
2. sensations provide material for other more complex mental processes (for example, deaf people will never be able to comprehend the sounds of a human voice, blind people - colors);
3. especially developed sensations are a condition for a person's success in a particular profession (for example, a taster, artist, musician, etc.);
4. depriving a person of sensations leads to sensory deprivation (sensory hunger - a lack of impressions), which can occur both in natural and laboratory conditions. (according to Lee, sensory deprivation is the main condition for creativity, since 95% of the energy spent on overcoming gravity goes to creativity);
5. there is the possibility of influencing the human condition through sensations (the sound of the surf, birdsong, aromatherapy, music).

Feeling (lat. sensus- perception) is a mental cognitive process of reflection individual properties of the real external world and the internal state of a person, which directly affect the sense organs At the moment.

Sensation does not give a person a complete picture of reflected objects. If, for example, a person is blindfolded and offered to touch an object unfamiliar to him (table, computer, mirror) with his fingertip, then the sensation will give him knowledge of only certain properties of the object (for example, that this object is hard, cold, smooth, etc.). P.).

Sensations are a sensory reflection of objective reality, as they arise due to the influence of various factors (irritants) on the sense organs (vision, hearing, etc.). They are characteristic of all living beings with a nervous system. Moreover, some animals (for example, eagles) have much sharper eyesight than humans, a more subtle sense of smell and hearing (dog). The eyes of ants distinguish ultraviolet rays that are inaccessible to the human eye. Bats and dolphins distinguish between ultrasounds that humans cannot hear. Rattlesnake distinguishes between insignificant temperature fluctuations - 0.001 degrees.

Feelings are both objective and subjective. Objectivity lies in the fact that they reflect a real-life external stimulus. Subjectivity is due to the dependence of sensations on individual characteristics and the current mental state of a person. This is what the well-known proverb says: "There are no comrades for the taste and color."

Associated with the emotional sphere of a person, sensations can give rise to various feelings in him, cause the simplest emotional experiences. For example, the sensation of the sharp sound of car brakes heard somewhere nearby can cause a person passing by to have unpleasant memories of their own driving practice. Negative experiences are generated by sensations of an unloved smell, color and taste.

The structure of the analyzers:

The physiological basis of sensations is laid down in the work of special nervous structures, called analyzers by I. Pavlov. Analyzers- these are the channels through which a person receives all the information about the world (both about the external environment and about his own, internal state).

Analyzer - a nervous formation that carries out the perception, analysis and synthesis of external and internal stimuli acting on the body.

Each type of analyzer is adapted to isolate a certain property: the eye reacts to light stimuli, the ear to sound stimuli, the olfactory organ to smells, etc.

The analyzer consists of 3 blocks:

1. Receptor - the peripheral part of the analyzer, which performs the function of receiving information from stimuli acting on the body. Receptor - a specialized cell designed to perceive a certain stimulus from the external or internal environment and to convert its energy from a physical or chemical form into a form of nervous excitation (impulse).

2. Afferent (conductive) and efferent (exit) paths. Afferent pathways are parts of the nervous system through which the resulting excitation enters the central nervous system. Efferent pathways are sections along which the response impulse (based on information processed in the central nervous system) is transmitted to receptors, determining their motor activity (reaction to a stimulus).

3. Cortical projection zones (central section of the analyzer) - areas of the cerebral cortex in which the processing of nerve impulses received from receptors takes place. Each analyzer in the cerebral cortex has its own “representation” (projection), where the analysis and synthesis of information of a certain sensitivity (sensory modality) takes place.

Sensation, in its essence, is a mental process that occurs during the processing of information received by the brain.

Depending on the type of sensitivity, visual, auditory, olfactory, gustatory, skin, motor and other analyzers are distinguished. Each analyzer from the whole variety of influences allocates incentives of a certain type. For example, the auditory analyzer highlights the waves formed as a result of vibrations of air particles. The gustatory analyzer generates an impulse as a result of the “chemical analysis” of molecules dissolved in saliva, and the olfactory analyzer generates an impulse in the air. The visual analyzer perceives electromagnetic oscillations, the characteristic of which generates one or another visual image.

As you know, the realization of personal potential is carried out in the process of life. It, in turn, is possible due to the person's knowledge of the surrounding conditions. Ensuring the interaction of the individual with the outside world is determined by attitudes and motives. Meanwhile, any mental phenomenon is a reflection of reality and is a link in the regulation system. The determining element in the functioning of the latter is feeling. Concept, physiological basis feelings, in turn, are associated with thinking and logical knowledge. Words and language as a whole play a significant role in this, they realize the function of generalization.

Inverse relationship

The physiological foundations of sensation, in short, are the basis on which human sensory experience is formed. His data, memory representations determine logical thinking. All, what is the physiological basis of sensations, acts as a link between a person and the outside world. Feelings allow you to know the world. Let us next consider how physiological basis of sensations in psychology (briefly).

Sensory organization

It represents the level of development of certain systems of sensitivity, the possibility of their combination. Sensory structures are called They act like. Sensory structures can be called receivers. Sensations enter them and are transformed into perceptions. Any receiver has a certain sensitivity. If we turn to representatives of the fauna, it can be noted that the physiological basis of their sensations is the activity of a certain type of sensors. This, in turn, acts as a generic sign of animals. For example, bats are sensitive to short ultrasonic pulses, dogs have an excellent sense of smell. If you touch physiological basis of sensations and perceptions human, it should be said that the sensory system has existed since the first days of life. However, its development will depend on the efforts and desires of the individual.

The concept of sensation: the physiological basis of the concept (briefly)

Before considering the mechanism of functioning of the elements of the sensory system, it is necessary to determine the terminology. Sensation is a manifestation of a general biological property - sensitivity. It is inherent in living matter. Through sensations, a person interacts with the external and his inner world. Due to them, information about ongoing phenomena enters the brain. All, what is the physiological basis of sensations, allows you to get different information about objects. For example, about their taste, color, smell, movement, sound. Sensors transmit information about the state of internal organs to the brain. From the sensations that arise, a picture of perception is formed. The physiological basis of the sensation process allows for primary data processing. They, in turn, act as a basis for more complex operations, for example, such processes as thinking, memory, perception, representation.

Data processing

It is carried out by the brain. The result of data processing is the development of a response or strategy. It can be aimed, for example, at increasing the tone, greater concentration of attention on the current operation, setting for accelerated inclusion in the cognitive process. The number of options available, as well as the quality of the choice of a particular reaction, depends on various factors. In particular, the individual characteristics of the individual, strategies for interacting with others, the level of organization and development of higher nervous functions, and so on, will be important.

Analyzers

The physiological basis of sensations is formed due to the functioning of special nervous apparatus. They include three components. The analyzer distinguishes between:

1. Receptor. It acts as a receiver. The receptor converts the external energy into a nerve operation.
2. Central department. It is represented by afferent or sensory nerves.
3. Cortical sections. In them, nerve impulses are processed.

Certain areas of the cortical regions correspond to specific receptors. Each sense organ has its own specialization. It depends not only on the structural features of the receptors. Equally important is the specialization of neurons, which are included in the central apparatus. They receive signals passing through the peripheral senses. It should be noted that the analyzer is not a passive receiver of sensations. It has the ability to reflex restructuring under the influence of stimuli.

Information properties

Allows you to describe the data coming through the sensors. Any information can be characterized by its inherent properties. The key ones include duration, intensity, spatial localization, quality. For example, the latter is a specific feature of a particular sensation, in which it differs from the rest. Quality varies within a certain modality. So, in the visual spectrum, such properties as brightness, color tone, saturation are distinguished. Auditory sensations have such qualities as pitch, timbre, loudness. With tactile contact, the brain receives information about the hardness, roughness of the object, and so on.

Features of differentiation

What can be physiological basis of sensations? Classification of sensations can be carried out on different grounds. The simplest is differentiation according to the modality of the stimulus. Accordingly, on this basis, one can distinguish and . Modality is a qualitative characteristic. It reflects the specificity of sensations as the simplest mental signals. Differentiation is carried out depending on the location of the receptors. On this basis, three groups of sensations are distinguished. The first includes those associated with surface receptors: skin, olfactory, gustatory, auditory, visual. The sensations that arise in them are called exteroceptive. The second group includes those associated with sensors located in the internal organs. These sensations are called interoreceptive. The third group includes those that are associated with receptors located on the muscles, tendons and ligaments. These are motor and static sensations - proprioceptive. Differentiation is also carried out according to the modality of the sensor. On this basis, sensations are distinguished contact (gustatory, tactile) and distant (auditory, visual).

Types

Physiological basis of sensations- complex elements of a single sensory system. These links allow you to recognize different properties of one object at the same time. This is due to the fact that they react to certain stimuli. Each receptor has its own agent. In accordance with this, there are such as:

1. Visual. They arise under the influence of light rays on the retina.
2. Auditory. These sensations are caused by speech, music or noise waves.
3. Vibrating. Such sensations arise due to the ability to capture the vibrations of the environment. Such sensitivity is poorly developed in humans.
4. Olfactory. They allow you to capture odors.
5. Tactile.
6. Skin.
7. Taste.
8. Painful.
9. Temperature.

The emotional coloring of pain is especially strong. They are visible and audible to others. Temperature sensitivity varies in different parts of the body. In some cases, a person may experience pseudo-sensations. They are expressed in the form of hallucinations and appear in the absence of an irritant.

Vision

The eye acts as the perceiving apparatus. This sense organ has a rather complex structure. Waves of light are reflected from objects, refracted as they pass through the lens, and are fixed on the retina. The eye is considered a distant receptor, since it gives an idea of ​​objects that are at a distance from a person. Reflection of space is provided due to the parity of the analyzer, changing the size of the image on the retina when approaching / moving away from / from the object, the ability to converge and dilute the eyes. The retina contains several tens of thousands of nerve endings. Under the influence of a wave of light, they are irritated. Nerve endings are distinguished by function and form.

Hearing

Sensory endings that allow you to perceive sound are located in the inner ear, the cochlea with a membrane and hairs. The external organ collects vibrations. The middle ear directs them to the cochlea. The sensitive endings of the latter are irritated due to resonance - nerves of different thickness and length begin to move when a certain number of vibrations per second arrives. The received signals are sent to the brain. Sound has the following properties: strength, timbre, pitch, duration and tempo-rhythmic pattern. Phonemic is called hearing, which allows you to distinguish between speech. It depends on the environment and is formed during life. With a good knowledge of a foreign language, a new system of phonemic hearing is developed. It has an impact on writing skills. Similarly, speech develops. Less important for a person are rustles and noises, if they do not interfere with his activities. They can also evoke pleasant emotions. For example, many people like the sound of rain, the rustle of leaves. At the same time, such sounds can also signal danger. For example, the hiss of gas.

Vibration sensitivity

It is considered a type of auditory sensation. Vibration sensitivity reflects fluctuations in the environment. It is figuratively called contact hearing. Humans do not have special vibrational receptors. Scientists believe that such sensitivity is the oldest on the planet. At the same time, all tissues in the body can reflect fluctuations in the external and internal environment. Vibrational sensitivity in human life is subject to visual and auditory. Its practical importance increases in those areas of activity where fluctuations act as signals of malfunctions or danger. Deaf-blind and deaf people have increased vibration sensitivity. It compensates for the absence of other sensations.

Smell

It refers to distant sensations. Elements of substances penetrating into the nasal cavity act as irritants that cause olfactory sensitivity. They dissolve in liquid and act on the receptor. In many animals, smell is the primary sense. They navigate by smell when looking for food or escaping from danger. The human sense of smell has little to do with orienteering. This is due to the presence of hearing and vision. The instability and underdevelopment of olfactory sensitivity is also indicated by the absence in the vocabulary of words that accurately denote sensations and are not related to the subject itself. For example, they say "the smell of lilies of the valley." The sense of smell is related to taste. It helps to recognize the quality of food. In some cases, the sense of smell allows you to distinguish substances by chemical composition.

Taste

It refers to contact sensations. Taste sensitivity is caused by irritation of the receptors located on the tongue with the object. They allow you to identify sour, salty, sweet, bitter foods. The combination of these qualities forms a set of taste sensations. Primary data processing is carried out in papillae. Each of them has 50-150 receptor cells. They wear out fairly quickly when in contact with food, but have a recovery function. Sensory signals are sent to the gustatory cortex via the hindbrain and thalamus. Like olfactory sensations, these sensations increase appetite. Receptors, evaluating the quality of food, perform a protective function, which is very important for survival.

Leather

It contains several independent sensory structures:

1. Tactile.
2. Painful.
3. Temperature.

Skin sensitivity belongs to the group of contact sensations. The maximum number of sensory cells is found on the palms, lips and fingertips. Information is transmitted from receptors to the spinal cord due to their contact with motor neurons. This ensures the implementation of reflex actions. For example, a person pulls his hand away from the hot. Temperature sensitivity ensures the regulation of heat exchange between the external environment and the body. It is worth saying that the distribution of cold and thermal sensors is uneven. The back is more sensitive to low temperature, the chest is less. Pain occurs due to strong pressure on the surface of the body. Nerve endings are located deeper than tactile receptors. The latter, in turn, allow you to form an idea of ​​the qualities of the subject.

Kinesthetic Sensitivity

It includes sensations of movement and staticness of individual elements of the body. Receptors are located in tendons and muscles. Irritation is caused by contraction and stretching of the muscles. Many motor sensors are located on the lips, tongue, and fingers. This is due to the need for these parts of the body to perform subtle and precise movements. The work of the analyzer provides control and coordination of movement. The formation of speech kinesthesia occurs in infancy and preschool age.

vestibular sensitivity

Static or gravitational sensations allow a person to understand their position in space. The corresponding receptors are located in the vestibular apparatus in the inner ear. The sacs and canals convert signals about relative movement and gravity, then transmitting them to the cerebellum, as well as to the cortex in the temporal region. A sharp and frequent change in the position of the body relative to the ground can lead to dizziness.

Conclusion

The physiological basis is of particular practical importance. Its study makes it possible to determine the pathways for the penetration of signals from the outside, to distribute them among receptors, and to trace the course of primary information processing. The physiological basis of sensations in psychology is the key to understanding the properties of the human sensory system. The analysis allows you to identify the causes of certain deviations in sensitivity, to assess the degree of impact of certain stimuli on receptors. The obtained information is used in various scientific and industrial fields. Research results play a special role in medicine. The study of the properties of receptors and stimuli allows you to create new drugs, develop more effective tactics for the treatment of mental and other diseases.

Sensation is a reflection of the properties of objects of the objective world, arising from their direct impact on the sense organs, this is, firstly, the initial moment of the sensorimotor reaction; secondly, the result of conscious activity.

The emergence of sensation is directly related to the work of human receptors. A receptor is an organ specially adapted for the reception of stimuli; it is more easily irritated than other organs or nerve fibers; its sensitivity is especially high. In addition, each receptor is specialized in relation to a particular stimulus.

In the process of biological evolution, the sense organs themselves were formed in the real relationship of the organism with the environment, under the influence of the outside world. The impact of the outside world forms the receptors themselves. Receptors are, as it were, anatomically fixed in the structure of the nervous system, imprints of the effects of irritation processes.

In sensation, absolute and differential thresholds are distinguished. Not every stimulus causes a sensation, but only one whose intensity has overcome the threshold of sensation. This minimum stimulus intensity at which a sensation occurs is called the lower absolute threshold. Along with the lower, there is also an upper absolute threshold, i.e. the maximum intensity possible to experience a given quality.

The thresholds of sensitivity are significantly shifted depending on the attitude of a person to the task that he solves.

For the sensitivity of an organ, its physiological state is also important. The significance of physiological moments is manifested primarily in the phenomena of adaptation, in the adaptation of an organ to a long-acting stimulus. The phenomenon of contrast is also associated with adaptation, which is associated with a change in sensitivity under the influence of a previous (or accompanying) stimulus.

The differentiation and specialization of receptors does not exclude their interaction, which is expressed in the effect that stimulation of one receptor has on the thresholds of another.

Classification of sensations

organic sensations. Organic sensations include sensations of hunger, thirst, sensations coming from the cardiovascular, respiratory and reproductive systems of the body, and all sensations associated with the state of the human body.

All organic sensations have a number of common features:

They are usually associated with organic needs, which are usually first reflected in consciousness through organic sensations.

All organic sensations are more or less brightly colored.

Organic sensations, reflecting needs, are usually associated with motor impulses and are interconnected in a psychomotor unity.

Static sensations. These are sensations associated with indications of the position of our body in space, its posture, passive and active movements of the body. The central organ that regulates the balance of the body in space is the vestibular apparatus.

kinesthetic sensations. Sensations of movement of various parts of the body are caused by excitations coming from proprioreceptors located in the joints, ligaments and muscles. Through kinesthetic sensations, a person can determine the position and movement of their body parts. Impulses entering the central nervous system from proprioreceptors due to changes that occur during movement in the muscles cause reflex reactions and play a significant role in muscle tone and coordination of movements.

Skin sensitivity. Skin sensitivity is subdivided by the classical physiology of the sense organs into 4 types. These are the receptions of pain, heat, cold and touch (pressure). It is assumed that each of these types of sensitivity also has specific receptors.

Touch. Touch includes sensations of touch and pressure in unity with kinesthetic, muscular-articular sensations. The proprioceptive components of touch come from receptors located in muscles, ligaments, and articular bags. When moving, they are irritated by a change in voltage.

Olfactory sensations. Olfactory sensations arise when molecules of various substances enter the nasal cavity together with the inhaled air and are transmitted to the central nervous system through the olfactory receptor.

Taste sensations. Taste sensations, like olfactory sensations, are due to the chemical properties of substances. Taste sensations play an important role in adjusting the emotional state of a person, their role is determined by the state of the body's need for food. Arise through the taste receptor, the peripheral part of which is located in the oral cavity.

Auditory sensations. Auditory sensations are a reflection of sound waves affecting the auditory receptor, which are generated by the sounding body and represent a variable condensation and rarefaction of air.

visual sensations. Visual sensations are caused by exposure to the visual analyzer of a light wave, which differ in length and frequency of oscillations.

4.2. Feel

The concept of feeling. Objects and phenomena of the external world have many different properties and qualities: color, taste, smell, sound, etc. In order for them to be reflected by a person, they must affect him with any of these properties and qualities. Cognition is carried out primarily by the sense organs - the only channels through which the external world penetrates into the human mind. Images of objects and phenomena of reality that arise in the process of sensory cognition are called sensations.

Feel- this is the simplest mental cognitive process of reflecting the individual properties of objects and phenomena of the surrounding world, as well as the internal states of the body, arising from their direct impact on the senses.

Our consciousness exists only due to the presence of sensations. If a person is deprived of the opportunity to feel and perceive the surrounding reality, he will not be able to navigate the world, he will not be able to do anything. In conditions of "sensory deprivation" (lack of sensations), a person in less than a day has a sharp decrease in attention, a decrease in memory, and serious changes in mental activity occur.

No wonder this is one of the most difficult tests for future astronauts, polar explorers, speleologists.

In ordinary life, it is not so much the lack of sensations that tires us, but their abundance - sensory overload. Therefore, it is so important to observe the elementary rules of mental hygiene.

The physiological basis of sensations is activity analyzer- a special nervous apparatus that performs the function of analysis and synthesis of stimuli emanating from the external and internal environment of the body. Any analyzer consists of three parts.

1. Receptor (peripheral) department- receptor, the main part of any sense organ, specialized for receiving the effects of certain stimuli. Here, the energy of an external stimulus (heat, light, smell, taste, sound) is transformed into physiological energy - a nerve impulse.

2. conductor department- sensory nerves that can be afferent(centripetal), conducting the resulting excitation to the central section of the analyzer, and efferent(centrifugal, through which the nerve impulse enters the working body (effector)).

3. Central department- the cortical section of the analyzer, a specialized section of the cerebral cortex, where the conversion of nervous energy into a mental phenomenon takes place - sensation.

The central part of the analyzer consists of a nucleus and nerve cells scattered throughout the cortex, which are called peripheral elements. The main mass of receptor cells is concentrated in the nucleus, due to which the most subtle analysis and synthesis of stimuli is carried out; at the expense of peripheral elements, a rough analysis is made, for example, light differs from darkness. Scattered elements of the cortical part of the analyzer are involved in establishing communication and interaction between different analyzer systems. Since each analyzer has its own central section, the entire cerebral cortex is a kind of mosaic, an interconnected system of cortical ends of the analyzers. Despite the common structure of all analyzers, the detailed structure of each of them is very specific.

A sensation always arises in consciousness in the form of an image. The energy of an external stimulus turns into a fact of consciousness when a person who has an image of the object that caused the irritation can designate it with a word.

Sensation is always associated with a response like a reflex ring with obligatory feedback. The sense organ is alternately either a receptor or an effector (working organ).

Types and classification of sensations. According to the five sense organs known to the ancient Greeks, the following types of sensations are distinguished: visual, auditory, gustatory, olfactory, tactile (tactile). In addition, there are intermediate sensations between tactile and auditory - vibration. There are also complex sensations, consisting of several independent analytical systems: for example, touch is tactile and muscular-articular sensations; skin sensations include tactile, temperature and pain. There are organic sensations (hunger, thirst, nausea, etc.), static sensations, sensations of balance, reflecting the position of the body in space.

The following criteria for classifying sensations are distinguished.

I. Location of receptors- exteroceptive and interoceptive. Receptors exteroceptive sensations are located on the surface of the body and receive stimuli from the outside world, and receptors interoceptive(organic) sensations are located in the internal organs and signal the functioning of the latter. These sensations form the organic feeling (well-being) of a person.

II. By the presence or absence of direct contact with the irritant, causing sensations, exteroceptive sensations are divided into contact and distant. Contact sensations involve direct interaction with the stimulus. These include taste, skin, pain, temperature, etc. distant sensations provide orientation in the nearest environment - these are visual, auditory and olfactory sensations.

A special subclass of interoceptive sensations are sensations proprioceptive, whose receptors are located in ligaments, muscles and tendons and receive irritation from the musculoskeletal system. These sensations also indicate the position of the body in space.

Sensations have a number of characteristics and patterns that are manifested in each type of sensitivity. Three groups of regularities of sensations can be distinguished.

1. Timing ratios between the beginning (end) of the action of the stimulus and the appearance (disappearance) of sensations:

The beginning of the action of the stimulus and the occurrence of sensations do not coincide - the sensation occurs somewhat later than the onset of the action of the stimulus, since the nerve impulse needs some time to deliver information to the cortical section of the analyzer, and after the analysis and synthesis carried out in it, back to the working organ. This is the so-called latent (latent) reaction period;

Sensations do not disappear immediately with the end of the action of the stimulus, which can be illustrated by successive images - positive and negative. The physiological mechanism for the emergence of a sequential image is associated with the phenomena of the aftereffect of the stimulus on the nervous system. Termination of the action of the stimulus does not cause an instant cessation of the process of irritation in the receptor and excitation in the cortical parts of the analyzer.

2. The ratio of sensations and intensity of the stimulus. Not every force of the stimulus is capable of causing a sensation - it occurs when exposed to a stimulus of known intensity. It is customary to distinguish between the threshold of absolute sensitivity and the threshold of sensitivity to discrimination.

The smallest amount of stimulus that produces a barely perceptible sensation is called the lower absolute threshold of sensitivity.

There is an inverse relationship between sensitivity and the strength of the stimulus: the greater the force needed to create a sensation, the lower the sensitivity. There may be subthreshold stimuli that do not cause sensations, since signals about them are not transmitted to the brain.

The maximum value of the stimulus that the analyzer is able to adequately perceive (in other words, at which the sensation of this type is still preserved) is called the upper absolute threshold of sensitivity.

The interval between the lower and upper thresholds is called sensitivity range. It has been established that the range of color sensitivity is the oscillations of electromagnetic waves with a frequency of 390 (violet) to 780 (red) millimicrons, and sound - the oscillations of sound waves from 20 to 20,000 Hertz. Ultra-high intensity stimuli instead of sensations of a certain type cause pain.

Threshold of sensitivity to discrimination(differential) - this is the minimum difference between two stimuli, which causes a subtle difference in sensations. In other words, this is the smallest amount by which it is necessary to change (increase or decrease) the intensity of the stimulus in order for a change in sensation to occur. German scientists - physiologist E. Weber and physicist G. Fechner - formulated a law that is valid for stimuli of medium strength: the ratio of an additional stimulus to the main one is a constant value. This value for each type of sensation is certain: for visual - 1/1000, For auditory - 1/10, for tactile - 1/30 of the initial stimulus value.

III. Changing the sensitivity of the analyzer. This change can be illustrated by the patterns of sensations such as adaptation, sensitization, and interaction.

Adaptation(from lat. adaptare - to adapt, adjust, get used to) - this is a change in sensitivity under the influence of constantly

active stimulus. Adaptation depends on environmental conditions. The general pattern is as follows: when moving from strong to weak stimuli, sensitivity increases, and vice versa, when moving from weak to strong, it decreases. The biological expediency of this mechanism is obvious: when stimuli are strong, subtle sensitivity is not needed, but when they are weak, the ability to catch them is important.

There are two types of adaptation: positive and negative. Positive(positive, dark) adaptation is associated with an increase in sensitivity under the influence of a weak stimulus. Thus, during the transition from light to darkness, the area of ​​the pupil increases by 17 times, there is a transition from cone vision to rod vision, but basically the increase in sensitivity occurs due to the conditioned reflex work of the central mechanisms of the analyzer. Negative(negative, light) adaptation can manifest itself as a decrease in sensitivity under the influence of a strong stimulus and as a complete disappearance of sensations during prolonged action of the stimulus.

Another pattern of sensations is interaction of analyzers, which manifests itself in a change in the sensitivity of one analyzer system under the influence of the activity of another. The general regularity of the interaction of sensations can be expressed in the following formulation: irritations of one analyzer that are weak in intensity increase the sensitivity of the other, and strong irritations decrease it.

Increasing the sensitivity of the analyzer is called sensitization. It can manifest itself in two areas: either as a result of sensory exercises, training, or as a need to compensate for sensory defects. The defect in the work of one analyzer is usually compensated by the increased work and improvement of the other.

A special case of the interaction of sensations is synesthesia, in which the joint work of the senses occurs; in this case, the qualities of sensations of one kind are transferred to another kind of sensations and co-sensations arise. In everyday life, synesthesias are used very often: “velvet voice”, “screaming color”, “sweet sounds”, “cold tone”, “pungent taste”, etc. .