Auditory sensations are the effect of sound waves on the auditory receptor, which are air rarefaction.

Sound waves differ in amplitude, frequency and duration of vibrations. Auditory sensations are caused by periodic and non-periodic oscillatory processes, which are expressed in musical sounds and noises.

Sound properties:

1) volume. Depends on the strength and amplitude of the vibration of the sound wave;

2) height. Reflects the frequency of the sound wave. The human ear does not perceive all sounds. Ultrasounds and infrasounds remain out of hearing;

3) timbre. Each sound is characterized by a special character and color. Timbre shows

acoustic composition of sound.

Binaural hearing is the ability of the ear to determine the direction a sound is coming from. There are phase (the direction of the sound is due to the difference in the times of arrival of the same phases of the sound wave to both ears) and amplitude (the direction of the sound is due to the difference in loudness obtained in both ears) binaural effect.

Touch is the sensation of touch and pressure. The organ of touch of a person is a moving hand, it is an organ of labor and knowledge of reality. It gives us knowledge of the properties of the material world. The basic properties of the material world (hardness, elasticity, impenetrability) are known by the moving hand and transmitted by sensations. Skin sensations are a specific human feeling of a working and moving hand. When cognizing the material world, motor processes are performed that turn into sensations, i.e. into effective knowledge of objects. The components of touch come from receptors that are located in muscles, ligaments, and joint bags. When moving, the receptors are stimulated by voltage. However, sensation is not limited to sensations of pressure or touch. Such tactile sensations as touch, muscular-articular pressure, combined with skin sensitivity, reflect the properties through which objects of the world around us are known. The interaction of sensations of pressure and temperature gives us the sensation of moisture, and the combination of moisture with permeability allows us to distinguish between solid and liquid bodies. The interaction of a moving hand with material bodies makes it possible to determine viscosity, roughness, smoothness and oiliness. The sense of touch functions in parallel with vision and under its control. In the blind, touch is separate from sight. The teaching of the blind is based on the sense of touch and the moving hand.

OLFACTORY SENSATIONS

In general, sensation is the simplest mental process of reflection in the cerebral cortex of individual properties of objects and phenomena of the surrounding world that currently affect the human brain through the corresponding sensory organs. Sense of smell is the ability to perceive and distinguish odorous substances (for example, the smell of food).

Olfactory sensations refer to discant sensations that reflect the smells of objects surrounding a person. The organs of smell are olfactory cells located in the upper part of the nasal cavity, and the cortical part of the olfactory analyzer is located in the temporal part. Irritants of the olfactory organ are volatile substances that have a smell. These are substances that can penetrate into the olfactory area both from the outside, i.e. through the nostrils, and from the nasopharynx. Therefore, odorants in the form of, for example, vapour, gas, mist, dust or smoke reach the receptors when inhaled through the nose or mouth and spread through the nasopharynx into the nasal cavity. The receptors of the oral mucosa are also involved in the formation of the olfactory sensation. These include tactile, temperature, pain receptors. Substances that irritate only the olfactory receptors are called olfactive, but there are mixed substances that also irritate other receptors. Thus, the olfactory analyzer plays a role in determining the properties of a substance that is not only located at a certain distance from a person, but also that has entered the person's mouth.

It should be noted that the sense of smell in one and the same person can fluctuate within fairly wide limits. With prolonged contact of odorous substances with the mucous membrane, adaptation is observed, i.e. decreased olfactory sensitivity. Adaptation time for different people to different smells is not the same. With an increase in the concentration of substances, it decreases, so people who deal with strongly odorous substances quickly get used to them and stop feeling them. But complete adaptation to one smell does not exclude sensitivity to others.

In modern man, the olfactory analyzer is less developed than in his distant ancestors, since in a healthy person the orienting function is primarily performed by sight and hearing. But with damage to vision and hearing, the sense of smell, along with the remaining intact analyzers, becomes especially important. For example, the deaf-blind use their sense of smell, just as the sighted use their sight, i.e. smell familiar places and recognize familiar people.

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, 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) effects), 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. eight. .

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 light 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. In this way, The color of any object depends on which rays it reflects, absorbs and transmits..

Rice. 12.: 1 - chiasma; 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 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. thirteen. 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 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 action 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 mm 2) to which the malleus is attached, and the area of ​​the base of the stirrup (3 mm 2).

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 tympanic membrane 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. sixteen. . 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, beating on 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. .

High sensitivity zone	Low sensitivity zone
Tip of the tongue - 1 mm	Sacrum - 40.4 mm
Terminal phalanges of fingers - 2.2 mm	Buttock - 40.5 mm
The red part of the lips - 4.5 mm	Forearm and lower leg - 40.5 mm
Palmar side of the hand - 6.7 mm	Sternum - 45.5 mm
Terminal phalanx of the big toe - 11.2 mm	Neck below the back of the head - 54.1 mm
The back side of the second phalanges of the toes - 11.2 mm	Loin - 54.1 mm
The back side of the first phalanx of the big toe - 15.7 mm	Back and middle of the neck - 67.6 mm
	Shoulder and hip - 67.7 mm

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. nineteen. .

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.

There are several possible options for classifying those two dozen analyzer systems that a person possesses. The most used is the systematization proposed by the English physiologist I. Sherrington, who singled out three main classes of sensations:

1. exteroceptive, arising from the impact of external stimuli on receptors located on the surface of the body;

2. interoreceptive(organic), signaling what is happening in the body (feelings of hunger, thirst, pain, etc.);

3. proprioceptive located in muscles and tendons; with their help, the brain receives information about the movement and position of various parts of the body.

total mass exteroceptive sensations, the Sherrington scheme allows divide by distant (visual, auditory) and contact(tactile, gustatory). Olfactory sensations occupy an intermediate position in this case. Most ancient is organic(primarily pain) sensitivity, then contacts appeared(primarily tactile, that is, tactile) forms. And the most evolutionary auditory and especially visual systems should be considered young receptors. The most significant for the functioning of the human psyche are visual(85% of all information about the outside world), auditory, tactile, organic, olfactory and gustatory sensations.

According to the modality of the stimulus, sensations are divided into visual, auditory, olfactory, gustatory, tactile, static and kinesthetic, temperature, pain, thirst, and hunger.

Let us briefly describe each of these types of sensations.

visual sensations.

They result from the action of light rays (electromagnetic waves) on the sensitive part of our eye - retina, which is the receptor of the visual analyzer. Light affects two types of light-sensitive cells in the retina - rods and cones, so named for their external shape. (Stolyarenko)

electromagnetic waves, which the visual system reflects are located in the range from 380 to 780 billionths of a meter and together they occupy a very limited part of the electromagnetic spectrum. Waves that are within this range and differ in length, in turn, generate sensations of different colors (Table 1).

Table 1

Relationship between visually perceived wavelength

And the subjective sense of color

Auditory sensations. These sensations also refer to distant sensations and are also of great importance in human life. Thanks to them, a person hears speech, has the ability to communicate with other people. (Stolyarenko)

The human ear responds, unlike the eye, to mechanical influences, associated with changes in atmospheric pressure. Air pressure fluctuations (longitudinal oscillations of air particles), 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. (Nemov)

The human hearing organ responds to sounds in the range from 16 to 20,000 vibrations per second..

Everything auditory sensations can be reduced to three types - speech, musical, noise.(Stolyarenko)

vibration sensations.

Vibration sensitivity is adjacent to auditory sensations. They have a common nature of reflected physical phenomena. Vibration sensations reflect vibrations of an elastic medium. This type of sensitivity is figuratively called " contact hearing". No specific vibration receptors have been found in humans. At present, it is believed that all tissues of the body can reflect the vibrations of the external and internal environment. In humans, vibrational sensitivity is subordinated to auditory and visual. (Stolyarenko)

Olfactory sensations.

They refer to distant sensations that reflect smells objects around us. Olfactory organs are olfactory cells located in the upper part of the nasal cavity. (Stolyarenko) Anatomically, the olfactory organ is located in most living beings in the most advantageous place - in front, in a prominent part of the body. (Nemov)

The group of contact sensations includes taste, skin (pain, tactile, temperature) sensations.(Stolyarenko)

Taste sensations.

Caused by the action on taste receptors of substances, dissolved in saliva or water. Taste buds - taste buds located on the surface of the tongue, pharynx, palate, - There are four main modalities: sweet, salty, sour and bitter.. All other taste sensations are various combinations of these four basic sensations. (Stolyarenko; Nemov)

Skin sensations.

There are several analyzer systems in the skin: tactile(sensation of touch) temperature(feelings of cold and heat) painful.

Haptic Sensing System(sensations of pressure, touch, texture and vibration) covers the entire human body. The largest accumulation of tactile cells is observed on the palm, on the fingertips and on the lips. The tactile sensations of the hands, together with the muscular-articular sensitivity, form the sense of touch, thanks to which the hands can reflect the shape and spatial position of objects. Tactile sensations, together with temperature sensations, are one of the types of skin sensitivity that provides information about the position of bodies with which a person is in direct contact (smooth, rough, sticky, liquid, etc.), as well as information about the temperature parameters of these bodies and the entire environment. environment.

If you touch the surface of the body, then press on it, the pressure can cause pain sensation . Thus, tactile sensitivity gives knowledge about the properties of the subject and pain signals the body about the need to move away from the stimulus and has a pronounced emotional tone.

The third type of skin sensitivity - temperature sensations - associated with the regulation of heat exchange between the body and the environment. The distribution of heat and cold receptors on the skin is uneven. The back is most sensitive to cold, the least - the chest.

O position of the body in space signal static feeling. Static sensitivity receptors are located in the vestibular apparatus inner ear. Sudden and frequent changes in body position relative to the ground plane can lead to dizziness.

A special place and role in human life and activity is occupied by interoreceptive (organic) sensations that arise from receptors located in internal organs, and signal the functioning of the latter. These sensations form the organic feeling (well-being) of a person.

Organic sensations include, first of all, feelings hunger, thirst, satiety, as well as complexes of pain and sexual sensations. The feeling of hunger appears when the food center of the brain, located in the hypothalamus, is excited. Electrical stimulation of this center (with the help of electrodes implanted there) causes in animals a desire for continuous food intake, and destruction - to refuse it, that is, to death from exhaustion. (Stolyarenko)

All kinds of sensations arise as a result of the impact of appropriate stimuli-irritants on the sense organs. However, the sensation does not arise immediately, as soon as the desired stimulus begins to act. Between the beginning of the action of the stimulus and the appearance of sensation, a certain time elapses. It's called latency period. During the latent period, the energy of the acting stimuli is converted into nerve impulses, they pass through specific and non-specific structures of the nervous system, and they switch from one level of the nervous system to another. By the duration of the latent period, one can judge the afferent structures of the central nervous system through which nerve impulses pass before reaching the cerebral cortex. (Nemov)

Perception

If, as a result of sensation, a person receives knowledge about individual properties, qualities of objects (something hot burned, something bright flashed ahead, etc.), then perception gives a holistic image of an object or phenomenon. It presupposes the presence of various sensations and flows along with sensations, but cannot be reduced to their sum. Perception depends on certain relationships between sensations, the relationship of which, in turn, depends on the connections and relationships between qualities and properties, various parts that make up an object or phenomenon.

Perception is the mental process of reflecting objects and phenomena of reality in the aggregate of their various properties and parts with their direct impact on the senses. Perception is a reflection of a complex stimulus.

There are four operations or four levels perceptual action: detection, discrimination, identification and recognition. The first two relate to perceptual, the last - to identification actions.

Perception is the result of the activity of the system of analyzers. Every perception includes an active motor component.(feeling objects with a hand, eye movement when looking, etc.) and complex analytical-synthetic activity of the brain for the synthesis of a holistic image.(Stolyarenko)

The image formed as a result of the process of perception involves interaction, coordinated work of several analyzers at once. Depending on which one work more actively, process more information, receives the most significant features that testify to the properties of the perceived object, distinguish and types of perception. Accordingly, visual, auditory, tactile perception is distinguished . Four analyzers - visual, auditory, skin and muscle - most often act as leaders in the process of perception.(Nemov)

The pattern of subjectivity of perception - people perceive the same information in different ways, subjectively, depending on from their interests, needs, abilities etc. The dependence of perception on the content of a person’s mental life, on the characteristics of his personality is called apperceptions. The influence of a person's past experience on the process of perception is manifested in experiments with distorting glasses: in the first days of the experiment, when the subjects saw all the surrounding objects upside down, the exception was those objects whose reversed image, as people knew, was physically impossible. So, an unlit candle was perceived upside down, but as soon as it was lit, it was seen as normally oriented vertically, i.e., the flame was directed upwards. (Stolyarenko)

Perception properties:

objectivity perception lies in the fact that a person realizes the mental images of objects not as images, but like real items objectifying them. Objectivity of perception means adequacy, correspondence of images of perception to real objects of reality.

Integrity perception is the reflection of an object as stable set of elements, even if some of its parts are not observed under these conditions. However, the ability of a holistic visual perception of objects is not congenital. Perception is formed in the process of practice, i.e. perception - perceptual system action, that need to be mastered.

constancy perception - thanks to constancy, we perceive surrounding objects as relatively constant in shape, color, size etc. The source of the constancy of perception is the active actions of the perceptual system (the system of analyzers that provide the act of perception). Multiple perception of the same objects under different conditions makes it possible to single out a relatively constant invariant structure of the perceived object. Constancy of perception is not an innate property, but an acquired one. Violation of the constancy of perception occurs when a person finds himself in an unfamiliar situation, for example, when people look down from the upper floors of a high-rise building, cars and pedestrians seem small to them; at the same time, builders who work constantly at height report that they can see objects below without distorting their size.

Categorical human perception is manifested in the fact that it wears generalized character, and each perceived object we denote by a word-concept, belong to a certain class. In accordance with this class, we look for and see signs in the perceived object that are characteristic of all objects of this class and expressed in the volume and content of this concept.

Structurality Perception - Perception is not a simple sum of sensations. We actually perceive a generalized structure abstracted from these sensations. For instance, when listening to music, we perceive not individual sounds, but a melody, and we recognize it if it is performed by an orchestra, or a single piano, or a human voice, although individual sound sensations are different.

meaningfulness perception - perception closely associated with thinking, with understanding the essence of objects.

Selectivity perception - manifested in the predominant selection of some objects compared to others.

Types of perception allocate: perception of objects, time, perception of relationships, movements, space, perception of a person.(Stolyarenko; Nemov: Internet)

The described properties of objectivity, integrity, constancy and categorization of perception from birth are not inherent in a person; they gradually take shape in life experience, partly being a natural consequence of the work of analyzers, the synthetic activity of the brain.

Most often and most of all, the properties of perception were studied on the example vision - the leading sense organ in humans. Representatives of the gestalt psychology - direction of scientific research, established at the beginning of the XX century. in Germany. One of the first classification of factors influencing the organization of visual sensations into images in line with Gestalt psychology was proposed by M. Wertheimer. The factors he identified are:

1. The proximity to each other of the elements of the visual field that caused the corresponding sensations. The closer to each other spatially in the visual field are the corresponding elements, the more likely they are combined with each other and create a single image.

2. Similarity of elements to each other. This property is manifested in the fact that similar elements tend to combine.

3. Factor of "natural continuation". It manifests itself in the fact that elements that act as parts of figures, contours and forms familiar to us are more likely to be combined in our minds precisely in these figures, shapes and contours than in others.

4. Closure. This property of visual perception acts as the desire of the elements of the visual field to create complete, closed images. (Nemov)

Perception of time

There are large individual differences in the ability to estimate time. Experiments have shown that the same can pass for a ten-year-old child five times faster than for a sixty-year-old person. In the same subject, the perception of time varies greatly depending on the mental and physical state. When depressed or frustrated, time passes slowly. Time, saturated in the past with experiences, activities, is remembered as longer, and a long period of life, filled with uninteresting events, is remembered as quickly past.

The length of time is less 5 minutes when remembered it usually seems more its size, and longer gaps are remembered as smaller e.

Our ability to judge the length of time allows us to form time dimension- an axis of time on which we place events more or less exactly. The current moment (now) marks a special point on this axis, the events of the past are placed before, and the events of the expected future - after this point. This general perception of the relationship between the present and the future is called « time perspective». (Stolyarenko)

Visual sensations play a leading role in human cognition of the external world. It is known that 80-90% of information comes through the visual analyzer, about 80% of all work operations are carried out under visual control.

visual sensations arise as a result of exposure to light rays (electromagnetic waves) on the sensitive part of our eye - the retina, which is the receptor of the visual analyzer.

The eyeball lies in the deepening of the skull that protects it. The shape of the eyeball is close to spherical. .Its outer dense connective tissue sheath about 1 mm thick is called the sclera. At the front of the eye, the sclera becomes a transparent membrane called the cornea. Under the sclera is a thinner - about 0.3 mm - choroid, consisting mainly of blood vessels that feed the eyeball. The inner shell is the retina. The cornea and lens focus the light entering the eye onto the retina, which lines the posterior surface of the eyeball. It is in the retina that the light-sensitive cells are located. Light affects two types of light-sensitive cells in the retina - rods and cones, so named for their external shape. Light-sensitive receptors in the retina convert light energy into a neural impulse. Along the fibers of the optic nerve, signals are transmitted to the corresponding part of the brain, which receives and processes the information transmitted by the nerves. A schematic section of the eye is shown in fig. 5.

Rice. 5. Schematic section of the eye

Cones are less sensitive to light than rods. Rods are adapted to work in low light and give a black and white picture of the world, while cones, on the contrary, have the greatest sensitivity in good light conditions and provide color vision.

An interesting effect that occurs on the choroid of the human eye can be observed when the eye is exposed to a bright flash of light. The most common and well-known example of the “glow” of human eyes is "red eye effect" in photographs taken with flash. This effect occurs in low light, when the pupils are as wide as possible and when the photographer uses a flash to take a good picture. Although the pupil reacts to bright light fairly quickly (the reaction time is from 0.25 to 0.5 s), it does not have time to narrow at the moment of the flash. As a result of instantaneous exposure to bright light and its reflection from the choroid, observed through widely dilated pupils, the “red eye effect” is obtained. Therefore, many cameras are equipped with devices that reduce the likelihood of this effect. They are based on the fact that they give a "warning" flash - before starting the exposure of the film, for 0.75 s they affect the eyes of the photographed with bright light. In this case, the pupils constrict, and the effect of the flash on the choroid is reduced.

The colors that a person perceives are divided into achromatic and chromatic .

achromatic colors- black, white and gray intermediate between them (Fig. 6).

Fig.6. Achromatic colors in the transition from black to white

(from left to right).

Achromatic colors reflect rods that are located at the edges of the retina. Cones are located in the center of the retina, function only in daylight and reflect chromatic colors. The sticks function at any time of the day. Therefore, at night, all objects seem to us black and gray. In low light, the cones stop working and vision is carried out by the apparatus of the rods - a person sees mostly gray colors.

Chromatic colors are all shades of red, orange, yellow, green, blue, blue, purple. Newton's classical experiments on decomposing white color into its components and obtaining again composite radiation from its parts are the first steps towards understanding the problem of color perception by the eye.

An irritant for the visual analyzer are light waves with a wavelength of 390 to 760 nm. Therefore, when we talk about "blue" or "red" we actually mean short or long wavelength light, respectively, which thus affects the visual system to produce the sensation of blue or red. Light with a wavelength of about 650–700 nm gives the impression of red. At a wavelength of 570 nm, yellow sensations appear, at 500 nm - green, and at 470 nm - blue. White color is the result of the impact on the eye of all light waves that make up the spectrum.

In other words, colors depend on how the visual system interprets light rays with different wavelengths that are reflected from objects and affect the eye. Rays of light, paint, color filters and the like have no color. They only selectively use radiant energy, emitting or passing rays of a certain wavelength through themselves, reflecting some of them and absorbing others. Therefore, color is a product of the activity of the visual system, and not an integral property of the visible spectrum.

Sensations of different colors are caused by different wavelengths, as shown in Fig. 7.

Rice. 7. Color circle

Any color can be obtained by mixing two border colors with it. For example, red is obtained by mixing orange and purple. Opposite colors are called complementary colors - when mixed, they form a warm color.

In this case, the spectral sensitivity of the eye looks like a curve shown in Fig. 8. All color tones, including neutral (gray), can be obtained by mixing the three primary colors - red, blue and green (Fig. 9). This is the basis of the work of color television.

Violations of the rod and cone apparatus lead to certain defects in visual sensations. So, a malfunction of the rod apparatus (known as the disease "night blindness") is manifested in the fact that a person sees very poorly or does not see anything at dusk and at night, and during the day his vision is relatively normal.

When the action of the cone apparatus is weakened, a person poorly distinguishes or does not distinguish chromatic colors at all. This disease is called "color blindness" (after the English physicist Dalton, who first described it). The most common is red-green blindness. It is known that about 4% of men and 0.5% of women suffer from color blindness.

Color has a different effect on the well-being and performance of a person. It can help improve mood or, conversely, worsen it. Green, for example, creates an even, calm mood, red excites, dark blue depresses.

Along with color, the degree of illumination of the workplace affects the mental state. Insufficient lighting causes a change in eye strain during work, which leads to the rapid development of fatigue and the appearance of myopia.

auditory sensations

The sounds we hear are the result of the transformation of a certain form of mechanical energy and are patterns of subsequent pressure disturbances occurring in different media - liquid, solid or gaseous. Most of the sounds we perceive are transmitted through the air. Auditory sensations are distant sensations and are also of great importance in human life. Thanks to them, a person hears speech, music, has the opportunity to communicate with other people. The main physical characteristics of sound waves are frequency, amplitude, or intensity, and complexity.

Irritants for auditory sensations are sound waves - longitudinal vibrations of air particles, propagating in all directions from the sound source. The human hearing organ responds to sounds in the range from 16 to 20,000 vibrations per second. The human ear is most sensitive to sounds of 1000-3000 vibrations per second. The structure of the ear is shown in Figure 10.

Auditory sensations are a reflection of sounds of various heights (high - low), strength (loud - quiet) timbre , various quality (musical sounds, speech, noises).

The pitch of the sound depends on the frequency of the sound waves, the strength of the sound is determined by the amplitude of their oscillations, and the timbre is determined by the shape of the oscillations of the sound waves.

Rice. 9. Ear structure:

9 - external auditory meatus; 2 - eardrum;

3 - Eustachian tube; 4 - hammer; 5 - anvil;

6 - stirrup; 7 - semicircular canals; 8-10 - snail;

11-12 - Eustachian tube; 13 - temporal bones of the skull

musical sounds- singing and sounds of various musical instruments. Noises - this is, for example, the sound of a motor, the sound of rain, the roar of a train, etc.

Speech sounds combine musical sounds (vowels) and noises (consonants). Hearing for speech sounds is defined as phonemic. It is formed in vivo, in the process of communication, depending on the speech environment in which the child is brought up. Mastering a foreign language offers the development of a system of phonemic hearing, which requires a system of exercises. Musical ear is no less social than speech ear. It is brought up and formed in the same way as speech.

General concept of sensations.

Feel allow a person to perceive signals and reflect the properties and signs of things in the external world and the states of the organism. They connect a person with the outside world and are both the main source of knowledge and the main condition for his mental development.

Sensation is one of the simplest cognitive mental processes. The human body receives a variety of information about the state of the external and internal environment in the form of sensations with the help of the senses. Sensation is the very first connection of a person with the surrounding reality.

The process of sensation arises as a result of the impact on the sense organs of various material factors, which are called stimuli, and the process of this impact itself is irritation.

Feelings arise on the basis of irritability. Sensation is a product of development in the phylogenesis of irritability. Irritability is a common property of all living bodies to come into a state of activity under the influence of external influences (pre-psychic level), i.e. directly affecting the life of the organism. Irritation causes excitation, which passes through the centripetal, or afferent, nerves to the cerebral cortex, where sensations arise. At an early stage in the development of living things, the simplest organisms (for example, a ciliate shoe) do not need to distinguish between specific objects for their life activity - irritability is sufficient. At a more complex stage, when a living thing needs to determine any objects that it needs for life, and, consequently, the properties of this object as necessary for life, at this stage, irritability is transformed into sensitivity. Sensitivity - the ability to respond to neutral, indirect influences that do not affect the life of the organism (an example with a frog that reacts to a rustle). The totality of feelings creates elementary mental processes, processes of mental reflection.

Distinguish two main forms sensitivity, one of which depends on the environmental conditions and is called adaptation, and the other depends on the conditions of the state of the organism, is called sensitization.

Adaptation(adaptation, adjustment) is a change in sensitivity in the process of adapting to environmental conditions.

Three directions are distinguished:

1) increased sensitivity under the influence of a weak stimulus, for example, dark adaptation of the eye, when within 10-15 minutes. sensitivity increases more than 200 thousand times (at first we do not see objects, but gradually we begin to distinguish their outlines);

2) a decrease in sensitivity under the influence of a strong stimulus, for example, for hearing, this occurs in 20–30 seconds; with continuous and prolonged exposure to the stimulus, the corresponding receptors adapt to it, as a result of which the intensity of nerve excitations transmitted from the receptors to the cortex begins to decrease, which underlies adaptation.

3) the complete disappearance of sensation as a result of prolonged exposure to the stimulus, for example, after 1–1.5 minutes, a person ceases to feel any smell in the room.

Adaptation is especially manifested in the field of vision, hearing, smell, touch, taste and indicates a greater plasticity of the organism, its adaptation to environmental conditions.

Sensitization- this is an exacerbation of sensitivity as a result of a change in the internal state of the body under the influence of stimuli that enter other sense organs at the same time (for example, an increase in visual acuity under the influence of weak auditory or olfactory stimuli).

Types of sensations (skin, auditory, olfactory, visual, contact, distant).

There are various approaches to the classification of sensations. It has long been customary to distinguish five (according to the number of sensory organs) basic types of sensations: smell, taste, touch, sight and hearing. This classification of sensations according to the main modalities is correct, although not exhaustive. B.G. Ananiev spoke about eleven types of sensations. A.R. Luria believed that the classification of sensations can be carried out according to at least two basic principles - systematic and genetic (in other words, according to the principle of modality, on the one hand, and according to the principle of complexity or level of their construction, on the other).

As you know, a person has five senses. There are one more types of external sensations, since motor skills do not have a separate sense organ, but they also cause sensations. Therefore, a person can experience six types of external sensations: visual, auditory, olfactory, tactile (tactile), gustatory and kinesthetic sensations.

The main source of information about the outside world is visual analyzer. With its help, a person receives up to 80% of the total amount of information. The organ of visual sensation is the eye. At the level of sensations, he perceives information about light and color. Colors perceived by a person are divided into chromatic and achromatic. The former include the colors that make up the spectrum of the rainbow (i.e., the splitting of light - the well-known "Every hunter wants to know where the pheasant is sitting"). To the second - black, white and gray colors. Color shades containing about 150 smooth transitions from one to another are perceived by the eye depending on the parameters of the light wave.

visual sensations have a great influence on a person. All warm colors have a positive effect on a person's performance, excite him and cause a good mood. Cool colors calm a person. Dark colors have a depressing effect on the psyche. Colors can carry warning information: red indicates danger, yellow warns, green indicates safety, etc.

Next in importance in obtaining information is auditory analyzer. Sensations of sounds are usually divided into musical and noise. Their difference lies in the fact that musical sounds are created by periodic rhythmic vibrations of sound waves, and noises are created by non-rhythmic and irregular vibrations.

auditory sensations are also of great importance in human life. The source of auditory sensations is a variety of sounds acting on the organ of hearing. Auditory sensations reflect noise, musical and speech sounds.

Sensations of noise and rustle signal the presence of objects and phenomena that emit sounds, their location, approach or removal. They can warn of danger and cause a certain emotional experience.

Musical sensations are characterized by emotional tone and melody. These sensations are formed in a person on the basis of the upbringing and development of an ear for music and are associated with the general musical culture of human society.

Speech sensations are the sensory basis of human speech activity. On the basis of speech sensations, phonemic hearing is formed, thanks to which a person can distinguish and pronounce the sounds of speech. Phonemic hearing has an impact not only on the development of oral and written speech, but also on the acquisition of a foreign language.

Many people have an interesting feature - the combination of sound and visual sensations into one general sensation. In psychology, this phenomenon is called synesthesia. These are stable associations that arise between the objects of auditory perception, such as melodies, and color sensations. Often people can tell "what color" a given melody or word is.

Slightly less common is synesthesia, based on the association of color and smell. It is often inherent in people with a developed sense of smell. Such people can be found among tasters of perfumery products - not only a developed olfactory analyzer is important for them, but also synesthetic associations that allow the complex language of smells to be translated into a more universal language of color. In general, the olfactory analyzer, unfortunately, most often people are not very well developed. People like the hero of Patrick Suskind's novel The Perfumer are a rare and unique phenomenon.

Smell- a type of sensitivity that gives rise to specific sensations of smell. This is one of the most ancient, simple, but 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 of 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, and the lower a living being is on the evolutionary ladder, the more space it occupies in the mass of the brain. In fish, for example, the olfactory brain covers almost the entire surface of the hemispheres, in dogs - about one-third of it, in humans, its relative share in the volume of all brain structures is about one-twentieth.

These differences correspond to the development of other sense organs and the vital importance that this type of sensation has for living beings. For some species of animals, the meaning of smell goes beyond the perception of smells. In insects and higher apes, the sense of smell also serves as a means of intraspecific communication.

Senses of taste- a reflection of the quality of food, providing an individual with information about whether a given substance can be ingested. Taste sensations (often together with smell) are caused by the action of the chemical properties of substances dissolved in saliva or water on taste buds (taste buds), p They are located at the corners of the tetrahedron (quadrangular pyramid), and all other taste sensations are located on the planes of the Tetrahedron and represent them as combinations of two or more basic taste sensations.

Skin sensitivity, or touch, is the most widely presented and widespread type of sensitivity. We all know the sensation that occurs when an object touches the surface of the skin, is not an elementary tactile sensation. It is the result of a complex combination of four other, simpler types of sensations: pressure, pain, heat and cold, and for each of them there is a specific type of receptors, unevenly located in different parts of the skin surface.

By examples kinesthetic sensations and sense of balance it can be confirmed that not all sensations are conscious. In everyday speech, which we use, there is no word for sensations coming, for example, from receptors located in muscles and working when they contract or stretch. Nevertheless, these sensations still exist, providing control of movements, an assessment of the direction and speed of movement, and the magnitude of the distance. They are formed automatically, enter the brain and regulate movements at a subconscious level. To designate them in science, a word is adopted that comes from the concept of "motion" - kinetics, and therefore they are called kinesthetic.

contact sensations caused by the direct impact of the object on the senses. Taste and touch are examples of contact sensation.

distant sensations reflect the qualities of objects located at some distance from the senses. These senses include hearing and sight. It should be noted that the sense of smell, according to many authors, occupies an intermediate position between contact and distant sensations, since formally olfactory sensations occur at a distance from the object, but at the same time, the molecules that characterize the smell of the object, with which the olfactory receptor contacts, undoubtedly belong to this subject. This is the duality of the position occupied by the sense of smell in the classification of sensations.