PSYCHOLOGY OF FEELINGS.

Feeling- this is the simplest mental process, consisting in the reflection of individual properties of objects and phenomena of the material world, as well as the internal states of the body with the direct impact of material stimuli on the corresponding receptors.

Reflection- a universal property of matter, which consists in the ability of objects to reproduce with varying degrees of adequacy the features, structural characteristics and relationships of other objects.

Receptor- a specialized organic device located on the surface of the body or inside it and designed to perceive stimuli of various nature: physical, chemical, mechanical, etc., and convert them into nerve electrical impulses.

Sensation constitutes that initial region of the sphere of mental cognitive processes, which is located at the boundary that sharply separates mental and prepsychic phenomena. Mental cognitive processes- dynamically changing mental phenomena, in their totality providing knowledge as a process and as a result.

The term "sensation" has traditionally been used by psychologists to designate an elementary perceptual image and the mechanism of its construction. In psychology, they speak of sensation when a person is aware that some signal has arrived at his sense organs. Any change in the environment that is accessible to sight, hearing and other modalities is psychologically presented as a sensation. Sensation is the primary conscious representation of a formless and non-objective fragment of reality of a certain modality: color, light, sound, indefinite touch. In the realm of taste and smell, the difference between sensation and perception is much smaller, and sometimes there is actually none. If we cannot determine the product (sugar, honey) by taste, then we are talking only about sensations. If odors are not identified with their objective sources, then they are presented only as sensations. Pain signals are almost always presented as sensations, since only a person with a very rich imagination can "build" an image of pain.

The role of sensations in human life is extremely great, since they are the source of our knowledge about the world and about ourselves. We learn about the richness of the world around us, about sounds and colors, smells and temperature, sizes and much more through the senses. With the help of the sense organs, the human body in the form of sensations receives a variety of information about the state of the external and internal environment.

internal environment.

The sense organs receive, select, accumulate information and transmit it to the brain for processing. As a result, there is an adequate reflection of the surrounding world and the state of the organism itself. On this basis, nerve impulses are formed that come to the executive organs responsible for regulating body temperature, the functioning of the digestive organs, organs of movement, endocrine glands, for tuning the sense organs themselves, etc.

The sense organs are the only channels through which the external world "penetrates" the human consciousness. The sense organs enable a person to navigate in the world around him. If a person lost all his senses, he would not know what was happening around, could not communicate with people around him, get food, and avoid danger.

PHYSIOLOGICAL BASES OF SENSATIONS. THE CONCEPT OF THE ANALYZER

All living beings that have a nervous system have the ability to sense. As for conscious sensations (about the source and quality of which an account is given), only a person has them. In the evolution of living beings, sensations arose on the basis of primary irritability which is a property of living matter to respond to biologically significant environmental influences by changing its internal state and external behavior.

A person's sensations in their quality and diversity reflect the diversity of the properties of the environment that are significant for him. The sense organs, or human analyzers, from the moment of birth are adapted for the perception and processing of various types of energy in the form of stimuli-stimuli (physical, mechanical, chemical, and others).

Sensation arises as a reaction of the nervous system to a particular stimulus and, like any mental phenomenon, has a reflex character. Reaction- the body's response to a specific stimulus.

The physiological basis of sensation is a nervous process that occurs when a stimulus acts on an analyzer adequate to it. Analyzer- a concept (according to Pavlov), denoting a set of afferent and efferent nervous structures involved in the perception, processing and response to stimuli.

efferent is a process directed from the inside out, from the central nervous system to the periphery of the body.

Afferent- a concept that characterizes the course of the process of nervous excitation through the nervous system in the direction from the periphery of the body to the brain.

The analyzer consists of three parts:

1. Peripheral section (or receptor), which is a special transformer of external energy into the nervous process. There are two types of receptors: contact receptors- receptors that transmit irritation by direct contact with objects that act on them, and distant receptors - receptors that respond to stimuli emanating from a distant object.

Afferent (centripetal) and efferent (centrifugal) nerves, conducting paths connecting the peripheral section of the analyzer with the central one.

3. Subcortical and cortical sections (brain end) of the analyzer, where the processing of nerve impulses coming from the peripheral sections takes place.

In the cortical section of each analyzer is the core of the analyzer, i.e. the central part, where the main mass of receptor cells is concentrated, and the periphery, consisting of scattered cellular elements, which are located in one quantity or another in various areas of the cortex.

The nuclear part of the analyzer consists of a large mass of cells that are located in the area of ​​the cerebral cortex where the centripetal nerves from the receptor enter.

Scattered (peripheral) elements

of this analyzer are included in the areas adjacent to the cores of other analyzers. This ensures participation in a separate act of sensation of a large part of the entire cerebral cortex. The analyzer core performs the function of fine analysis and synthesis. Scattered elements are related to the coarse analysis function. Certain cells of the peripheral parts of the analyzer correspond to certain parts of the cortical cells.

For the sensation to arise, the work of the entire analyzer as a whole is necessary. The impact of the stimulus on the receptor causes the appearance of irritation. The beginning of this irritation lies in the transformation of external energy into a nervous process, which is produced by the receptor. From the receptor, this process along the centripetal nerve reaches the nuclear part of the analyzer located in the spinal cord or brain. When the excitation reaches the cortical cells of the analyzer, we feel the qualities of the stimuli, and after this, the body's response to the irritation occurs.

If the signal is due to an irritant that threatens to cause damage to the body, or is addressed to the autonomic nervous system, then it is very likely that it will immediately cause a reflex emanating from the spinal cord or another lower center, and this will happen before we are aware of this effect (reflex - automatic response " reaction of the body to the action of some internal or external stimulus).

If the signal continues its way through the spinal cord, then it goes along two different paths: one leads to the cerebral cortex through the thalamus, and the other, more diffuse, passes through reticular formation filter, which keeps the cortex awake and decides whether the signal transmitted directly is important enough for the cortex to "engage" in it. If the signal is considered important, a complex process will begin that will lead to a sensation in the truest sense of the word. This process involves changing the activity of many thousands of cortical neurons, which will have to structure and organize the sensory signal in order to give

him sense. (Sensory - associated with the work of the senses).

First of all, the attention of the cerebral cortex to the stimulus will now entail a series of movements of the eyes, head or torso. This will allow you to more deeply and in detail get acquainted with the information coming from the sensory organ - the primary source of this signal, and also, possibly, connect other senses. As new information becomes available, it will be associated with traces of similar events stored in memory.

Between the receptor and the brain there is not only a direct (centripetal), but also a reverse (centrifugal) connection .

Thus, sensation is not only the result of a centripetal process; it is based on a complete and complex reflex act, which in its formation and course obeys the general laws of reflex activity. In this case, the analyzer constitutes the initial and most important part of the entire path of nervous processes, or the reflex arc.

CLASSIFICATION OF SENSATIONS

The classification of sensations proceeds from the properties of the stimuli that cause them, and the receptors that are affected by these stimuli. So, by the nature of the reflection and the location of the sensation receptors are divided into three groups:

1 Interoceptive sensations having receptors located in the internal organs and tissues of the body and reflecting the state of the internal organs. The signals coming from the internal organs are in most cases not noticeable, except for painful symptoms. The information of interoreceptors informs the brain about the states of the internal environment of the body, such as the presence of biologically useful or harmful substances in it, body temperature, the chemical composition of the fluids present in it, pressure, and much more.

2. proprioceptive sensations, whose receptors are located in ligaments and muscles - they give information about the movement and position of our body. The subclass of proprioception that is the sensitivity to movement is called kinesthesia, and the corresponding receptors are called kinesthetic or kinesthetic.

3. Exteroceptive sensations reflecting the properties of objects and phenomena of the external environment and having receptors on the surface of the body. Exteroceptors can be divided into two groups: contact and remote. Contact receptors transmit irritation upon direct contact with objects that act on them; these are the tactile, taste buds. Distant receptors respond to stimuli emanating from a distant object; they are visual, auditory, olfactory receptors.

From the point of view of the data of modern science, the accepted division of sensations into external (exteroceptors) and internal (interoceptors) is not enough. Some types of sensations can be considered external-internal. These include, for example, temperature, pain, taste, vibration, muscular-articular and static-dynamic.

By belonging to the sense organs of sensation divided into taste, visual, olfactory, tactile, auditory.

Touch(or skin sensitivity) - the most widely represented type of sensitivity. The composition of touch, along with tactile sensations (sensations of touch: pressure, pain), includes an independent type of sensations - temperature sensations (heat and cold). They are a function of a special temperature analyzer. Temperature sensations are not only part of the sense of touch, but also have an independent, more general significance for the entire process of thermoregulation and heat exchange between the body and the environment.

Unlike other exteroreceptors localized in narrowly limited areas of the surface of the predominantly head end of the body, the receptors of the skin-mechanical analyzer, like other skin receptors, are located over the entire surface of the body, in areas bordering on the external environment. However, the specialization of skin receptors has not yet been accurately established. It is not clear whether there are receptors exclusively designed for the perception of one impact, generating differentiated sensations of pressure, pain, cold or heat, or the quality of the resulting sensation may vary depending on the specifics of the property affecting it.

The function of tactile receptors, like all others, is to receive the process of irritation and transform its energy into the corresponding nervous process. Irritation of nerve receptors is the process of mechanical contact of the stimulus with the area of ​​the skin surface in which this receptor is located. With a significant intensity of the action of the stimulus, contact turns into pressure. With the relative movement of the stimulus and the area of ​​the skin surface, contact and pressure are carried out under changing conditions of mechanical friction. Here irritation is carried out not by stationary, but by fluid, changing contact.

Research shows that sensations of touch or pressure only occur if a mechanical stimulus causes deformation of the skin surface. When pressure is applied to a very small area of ​​skin, the greatest deformation occurs precisely at the site of direct application of the stimulus. If pressure is exerted on a sufficiently large surface, then it is distributed unevenly - its least intensity is felt in the depressed parts of the surface, and the greatest is along the edges of the depressed area. G. Meisner's experiment shows that when a hand is immersed in water or mercury, the temperature of which is approximately equal to the temperature of the hand, pressure is felt only at the boundary of the part of the surface immersed in the liquid, i.e. precisely where the curvature of this surface and its deformation are most significant.

The intensity of the sensation of pressure depends on the speed at which the skin surface is deformed: the stronger the sensation, the faster the deformation occurs.

Smell- a type of sensitivity that gives rise to specific sensations of smell. This is one of the most ancient and vital sensations. Anatomically, the olfactory organ is located in most living beings in the most advantageous place - in front, in a prominent part of the body. The path from the olfactory receptors to those brain structures where the impulses received from them are received and processed is the shortest. Nerve fibers extending from the olfactory receptors directly enter the brain without intermediate switching.

The part of the brain called the olfactory is also the most ancient; the lower rung of the evolutionary ladder a living being is, the more space it occupies in the mass of the brain. In many ways, the sense of smell is the most mysterious. Many have noticed that although the smell helps to recall an event, it is almost impossible to remember the smell itself, just as we mentally restore an image or sound. Smell serves memory so well because the mechanism of smell is intimately connected to the part of the brain that controls memory and emotion, although we don't know exactly how that connection works.

Taste sensations have four main modalities: sweet, salty, sour and bitter. All other taste sensations are various combinations of these four basic sensations. Modality is a qualitative characteristic of sensations that arise under the influence of certain stimuli and reflect the properties of objective reality in a specifically encoded form.

Smell and taste are called chemical senses because their receptors respond to molecular signals. When molecules dissolved in a liquid, such as saliva, excite the taste buds on the tongue, we experience taste. When molecules in the air hit the olfactory receptors in the nose, we smell. Although in man and in most animals taste and smell, having developed from a common chemical sense, have become independent, they remain interconnected. In some cases, for example, when inhaling the smell of chloroform, we think that we smell it, but in fact it is a taste.

On the other hand, what we call the taste of a substance is often its smell. If you close your eyes and pinch your nose, you may not be able to tell a potato from an apple or wine from coffee. If you pinch your nose, you will lose 80 percent of the ability to smell the flavors of most foods. That is why people who do not breathe through the nose (runny nose) do not feel the taste of food well.

Although our olfactory apparatus is remarkably sensitive, humans and other primates sense smells much worse than most other animal species. Some scientists suggest that our distant ancestors lost their sense of smell when they climbed trees. Since visual acuity was more important at that time, the balance between different types of feelings was disturbed. During this process, the shape of the nose changed and the size of the olfactory organ decreased. It became less subtle and did not recover even when the ancestors of man descended from the trees.

However, in many animal species, the sense of smell is still one of the main means of communication. Possibly and for the person smells are more important, than it was supposed so far.

Substances have an odor only if they are volatile, that is, they easily pass from a solid or liquid to a gaseous state. However, the strength of the smell is not determined by volatility alone: ​​some less volatile substances, such as those contained in pepper, smell stronger than more volatile ones, such as alcohol. Salt and sugar are almost odorless, since their molecules are so tightly linked to each other by electrostatic forces that they hardly evaporate.

Although we are very good at detecting odors, we are not good at recognizing them in the absence of visual cues. This is the property of our perception mechanism.

Smell and the sense of smell are much more complex phenomena and affect our lives to a greater extent than we thought until recently, and it seems that scientists dealing with this range of problems are on the verge of many amazing discoveries.

visual sensations- a kind of sensations caused by exposure to the visual system of electromagnetic waves in the range from 380 to 780 billionths of a meter. This range occupies only a part of the electromagnetic spectrum. Waves that are within this range and differ in length give rise to sensations of different colors. The apparatus of vision is the eye. Light waves reflected by an object are refracted, passing through the lens of the eye, and formed on the retina in the form of an image - an image. Visual sensations are divided into:

Achromatic, reflecting the transition from darkness to light (from black to white) through a mass of shades of gray;

Chromatic, reflecting the color gamut with numerous shades and color transitions - red, orange, yellow, green, blue, indigo, violet.

The emotional impact of color is associated with its physiological, psychological and social meaning.

auditory sensations are the result of mechanical action on the receptors of sound waves with an oscillation frequency of 16 to 20,000 Hz. Hertz is a physical unit by which the frequency of air oscillations per second is estimated, numerically equal to one oscillation per second. Fluctuations in air pressure, following with a certain frequency and characterized by the periodic appearance of areas of high and low pressure, are perceived by us as sounds of a certain height and loudness. The higher the frequency of air pressure fluctuations, the higher the sound we perceive.

There are 3 types of sound sensations:

Noises and other sounds (arising in nature and in the artificial environment);

Speech, (associated with communication and mass media);

Musical (artificially created by man for artificial experiences).

In these types of sensations, the auditory analyzer distinguishes four qualities of sound:

Strength (loudness, measured in decibels);

Height (high and low oscillation frequency per unit time);

Timbre (originality of sound coloring - speech and music);

Duration (sounding time plus tempo-rhythmic pattern).

MAIN PROPERTIES OF SENSATIONS.

Different types of sensations are characterized not only by specificity, but also by properties common to them. These properties include:

Spatial localization- displaying the location of the stimulus in space. For example, contact sensations (tactile, pain, taste) are correlated with the part of the body that is affected by the stimulus. In this case, the localization of pain sensations is more "spilled" and less accurate than tactile ones. Spatial Threshold- the minimum size of a barely perceptible stimulus, as well as the minimum distance between stimuli, when this distance is still felt.

Feeling intensity- a quantitative characteristic that reflects the subjective magnitude of sensation and is determined by the strength of the stimulus and the functional state of the analyzer.

Emotional tone of sensations- the quality of sensation, manifested in its ability to cause certain positive or negative emotions.

Feeling speed(or time threshold) - the minimum time required to reflect external influences.

Differentiation, subtlety of sensations- an indicator of distinctive sensitivity, the ability to distinguish between two or more stimuli.

Adequacy, accuracy of feeling- the correspondence of the sensation to the characteristics of the stimulus.

Quality (feelings of a given modality)- this is the main feature of this sensation, which distinguishes it from other types of sensation and varies within a given type of sensation (a given modality). 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.

Sensitivity Stability- the duration of maintaining the required intensity of sensations.

Duration of sensation- 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. 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 is manifested in the 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 between positive and negative sequential 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 a certain period of 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.

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, that is, they can display these phenomena with greater or lesser accuracy. In order for a sensation to arise as a result of the action of a stimulus on the sense organs, it is necessary that the stimulus causing it reach a certain value. This value is called the lower absolute threshold of sensitivity. Lower absolute threshold of sensitivity- the minimum strength of the stimulus, causing a barely noticeable sensation. This is the threshold of conscious recognition of the stimulus.

However, there is a "lower" threshold - physiological. This threshold reflects the limit of sensitivity of each receptor, beyond which excitation can no longer occur. This threshold is genetically determined and can only change with age or other physiological factors. The threshold of perception (conscious recognition) is much less stable and depends, among other things, on the level of wakefulness of the brain, on the attention of the brain to a signal that has overcome the physiological threshold. Between these two thresholds there is a zone of sensitivity in which the excitation of the receptors entails the transmission of a message, but it does not reach consciousness. Despite the fact that the environment at any moment sends us thousands of various signals, we can only catch a small part of them.

At the same time, being unconscious, being below the lower threshold of sensitivity, these stimuli (subsensory) are capable of influencing conscious sensations. With the help of such sensitivity, for example, our mood can change, in some cases they affect the desires and interest of a person in certain objects of reality.

At present, there is a hypothesis that in the zone * below the level of consciousness - in the subthreshold zone - the signals perceived by the senses may be processed by the lower centers of our brain. If so, then every second there must be hundreds of signals that pass by our consciousness, but are nevertheless registered at lower levels.

This hypothesis allows us to find an explanation for many controversial phenomena. Especially when it comes to perceptual defense, subthreshold and extrasensory perception, awareness of inner reality in conditions such as sensory isolation or in a state of meditation.

The fact that stimuli of lesser strength (subthreshold) do not cause sensations is biologically expedient. The cortex at every single moment of an infinite number of impulses perceives only the vital ones, delaying all the rest, including impulses from the internal organs. 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 "guards" 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.

A brief digression into the development of the concept of sensations

Feel- “the law of the specific energy of the sense organ”, that is, sensation does not depend on the nature of the stimulus, but on the organ or nerve in which the process of irritation occurs. The eye sees, the ear hears. The eye cannot see, but the ear cannot see. 1827

The objective world is fundamentally unknowable. The result of the sensation process is a partial, that is, a partial image of the world. All that we perceive is the process of specific impact on the senses. "Mental processes" Vecker L.M.

Power dependence of the change in sensations with a change in the intensity of stimuli (Stevens law)

The lower and upper absolute thresholds of sensations (absolute sensitivity) and the thresholds of discrimination (relative sensitivity) characterize the limits of human sensitivity. In addition to this, there are operational thresholds of sensations— the magnitude of the difference between the signals, at which the accuracy and speed of their discrimination reach a maximum. (This value is an order of magnitude greater than the difference threshold value.)

2. Adaptation. The sensitivity of the analyzer is not stable, it changes depending on various conditions.

So, entering a poorly lit room, at first we do not distinguish objects, but gradually the sensitivity of the analyzer increases; being in a room with any smells, after a while we stop noticing these smells (the sensitivity of the analyzer decreases); when we get from a poorly lit space into a brightly lit one, the sensitivity of the visual analyzer gradually decreases.

A change in the sensitivity of the analyzer as a result of its adaptation to the strength and duration of the acting stimulus is called adaptation(from lat. adaptatio- fixture).

Different analyzers have different speed and range of adaptation. To some stimuli, adaptation occurs quickly, to others - more slowly. Olfactory and tactile adapt faster (from the Greek. taktilos- touch) analyzers. Auditory, gustatory and visual analyzers adapt more slowly.

Full adaptation to the smell of iodine occurs in a minute. After three seconds, the sensation of pressure reflects only 1/5 of the strength of the stimulus. (Searching for glasses shifted to the forehead is one example of tactile adaptation.) Full dark adaptation of the visual analyzer takes 45 minutes. However, visual sensitivity has the largest range of adaptation - it changes 200,000 times.

The phenomenon of adaptation has expedient biological significance. It contributes to the reflection of weak stimuli and protects the analyzers from excessive exposure to strong ones. Adaptation, like getting used to constant conditions, provides an increased orientation to all new influences. Sensitivity depends not only on the strength of the impact of external stimuli, but also on internal states.

3. Sensitization. Increasing the sensitivity of analyzers under the influence of internal (mental) factors is called sensitization(from lat. sensibilis- sensitive). It can be caused by: 1) the interaction of sensations (for example, weak taste sensations increase visual sensitivity. This is due to the interconnection of analyzers, their systemic work); 2) physiological factors (the state of the body, the introduction of certain substances into the body; for example, vitamin A is essential to increase visual sensitivity); 3) the expectation of a particular impact, its significance, a special setting to distinguish between stimuli; 4) exercise, experience (thus, tasters, by 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, this deficiency is compensated (compensated) by increasing the sensitivity of other organs (for example, increased auditory and olfactory sensitivity in the blind). This so-called compensatory sensitization.

Strong excitation of some analyzers always lowers the sensitivity of others. This phenomenon is called desensitization. So, the increased noise level in "loud shops" lowers visual sensitivity; visual desensitization occurs.

Rice. 4. . The inner squares produce sensations of varying intensities of gray. In reality they are the same. Sensitivity to the properties of phenomena depends on adjacent and successive contrast effects.

4. . One of the manifestations of the interaction of sensations is their contrast(from lat. contraste- a sharp contrast) - an increase in sensitivity to one property under the influence of other, opposite, properties of reality. So, the same gray figure appears dark on a white background, and white on a black one (Fig. 4).

5. Synesthesia. An associative (phantom) non-modal sensation that accompanies a real one (the sight of a lemon causes a sensation of sourness) is called synesthesia(from Greek. synaisthesis shared feeling).

Rice. 5.

Features of certain types of sensations.

visual sensations. The colors perceived by a person are divided into chromatic (from the Greek. chroma- color) and achromatic - colorless (black, white and intermediate shades of gray).

For the appearance of visual sensations, the impact of electromagnetic waves on the visual receptor, the retina of the eye (an accumulation of photosensitive nerve cells located at the bottom of the eyeball), is necessary. In the central part of the retina, nerve cells predominate - cones, which provide a sense of color. At the edges of the retina, rods sensitive to brightness changes predominate (Fig. 5, 6).

Rice. 6. . To light-sensitive receptors - rods (reacting to changes in brightness) and cones (reacting to different wavelengths of electromagnetic waves, i.e. to chromatic (color) influences), light penetrates, bypassing ganglion and bipolar cells, which carry out the primary elementary analysis of nerve impulses going already from the retina. For the occurrence of visual excitation, it is necessary that the electromagnetic energy that enters the retina be absorbed by its visual pigment: rod pigment - rhodopsin and cone pigment - iodopsin. Photochemical transformations in these pigments give rise to the visual process. At all levels of the visual system, this process: manifests itself in the form of electrical potentials, which are recorded by special devices -, electroretinograph,.

Light (electromagnetic) beams of different lengths cause different color sensations. Color - a mental phenomenon - human sensations caused by different frequencies of electromagnetic radiation (Fig. 7). The eye is sensitive to the part of the electromagnetic spectrum from 380 to 780 nm (Fig. 8). The wavelength of 680 nm gives the impression of red; 580 - yellow; 520 - green; 430 - blue; 390 - purple flowers.

electromagnetic radiation.

Rice. 7. electromagnetic spectrum and its visible part (NM - nanometer - one billionth of a meter)

Rice. 8. .

Rice. 9. . Opposite colors are called complementary colors - when mixed, they form white. Any color can be obtained by mixing two border colors with it. For example: red - a mixture of orange and purple).

The mixture of all perceived electromagnetic waves gives the sensation of white.

There is a three-component theory of color vision, according to which the whole variety of color sensations arises as a result of the work of only three color-perceived receptors - red, green and blue. Cones are divided into groups of these three colors. Depending on the degree of excitation of these color receptors, various color sensations arise. If all three receptors are excited to the same extent, then there is a sensation of white color.

Rice. 10. .

To different parts of the electromagnetic spectrum, our eye has unequal sensitivity. It is most sensitive to light rays with a wavelength of 555 - 565 nm (light green color tone). The sensitivity of the visual analyzer at dusk moves towards shorter wavelengths - 500 nm (blue color). These rays begin to appear lighter (Purkinje phenomenon). The rod apparatus is more sensitive to ultraviolet color.

In conditions of sufficiently bright lighting, the cones turn on, the rod apparatus turns off. In low light, only sticks are included in the work. Therefore, in twilight lighting, we do not distinguish the chromatic color, the color of objects.

Rice. eleven. . Information about events in the right half of the visual field enters the left occipital lobe from the left side of each retina; information about the right half of the visual field is sent to the left occipital lobe from the right parts of both retinas. The redistribution of information from each eye occurs as a result of the crossing of part of the optic nerve fibers in the chiasm.

Visual excitations are characterized by some inertia. This is the reason for the preservation of a trace of light irritation after the cessation of exposure to the stimulus. (Therefore, we do not notice gaps between frames of the film, which turn out to be filled with traces from the previous frame.)

People with weakened cone apparatus have difficulty distinguishing chromatic colors. (This drawback, described by the English physicist D. Dalton, is called color blind). The weakening of the rod apparatus makes it difficult to see objects in twilight lighting (this drawback is called "night blindness".)

For the visual analyzer, the difference in brightness is essential - contrast. The visual analyzer is capable of distinguishing contrast within certain limits (optimum 1:30). Strengthening and weakening of contrasts is possible through the use of various means. (To reveal a subtle relief, shadow contrast is enhanced by side lighting, the use of filters.)

The color of each object is characterized by those rays of the light spectrum that the object reflects. (A red object, for example, absorbs all rays of the light spectrum, except for the red, which is reflected by it.) The color of transparent objects is characterized by the rays that they transmit. Thus, The color of any object depends on which rays it reflects, absorbs and transmits..

Rice. 12.: 1 - chiasm; 2 - visual tubercle; 3 - occipital lobe of the cerebral cortex.

In most cases, objects reflect electromagnetic waves of various lengths. But the visual analyzer perceives them not separately, but in total. For example, exposure to red and yellow colors is perceived as orange, and a mixture of colors occurs.

Signals from photoreceptors - light-sensitive formations (130 million cones and rods) go to 1 million larger (ganglion) retinal neurons. Each ganglion cell sends its own process (axon) to the optic nerve. Impulses traveling to the brain along the optic nerve receive primary processing in the diencephalon. Here, the contrast characteristics of the signals and their temporal sequence are enhanced. And already from here, nerve impulses enter the primary visual cortex, localized in the occipital region of the cerebral hemispheres (fields 17–19 according to Brodmann) (Fig. 11, 12). Here, individual elements of the visual image are distinguished - points, angles, lines, directions of these lines. (Established by Boston researchers, 1981 Nobel Prize winners Hubel and Wiesel.)

Rice. 13. optogram taken from the retina of a dog's eye after her death. This indicates the screen principle of functioning of the retina.

The visual image is formed in the secondary visual cortex, where the sensory material is compared (associated) with previously formed visual standards - the image of the object is recognized. (It takes 0.2 seconds from the beginning of the stimulus to the appearance of a visual image.) However, a screen display of the perceived object occurs already at the level of the retina (Fig. 13).

auditory sensations. There is an opinion that we receive 90% of information about the world around us through vision. It can hardly be calculated. After all, what we see with the eye should be covered by our conceptual system, which is formed integratively, as a synthesis of all sensory activity.

Rice. 14. Deviations from normal vision - nearsightedness and farsightedness. These deviations can usually be compensated for with glasses with specially selected lenses.

The work of the auditory analyzer is no less complex and important than the work of the visual analyzer. This channel is the main flow of speech information. A person feels sound 35 - 175 ms after he has reached the auricle. Another 200 - 500 ms is necessary for maximum sensitivity to a given sound. It also takes time to turn the head and properly orient the auricle in relation to the source of a weak sound.

From the tragus of the auricle, the oval auditory canal deepens into the temporal bone (its length is 2.7 cm). Already in the oval passage, the sound is significantly amplified (due to the resonant properties). The oval passage is closed by the tympanic membrane (its thickness is 0.1 mm, and its length is 1 cm), which constantly vibrates under the influence of sound influences. The tympanic membrane separates the outer ear from the middle ear - a small chamber with a volume of 1 cm³ (Fig. 15).

The middle ear cavity is connected to the inner ear and the nasopharynx. (The air coming from the nasopharynx balances the external and internal pressure on the tympanic membrane.) In the middle ear, sound is repeatedly amplified by the system of bones (hammer, anvil and stirrup). These ossicles are supported in weight by two muscles that tighten when sounds are too loud and weaken the ossicles, protecting the hearing aid from injury. With weak sounds, the muscles increase the work of the bones. The intensity of sound in the middle ear increases 30 times due to the difference between the area of ​​the tympanic membrane (90 mm2) to which the malleus is attached and the area of ​​the base of the stirrup (3 mm2).

Rice. 15. . Sound vibrations of the external environment pass through the ear canal to the tympanic membrane, located between the outer and middle ear. The tympanic membrane transmits vibrations and the bony mechanism of the middle ear, which, acting on a lever principle, amplifies the sound by about 30 times. As a result of this, slight changes in pressure at the eardrum are transmitted by a piston-like movement to the oval window of the inner ear, which causes the movement of fluid in the cochlea. Acting on the elastic walls of the cochlear canal, the movement of the fluid causes an oscillatory movement of the auditory membrane, more precisely, of a certain part of it, resonating at the appropriate frequencies. At the same time, thousands of hair-like neurons transform the oscillatory movement into electrical impulses of a certain frequency. The round window and the Eustachian tube coming from it serve to equalize the pressure with the external environment; leaving the nasopharynx, the Eustachian tube opens slightly during swallowing movements.

The purpose of the auditory analyzer is to receive and analyze signals transmitted by vibrations of an elastic medium in the range of 16-20,000 Hz (sound range).

The receptor part of the auditory system - the inner ear - the so-called cochlea. It has 2.5 turns and is divided transversely by a membrane into two isolated channels filled with liquid (relymph). Along the membrane, which narrows from the lower coil of the cochlea to its upper coil, there are 30 thousand sensitive cilia formations - they are sound receptors, forming the so-called organ of Corti. In the cochlea, the primary dissection of sound vibrations occurs. Low sounds affect long eyelashes, high sounds affect short ones. The vibrations of the corresponding sound cilia create nerve impulses that enter the temporal part of the brain, where complex analytical and synthetic activity is carried out. The most important verbal signals for a person are encoded in neural ensembles.

The intensity of the auditory sensation - loudness - depends on the intensity of the sound, that is, on the amplitude of the vibrations of the sound source and on the pitch of the sound. The pitch of the sound is determined by the oscillation frequency of the sound wave, the timbre of the sound is determined by overtones (additional oscillations in each main phase) (Fig. 16).

The pitch of a sound is determined by the number of oscillations of the sound source in 1 second (1 oscillation per second is called hertz). The organ of hearing is sensitive to sounds in the range from 20 to 20,000 Hz, but the highest sensitivity lies in the range of 2000 - 3000 Hz (this is the pitch corresponding to the cry of a frightened woman). A person does not feel the sounds of the lowest frequencies (infrasounds). The sound sensitivity of the ear starts at 16 Hz.

Rice. 16. . The intensity of sound is determined by the amplitude of the vibration of its source. Height - vibration frequency. Timbre - additional vibrations (overtones) in each "time" (middle figure).
However, subthreshold low-frequency sounds affect the mental state of a person. So, sounds with a frequency of 6 Hz cause a person to feel dizzy, tired, depressed, and sounds with a frequency of 7 Hz can even cause cardiac arrest. Getting into the natural resonance of the work of internal organs, infrasounds can disrupt their activity. Other infrasounds also selectively affect the human psyche, increasing its suggestibility, learning ability, etc.

Human sensitivity to high frequency sounds is limited to 20,000 Hz. Sounds that lie beyond the upper threshold of sound sensitivity (that is, over 20,000 Hz) are called ultrasounds. (Ultrasonic frequencies of 60 and even 100,000 Hz are available to animals.) However, since sounds up to 140,000 Hz are found in our speech, we can assume that they are perceived by us at a subconscious level and carry emotionally significant information.

The thresholds for distinguishing sounds by their height are 1/20 of a semitone (that is, up to 20 intermediate steps differ between the sounds produced by two adjacent piano keys).

In addition to high-frequency and low-frequency sensitivity, there are lower and upper thresholds for sensitivity to sound intensity. Sound sensitivity decreases with age. So, for the perception of speech at the age of 30, a sound volume of 40 dB is required, and for the perception of speech at the age of 70, its volume must be at least 65 dB. The upper threshold of auditory sensitivity (in terms of volume) is 130 dB. Noise above 90 dB is harmful to humans. Sudden loud sounds are also dangerous, hitting the autonomic nervous system and leading to a sharp narrowing of the lumen of blood vessels, an increase in heart rate and an increase in the level of adrenaline in the blood. The optimal level is 40 - 50 dB.

Tactile sensation(from Greek. taktilos- touch - the feeling of being touched. Tactile receptors (Fig. 17) are most numerous at the fingertips and tongue. If on the back two touch points are perceived separately only at a distance of 67 mm, then on the tip of the fingers and tongue - at a distance of 1 mm (see table).
Spatial thresholds of tactile sensitivity.

Rice. 17. .

The threshold of spatial tactile sensitivity is the minimum distance between two point touches at which these effects are perceived separately. The range of tactile distinctive sensitivity is from 1 to 68 mm. The zone of high sensitivity is from 1 to 20 mm. The low sensitivity zone is from 41 to 68 mm.

Tactile sensations combined with motor sensations form tactile sensitivity underlying the subject actions. Tactile sensations are a kind of skin sensations, which also include temperature and pain sensations.

Kinesthetic (motor) sensations.

Rice. 18. (according to Penfield)

Actions are associated with kinesthetic sensations (from the Greek. kineo- movement and aesthesia- sensitivity) - a sense of the position and movement of parts of one's own body. The labor movements of the hand were of decisive importance in the formation of the brain, the human psyche.

Based on muscle-articular sensations, a person determines compliance or inconsistency
their movements to external circumstances. Kinesthetic sensations perform an integrating function in the entire human sensory system. Well-differentiated voluntary movements are the result of the analytical-synthetic activity of a vast cortical zone located in the parietal region of the brain. The motor, motor area of ​​the cerebral cortex is especially closely connected with the frontal lobes of the brain, which perform intellectual and speech functions, and with the visual areas of the brain.

Rice. 19. .

Muscle spindle receptors are especially numerous in the fingers and toes. When moving various parts of the body, hands, fingers, the brain constantly receives information about their current spatial position (Fig. 18), compares this information with the image of the final result of the action and carries out the appropriate correction of the movement. As a result of training, the images of intermediate positions of various parts of the body are generalized in a single general model of a specific action - the action is stereotyped. All movements are regulated on the basis of motor sensations, on the basis of feedback.

The motor physical activity of the body is essential for optimizing the work of the brain: skeletal muscle proprioceptors send stimulating impulses to the brain, increase the tone of the cerebral cortex.

Rice. 20. : 1. Permissible vibration limits for individual parts of the body. 2. The limits of permissible vibrations acting on the entire human body. 3. Borders of weakly felt vibrations.

Static sensations- sensations of the position of the body in space relative to the direction of gravity, a sense of balance. The receptors for these sensations (gravitoreceptors) are located in the inner ear.

receptor rotational body movements are cells with hair endings located in semicircular canals inner ear, located in three mutually perpendicular planes. When accelerating or decelerating the rotational movement, the fluid filling the semicircular canals exerts pressure (according to the law of inertia) on the sensitive hairs, in which the corresponding excitation is caused.

Moving into space in a straight line reflected in otolith apparatus. It consists of sensitive cells with hairs, over which are located otoliths (cushions with crystalline inclusions). Changing the position of the crystals signals to the brain the direction of the rectilinear movement of the body. The semicircular canals and the otolithic apparatus are called vestibular apparatus. It is connected with the temporal region of the cortex and with the cerebellum through the vestibular branch of the auditory nerve (Fig. 19). (Strong overexcitation of the vestibular apparatus causes nausea, since this apparatus is also connected with the internal organs.)

vibration sensations arise as a result of reflection of oscillations from 15 to 1500 Hz in an elastic medium. These vibrations are reflected by all parts of the body. Vibrations are tiring and even painful for a person. Many of them are unacceptable (Fig. 20).

Rice. 21. . The olfactory bulb is the brain center of smell.

Olfactory sensations arise as a result of irritation by particles of odorous substances in the air, the mucous membrane of the nasal cavity, where the olfactory cells are located.
Substances that irritate the olfactory receptors enter the nasopharyngeal cavity from the side of the nose and nasopharynx (Fig. 21). This allows you to determine the smell of a substance both at a distance and if it is in the mouth.

Rice. 22. . The relative concentration of taste receptors on the surface of the tongue.

Taste sensations. The whole variety of taste sensations consists of a combination of four tastes: bitter, salty, sour and sweet. Taste sensations are caused by chemicals dissolved in saliva or water. Taste receptors are nerve endings located on the surface of the tongue - taste buds. They are located on the surface of the tongue unevenly. Separate areas of the surface of the tongue are most sensitive to certain taste influences: the tip of the tongue is more sensitive to sweet, the back to bitter, and the edges to sour (Fig. 22).

The surface of the tongue is sensitive to touch, that is, it is involved in the formation of tactile sensations (the texture of food affects taste sensations).

Temperature sensations arise from irritation of thermoreceptors of the skin. There are separate receptors for the sensation of heat and cold. On the surface of the body, they are located in some places more, in others - less. For example, the skin of the back and neck is most sensitive to cold, and the tips of the fingers and tongue are most sensitive to hot. Different parts of the skin themselves have different temperatures (Fig. 23).

Pain are caused by mechanical, thermal and chemical influences that have reached a superthreshold intensity. Pain sensation is largely associated with subcortical centers, which are regulated by the cerebral cortex. Therefore, they are amenable to some degree of inhibition through the second signal system.

Rice. 23. (according to A.L. Slonim)

Expectations and fears, fatigue and insomnia increase a person's sensitivity to pain; with deep fatigue, the pain dulls. Cold intensifies and heat relieves pain. Pain, temperature, tactile sensations and pressure sensations are related to skin sensations.

organic sensations- sensations associated with interoreceptors located in the internal organs. These include feelings of satiety, hunger, suffocation, nausea, etc.

This classification of sensations was introduced by the famous English physiologist Ch.S. Sherrington (1906);

There are three types of visual sensations: 1) photopic - daytime, 2) scotopic - night and 3) mesopic - twilight. The greatest photopic visual acuity is located in the central field of view; it corresponds to the central, foveal region of the retina. In scotopic vision, maximum light sensitivity is provided by paramolecular areas of the retina, which are characterized by the largest accumulation of rods. They provide the greatest light sensitivity.

Sources and literature

• Enikeev M.I. Psychological encyclopedic dictionary. M., 2010.
• Zinchenko T.P., Kondakov I.M. Psychology. Illustrated dictionary. M. 2003.