The sensitivity of analyzers, determined by the value of absolute thresholds, is not constant and changes under the influence of a number of physiological and psychological conditions, among which the phenomenon of adaptation occupies a special place.

Adaptation or adaptation , is a change in the sensitivity of the senses under the influence of a stimulus. Three types of this phenomenon can be distinguished. Adaptation as the complete disappearance of sensation during prolonged action of the stimulus. For example, a light weight resting on the skin soon ceases to be felt. Adaptation is also called another phenomenon, close to the one described, which is expressed in a dulling of sensation under the influence of a strong stimulus.. The two types of adaptation described can be combined with the term Negative adaptation, since as a result they reduce the sensitivity of the analyzers. Finally, adaptation is called Increased sensitivity under the influence of a weak stimulus. This type of adaptation, characteristic of certain types of sensations, can be defined as positive adaptation.

Contrast of sensations This is a change in the intensity and quality of sensations under the influence of a preliminary or accompanying stimulus. In the case of simultaneous action of two stimuli, a simultaneous contrast occurs. This contrast can be traced in visual sensations. The same figure appears lighter on a black background, and darker on a white background. A green object against a red background appears more saturated. The phenomenon of sequential contrast is also well known. After a cold one, a weak warm stimulus seems hot. The feeling of sour increases sensitivity to sweets.

Sensitization. Increased sensitivity as a result of the interaction of analyzers and exercise is called sensitization. Knowing the patterns of changes in the sensitivity of the sense organs, it is possible, by using specially selected side stimuli, to sensitize one or another receptor, i.e., increase its sensitivity. Sensitization can also be achieved as a result of exercise. It is known, for example, how pitch hearing develops in children involved in music.

Synesthesia. The interaction of sensations manifests itself in another type of phenomenon called synesthesia. Synesthesia is the occurrence, under the influence of stimulation of one analyzer, of a sensation characteristic of another analyzer. Synesthesia is observed in the most various types sensations. The most common is visual-auditory synesthesia, when the subject experiences visual images when exposed to sound stimuli.

Sensitization of the senses is possible not only through the use of side stimuli, but also through exercise. The possibilities for training the senses and improving them are endless. There are two areas that determine increased sensitivity of the senses:

1) sensitization, which spontaneously results from the need to compensate for sensory defects (blindness, deafness);

2) sensitization caused by the activity and specific requirements of the subject’s profession.

The loss of vision or hearing is to a certain extent compensated by the development of other types of sensitivity. There are cases when people deprived of vision engage in sculpture; they have a well-developed sense of touch. The development of vibration sensations in the deaf also belongs to this group of phenomena.

Some people who are deaf develop vibration sensitivity so strongly that they can even listen to music. To do this, they place their hand on the instrument or turn their back to the orchestra. Some deaf-blind people, holding their hand at the throat of the speaking interlocutor, can thus recognize him by his voice and understand what he is talking about. Due to their highly developed olfactory sensitivity, they can associate many close people and acquaintances with the smells emanating from them.

Of particular interest is the emergence in humans of sensitivity to stimuli for which there is no adequate receptor. This is, for example, remote sensitivity to obstacles in the blind.

The phenomena of sensitization of the sense organs are observed in persons with certain special professions. Grinders are known to have extraordinary visual acuity. They see gaps from 0.0005 millimeters, while untrained people see only up to 0.1 millimeters. Fabric dyeing specialists distinguish between 40 and 60 shades of black. To the untrained eye they appear exactly the same. Experienced steelmakers are able to quite accurately determine its temperature and the amount of impurities in it by the faint color shades of molten steel.

The olfactory and gustatory sensations of tasters of tea, cheese, wine, and tobacco reach a high degree of perfection. Tasters can accurately tell not only what type of grape the wine is made from, but also name the place where these grapes grew.

Painting places special demands on the perception of shapes, proportions and color relationships when depicting objects. Experiments show that the artist's eye is extremely sensitive to assessing proportions. It distinguishes changes equal to 1/60-1/150 of the size of the object. The subtlety of color sensations can be judged by the mosaic workshop in Rome - it contains more than 20,000 shades of primary colors created by man.

The possibilities for developing auditory sensitivity are also quite large. So, playing the violin requires special development pitch hearing, and violinists have it more developed than pianists. For people who have difficulty distinguishing the pitch of sounds, it is possible, through special training, to improve their pitch hearing. Experienced pilots can easily determine the number of engine revolutions by ear. They freely distinguish 1300 from 1340 rpm. Untrained people only notice the difference between 1300 and 1400 rpm.

All this is proof that our sensations develop under the influence of living conditions and the requirements of practical work activity.

Sensory adaptation is a change in sensitivity that occurs as a result of the adaptation of a sensory organ to the stimuli acting on it. As a rule, adaptation is expressed in the fact that when the sense organs are exposed to sufficiently strong stimuli, sensitivity decreases, and when exposed to weak stimuli or in the absence of a stimulus, sensitivity increases.

Sensitization(Latin sensibilis – sensitive)– this is an increase in the sensitivity of analyzers under the influence of internal (mental) factors. Sensitization, i.e. exacerbation of sensitivity may be caused by:

· interaction, systemic work of analyzers, when weak sensations of one modality can cause an increase in the strength of sensations of another modality. For example, visual sensitivity increases with weak cooling of the skin or a low sound;

· the physiological state of the body, the introduction of certain substances into the body. Thus, vitamin A is essential for increasing visual sensitivity.;

· expectation of this or that influence, its significance, the determination to distinguish between certain stimuli. For example, waiting in the dentist's office can encourage more toothache;

· experience acquired in the process of performing any activity. It is known that good tasters can determine the type of wine or tea by subtle nuances..

In the absence of any type of sensitivity, this deficiency is compensated by increasing the sensitivity of other analyzers. This phenomenon is called compensation for sensations , or compensatory sensitization .

If sensitization - this is an increase in sensitivity, then the opposite process - a decrease in the sensitivity of some analyzers as a result of strong excitation of others - is called desensitization . For example, increased level noise in " loud» workshops reduces visual sensitivity, i.e. desensitization of visual sensations occurs.

Synesthesia(Greek synaisthesis – joint, simultaneous sensation)- a phenomenon in which sensations of one modality arise under the influence of a stimulus of another modality.

Contrast of sensations (French contraste - sharp contrast)- this is an increase in sensitivity to one stimulus when it is compared with a previous stimulus of the opposite type. Yes, the same figure white on a light background it appears gray, and on a black background it appears flawlessly white. A gray circle on a green background appears reddish, while on a red background it appears greenish.

Adaptation, or adaptation, is a change in the sensitivity of the senses under the influence of a stimulus.

Three types of this phenomenon can be distinguished.

1. Adaptation as the complete disappearance of sensation during the prolonged action of a stimulus. In the case of constant stimuli, the sensation tends to fade. For example, a light weight resting on the skin soon ceases to be felt. A common fact is the distinct disappearance of olfactory sensations soon after we enter an atmosphere with an unpleasant odor. The intensity of the taste sensation weakens if the corresponding substance is kept in the mouth for some time and, finally, the sensation may fade away completely.

Full adaptation of the visual analyzer does not occur under the influence of a constant and motionless stimulus. This is explained by compensation for the immobility of the stimulus due to movements of the receptor apparatus itself. Constant voluntary and involuntary eye movements ensure continuity of visual sensation. Experiments in which conditions were artificially created to stabilize1 the image relative to the retina showed that the visual sensation disappears 2-3 seconds after its onset, i.e. complete adaptation occurs.

2. Adaptation is also called another phenomenon, close to the one described, which is expressed in a dulling of sensation under the influence of a strong stimulus. For example, when immersing your hand in cold water the intensity of the sensation caused by the temperature stimulus decreases. When we move from a dimly lit room into a brightly lit space, we are initially blinded and unable to discern any details around us. After some time, the sensitivity of the visual analyzer decreases sharply, and we begin to see normally. This decrease in eye sensitivity under intense light stimulation is called light adaptation.

The two types of adaptation described can be combined with the term negative adaptation, since as a result they reduce the sensitivity of the analyzers.

3. Adaptation is an increase in sensitivity under the influence of a weak stimulus. This type of adaptation, characteristic of certain types of sensations, can be defined as positive adaptation.

In the visual analyzer, this is a dark adaptation, when the sensitivity of the eye increases under the influence of being in the dark. A similar form of auditory adaptation is adaptation to silence.

Adaptive regulation of the level of sensitivity depending on what stimuli (weak or strong) affects the receptors is of great biological importance. Adaptation helps the sensory organs to detect weak stimuli and protects the sensory organs from excessive irritation in the event of unusually strong influences.

The phenomenon of adaptation can be explained by those peripheral changes that occur in the functioning of the receptor during prolonged exposure to a stimulus. Thus, it is known that under the influence of light, visual purple, located in the rods of the retina, decomposes. In the dark, on the contrary, visual purple is restored, which leads to increased sensitivity. The phenomenon of adaptation is also explained by the processes occurring in the central sections of the analyzers. With prolonged stimulation, the cerebral cortex responds with internal protective inhibition, reducing sensitivity. The development of inhibition causes increased excitation of other foci, which contributes to increased sensitivity in new conditions.

The intensity of sensations depends not only on the strength of the stimulus and the level of adaptation of the receptor, but also on the stimuli acting in this moment to other senses. A change in the sensitivity of the analyzer under the influence of irritation of other senses is called the interaction of sensations.

The literature describes numerous facts of changes in sensitivity caused by the interaction of sensations. Thus, the sensitivity of the visual analyzer changes under the influence of auditory stimulation.

Weak sound stimuli increase the color sensitivity of the visual analyzer. At the same time it is observed sharp deterioration distinctive sensitivity of the eye when, for example, the loud noise of an aircraft engine is used as an auditory stimulus.

Visual sensitivity also increases under the influence of certain olfactory stimuli. However, with a pronounced negative emotional connotation of the smell, a decrease in visual sensitivity is observed. Similarly, with weak light stimuli, auditory sensations increase, and exposure to intense light stimuli worsens auditory sensitivity. There are known facts of increased visual, auditory, tactile and olfactory sensitivity under the influence of weak painful stimuli.

A change in the sensitivity of any analyzer is also observed with subthreshold stimulation of other analyzers. So, P.P. Lazarev (1878-1942) obtained evidence of a decrease in visual sensitivity under the influence of skin irradiation with ultraviolet rays.

Thus, all our analyzing systems are capable of influencing each other to a greater or lesser extent. In this case, the interaction of sensations, like adaptation, manifests itself in two opposite processes: an increase and decrease in sensitivity. The general pattern here is that weak stimuli increase, and strong ones decrease, the sensitivity of the analyzers during their interaction.

The interaction of sensations manifests itself in another type of phenomenon called synesthesia. Synesthesia is the occurrence, under the influence of stimulation of one analyzer, of a sensation characteristic of another analyzer. Synesthesia is observed in a wide variety of sensations. The most common is visual-auditory synesthesia, when the subject experiences visual images when exposed to sound stimuli. U different people There is no overlap in these synesthesias, however, they are quite constant for each individual.

The creation in last years color-musical devices that transform sound images into color ones. Less common are cases of auditory sensations arising when exposed to visual stimuli, gustatory sensations in response to auditory stimuli, etc. Not all people have synesthesia, although it is quite widespread. The phenomenon of synesthesia is another evidence of the constant interconnection of analytical systems human body, the integrity of the sensory reflection of the objective world.

Increased sensitivity as a result of the interaction of analyzers and exercise is called sensitization.

The physiological mechanism for the interaction of sensations is the processes of irradiation and concentration of excitation in the cerebral cortex, where the central sections of the analyzers are represented. According to I.P. Pavlova, a weak stimulus causes in the cortex cerebral hemispheres a process of excitation that easily radiates (spreads). As a result of the irradiation of the excitation process, the sensitivity of the other analyzer increases. When exposed to a strong stimulus, a process of excitation occurs, which, on the contrary, tends to concentrate. According to the law of mutual induction, this leads to inhibition in the central sections of other analyzers and a decrease in the sensitivity of the latter.

The lower threshold of sensations is the minimum amount of stimulus that causes a barely noticeable sensation. The upper threshold of sensations is the maximum magnitude of the stimulus that the analyzer is capable of adequately perceiving. Sensitivity range - the interval between the lower and upper threshold of sensations.

Differential threshold - the smallest magnitude of differences between stimuli when the difference between them is still perceived (Weber's law).

Operational threshold - the magnitude of the difference between signals at which the accuracy and speed of discrimination reach a maximum. The value of the operational threshold is 10-15 times greater than the value of the differential threshold.

Time threshold - the minimum duration of exposure to a stimulus required for the sensation to occur.

Latent period of reaction - the period of time from the moment the signal is given to the moment the sensation occurs.

Inertia - the time the sensation disappears after the end of the effect.

To effectively influence a person, it is necessary to take into account the characteristics of his analyzers, which are determined empirically (for example, changing the tempo of speech) or have already been determined and documented in the specialized literature. It is known, for example, that the inertia of vision in normal person is 0.1-0.2 seconds, therefore the duration of the signal and the interval between appearing signals must be no less than the retention time of sensations, equal to 0.2-0.5 seconds. Otherwise, the speed and accuracy of the response will slow down, since when a new signal arrives, the person will still have an image of the previous one.

In the process of communication - the feeling of a person by a person - there is also inertia, dictating its “law”: as long as you see that the perception of your “old” image is still fresh in your memory, do not strive to quickly and obsessively manifest yourself in a new capacity: this is explained by the fact that an adequate reaction will not follow, and the more impressionable the person on whom the influence is made, the more inert he will react to changes.

Sensations and their adequacy, or, in other words, a person’s psychological capabilities to receive information, are most important in the activities of those people whose work requires a high degree of accuracy: engineers, doctors, etc.

The sensitivity of analyzers is not constant and changes under the influence of physiological and psychological conditions. The sense organs have the property devices, or adaptation. Adaptation can manifest itself as a complete disappearance of sensation during prolonged exposure to the stimulus, and as a decrease or increase in sensitivity under the influence of the stimulus.

The intensity of sensations depends not only on the strength of the stimulus and the level of adaptation of the receptors, but also on the irritations currently affecting other sense organs. A change in the sensitivity of analyzers under the influence of irritation of other sense organs is called interaction of sensations. The interaction of sensations is manifested in an increase and decrease in sensitivity: weak stimuli increase the sensitivity of the analyzers, and strong ones decrease it.

The interaction of sensations is manifested in the phenomena of sensitization and synesthesia. Sensitization(Latin sensibilis - sensitive) - increased sensitivity of nerve centers under the influence of a stimulus. Sensitization can develop not only through the use of side stimuli, but also through exercise. Thus, musicians develop high auditory sensitivity, tasters develop olfactory and gustatory sensations. Synesthesia - This is the occurrence, under the influence of irritation of a certain analyzer, of a sensation characteristic of another analyzer. Thus, when exposed to sound stimuli, a person may experience visual images.

Perception, its types and properties

Perception is a holistic reflection of objects and phenomena of the objective world with their direct impact at the moment on the senses. Together with the processes of sensation, perception provides direct sensory orientation in the surrounding world. Perception is the result of the activity of the analyzer system; it involves isolating the main and most significant features from the complex of influencing features, while simultaneously abstracting from the unimportant. Perception makes it possible to create an integral picture of reality, in contrast to sensations that reflect individual qualities of reality.

Since perception requires the integration of basic essential features and comparison of what is perceived with past experience, the phenomenon arises stereotyping. A stereotype is a specific idea about an object or phenomenon that is stable for a given period of time.

Perception is subjective, since people perceive the same information differently, depending on interests, needs, abilities, etc. The dependence of perception on past experience, on the general content of a person’s mental activity and his individual characteristics is called apperception.

Properties of perception

Integrity - internal organic relationship of parts and the whole in the image. This property manifests itself in two aspects: a) the unification of different elements as a whole; b) independence of the formed whole from the quality of its constituent elements.

Objectivity - the object is perceived by us as a separate physical body isolated in space and time. This property is most clearly manifested in the mutual isolation of figure and background.

Generality - assigning each image to a certain class of objects.

Constancy - relative constancy of image perception. Our perception, within certain limits, preserves the parameters of their size, shape and color, regardless of the conditions of perception (distance to the perceived object, lighting conditions, angle of perception).

Meaningfulness - connection with understanding the essence of objects and phenomena through the thinking process.

Selectivity - preferential selection of some objects over others in the process of perception.

Perception is divided into the following types:

perception of objects and phenomena of the surrounding world;

person's perception by person;

time perception;

movement perception;

perception of space;

perception of the type of activity.

Perceptions time, movements And space - This complex shapes perceptions that have numerous characteristics: long - short-term, large - small, high - low, distant - close, fast - slow. Perception activities divided by type: artistic, technical, musical, etc.

There are perceptions externally directed(perception of objects and phenomena of the external world), and internally directed(perception of one’s own thoughts and feelings).

According to the time of occurrence of perception, there are relevant And irrelevant.

Perception may be erroneous (illusory). An illusion is a distorted perception of a truly existing reality. Illusions are detected in the activities of various analyzers. Best known visual illusions, which have a variety of reasons: practical experience, features of analyzers, changes in usual conditions. For example, due to the fact that vertical eye movement requires more effort than horizontal movement, the illusion of perceiving straight lines of the same length, located differently, arises: it seems to us that vertical lines are longer than horizontal ones.

Perception can not only be erroneous, but also ineffective. Empirically, you can verify that the level of perception of a text when reading it by speaking out loud is much lower than when reading silently. The fact is that the bandwidth of hearing is lower than the bandwidth of vision.

Sensation and perception are processes whose acuity can be developed by working on yourself and performing a series of special exercises. In order to train your eye, it is recommended to practice for several days, dividing a straight line in half on a clean (unlined) sheet of paper. You should perform 10 exercises daily and record the magnitude of the deviations.

In order to increase your reading speed and get rid of the habit of pronouncing what you read, you can use the following exercise: for several days, read a literary text to yourself for three minutes, saying the following out loud: “one, two, three.” This is necessary in order to prevent the text from being spoken.

The development of perception has great importance for educational activities. Developed perception helps to absorb a larger amount of information with less energy expenditure.

Chapter 2. Attention

Despite the variety of types of sensations, there are some patterns common to all sensations. These include:

• relationship between sensitivity and sensation thresholds,
• adaptation phenomenon,
• interaction of sensations and some others.

Sensitivity and sensation thresholds. The sensation arises as a result of the action of an external or internal stimulus. However, for the sensation to occur, a certain strength of the stimulus is necessary. If the stimulus is very weak, it will not cause sensation. It is known that he does not feel the touch of dust particles on his face, and does not see the light of stars of the sixth, seventh, etc. magnitude with his naked eyes. The minimum magnitude of the stimulus at which a barely noticeable sensation occurs is called the lower or absolute threshold of sensation. Stimuli that act on human analyzers, but do not cause sensations due to low intensity, are called subthreshold. Thus, absolute sensitivity is the ability of the analyzer to respond to the minimum magnitude of the stimulus.

Determination of sensitivity.

Sensitivity- This is a person’s ability to have sensations. The lower threshold of sensations is opposed by the upper threshold. It limits sensitivity on the other hand. If we go from the lower threshold of sensations to the upper one, gradually increasing the strength of the stimulus, then we will get a series of sensations of greater and greater intensity. However, this will be observed only up to a certain limit (up to the upper threshold), after which a change in the strength of the stimulus will not cause a change in the intensity of the sensation. It will still be the same threshold value or will turn into a painful sensation. Thus, the upper threshold of sensations is called greatest strength stimulus, up to which a change in the intensity of sensations is observed and sensations of this type are generally possible (visual, auditory, etc.).

Determination of sensitivity | Increased sensitivity | Sensitivity threshold | Pain sensitivity | Types of sensitivity | Absolute sensitivity

• High sensitivity

There is an inverse relationship between sensitivity and sensation thresholds. Special experiments have established that the absolute sensitivity of any analyzer is characterized by the value of the lower threshold: the lower the value of the lower threshold of sensations (the lower it is), the greater (higher) the absolute sensitivity to these stimuli. If a person perceives very faint odors, this means that he has high sensitivity to them. The absolute sensitivity of the same analyzer varies among people. For some it is higher, for others it is lower. However, it can be increased through exercise.

• Increased sensitivity.

There are absolute thresholds of sensations not only in intensity, but also in the quality of sensations. Thus, light sensations arise and change only under the influence of electromagnetic waves of a certain length - from 390 (violet) to 780 millimicrons (red). Shorter and longer wavelengths of light do not cause sensations. Auditory sensations in humans are possible only when sound waves oscillate in the range from 16 (the lowest sounds) to 20,000 hertz (the highest sounds).

In addition to the absolute thresholds of sensations and absolute sensitivity, there are also discrimination thresholds and, accordingly, discriminative sensitivity. The fact is that not every change in the magnitude of the stimulus causes a change in sensation. Within certain limits, we do not notice this change in the stimulus. Experiments have shown, for example, that when weighing a body by hand, an increase in a load weighing 500 g by 10 g or even 15 g will go unnoticed. To feel a barely noticeable difference in body weight, you need to increase (or decrease) the weight by one-half of its original value. This means that 3.3 g must be added to a load of 100 g and 33 g to a load of 1000 g. The discrimination threshold is the minimum increase (or decrease) in the magnitude of the stimulus, causing a barely noticeable change in sensations. Distinctive sensitivity is usually understood as the ability to respond to changes in stimuli.

• Sensitivity threshold.

The threshold value depends not on the absolute, but on the relative magnitude of the stimuli: the greater the intensity of the initial stimulus, the more it must be increased in order to obtain a barely noticeable difference in sensations. This pattern is clearly expressed for sensations of medium intensity; sensations close to the threshold have some deviations from it.

Each analyzer has its own discrimination threshold and its own degree of sensitivity. Thus, the threshold for distinguishing auditory sensations is 1/10, sensations of weight - 1/30, visual sensations - 1/100. From a comparison of values, we can conclude that the visual analyzer has the greatest discriminative sensitivity.

The relationship between the discrimination threshold and discriminative sensitivity can be expressed as follows: the lower the discrimination threshold, the greater (higher) discriminative sensitivity.

The absolute and discriminative sensitivity of analyzers to stimuli does not remain constant, but varies depending on a number of conditions:

a) from external conditions accompanying the main stimulus (in silence, hearing acuity increases, in noise it decreases); b) from the receptor (when it becomes tired, it decreases); c) on the state of the central sections of the analyzers and d) on the interaction of the analyzers.

Adaptation of vision has been best studied experimentally (studies by S. V. Kravkov, K. X. Kekcheev, etc.). There are two types of visual adaptation: adaptation to darkness and adaptation to light. When moving from a lighted room to darkness, a person sees nothing for the first minutes, then the sensitivity of vision first slowly, then quickly increases. After 45-50 minutes we clearly see the outlines of objects. It has been proven that eye sensitivity can increase 200,000 times or more in the dark. The described phenomenon is called dark adaptation. When moving from darkness to light, a person also does not see clearly enough for the first minute, but then the visual analyzer adapts to the light. If in the dark adaptation sensitivity vision increases, then with light adaptation it decreases. The brighter the light, the lower the sensitivity of vision.

The same thing happens with auditory adaptation: in loud noise, hearing sensitivity decreases, in silence it increases.

• Pain sensitivity.

A similar phenomenon is observed in the olfactory, skin and taste sensations. General pattern can be expressed as follows: under the influence of strong (and even more so long-term) stimuli, the sensitivity of the analyzers decreases; under the action of weak stimuli, it increases.

However, adaptation is poorly expressed in pain, which has its own explanation. Pain sensitivity arose in the process evolutionary development as one of the forms of the body’s protective adaptation to environment. Pain warns the body of danger. Lack of pain sensitivity could lead to irreversible damage and even death of the body.

Adaptation is also very weakly expressed in kinesthetic sensations, which is again biologically justified: if we did not feel the position of our arms and legs and get used to it, then control over body movements in these cases would have to be carried out mainly through vision, which is not economically.

Physiological adaptation mechanisms are processes occurring both in the peripheral organs of the analyzers (receptors) and in the cerebral cortex. For example, the photosensitive substance of the retinas of the eyes (visual purple) disintegrates under the influence of light and is restored in the dark, which leads in the first case to a decrease in sensitivity, and in the second to its increase. At the same time, cortical nerve cells according to the laws.

Interaction of sensations. In sensations different types there is interaction. Sensations of a certain type are enhanced or weakened by sensations of other types, and the nature of the interaction depends on the strength of the side sensations. Let us give an example of the interaction of auditory and visual sensations. If you alternately light and darken a room while a relatively loud sound is playing continuously, the sound will seem louder in the light than in the dark. There will be an impression of a “beating” sound. In this case, the visual sensation increased the sensitivity of hearing. At the same time, blinding light reduces auditory sensitivity.

Melodious quiet sounds increase the sensitivity of vision, deafening noise reduces it.

Special studies have shown that the sensitivity of the eye in the dark increases under the influence of light muscular work (raising and lowering the arms), increased breathing, wiping the forehead and neck with cool water, and mild taste irritations.

In a sitting position, night vision sensitivity is higher than in standing and lying positions.

Hearing sensitivity is also higher in a sitting position than in a standing or lying position.

The general pattern of interaction of sensations can be formulated as follows: weak stimuli increase sensitivity to other, simultaneously acting stimuli, while strong stimuli reduce it.

Processes of interaction between sensations take place in. An increase in the sensitivity of the analyzer under the influence of weak stimuli from other analyzers is called sensitization. During sensitization, a summation of excitations in the cortex occurs, strengthening the focus of optimal excitability of the main analyzer under given conditions due to weak excitations from other analyzers (dominant phenomenon). The decrease in the sensitivity of the leading analyzer under the influence of strong stimulation of other analyzers is explained by the well-known law of simultaneous negative induction.

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