General patterns of sensations in psychology briefly. Basic laws of sensations

07.05.2020

Not everything that acts on our senses produces a sensation in us. We don’t feel the touch of dust particles falling on our skin, we don’t see the light of distant stars, we don’t hear the ticking of a clock in the next room, we don’t feel those faint smells that a dog following the trail catches well. Why? For a sensation to arise, the irritation must reach a certain level. Too weak stimuli do not cause sensations.

The minimum amount of stimulus that gives a noticeable sensation is called absolute threshold of sensation.

The value of the absolute threshold characterizes the absolute sensitivity of the sense organs or their ability to respond to minimal impacts. The lower the value of the sensation threshold, the higher the absolute sensitivity to these stimuli.

The absolute sensitivity of certain analyzers varies from person to person.. In the world there is absolutely no the same people Therefore, the thresholds of sensation are different for everyone. So, one person hears very weak sounds (for example, the ticking of a clock located at a great distance from his ear), while the other does not hear. In order for the latter to have an auditory sensation, it is necessary to increase the strength of this stimulus (for example, by bringing a ticking clock closer). In this way it can be found that the absolute auditory sensitivity of the former is higher than that of the latter, and the difference observed here can be accurately measured. Or one person may notice a very faint, dim light, while for another, this light must be a little brighter in order to be felt.

Thresholds of absolute sensitivity do not remain unchanged throughout a person's life. Sensitivity in children develops, by adolescence the thresholds become lower, and the sensitivity reaches the optimal level. With age, the thresholds of sensitivity increase. A significant influence on the change in thresholds is exerted by activities in the course of which a person relies on these types of sensitivity.

The natural possibilities of our analyzers are much wider than the framework within which they operate. This is especially evident in people who have defects in one or another analyzer. Thus, it is known that a decrease in vision leads to an aggravation of hearing and smell, and a decrease in hearing increases vibration sensitivity. Such compensation for the insufficient work of one analyzer by strengthening the functioning of another is possible precisely because mobility of sensitivity thresholds. This opens up new perspectives in the development and improvement of human cognitive processes. Most favorable period for this are baby and school years life.

Another important characteristic of the analyzer is its ability to distinguish changes in the strength of a stimulus.

That smallest increase in the strength of the acting stimulus, at which there is a barely noticeable difference in the strength or quality of sensations, is called sensitivity threshold for discrimination.

In life, we constantly notice a change in illumination, an increase or decrease in the strength of a sound, but will we feel the difference in the strength of a light source of 1000 and 1005 W?

The discrimination threshold has a constant relative value for a certain type of sensation and is expressed as a ratio (fraction). For vision, the discrimination threshold is 1/100. If the initial illumination of the hall is 1000 W, then the increase should be at least 10 W so that a person feels a barely noticeable change in illumination. For auditory sensations, the discrimination threshold is 1/10. This means that if 7-8 of the same singers are added to a choir of 100 people, then the person will not notice the amplification of the sound, only 10 singers will hardly noticeably amplify the choir.

The development of distinctive sensitivity is of vital importance. It helps to correctly orient oneself in the surrounding world, makes it possible to act in accordance with the slightest changes in it.

The sensitivity of analyzers can change under the influence of existing stimuli.. This adaptation of the sense organs to external influences is called adaptation(from lat. adaptare - to fit, get used to). She is well known to everyone. We enter the river to swim, at first the water seems terribly cold, then the feeling of cold disappears, the water becomes quite tolerable, warm enough. Or: leaving a dark room into a bright light, in the first moments we see very poorly, the strong light is blinding, and we involuntarily close our eyes. But after a few minutes, the eyes get used to the bright light and see normally. Coming home from the street, we feel all the home smells, and after a few minutes we stop noticing them.

There is a general pattern of sensitivity changes: when moving from strong to weak stimuli, sensitivity increases, when moving from weak to strong, it decreases. This manifests biological expediency: when stimuli are strong, subtle sensitivity is not needed; when they are weak, the ability to catch them is important.

Visual, olfactory, temperature, skin (tactile) sensations have a high ability to adapt, and auditory and pain sensations have a weak ability to adapt. You can get used to noise and pain, that is, you can distract yourself from them, stop paying attention to them, but you don’t stop feeling them, while the skin stops feeling the pressure of clothes. Our senses do not adapt to pain because pain is alarm signal. It is supplied by our body, warning of danger. If we stopped feeling pain, we would not have time to help ourselves.

Sensations, as a rule, do not exist independently and in isolation from each other. The work of one analyzer can influence the work of another, strengthening or weakening it. For example, weak musical sounds can increase the sensitivity of the visual analyzer, while sharp or strong sounds, on the contrary, impair vision. Rubbing the face with cool water (temperature sensations), weak sweet and sour taste sensations can also sharpen our vision.

General properties of sensations. Sensations are a form of reflection of adequate stimuli. So, an adequate stimulus of visual sensation is electromagnetic radiation, characterized by wavelengths in the range from 380 to 770 millimicrons, which are transformed in the visual analyzer into nervous process that generates a visual sensation. Auditory sensations are the result of the reflection of sound waves affecting the receptors with an oscillation frequency of 16 to 20,000. Tactile sensations are caused by the action of mechanical stimuli on the skin surface. Vibratory, which acquire special significance for the deaf, are caused by the vibration of objects. Other sensations (temperature, olfactory, taste) also have their own specific stimuli. However, different types of sensations are characterized not only by specificity, but also by properties common to them. These properties include quality, intensity, duration And spatial localization.

Quality - this is the main feature of this sensation, which distinguishes it from other types of sensations and varies within this type. So, auditory sensations differ in pitch, timbre, loudness; visual - by saturation, color tone, etc. The qualitative variety of sensations reflects the infinite variety of forms of motion of matter.

Intensity sensations is his quantitative characteristic and is determined by the strength of the acting stimulus and the functional state of the receptor.

Duration sensation is its temporal characteristic. It is also determined by the functional state of the sense organ, but mainly by the duration of the stimulus and its intensity. When an irritant is exposed to a sensory organ, the sensation does not occur immediately, but after some time, which is called latent (hidden) period of sensation. The latent period for different types of sensations is not the same: for tactile sensations, for example, it is 130 milliseconds, for pain - 370 milliseconds. A taste sensation occurs 50 milliseconds after a chemical irritant is applied to the surface of the tongue.

Just as a sensation does not arise simultaneously with the beginning of the action of the stimulus, it does not disappear simultaneously with the termination of the latter. This inertia of sensations manifests itself in so-called aftereffect.

The visual sensation has some inertia and does not disappear immediately after the stimulus that caused it ceases to act. The trace from the stimulus remains in the form sequential image. Distinguish positive And negative serial images. A positive consistent image in terms of lightness and color corresponds to the initial irritation. The principle of cinematography is based on the inertia of vision, on the preservation of a visual impression for some time in the form of a positive consistent image. The sequential image changes in time, while the positive image is replaced by a negative one. With colored light sources, there is a transition of a sequential image into a complementary color.

I. Goethe wrote in his “Essay on the Doctrine of Color”: “When one evening I went into a hotel and a tall girl with a dazzlingly white face, black hair and a bright red bodice came into my room, I looked intently at her standing in the semi-darkness at some distance from me. After she left there, I saw on the light wall opposite me a black face, surrounded by a bright glow, while the clothes of a completely clear figure seemed to me the beautiful green color of the sea wave. .

The appearance of successive images can be scientifically explained. As is known, the presence of color-sensing elements of three types is assumed in the retina of the eye. In the process of irritation, they get tired and become less sensitive. When we look at red, the corresponding receivers get more fatigued than the others, so when white light then falls on the same area of the retina, the other two types of receivers remain more sensitive and we see blue-green.

Auditory sensations, like visual sensations, can also be accompanied by successive images. The most comparable phenomenon in this case is “ringing in the ears”, i.e. an unpleasant sensation that often accompanies exposure to deafening sounds. After a series of short sound impulses acts on the auditory analyzer for several seconds, they begin to be perceived in a single or muffled way. This phenomenon is observed after the termination of the sound pulse and continues for several seconds, depending on the intensity and duration of the pulse.

A similar phenomenon occurs in other analyzers. For example, temperature, pain and taste sensations also continue for some time after the action of the stimulus.

Finally, sensations are characterized spatial localization of the stimulus . Spatial analysis, carried out by distant receptors, gives us information about the localization of the stimulus in space. Contact sensations (tactile, pain, taste) are correlated with the part of the body that is affected by the stimulus. At the same time, the localization of pain sensations is more diffuse and less accurate than tactile ones.

Sensitivity and its measurement. Various sense organs that give us information about the state of the external world around us can be more or less sensitive to the phenomena they display, i.e. can display these phenomena with greater or lesser accuracy. The sensitivity of the sense organ is determined by the minimum stimulus that, under given conditions, is capable of causing a sensation. The minimum strength of the stimulus that causes a barely noticeable sensation is called the lower absolute threshold of sensitivity.

Irritants of lesser strength, the so-called subthreshold, do not cause sensations, and signals about them are not transmitted to the cerebral cortex. The bark at each individual moment from an infinite number of impulses perceives only vital ones, delaying all the rest, including impulses from internal organs. This position is biologically reasonable. It is impossible to imagine the life of an organism in which the cerebral cortex would equally perceive all impulses and provide reactions to them. This would lead the body to inevitable death. It is the cerebral cortex that stands guard over the vital interests of the body and, by raising the threshold of its excitability, turns irrelevant impulses into subthreshold ones, thereby relieving the body of unnecessary reactions.

However, subthreshold impulses are not indifferent to the body. This is confirmed by numerous facts obtained in the clinic of nervous diseases, when it is precisely weak, subcortical stimuli from the external environment that create a dominant focus in the cerebral cortex and contribute to the occurrence of hallucinations and "deception of the senses." Subthreshold sounds can be perceived by the patient as a host of intrusive voices with simultaneous complete indifference to real human speech; a weak, barely noticeable beam of light can cause hallucinatory visual sensations of various contents; barely noticeable tactile sensations - from skin contact with clothing - a series of perverse sharp skin sensations.

lower threshold sensations determines the level of absolute sensitivity this analyzer. There is an inverse relationship between absolute sensitivity and threshold value:

the lower the threshold value, the higher the sensitivity this analyzer. This relationship can be expressed by the formula:

E = 1/R,

where E is sensitivity, and P is the threshold value of the stimulus.

Our analyzers have different sensitivities. The threshold of one human olfactory cell for the corresponding odorous substances does not exceed 8 molecules. It takes at least 25,000 times more molecules to produce a taste sensation than it does to create an olfactory sensation.

The sensitivity of the visual and auditory analyzer is very high. The human eye, as experiments have shown S.I. Vavilov(1891-1951), is able to see light when only 2-8 quanta of radiant energy hit the retina. This means that we would be able to see a burning candle in complete darkness at a distance of up to 27 kilometers. At the same time, in order for us to feel touch, we need 100-10,000,000 times more energy than with visual or auditory sensations.

The absolute sensitivity of the analyzer is limited not only by the lower, but also by the upper threshold of sensation. Upper absolute threshold of sensitivity called the maximum strength of the stimulus, at which there is still an adequate sensation to the acting stimulus. A further increase in the strength of stimuli acting on our receptors causes only a painful sensation in them (for example, an ultra-loud sound, blinding brightness).

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

With the help of the sense organs, we can not only ascertain the presence or absence of a particular stimulus, but also distinguish stimuli by their strength and quality. The smallest difference between two stimuli that produces a subtle difference in sensation called the threshold or difference threshold. German physiologist E. Weber(1795-1878), testing a person's ability to determine the heavier of two objects in the right and left hand, found that differential sensitivity is relative, not absolute. This means that the ratio of the additional stimulus to the main stimulus must be a constant value. So, if there is a load of 100 grams on the arm, then for a barely noticeable sensation of an increase in weight, you need to add about 3.4 grams. If the weight of the load is 1000 grams, then for a sensation of a barely noticeable difference, you need to add about 33.3 grams. Thus, the greater the value of the initial stimulus, the greater should be the increase to it.

The discrimination threshold is characterized by a relative value that is constant for a given analyzer. For the visual analyzer, this ratio is approximately 1/100, for the auditory - 1/10, for the tactile - 1/30. Experimental verification of this provision showed that it is valid only for stimuli of medium strength.

Based on Weber's experimental data, the German physicist G. Fechner(1801-1887) expressed the dependence of the intensity of sensations on the strength of the stimulus by the following formula:

S = KlgJ + C,

where S is the intensity of sensations, J is the strength of the stimulus, K and C are constants. According to this provision, which is called basic psychophysical law, the intensity of sensation is proportional to the logarithm of the strength of the stimulus. In other words, with an increase in the strength of the stimulus in geometric progression the intensity of sensation increases in arithmetic progression(Weber-Fechner law).

Difference sensitivity, or discrimination sensitivity, is also inversely related to the difference threshold value: the higher the discrimination threshold, the lower the difference sensitivity.

The concept of differential sensitivity is used not only to characterize the discrimination of stimuli by intensity, but also in relation to other features of certain types of sensitivity. For example, they talk about sensitivity to distinguishing shapes, sizes and colors of visually perceived objects or to sound-altitude sensitivity.

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

Adaptation, or adaptation, is a change in the sensitivity of the sense organs under the influence of the action of a stimulus.

Three varieties of this phenomenon can be distinguished.

1. Adaptation as complete loss of sensation during prolonged action of the stimulus. We mentioned this phenomenon at the beginning of this chapter, speaking of the peculiar disposition of the analyzers to change the stimulus. In the case of constant stimuli, the sensation tends to fade. For example, a light load resting on the skin soon ceases to be felt. The distinct disappearance of olfactory sensations shortly after we enter an atmosphere with an unpleasant odor is also a common fact. The intensity of the taste sensation weakens if the corresponding substance is kept in the mouth for some time and, finally, the sensation may die out altogether.

Full adaptation of the visual analyzer under the action of a constant and immobile stimulus does not occur. This is due to compensation for the immobility of the stimulus due to the movements of the receptor apparatus itself. Constant voluntary and involuntary eye movements ensure the continuity of the visual sensation. Experiments in which the conditions for image stabilization relative to the retina were artificially created showed that in this case, the visual sensation disappears 2–3 seconds after its occurrence, i.e. complete adaptation.

2. Adaptation is also called another phenomenon, close to the one described, which is expressed in the dulling of sensation under the influence of a strong stimulus. For example, when a hand is immersed in cold water, the intensity of the sensation caused by a cold stimulus decreases. When we move from a semi-dark room into a brightly lit space, we are first blinded and unable to distinguish any details around. After some time, the sensitivity of the visual analyzer decreases sharply, and we begin to see normally. This decrease in the sensitivity of the eye to 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 of them the sensitivity of the analyzers decreases.

3. Finally, adaptation is called an increase in sensitivity under the influence of a weak stimulus. This kind of adaptation, inherent in certain types of sensations, can be defined as positive adaptation.

In the visual analyzer, this is dark adaptation, when the sensitivity of the eye increases under the influence of being in the dark. A similar form of auditory adaptation is silence adaptation. In temperature sensations, positive adaptation is found when a pre-cooled hand feels warm, and a pre-heated hand feels cold when immersed in water of the same temperature. The question of the existence of negative pain adaptation has long been controversial. It is known that repeated use of a painful stimulus does not reveal negative adaptation, but, on the contrary, acts more and more strongly over time. However, new facts indicate the presence of a complete negative adaptation to needle pricks and intense hot irradiation.

Studies have shown that some analyzers detect fast adaptation, others slow. For example, touch receptors adapt very quickly. On their sensory nerve, when any prolonged stimulus is applied, only a small burst of impulses runs through at the beginning of the action of the stimulus. The visual receptor adapts relatively slowly (the time of dark adaptation reaches several tens of minutes), the olfactory and gustatory receptors.

Adaptive regulation of the level of sensitivity, depending on which stimuli (weak or strong) affect the receptors, is of great biological importance. Adaptation helps to catch weak stimuli through the sense organs and protects the sense organs from excessive irritation in case of unusually strong influences.

The phenomenon of adaptation can be explained by peripheral changes that occur in the functioning of the receptor with prolonged exposure to an irritant. So, it is known that under the influence of light, visual purple, located in the rods of the retina, decomposes (fades). In the dark, on the contrary, visual purple is restored, which leads to an increase in sensitivity. With regard to other sense organs, it has not yet been proven that their receptor apparatuses contain any substances that chemically decompose when exposed to a stimulus and are restored in the absence of such exposure. The phenomenon of adaptation is also explained by the processes taking place in central departments of analyzers. With prolonged stimulation, the cerebral cortex responds to internal protective braking, reducing sensitivity. The development of inhibition causes increased excitation of other foci, which contributes to an increase in sensitivity in new conditions (the phenomenon of successive mutual induction).

The interaction of sensations. 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 currently affecting other sense organs. A change in the sensitivity of the analyzer under the influence of irritation of other sense organs is called the interaction of sensations.

The literature describes numerous facts of sensitivity changes caused by the interaction of sensations. Thus, the sensitivity of the visual analyzer changes under the influence of auditory stimulation. S.V. Kravkov(1893-1951) showed that this change depends on the loudness of auditory stimuli. Weak sound stimuli increase the color sensitivity of the visual analyzer. At the same time, a sharp deterioration in the distinctive sensitivity of the eye is observed 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 coloring of the smell, a decrease in visual sensitivity is observed. Similarly, with weak light stimuli, auditory sensations are enhanced, and exposure to intense light stimuli worsens auditory sensitivity. There are known facts of increasing visual, auditory, tactile and olfactory sensitivity under the influence of weak pain stimuli.

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

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

Sensitization. An increase in 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. By I. P. Pavlov, a weak stimulus causes an excitation process in the cerebral cortex, which easily irradiates (spreads). As a result of the irradiation of the excitation process, the sensitivity of another analyzer increases. Under the action of a strong stimulus, a process of excitation occurs, which, on the contrary, has a tendency to concentration. 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.

Changes in the sensitivity of the analyzers can be caused by exposure to secondary signal stimuli. Thus, the facts of changes in the electrical sensitivity of the eyes and tongue in response to the presentation of the words "sour as a lemon" to the subjects were obtained. These changes were similar to those observed when the tongue was actually irritated with lemon juice.

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 through exercise. It is known, for example, how pitch hearing develops in children who study music.

Synesthesia. The interaction of sensations is manifested in another kind of phenomena called synesthesia. Synesthesia is the occurrence under the influence of irritation of one analyzer of a sensation characteristic of another analyzer. Synesthesia is seen in a wide variety of sensations. The most common visual-auditory synesthesia, when, under the influence of sound stimuli, the subject has visual images. There is no overlap in these synesthesias among different people, but they are fairly constant for each individual. It is known that some composers possessed the ability of color hearing. (N.A. Rimsky-Korsakov, A.N. Skryabin and etc.). We find a vivid manifestation of this kind of synesthesia in the work of the Lithuanian artist M.K. Ciurlionis - in his symphonies of colors.

The phenomenon of synesthesia is based on the creation in last years color-music apparatuses that transform sound images into color ones, and intensive study of color music. Less common are cases of auditory sensations when exposed to visual stimuli, taste sensations in response to auditory stimuli, etc. Not all people have synesthesia, although it is quite widespread. No one doubts the possibility of using such expressions as "sharp taste", "screaming color", "sweet sounds", etc. The phenomenon of synesthesia is another evidence of the constant interconnection of analyzer systems human body, the integrity of the sensory reflection of the objective world.

Sensitivity and exercise. Sensitization of the sense organs is possible not only through the use of side stimuli, but also through exercise. The possibilities for training the sense organs and their improvement are very great. There are two areas that determine the increase in the sensitivity of the senses: 1) sensitization, which spontaneously leads to the need to compensate for sensory defects(blindness, deafness) and 2) sensitization caused by activity, specific requirements of the subject's profession.

Loss of sight or hearing is compensated to a certain extent by the development of other types of sensitivity.

There are cases when people deprived of sight are engaged in sculpture, their sense of touch is highly developed. The development of vibrational sensations in the deaf belongs to the same group of phenomena. Some deaf people develop vibration sensitivity to such an extent that they can even listen to music. To do this, they put their hand on the instrument or turn their backs to the orchestra. Deaf-blind O. Skorokhodova, holding her hand to her throat speaking interlocutor can thus recognize him by his voice and understand what he is talking about. The deaf-blind-mute Helen Keller has such a highly developed olfactory sensitivity that she can associate many friends and visitors with their smells, and her memories of acquaintances are as well associated with the sense of smell as most people are associated with the voice.

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

The phenomena of sensitization of the sense organs are observed in persons who have been engaged in certain special professions for a long time.

The extraordinary visual acuity of grinders is known. They see gaps from 0.0005 millimeters, while untrained people only up to 0.1 millimeters. Fabric dyeers 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 from the faint color shades of molten steel.

A high degree of perfection is achieved by olfactory and gustatory sensations in tasters of tea, cheese, wine, and tobacco. Tasters can accurately indicate not only what grape variety the wine is made from, but also the place where this grape was grown.

Painting makes 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 the assessment of proportions. He distinguishes between changes equal to 1/60-1/150 of the size of the subject. 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.

Opportunities for the development of auditory sensitivity are also quite large. Thus, playing the violin requires a special development of pitch hearing, and violinists have it more developed than pianists. Experienced pilots can easily determine the number of engine revolutions by ear. They freely distinguish between 1300 and 1340 rpm. Untrained people catch the difference only 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.

Despite the large number of such facts, the problem of exercising the sense organs has not yet been studied enough. What underlies the exercise of the sense organs? It is not yet possible to give an exhaustive answer to this question. An attempt has been made to explain the increased tactile sensitivity in the blind. It was possible to isolate tactile receptors - Pachintsev bodies, present in the skin of the fingers of blind people. For comparison, the same study was conducted on the skin of sighted people of various professions. It turned out that the number of tactile receptors is increased in the blind. So, if in the skin of the nail phalanx of the first finger in the sighted, the number of bodies on average reached 186, then in the blind born it was 270.

Thus, the structure of receptors is not constant, it is plastic, mobile, constantly changing, adapting to the best performance of a given receptor function. Together with the receptors and inseparably from them, the structure of the analyzer as a whole is rebuilt in accordance with the new conditions and requirements of practical activity.

The progress of technology entails a colossal information overload of the main channels of communication between a person and the external environment - visual and auditory. The need to unload the visual and auditory analyzers is inevitably associated with the activation of other communication systems, in particular, skin systems. Animals have been developing vibrational sensitivity for millions of years, while the idea of transmitting signals through the skin is still new for humans. And the possibilities in this regard are quite large: after all, the area human body, capable of receiving information, is large enough.

For a number of years, attempts have been made to develop "skin hearing" based on the use of stimulus properties adequate for vibrational sensitivity, such as the location of the stimulus, its intensity, duration, and frequency of vibrations. The use of the first three of the listed qualities of stimuli made it possible to create and successfully apply a system of coded vibrational signals. A subject who learned the alphabet of the "vibrational language" could, after some training, perceive sentences delivered at a speed of 38 words per minute, and this result was not the limit. Obviously, the possibilities of using vibrational and other types of sensitivity to transmit information to a person are far from being exhausted, and the importance of developing research in this area can hardly be overestimated.

1 Goethe I. Select. op. in natural science. - L.-M.: Publishing House of the Academy of Sciences of the USSR, 1957. - S.288.

2 Stabilization was achieved using a special suction cup, on which an image was placed that moved with the eye.

The main patterns of sensations include sensitivity thresholds, adaptation, interaction, contrast and synesthesia.

Let us describe each concept in more detail.

In psychophysiology, two types of thresholds are distinguished: the threshold of absolute sensitivity and the threshold of sensitivity to discrimination.

That smallest stimulus strength at which a barely noticeable sensation first occurs is called the lower absolute threshold of sensitivity. And that greatest strength stimulus, at which there is still a sensation of this type, is called the upper absolute threshold of sensitivity.

Thresholds limit the analyzer's sensitivity zone to a given type of stimuli. For example, out of all electromagnetic oscillations the eye is capable of reflecting wavelengths from 390 (purple) to 780 (red) millimicrons; vibrations that are distinguished by the ear as sound occupy an area from 20 to 20 thousand hertz. At present, the characteristics of the upper and lower thresholds of all types of sensitivity have been studied in detail.

The action on the nervous system of stimuli that do not reach the threshold value does not remain without a trace. These stimuli change the sensitivity thresholds and can subconsciously correct movements and actions.

To measure the thresholds of absolute sensitivity, devices have been created with scales for continuously changing the strength of the stimulus. Starting the impact on the analyzer with a subthreshold stimulus, the experimenter gradually increases the strength of the stimulus until the subject says that he has a sensation. In accordance with the indicators of the subject, the physical strength of the stimulus is recorded. The measurement is made several times. Then the conditions of the experiment change: the strength of the stimulus that causes the sensation decreases until the subject says that the sensation has disappeared. Having made several such measurements, the experimenter calculates the arithmetic mean of all values, which is considered the threshold strength of the stimulus.

As we said above, in addition to strength, the stimulus is characterized by the duration of exposure, i.e. the length of time during which it acts on the analyzer. It is known that there is a relationship between the strength of the stimulus and the duration of its exposure required to reach the threshold value. The weaker the stimulus, the longer it takes for it to cause a sensation. With prolonged exposure (more than a second), the occurrence of sensations begins to depend only on the strength of the stimulus.

There is an inverse relationship between sensitivity (threshold) and the strength of the stimulus: the greater the force needed to create a sensation, the lower the sensitivity of a person. Sensitivity thresholds are individual for each person. This psychological regularity of sensations should be provided for by the teacher, especially in primary school. Because sometimes there are children with reduced auditory and visual sensitivity. In order for them to see and hear clearly, it is necessary to create conditions for the best distinction between the teacher's speech and the notes on the board.

The thresholds of absolute sensitivity do not remain unchanged throughout a person's life: sensitivity in children develops, reaching adolescence top level.

In addition to the thresholds of absolute sensitivity, sensations are also characterized by thresholds of sensitivity to discrimination. That smallest increase in the strength of the acting stimulus, at which there is a barely noticeable difference in the strength or quality of sensations, is called the threshold of sensitivity to discrimination.

In life, we constantly notice a change in illumination, an increase or decrease in the strength of sound. This is a manifestation of the threshold of discrimination. I'll give you an example. If you ask two or three people to divide in half a line about a meter long. It turns out that each of the subjects will put their middle point. Let's measure with a millimeter ruler who divided more accurately - this subject will have the best sensitivity to distinguish.

Sensitivity to discrimination, as noted by B.G. Ananiev, is the source of such a complex thought process as comparison. In the development of distinctive sensitivity, an exceptional role belongs to the word. The word highlights and fixes barely noticeable differences in sensations, draws a person's attention to the qualitative and quantitative characteristics of the properties of the reflected object and leads to the development of observation. Therefore, the improvement of distinctive sensitivity in children is inextricably linked with the development of speech in the learning process.

The degree of adaptation of various analyzer systems is not the same: high adaptability is noted in olfactory sensations, tactile (we do not notice the pressure of clothing on the body), light, and much less adaptability in auditory, cold. With a slight adaptation we meet in pain sensations. Pain signals the destruction of an organ, and it is clear that adaptation to pain can lead to the death of the body.

In the visual analyzer, dark and light adaptation are distinguished.

The course of dark adaptation has been studied in detail. Getting into a darkened room, a person at first does not see anything, after 3-5 minutes he begins to distinguish well the light penetrating there. Staying in absolute darkness increases the sensitivity to light in 40 minutes by about 200,000 times. Various reasons affect the increase in sensitivity: changes occur in the receptor, the opening of the pupil increases, the work of the rod apparatus increases, but basically the sensitivity increases due to the conditioned reflex work of the central mechanisms of the analyzer. If dark adaptation is associated with an increase in sensitivity, then light adaptation is associated with a decrease in light sensitivity.

Let us pay special attention to the interaction of sensations.

The general pattern of the interaction of sensations is as follows: weak stimuli in one analyzer system increase sensitivity, and in another they decrease. For example, weak taste sensations (sour) increase visual sensitivity, mutual influence is noted between sound and visual sensations. An increase in sensitivity as a result of the interaction of analyzers, as well as systematic exercises, is called sensitization. So, for example, weak taste sensations increase visual sensitivity. This is due to the interconnection of these analyzers, their system work.

Sensitization, exacerbation of sensitivity, can be caused not only by the interaction of sensations, but also by physiological factors, the introduction of certain substances into the body. For example, vitamin A is essential to increase visual sensitivity.

Sensitivity increases if a person expects one or another weak stimulus when a special task discrimination of stimuli. The sensitivity of the individual is improved as a result of the exercise. So, tasters, specially exercising taste and olfactory sensitivity, distinguish between various varieties of wines, teas, and can even determine when and where the product was made.

In people deprived of any kind of sensitivity, compensation (compensation) for this deficiency is carried out by increasing the sensitivity of other analyzers (for example, increasing auditory and olfactory sensitivity in the blind).

One of the manifestations of the interaction of sensations is the contrast of sensations. The contrast of sensations is an increase in sensitivity to one property under the influence of other, opposite properties of reality. We are all very familiar with the contrast of sensations. For example, the same gray figure appears dark on a white background, and light on a black one.

Next, we turn to the consideration of such a phenomenon as synesthesia. Synesthesia is the excitation of sensations of one modality of sensations of another modality. Note that a feature of sensations is the monomodality of the image. However, the interaction of sensations that occurs in the central nuclei of the analyzer leads to the fact that a person under pressure, for example, sounds, can experience color sensations, color can cause a feeling of cold. This interaction is called synesthesia. Synesthesia can be thought of as special case interaction of sensations, which is expressed not in a change in the level of sensitivity, but in the fact that the impact of sensations of a given modality is enhanced through the excitation of sensations of other modalities. Synesthesia enhances the sensory tone of sensations. The phenomenon of synesthesia extends to all modalities. This is expressed in stable phrases: velvet voice, dark sound, cold color, etc. The manifestations of synesthesia are individual. There are people with a very strong ability to synesthesia and people who have almost no synesthesia.

The considered patterns reveal the high dynamism of sensations, their dependence on the strength of the stimulus, on the functional state of the analyzer system caused by the onset or termination of the stimulus, as well as the result of the simultaneous action of several stimuli on one analyzer or adjacent analyzers.

Thus, it can be noted that the patterns of sensations determine the conditions under which the stimulus (irritation) reaches consciousness. So biologically important stimuli affect the brain at lower thresholds and increased sensitivity, and stimuli that have lost their biological significance - at higher thresholds.

Patterns of sensations

Sensitivity threshold

The smallest force of the stimulus, which, acting on the analyzer, causes a barely noticeable sensation, is called lower absolute sensitivity threshold. The lower threshold characterizes the sensitivity of the analyzer.

There is a visual relationship between absolute sensitivity and threshold value: the lower the threshold, the higher the sensitivity, and vice versa.

Sensitivity thresholds are individual for each person.

Adaptation

Adaptation, or adaptation, is a change in sensitivity under the influence of a constantly acting stimulus, manifested in a decrease or increase in thresholds.

Interaction of sensations

Interaction of sensations- this is a change in the sensitivity of one analyzer system under the influence of the activity of another system. The general pattern of the interaction of sensations is as follows: weak stimuli of one analyzer system increase the sensitivity of another system, strong ones decrease it.

Sensitization

Sensitization is an increase in sensitivity as a result of the interaction of analyzers, as well as systematic exercises.

The contrast of sensations

The contrast of sensations- this is a change in the intensity and quality of sensations under the influence of a preliminary or accompanying stimulus.

Synesthesia

The interaction of sensations manifests itself in a phenomenon called synesthesia.

Synesthesia- this is the occurrence under the influence of irritation of one analyzer of a sensation characteristic of another analyzer.

Synesthesia is seen in a wide variety of sensations. The most common visual-auditory synesthesia, when, under the influence of sound stimuli, the subject has visual images. There is no overlap between different people in these synesthesias, however, they are quite constant for each individual.

Less common are cases of auditory sensations when exposed to visual stimuli, taste 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 the analyzer systems of the human body, the integrity of the sensory reflection of the objective world.

The contrast of sensations

The contrast of sensations - this is an increase in sensitivity to one property under the influence of other, opposite properties of reality. For example, the same gray figure appears dark on a white background, and light on a black one.

Adaptation

adaptation or adjustment , is a change in the sensitivity of the sense organs under the influence of the action of the stimulus.

Varieties of adaptation:

1) Adaptation as the complete disappearance of sensation in the process of prolonged action of the stimulus;

In the case of constant stimuli, the sensation tends to fade. For example, a light load resting on the skin soon ceases to be felt. The distinct disappearance of olfactory sensations shortly after we enter an atmosphere with an unpleasant odor is also a common fact. The intensity of the taste sensation weakens if the corresponding substance is kept in the mouth for some time and, finally, the sensation may die out altogether.

Constant voluntary and involuntary eye movements ensure the continuity of the visual sensation. Experiments in which the conditions for image stabilization relative to the retina were artificially created showed that in this case, the visual sensation disappears 2–3 seconds after its occurrence, i.e. complete adaptation.

2) dullness of sensation under the influence of a strong stimulus;

For example, when a hand is immersed in cold water, the intensity of sensation caused by a temperature stimulus decreases. When we move from a semi-dark room into a brightly lit space, we are first blinded and unable to distinguish any details around. After some time, the sensitivity of the visual analyzer decreases sharply, and we begin to see normally. This decrease in the sensitivity of the eye to intense light stimulation is called light adaptation.

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

3) increased sensitivity under the influence of a weak stimulus.

This kind of adaptation, which is characteristic of certain types of sensations, can be defined as positive adaptation.

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

The phenomenon of adaptation can be explained by those peripheral changes that occur in the functioning of the receptor with prolonged exposure to a stimulus. So, 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 an increase in sensitivity. The phenomenon of adaptation is also explained by the processes taking place in the central sections of the analyzers. With prolonged stimulation, the cerebral cortex responds with internal protective inhibition, which reduces sensitivity. The development of inhibition causes increased excitation of other foci, which contributes to an increase in sensitivity in new conditions.

The main patterns of sensations include sensitivity thresholds, adaptation, interaction, contrast and synesthesia.

Let us describe each concept in more detail.

Thresholds of sensitivity. Not every force of stimulus is capable of evoking sensations. So, for example, the touch of a fluff on the body cannot be felt. And under the action of a very strong stimulus, a moment may come when sensations cease to arise at all. We do not hear sounds with a frequency above 20 thousand hertz. A super-strong stimulus instead of a sensation of this type causes pain. Therefore, sensations arise when exposed to a stimulus of a certain intensity. The psychological characteristic of the relationship between the intensity of sensation and the strength of stimuli is expressed by the concept of the threshold of sensations, or the threshold of sensitivity. In psychophysiology, two types of thresholds are distinguished: the threshold of absolute sensitivity and the threshold of sensitivity to discrimination. That smallest stimulus strength at which a barely noticeable sensation first occurs is called the lower absolute threshold of sensitivity. And that greatest strength of the stimulus, at which there is still a sensation of this type, is called the upper absolute threshold of sensitivity.

Thresholds limit the analyzer's sensitivity zone to a given type of stimuli. For example, of all electromagnetic vibrations, the eye is capable of reflecting wavelengths from 390 (violet) to 780 (red) millimicrons; vibrations that are distinguished by the ear as sound occupy an area from 20 to 20 thousand hertz. At present, the characteristics of the upper and lower thresholds of all types of sensitivity have been studied in detail. The action on the nervous system of stimuli that do not reach the threshold value does not remain without a trace. These stimuli change the sensitivity thresholds and can subconsciously correct movements and actions. To measure the thresholds of absolute sensitivity, devices have been created with scales for continuously changing the strength of the stimulus. Starting the impact on the analyzer with a subthreshold stimulus, the experimenter gradually increases the strength of the stimulus until the subject says that he has a sensation. In accordance with the indicators of the subject, the physical strength of the stimulus is recorded. The measurement is made several times. Then the conditions of the experiment change: the strength of the stimulus that causes the sensation decreases until the subject says that the sensation has disappeared. Having made several such measurements, the experimenter calculates the arithmetic mean of all values, which is considered the threshold strength of the stimulus.

As we said above, in addition to strength, the stimulus is characterized by the duration of the impact, that is, the length of time during which it acts on the analyzer. It is known that there is a relationship between the strength of the stimulus and the duration of its exposure required to reach the threshold value. The weaker the stimulus, the longer it takes for it to cause a sensation. With prolonged exposure (more than a second), the occurrence of sensations begins to depend only on the strength of the stimulus.

There is an inverse relationship between sensitivity (threshold) and the strength of the stimulus: the greater the force needed to create a sensation, the lower the sensitivity of a person. Sensitivity thresholds are individual for each person. This psychological pattern of sensations should be provided for by the teacher, especially in the primary grades. Because sometimes there are children with reduced auditory and visual sensitivity. In order for them to see and hear clearly, it is necessary to create conditions for the best distinction between the teacher's speech and the notes on the board.

The thresholds of absolute sensitivity do not remain unchanged throughout a person's life: sensitivity in children develops, reaching the highest level by adolescence. In addition to the thresholds of absolute sensitivity, sensations are also characterized by thresholds of sensitivity to discrimination. That smallest increase in the strength of the acting stimulus, at which there is a barely noticeable difference in the strength or quality of sensations, is called the threshold of sensitivity to discrimination.

An experimental study of sensitivity to discrimination made it possible to formulate the following law, which is valid for stimuli of medium strength, i.e., not approaching the lower or upper thresholds of absolute sensitivity: the ratio of the surplus strength of the stimulus to the main one is a constant value for this type of sensitivity. So, in the sensation of pressure (tactile sensitivity), this increase is equal to 1/30 of the weight of the original stimulus. This means that 3.4 g must be added to 100 g in order to feel a change in pressure, and 34 g to 1 kg. For auditory sensations, this constant is 1/10, for visual sensations - 1/100. Sensitivity to discrimination, as noted by B.G. Ananiev, is the source of such a complex thought process as comparison. In the development of distinctive sensitivity, an exceptional role belongs to the word. The word highlights and fixes barely noticeable differences in sensations, draws a person's attention to the qualitative and quantitative characteristics of the properties of the reflected object and leads to the development of observation. Therefore, the improvement of distinctive sensitivity in children is inextricably linked with the development of speech in the learning process.

The next pattern we will focus on is adaptation. Adaptation is an adaptation of sensitivity to a constantly acting stimulus, manifested in a decrease or increase in thresholds. In life, the phenomenon of adaptation is well known to everyone. So in the first minute, when a person enters the river, the water seems cold to him. Then the feeling of cold disappears, and the water seems warm enough. This is observed in all types of sensitivity, except for pain. The degree of adaptation of various analyzer systems is not the same: high adaptability is noted in olfactory sensations, tactile (we do not notice the pressure of clothing on the body), light, and much less adaptability in auditory, cold. With a slight adaptation we meet in pain sensations. Pain signals the destruction of an organ, and it is clear that adaptation to pain can lead to the death of the body.

In the visual analyzer, dark and light adaptation are distinguished.

Let us pay special attention to the interaction of sensations.

The interaction of sensations is a change in the sensitivity of one analyzer system under the influence of the activity of another analyzer system. The change in sensitivity is explained by cortical connections between the analyzers, to a large extent by the law of simultaneous induction. The general pattern of the interaction of sensations is as follows: weak stimuli in one analyzer system increase sensitivity, and in another they decrease. For example, weak taste sensations (sour) increase visual sensitivity, mutual influence is noted between sound and visual sensations. An increase in sensitivity as a result of the interaction of analyzers, as well as systematic exercises, is called sensitization.

So, for example, weak taste sensations increase visual sensitivity. This is due to the interconnection of these analyzers, their system work. Sensitization, exacerbation of sensitivity, can be caused not only by the interaction of sensations, but also by physiological factors, the introduction of certain substances into the body. For example, vitamin A is essential to increase visual sensitivity. Sensitivity increases if a person expects one or another weak stimulus, when a special task of distinguishing stimuli is put forward before him. The sensitivity of the individual is improved as a result of the exercise. So, tasters, specially exercising taste and olfactory sensitivity, distinguish between various varieties of wines, teas, and can even determine when and where the product was made.

The interaction of sensations in some cases leads to sensitization, to an increase in sensitivity, and in other cases - to its decrease, i.e. to desensitization. Strong excitation of some analyzers always lowers the sensitivity of other analyzers. So, the increased noise level in "loud shops" lowers visual sensitivity. One of the manifestations of the interaction of sensations is the contrast of sensations. The contrast of sensations is an increase in sensitivity to one property under the influence of other, opposite properties of reality. We are all very familiar with the contrast of sensations. For example, the same gray figure appears dark on a white background, and light on a black one.

Next, we turn to the consideration of such a phenomenon as synesthesia. Synesthesia is the excitation of sensations of one modality of sensations of another modality. Note that a feature of sensations is the monomodality of the image. However, the interaction of sensations that occurs in the central nuclei of the analyzer leads to the fact that a person under pressure, for example, sounds, can experience color sensations, color can cause a feeling of cold. This interaction is called synesthesia. Synesthesia can be considered as a special case of the interaction of sensations, which is expressed not in a change in the level of sensitivity, but in the fact that the influence of sensations of a given modality is enhanced through the excitation of sensations of other modalities. Synesthesia enhances the sensory tone of sensations. The phenomenon of synesthesia extends to all modalities. This is expressed in stable phrases: velvet voice, dark sound, cold color, etc. The manifestations of synesthesia are individual. There are people with a very strong ability to synesthesia and people who have almost no synesthesia.