Sensation of patterns and properties of sensations. Basic laws of sensations. Basic properties of memory

Sensation as an elementary reflection of the material world naturally reflects the main characteristics of objects and phenomena - qualitative, quantitative and spatio-temporal. These patterns clearly manifest the nature of sensory images, which are a subjective reflection of the objective world.

The main characteristic of sensations, in which their specificity is manifested, due to the physicochemical properties of stimuli adequate for the corresponding analyzer, is their quality. Incomplete are the ideas that a person has only five senses - sight, hearing, taste, smell and touch. In fact, a person has much more sensations and their analyzer apparatus. An independent variety is temperature sensations, which play an important role in the processes of heat exchange between the body and the environment. Common to various sense organs are pain sensations that arise as a result of exposure to too strong stimuli, but also have their own independent receptors. Information about the movement and position of our body and about the properties of the objects with which we act is provided by muscular-articular sensations (kinesthetic and static), their receptors are contained in muscles, joints and ligaments. An important role in the spatial analysis is played by the vestibular sensation, the organ of which is the pivcol canals and the otolitis apparatus of the ear. An intermediate position between dotik and auditory sensations is occupied by vibrational sensations. Finally, various information about the internal state of a person is provided by receptors located in the organs and tissues of the body (Fig. 11).

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Every second, sense organs and receptors receive, filter, transform and transmit huge flows of information to the brain, which makes it possible to navigate the world. But for some vital factors, a person does not have the corresponding sense organs, because they arose as a result of man-made human impacts on the environment. The lack of appropriate sensations prevents, for example, some people who live in a zone of radiation contamination from realizing the danger and preventing it.

Mankind successfully overcomes the limitations of information carried by the senses. Technical devices are used that expand the range of environmental factors that are perceived by a person. Thanks to devices that continue the sense organs, a person perceives both the voltage of the electromagnetic field and ultrasonic waves, and ionizing radiation.

The sensation reflects the general properties of stimuli of one kind or another and the special manifestations of these properties in a particular object. For example, the retina of the eye converts electromagnetic waves into physiological processes - this is a manifestation of the general function of receptors that can be excited under the influence of an electromagnetic field. At the same time every minute, the retinal receptors are excited by exposure to waves of a certain length, due to which a sensation of a certain color arises. An example of the qualities of sensations in a narrower sense are different color tones and shades, sounds of different heights and timbres, certain smells, tastes, and the like.

The quality of sensation depends not only on the nature of the stimulus, but also on the neuropsychic state of the person, the existing attitude, the tendency to suggestion, and the like.

The intensity of the action of stimuli on the analyzers is reflected in the intensity of sensations. The quantitative relationship between stimulus and sensation is quite complex. The intensity of sensation is determined not only by the strength (energy) of the acting stimulus, but also by the functional state of the sensory organ, which in turn depends on the state of the organism, the significance of the stimulus, and spatio-temporal conditions of perception.

For a sensation to occur, a certain energy of the stimulus is required. The minimum strength of the stimulus that causes a barely noticeable sensation is called the lowest absolute sensitivity threshold of a given analyzer. For each type of sensation there are absolute thresholds. The sensitivity of the main analyzers to the action of physical and chemical stimuli is very significant (Table 4).

In addition to the lowest, there is an upper absolute threshold of sensitivity. This is the maximum strength of the stimulus, which causes an adequate sensation to it. A further increase in the strength of the stimulus causes a pain reaction.

The transition from stimuli that are not perceived to those that cause sensation occurs abruptly. Sometimes it is enough to slightly change the intensity of the stimulus, so that from one that is not perceived at all, it becomes one that is perceived completely. Also, significant changes in the intensity of stimuli that exceed the upper threshold also do not cause changes in sensation. This pattern in the form of psycho

Table 4. c

metric curve is shown in fig. 12. The dotted line shows the value of the stimulus, which corresponds to 50% of the occurrence and absence of sensations. This value is taken as an absolute threshold value, that is, one that separates between stimuli that are mostly not perceived and stimuli that are mostly perceived.

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Not every difference between acting stimuli is noticed by a person. In order for this difference to become tangible, it must reach a certain value. The minimum difference in the strength of two stimuli, which causes a barely noticeable difference in sensations, is called the threshold of discrimination. For individual sensations, the ratio of the threshold of discrimination to the magnitude of the primary stimulus remains more or less unchanged. This ratio is called the differential sensitivity threshold. In order, for example, to notice a difference in weight, it is necessary to add 1/30 of its part to the initial weight, for auditory sensations the differential threshold is 1/10, and for visual sensations - 1/100 of the initial stimulus value.

How does the increase in the intensity of sensation depend on the increase in the strength of the stimulus? Experimental data have shown that this increase most often does not occur in direct proportion to the increase in the strength of the stimulus.

Rice. 13. in

In the middle of the XIX century. the German physicist and mathematician G. Fechner showed that the intensity of sensations is proportional to the logarithm of the intensity of the stimulus (Fig. 13). In accordance with this law, as the strength of the stimulus increases in the geometric profession, the strength of sensation increases in the arithmetic profession.

Later, thanks to the invention of the electron microscope and the study of the electrical activity of individual neurons with its help, it was found that the generation of impulses in the receptor under the action of an irritant falls under the law, according to Fechner. This indicates that this law describes the electrochemical processes in the nervous system.

V mathematical form Fechner's law is expressed as follows: E \u003d klgR + c, where E is the intensity of sensation, R is the strength of the stimulus, k and c are constants.

At the beginning of the XX century. the American psychologist S. Stevens described the relationship between physical stimulus and sensation in a more differentiated way. He showed that there is more often a power-law relationship between the stimulus and the sensation:

E \u003d aRn, where E is the intensity of sensation, R is the strength of the stimulus, n is the exponent, and is a constant.

For sensations of different quality, the exponent changes. So, for the sensation of light, it is 0.33, and for the sensation of an electric shock, it is 3.5. This means that, for example, doubling the brightness of light changes its apparent brightness by only 25%, while doubling the strength of the electric current will increase the sensation by 10 times. Stevens's data testify to the fact that, being visualized in sensations of one quality, a number of physical quantities seem to "compress", in sensations of a different quality it can "expand" or remain unchanged. The specific nature of the reflection of a physical stimulus in sensations is determined by the role that sensations of different quality play in behavior and activity.

The sensitivity of analyzers is not a constant value. It can vary greatly depending on fluctuations in the intensity of the stimulus. The adaptation of the level of sensitivity to the intensity of the stimulus is called sensory adaptation. The process of adaptation is manifested in a decrease in sensitivity at high intensities of stimuli and an increase at low ones. The phenomenon of adaptation, for example, of the visual analyzer is well known to everyone. When a person from a dark room enters a sunny one, she sees nothing for some time. In this case, the light intensity may exceed the upper absolute threshold and cause pain. But after a few minutes, the sensitivity of the eyes decreases and the surrounding objects become visible again. Entering from a bright room into a dark one, a person also sees nothing at first, and gradually the sensitivity of the visual analyzer increases, and blindness disappears.

The dark-adapted eye is more sensitive to electromagnetic waves that are in the green-blue part of the spectrum than to those in the orange-red part of it. This fact can be illustrated as follows. If you show a person red and blue images on a black background in daylight, she will see them equally clearly. But if a person looks at these images at dusk, it will seem to her that the red part has disappeared and only the blue remains. For this reason, the identification marks indicating the contours of the runway of the airfield are indicated in blue.

Adaptive regulation of mass sensitivity is of great biological importance. Adaptation helps to catch weak stimuli and protects the senses from too large or long-acting stimuli. Changes in the sensitivity of the sense organs can be of a sustainable nature, associated, in particular, with the requirements of professional activity. For example, fabric dyeers can distinguish up to 60 shades of black. To the untrained eye, they appear to be the same. A high degree of perfection is acquired by olfactory or taste sensations from tasters.

The phenomenon of increasing the sensitivity of analyzers as a result of their training is called sensitization. It is proof that a person's sensations are adapted to the conditions of his life and activity and can largely develop under the influence of social practice.

Knowledge of the quantitative relationships between stimuli and the sensations they cause is of great practical importance in connection with the activities of operators involved in processing information about production processes. On the basis of such connections, the optimal zone is determined, in which perception is fragmented! signals addressed to a human operator are carried out with the greatest speed and accuracy. So, when choosing the signal intensity, they are guided by the middle, most extreme part of the analyzer sensitivity scale, the interval between the intensities of several stimuli is determined taking into account the value of the differential threshold of a certain analyzer, and the like.

Spatial characteristics of stimuli are reflected in the spatial properties of sensations. Such a mapping turns out to be in the localization of the sensation where the stimulus is located. For example, in a surgeon who feels a bullet in a wound with a probe, tactile sensations are localized not at the fingertips, but at the border of the probe and the bullet, that is, on the surface of the object, the surgeon examines it. Feeling the light, we relate it to the corresponding source, which occupies a certain place in space. Perceiving sound, we set the direction and distance to the object that generates it: When touched, we know which part of our body the stimulus collided with.

When an organ is stimulated by an inappropriate stimulus (for example, the eye or ear is stimulated with an electric current), it feels like it is localized in the space of the receptor itself. Then the person says: "Sparks were sent from the eyes," "Ringing in the ears." In some types of strabismus, the sensation is not localized where the irritant is located.

Due to this, a person reflects stimuli in those coordinates of space where they are located. Localization of the stimulus in a certain place on the surface of the body is characteristic, for example, for tactile sensations and depends on the localization of foci of excitation in the brain. This is confirmed by observational data on the dotik sensations of patients in the first minutes after the operation of skin grafting from one place to another. In such patients, the effect of the stimulus on the new location of the transferred piece of skin is localized in the old place. In the brain, a focus of excitation is formed in the old section, which for some time retains nerve connections with the previous place.

The main role in the localization of the stimulus in the external space is played by the interaction of sensations of different quality. Such systems of sensations always include kinesthetic sensations from muscle movement. For example, the visual sensation of the distance at which the stimulus is contained is provided by the joint activity of the retina and the motor structures of the eye (the muscles that reduce and separate the eyeballs change the curvature of the lens, etc.). Excitation of visual receptors in the muscles, together with a change in the image on the retina, is a signal of the distance from the observer to the object. Eye movements are also important for the perception of distance, in particular, their erection on an object, perspective reduction of objects, overlapping of distant objects by closer ones.

Displaying the direction of localization of the stimulus in the external space is achieved through the joint activity of paired sensory organs. Thus, the direction of sound source localization depends on the difference in time between the arrival of sound signals from the left and right ear, which, in turn, ensures the sequential processing of these signals in the cerebral cortex.

The ability to analyze the spatial characteristics of stimuli may vary. For example, visual acuity in different people or the same person at different times has great variability depending on the characteristics of professional activity, motivation, state of the body, and the like.

The duration of the action of stimuli on the sense organs is displayed in the temporal characteristics of sensations. Like other properties of sensations, the duration of sensation contains a subjective component. It manifests itself in the fact that the sensation arises somewhat later from the onset of the stimulus and does not disappear immediately after the end of its action. The inertia of sensations is called aftereffect. Due to the aftereffect in the visual analyzer, individual film frames at a certain projection speed are perceived as a continuous image.

So, the nature of sensation is determined by the properties of stimuli (qualitative, quantitative, spatio-temporal), but at the same time it depends on the characteristics of the neuropsychic organization and the state of the subject of reflection. This indicates that feelings, like other mental processes, are not a passive reflection of the influences of the external environment. The image of sensation most fully reflects what can satisfy the needs of the subject, orients him during the organization of activity and behavior. Therefore, correspondence to the image of an object is always relative. Their complete adequacy is unattainable, and unnecessary

So far, we have been talking about the qualitative difference between the types of sensations. However, quantitative research, in other words, their measurement, is equally important. The human senses are remarkably delicate apparatuses. So, the human eye can distinguish a light signal of 1/1000 of a candle at a distance of a kilometer. The energy of this stimulation is so small that it would take 60,000 years to heat 1 cm3 of water by 1° with its help.

However, not every irritation causes a sensation. For a sensation to arise, the stimulus must reach a certain magnitude. The minimum value of the stimulus at which a sensation first occurs is called absolute threshold of sensation. Stimuli that do not reach it lie below the threshold of sensation. So, we do not feel individual dust particles and small particles descending on our skin. Light stimuli below a certain brightness limit do not cause visual sensations.

The value of the absolute threshold characterizes absolute sensitivity sense organs. The weaker the stimuli that cause sensations (ie, the lower the value of the absolute threshold), the higher the ability of the senses to respond to these influences. Thus, absolute sensitivity is numerically equal to a value inversely proportional to the absolute threshold of sensations. If the absolute sensitivity is denoted by the letter E, and the value of the absolute threshold P, then the relationship between the absolute sensitivity and the absolute threshold can be expressed by the formula E=1/P.

Different 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 as many molecules to produce a taste sensation as it does to produce an olfactory sensation. A person has a very high sensitivity of visual and auditory analyzers.

The absolute sensitivity of the analyzer is limited not only by the lower, but also by the upper threshold of sensation. The upper absolute threshold of sensitivity is the maximum strength of the stimulus at which a sensation adequate to the acting stimulus still arises. A further increase in the strength of stimuli acting on our receptors causes a painful sensation (super-loud sound, blinding brightness). The value of absolute thresholds, both lower and upper, varies depending on various conditions: the nature of the activity and age of the person, the functional state of the receptor, the strength and duration of the action of irritation, etc.

From absolute sensitivity it is necessary to distinguish relative, or difference, sensitivity, i.e. sensitivity to a change in stimulus. In the first half of the XIX century. German scientist M. Weber, investigating the sensation of heaviness, came to the conclusion that when comparing objects and observing the differences between them, we perceive not the differences between the objects, but the ratio of the difference to the size of the compared objects. Similarly, we notice changes in the illumination of a room depending on the initial level of illumination. If the initial illumination is 100 lux (lux), then the increase in illumination, which we notice for the first time, should be at least 1 lux. If, however, the illumination is 1000 lux, then the increase should be at least 10 lux. The same applies to auditory, motor, and other sensations.

The minimum difference between two stimuli that causes a barely perceptible difference in sensations is called the discrimination threshold, or difference threshold. As already mentioned, the difference sensitivity is a relative value, not an absolute one. This means that the ratio of the additional stimulus to the main stimulus must be a constant value. At the same time, 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 1/1000, for the auditory - 1/10, for the tactile - 1/30.

Based on the experimental data of Weber, another German scientist, G. Fechner, expressed the dependence of the intensity of sensations on the strength of the stimulus by the formula. Y \u003d K lg j + C, (where S is the intensity of sensation; j is the strength of the stimulus; K and C are constants). According to this provision, which is called the 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 exponentially, the intensity of sensation increases in an 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 phenomenon of adaptation

It would be wrong to think that both the absolute and relative sensitivity of our sense organs remains unchanged and its thresholds are expressed in constant numbers. So, it is known that in the dark our vision becomes sharper, and in strong light its sensitivity decreases. This can be observed when you move from a dark room to light or from a brightly lit room to darkness. As studies have shown, this change is very large, and the sensitivity of the eye during the transition from bright illumination to darkness is aggravated by 200,000 times.

The described changes in sensitivity, depending on environmental conditions and bearing the name adaptation sense organs to the surrounding conditions, exist both in the auditory sphere, and in the sphere of smell, touch, taste. So, in order for vision in a dark room to acquire the necessary sensitivity, about 30 minutes should pass. Only after that a person acquires the ability to navigate well in the dark. The adaptation of the auditory organs is much faster. Human hearing adapts to the surrounding background after 15 seconds. Just as quickly, there is a change in sensitivity in touch (a slight touch on the skin ceases to be perceived after a few seconds).

The phenomena of thermal adaptation (addiction to a change in temperature) are well known. However, these phenomena are clearly expressed only in the middle range, and getting used to extreme cold or extreme heat, as well as to pain stimuli, almost does not take place. The phenomena of adaptation to smells are also known.

1. Adaptation is the complete disappearance of sensation during prolonged action of the stimulus.
2. Adaptation as a dulling of sensation under the influence of a strong stimulus.
   (These two types of adaptation are combined by the term “negative adaptation”, since as a result of it the sensitivity of the analyzers decreases.)
3. An adaptation is also called an increase in sensitivity under the influence of a weak stimulus. This type of adaptation is defined as positive adaptation. In the visual analyzer, the dark adaptation of the eye, when its sensitivity increases under the influence of darkness, is a positive adaptation. A similar form of auditory adaptation is silence adaptation.

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 interaction of sensations.

Studies conducted by S. V. Kravkov showed that no sense organ can work without affecting the functioning of other organs. So, it turned out that sound stimulation (for example, whistling) can sharpen the work of visual sensation, increasing its sensitivity to light stimuli. In the same way, some odors also affect, increasing or decreasing light and auditory sensitivity. The general pattern is that weak stimuli increase and strong ones decrease the sensitivity of the analyzers during their interaction.

The increase in sensitivity as a result of the interaction of analyzers and exercises is called sensitization. A. R. Luria distinguishes two sides of increased sensitivity according to the type of sensitization: the first is of a long-term permanent nature and depends mainly on stable changes occurring in the body; the second is temporary and depends on emergency effects on the state of the subject - physiological and psychological. The age of the subject is clearly related to the change in sensitivity. Studies have shown that the acuteness of the sensitivity of the sense organs increases with age, reaching a maximum by the age of 20-30 in order to gradually decrease in the future.

In another experiment, facts were obtained, 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. These changes were similar to those observed when the tongue was actually irritated with lemon juice. Knowing the patterns, changes in the sensitivity of the sense organs, it is possible, by selecting side stimuli, to sensitize one or another receptor.

The interaction of sensations is also manifested in a phenomenon called synesthesia- the appearance under the influence of irritation of one analyzer of a sensation characteristic of other analyzers. In psychology, the facts of “colored hearing” are well known, which occurs in many people, and especially in many musicians (for example, in Scriabin). So, it is widely known that we regard high sounds as “light”, and low ones as “dark”.

It is characteristic that the phenomenon of synesthesia is not distributed equally among all people. One of these subjects with an exceptional manifestation of synesthesia, the famous mnemonist Sh., was studied in detail by A. R. Luria. This person perceived all voices as colored and often said that the voice of a person addressing him, for example, was “yellow and crumbly.” The tones he heard caused him visual sensations of various shades (from bright yellow to purple). Perceived colors were felt by him as "sonorous" or "deaf", as "salty" or "crunchy". Similar phenomena in more obliterated forms occur quite often in the form of a direct tendency to “color” numbers, days of the week, names of months in different colors.

Improvement of sensations in the course of exercises

We have already mentioned that sensitization of the sense organs is possible through exercise. Two ways usually lead to such sensitization: firstly, the need to compensate for sensory defects (blindness, deafness); secondly, the specific requirements of certain professions. Thus, the 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 were engaged in sculpture, which indicates a highly developed sense of touch. The development of vibrational sensations in the deaf belongs to the same group of phenomena. Some deaf people develop vibrational Sensitivity so strongly that they can even hear music. To do this, they put their hand on the instrument or turn their backs to the orchestra. The deaf-blind O. Skorokhodova, holding her hand to the throat of the speaking interlocutor, could thus recognize him by his voice and understand what he was talking about. Many deaf-blind and blind people have a well-developed olfactory sensitivity. They can recognize people they know by smell.

The phenomena of sensitization of the sense organs are observed in persons who have been engaged in certain special professions for a long time. Thus, it has been established that dyers can distinguish up to 50-60 shades of black; steelmakers distinguish the finest shades of a hot metal stream, indicating the presence of impurities. It is well known what subtleties can be achieved by the taste nuances of tasters, or the ability of musicians to detect differences in tones that are completely unperceivable to the average listener.

All these facts show that under the conditions of the development of complex forms of conscious activity, the sharpness of absolute and difference sensitivity can change significantly, and that the inclusion of one or another feature in a person's conscious activity can change the sharpness of this sensitivity to a significant extent.

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.

Action on nervous system 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 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.

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.

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 singles out 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.

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 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.

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).

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 under pressure, for example, sounds, color sensations can occur in a person, 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 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 laws 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.

In the field of sensations, there are certain patterns. The central regularity of sensations is the existence of sensitivity thresholds. Thresholds of sensations the magnitudes (according to intensity) of stimuli are called, at which sensations arise, can be preserved, and homogeneous sensations differ from each other. There are three such thresholds: the lower or absolute, the upper and the threshold of discrimination.

lower, or absolute threshold called the minimum strength of irritation at which a barely noticeable sensation occurs.

upper threshold called the greatest strength of the stimulus, at which a sensation of a certain type is still preserved.

It has been established that the lower and upper thresholds, for example, of color sensations are oscillations of electromagnetic waves with a frequency of 390 (violet) to 780 (red) millimicrons, and sound sensations are oscillations of sound waves from 20 to 20,000 Hz. Ultra-high intensity stimuli instead of sensations of a certain type cause pain.

Discrimination threshold called the smallest amount by which you need to increase or decrease the intensity of the current irritation, in order for the first time there is a feeling of its change. This value for each type of sensation is definite and relatively constant. For visual sensations, it is - 1/100, for auditory - 1/10, for tactile - 1/30.

Thresholds of sensations are closely related to the sensitivity of the analyzers. However, the relationship between them is inverse: the lower the absolute threshold, or threshold of discrimination, the higher the sensitivity. Sensitivity and thresholds of sensations are not the same in different people. It depends on many factors, including the innate personality traits. A person with a melancholic temperament is more sensitive than a person with a phlegmatic temperament. It also depends on the specifics of the professional activity. For example, sensitivity, and consequently, the corresponding sensations reach the highest degree development in tasters of perfumes, tobaccos, cheeses, wines. Sensitivity also depends on special training in the process of activity.

Fatigue has a negative effect on sensitivity, and therefore on the thresholds of sensations.

The next pattern of sensations is adaptation. The phenomenon of adaptation is in the adaptation of analyzers to functioning in changing environmental conditions. It consists in increasing or decreasing their sensitivity. Such, for example, is visual light adaptation. Under the influence of bright light, the sensitivity of the visual analyzer always steadily decreases. When moving from a dark room to a brightly lit room, it takes at least 3–5 minutes for the eye to “adapt” to the increased (compared to the previous) illumination.

In each system of analyzers - visual, auditory, kinesthetic and others - there are analyzer connections between cortical elements. At the same time, there are also inter-analyzer connections that ensure the interaction of analyzers. It manifests itself in a change in the sensitivity of one analyzer under the influence of some other or others. It has been established that if any piece of music is accompanied by a gamut of colors selected in a certain way, shown on the screen, then the sensitivity to music increases. It is also known that a slight taste sensation of sour increases visual sensitivity. The general regularity of the interaction of sensations is manifested in the fact that irritations of one analyzer that are weak in intensity (hence, sensations that are not very bright) increase the sensitivity of the other; the strong, on the contrary, lower it. This is of great practical importance and allows us to speak about the originality of the human sensory organization. It represents a certain level of development of various types of sensitivity and the originality of the connections between them in each person and therefore is one of the essential characteristics of individuality. The sensory organization is formed throughout a person's life under the influence of the specific conditions of various types of his activity. This underlies the peculiarities of the manifestations and development of the sensitivity of various professions.

Types of sensations. Already the ancient Greeks distinguished five sense organs and their corresponding sensations: visual, auditory, tactile, olfactory and gustatory. Modern science has significantly expanded our understanding of the types of human sensations. Currently, there are about two dozen different analyzer systems that reflect the impact of the external and internal environment on receptors.

visual sensations - it is the sensation of light and color. Everything we see has some color. Only a completely transparent object that we cannot see can be colorless. Colors come in achromatic(white and black and shades of gray in between) and chromatic(various shades of red, yellow, green, blue).

Visual sensations arise as a result of the action of light rays (electromagnetic waves) on the sensitive part of our eye. The light-sensitive organ of the eye is the retina, which contains two types of cells - rods and cones, so named for their external shape. There are a lot of such cells in the retina - about 130 rods and 7 million cones.

In daylight, only cones are active (for rods, such light is too bright). As a result, we see colors, i.e. there is a sensation of chromatic colors - all colors of the spectrum. In low light (at dusk), the cones stop working (there is not enough light for them), and vision is carried out only by the rod apparatus - a person sees mostly gray colors (all transitions from white to black, i.e. achromatic colors).

Color has a different effect on the well-being and performance of a person, on the success of educational activities. Psychologists note that the most acceptable color for painting the walls of classrooms is orange-yellow, which creates a cheerful, upbeat mood, and green, which creates an even, calm mood. Red excites, dark blue depresses, and both tire the eyes. In some cases, people experience violations of normal color perception. The reasons for this may be heredity, diseases and eye injury. The most common is red-green blindness, called color blindness (after the English scientist D. Dalton, who first described this phenomenon). Colorblind people do not distinguish between red and green, do not understand why people designate a color with two words. Such a feature of vision as color blindness should be taken into account when choosing a profession. Color-blind people cannot be drivers, pilots, they cannot be painters and fashion designers, etc. A complete lack of sensitivity to chromatic colors is very rare. The less light, the worse a person sees. Therefore, one should not read in poor lighting, at dusk, so as not to cause excessive eye strain, which can be harmful to vision, contribute to the development of myopia, especially in children and schoolchildren.

auditory sensations occur with the help of the organ of hearing. There are three types of auditory sensations: speech, music and noises. In these types of sensations, the sound analyzer identifies four qualities: sound power(loud-weak), height(high Low), timbre(the peculiarity of a voice or musical instrument), sound duration(playing time) and tempo-rhythmic features successive sounds.

Rumor to speech sounds called phonemic. It is formed depending on the speech environment in which the child is brought up. Mastering a foreign language involves the development of a new system of phonemic hearing. The developed phonemic hearing of the child significantly affects the accuracy of written speech, especially in elementary school. Ear for music the child is brought up and formed, as well as speech hearing. Here, the early introduction of the child to the musical culture of mankind is of great importance.

Noises can cause a certain emotional mood in a person (the sound of rain, the rustle of leaves, the howling of the wind), sometimes they serve as a signal of approaching danger (the hissing of a snake, the menacing barking of a dog, the rumble of a moving train) or joy (the clatter of a child’s feet, the steps of an approaching loved one, the thunder of fireworks) . In school practice, one often encounters the negative effect of noise: it tires the human nervous system.

vibration sensations reflect vibrations of an elastic medium. A person receives such sensations, for example, when touching the lid of a sounding piano with his hand. Vibratory sensations usually do not play an important role for a person and are very poorly developed. However, they reach very high level development in many deaf people, with which they partially replace the missing hearing.

Olfactory sensations. The ability to smell is called the sense of smell. The organs of smell are special sensitive cells that are located deep in the nasal cavity. Separate particles of various substances enter the nose along with the air that we inhale. This is how we get olfactory sensations. In modern man, olfactory sensations play a relatively minor role. But deaf-deaf people use their sense of smell, as sighted people use sight with hearing: they identify familiar places by smell, recognize familiar people, receive danger signals, etc. A person’s olfactory sensitivity is closely related to taste, helps to recognize the quality of food. Olfactory sensations warn a person about an air environment dangerous for the body (smell of gas, burning). The incense of objects has a great influence on the emotional state of a person. The existence of the perfume industry is entirely due to the aesthetic need of people for pleasant smells.

Taste sensations arise with the help of the organs of taste - taste buds located on the surface of the tongue, pharynx and palate. There are four types of basic taste sensations: sweet, bitter, sour, salty. The variety of taste depends on the nature of the combinations of these sensations: bitter-salty, sour-sweet, etc. A small number of qualities of taste sensations does not mean, however, that taste sensations are limited. Within the limits of salty, sour, sweet, bitter, a whole range of shades arise, each of which gives a new originality to taste sensations. Taste sensations of a person are highly dependent on the feeling of hunger, tasteless food seems tastier in a state of hunger. Taste sensations are very dependent on olfactory ones. With a severe cold, any, even the most beloved, dish seems tasteless. The tip of the tongue feels sweet best. The edges of the tongue are sensitive to sour, and its base to bitter.

Skin sensations - tactile (sensation of touch) and temperature(feelings of warmth or cold). On the surface of the skin there are different types of nerve endings, each of which gives a feeling of either touch, or cold, or heat. The sensitivity of different parts of the skin to each type of irritation is different. Touch is most felt on the tip of the tongue and on the fingertips, the back is less sensitive to touch. The most sensitive to the effects of heat and cold are the skin of those parts of the body that are usually covered by clothing, the lower back, abdomen, and chest. Temperature sensations have a very pronounced emotional tone. So, average temperatures are accompanied by a positive feeling, the nature of the emotional coloring for heat and cold is different: cold is experienced as an invigorating feeling, warmth as a relaxing one. The temperature of high indicators, both in the direction of cold and heat, causes negative emotional experiences.

Visual, auditory, vibrational, gustatory, olfactory and skin sensations reflect the influence of the external world, therefore the organs of all these sensations are located on the surface of the body or near it. Without these sensations, we could not know anything about the world around us. Another group of sensations tells us about the changes, condition and movement in our own body. These feelings include motor, organic, balance sensations, tactile, pain. Without these sensations, we would not know anything about ourselves.

Motor (or kinesthetic) sensations - These are sensations of movement and position of body parts. Thanks to the activity of the motor analyzer, a person gets the opportunity to coordinate and control his movements. Receptors for motor sensations are located in the muscles and tendons, as well as in the fingers, tongue and lips, since it is these organs that carry out precise and subtle working and speech movements.

The development of kinesthetic sensations is one of the important tasks of training. Labor, physical education, drawing, drawing, reading lessons should be planned taking into account the possibilities and prospects for the development of the motor analyzer. For mastering movements, their aesthetic expressive side is of great importance. Children master movements and, consequently, their bodies in dancing, rhythmic gymnastics and other sports that develop the beauty and ease of movement. Without the development of movements and their mastery, educational and labor activity is impossible. The formation of speech movement, the correct motor image of the word increases the culture of students, improves the literacy of written speech. Teaching a foreign language requires the development of such motor speech movements that are not typical for the Russian language.

organic sensations tell us about the work of our body, our internal organs - the esophagus, stomach, intestines and many others, in the walls of which the corresponding receptors are located. While we are full and healthy, we do not notice any organic sensations at all. They appear only when something is disturbed in the work of the body. For example, if a person has eaten something that is not very fresh, the work of his stomach will be disrupted, and he will immediately feel it: pain in the abdomen will appear.

Hunger, thirst, nausea, pain, sexual sensations, sensations related to the activity of the heart, breathing, etc. These are all organic sensations. Without them, we would not be able to recognize any disease in time and help our body cope with it.

“There is no doubt,” said I.P. Pavlov, “that not only the analysis of the external world is important for the organism, it also needs signaling upwards and analysis of what is happening in itself.”

tactile sensations- a combination of skin and motor sensations when touching objects that is, when touched by a moving hand. A small child begins to explore the world with touch, feeling objects. This is one of the important sources of obtaining information about the objects surrounding it.

In people deprived of sight, touch is one of the most important means of orientation and cognition. As a result of practice, it reaches great perfection. Such people can thread a needle, do modeling, simple design, even sewing, cooking. The combination of skin and motor sensations arising from the palpation of objects, i.e. when touched by a moving hand, is called touch. The organ of touch is the hand.

Feelings of balance reflect the position occupied by our body in space. When we first sit on a two-wheeled bicycle, stand on skates, roller skates, water skis, the most difficult thing is to keep our balance and not fall. The sense of balance is given to us by an organ located in the inner ear. It looks like a snail shell and is called labyrinth. When the position of the body changes, a special fluid (lymph) oscillates in the labyrinth of the inner ear, called vestibular apparatus. The organs of balance are closely connected with other internal organs. With a strong overexcitation of the balance organs, nausea, vomiting (the so-called sea or air sickness) are observed. With regular training, the stability of the balance organs increases significantly. The vestibular apparatus gives signals about the movement and position of the head. If the labyrinth is damaged, a person can neither stand, nor sit, nor walk, he will fall all the time.

Pain have a protective value: they signal to a person about the trouble that has arisen in his body. If there was no sensation of pain, a person would not even feel serious injuries. Complete insensitivity to pain is a rare anomaly, and it brings a person serious trouble. Pain sensations are of a different nature. First, there are “pain points” (special receptors) located on the surface of the skin and in the internal organs and muscles. Mechanical damage to the skin, muscles, diseases of internal organs give a feeling of pain. Secondly, sensations of pain arise under the action of a superstrong stimulus on any analyzer. Blinding light, deafening sound, intense cold or heat radiation, a very pungent smell also cause pain.

There are various classifications of sensations. The classification according to the modality of sensations (the specificity of the sense organs) is widespread - this is the division of sensations into visual, auditory, vestibular, tactile, olfactory, gustatory, motor, visceral. There are intermodal sensations - synesthesia. Ch. Sherrington's classification is well-known, distinguishing the following types of sensations:

exteroceptive sensations (arising from the action of external stimuli on receptors located on the surface of the body, from the outside);

proprioceptive (kinesthetic) sensations (reflecting the movement and relative position of body parts with the help of receptors located in muscles, tendons, articular bags);

interoceptive (organic) sensations - arising from the reflection of metabolic processes in the body with the help of specialized receptors.

Despite the variety of sensations that arise during the operation of the sense organs, one can find a number of fundamentally common features in their structure and functioning. In general, it can be said that analyzers are a set of interacting formations of the peripheral and central nervous systems that receive and analyze information about phenomena occurring both inside and outside the body.

The classification of sensations is made on several grounds. By the presence or absence of direct contact of the receptor with the stimulus that causes sensation, distant and contact reception are distinguished. Vision, hearing, smell are related to distant reception. These types of sensations provide orientation in the nearest environment. Taste, pain, tactile sensations - contact.

By location on the surface of the body, in muscles and tendons or inside the body, respectively, exteroception (visual, auditory, tactile, etc.), proprioception (sensations from muscles, tendons) and interoception (sensation of hunger, thirst) are distinguished.

According to the time of occurrence during the evolution of the animal world, ancient and new sensitivity are distinguished. So, distant reception can be considered new in comparison with contact, but in the structure of the contact analyzers themselves, more ancient and newer functions are distinguished. Pain sensitivity is more ancient than tactile.

Consider the basic patterns of sensations. These include thresholds, adaptation, sensitization, interaction, contrast, and synesthesia.

Thresholds of sensitivity. Sensations arise when exposed to a stimulus of a certain intensity. The psychological characteristic of the "dependence" 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. 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 zone of sensitivity to stimuli. For example, of all electromagnetic vibrations, the eye is capable of reflecting wavelengths from 390 (violet) to 780 (red) millimicrons;

There is an inverse relationship between sensitivity (threshold) and the strength of the stimulus: the greater the force needed to cause a sensation, the lower the sensitivity of a person. Sensitivity thresholds are individual for each person.

An experimental study of sensitivity to discrimination made it possible to formulate the following law: 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.

Adaptation- 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. The first minute a person enters the river, the water seems cold to him. Then the feeling of cold disappears, the water seems warm enough. This is observed in all types of sensitivity, except for pain. Staying in absolute darkness increases the sensitivity to light in 40 minutes by about 200,000 times. The interaction of sensations. (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 analyzers, largely 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 in another. An increase in sensitivity as a result of the interaction of analyzers, as well as systematic exercises, is called sensitization.

Feeling contrast. Contrast is a change in the intensity and quality of sensations under the influence of a previous or accompanying stimulus. With the simultaneous action of two stimuli, a simultaneous contrast occurs. Such a contrast is well traced in visual sensations. The same figure appears lighter on a black background, darker on a white one. A green object on a red background seems more saturated.

The phenomenon of successive contrast is widely known. After a cold, a weak thermal stimulus seems hot. The physiological mechanism for the emergence of a sequential image is associated with the phenomena of the aftereffect of the stimulus on the nervous system. Termination of the action of the stimulus does not cause an instant cessation of the process of irritation in the receptor and excitation in the cortical parts of the analyzer.

The phenomenon of synesthesia. Synesthesia is the excitation of sensations of one modality of sensations of another modality. 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. (So, the sound becomes colored, etc.)