Feeling- a cognitive process in which, as a result of the direct impact of stimuli on the sensory organs, individual properties of objects of the objective world are reflected.

Sensations are considered the simplest and primary form of orientation of the organism in the surrounding world. The ability to sense is present in all living beings with a nervous system.. Lowly organized animals reflect only individual that are of direct importance for their life properties of objects and phenomena. The same for a newborn. In the first weeks of life, he reacts only to certain properties of objects. These facts indicate that sensation is the initial form of development of cognitive activity.

Unlike animals, a person's feelings are influenced by socio-historical development. People's feelings are mediated by their practical activities, consciousness, and individual characteristics. In sensation, it is conditionally possible to distinguish objective and subjective side. The objective side is connected with the characteristics of the influences of the external world, with the peculiarities of the properties of reflected objects and phenomena. The subjective side of sensations is determined by the individual characteristics of the sense organs, which are determined by both genetic and life-acquired factors. It is proved that the nature of sensations can change under the influence of ongoing activities, diseases, special exercises, etc.

Physiological bases of sensations. Sensation can arise only when an object acts on the sense organ. A sense organ is an anatomical and physiological apparatus located on the periphery of the body or in internal organs and designed to receive the effects of certain stimuli from the external and internal environment.

The physiological foundations of sensation are deeply and systematically studied within the framework of the reflex concept of I. M. Sechenov and I. P. Pavlov. It is shown that its essence sensation is a holistic reflex, uniting the peripheral and central parts of the nervous system. I. P. Pavlov introduced the concept "analyzer" and showed that the activity of the analyzers reveals the physiological mechanism of the emergence of sensations. Analyzer- a nervous formation that carries out the perception, analysis and synthesis of external and internal stimuli acting on the body.

The analyzer consists of 3 blocks:

1). Receptor- the peripheral part of the analyzer, which performs the function of receiving information from stimuli acting on the body. The receptor is designed to perceive a certain stimulus from the external or internal environment and to convert its energy from a physical or chemical form into a form of nervous excitation (impulse).

2). Afferent(conductive) and efferent(exit) paths. Afferent pathways are parts of the nervous system through which the resulting excitation enters the central nervous system. Efferent pathways are sections along which the response impulse (based on information processed in the central nervous system) is transmitted to receptors, determining their motor activity (reaction to a stimulus).

3). Cortical projection zones(central section of the analyzer) - areas of the cerebral cortex in which the processing of nerve impulses received from receptors takes place. Each analyzer in the cerebral cortex has its own "representation" (projection), where the analysis and synthesis of information of a certain sensitivity (sensory modality) takes place.

Thus, sensation is essentially a mental process that occurs during the processing of information received by the brain.

Depending on the type of sensitivity, there are visual, auditory, olfactory, taste, cutaneous, motor and others analyzers. Each analyzer from the whole variety of influences allocates incentives of only a certain type. For example, the auditory analyzer highlights the waves formed as a result of vibrations of air particles. The gustatory analyzer generates an impulse as a result of the “chemical analysis” of molecules dissolved in saliva, and the olfactory analyzer generates an impulse in the air. The visual analyzer perceives electromagnetic oscillations, the characteristic of which generates one or another visual image.

The transformation of the energy of an external influence into a nerve impulse, its transmission to the brain, the formation of a sensation and a response - all this is unfolded in time. The period of time from the application of irritation to the occurrence of a response is called latent(hidden) period. It is not the same for different sensations. So, the latent period of tactile sensations is 130 milliseconds, pain - 370.

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. four. . 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. 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. ten. .

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 - 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 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. fourteen. 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. fifteen. . 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. .

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. 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.

All processes begin with sensation.

Sensation arises with how the stimulus affects us. Sensations are tactile, olfactory, auditory. The essence of sensations - through sensations we know the individual qualities of objects.

Feeling - this is a reflection in the human mind of individual properties, objects and phenomena of the surrounding world with their direct impact on the senses.

Sensation is a reflection in consciousness, it is a mental phenomenon in which we give ourselves an account.

Reflection in sensations occurs only with the direct action of the stimulus on the sense organs.

The physiological mechanism of sensation

Behind every sensation is an analyzer.

Analyzer- This is an anatomical and physiological apparatus, specialized for receiving the effects of certain stimuli and processing them into sensations.

receptor

CNS (cerebral cortex)

Physical Physiological

Stimulus

process process

Pathways (nerve endings)

Working body

irritation excitation

Reverse aphentation

The role of sensations in human life

Through sensations, we promptly and quickly receive information about the state of the external and internal environment. Feelings allow us to instantly reflect any changes that occur within us. Feeling is the source of our knowledge of the world. Feelings are the source of our emotions. Due to the fact that with the help of sensations we gain some knowledge, we understand that sensations connect a person with the outside world. Sensations are the main condition (source) of mental development.

Types of sensations

1. By type of feeling: smell, touch, taste, sight, hearing

2. Systematic classification of the main types of sensations(C. Sherington)

Exteroceptive sensations

Contact

Touch

Temperature

Interoceptive sensations

organic

propreceptive sensations

Traffic

equilibrium

remote

Exteroceptive sensations bring information from the outside world and are the main group of sensations that connect a person with the external environment.

contact sensations caused by direct action on the sense organs.

Distant sensations reflect the qualities of objects located at some distance from the senses.

Interoceptive sensations bring to the person information about the state of the internal processes of the body. They arise due to receptors located on the walls of the stomach, intestines, heart, circulatory system and other internal organs. They are among the least conscious and most diffuse forms of sensation and always retain their proximity to emotional states. These are the most ancient forms of sensitivity, they are among the least recognizable and most diffuse.

propreceptive sensations These are sensations that transmit signals about the position of the body in space, and form the afferent basis of human movements, playing an important role in their regulation. They allow us to reflect our posture. Receptors are found in muscles, joints, tendons, and ligaments.

Basic properties of sensations

Each group of sensations can be described in terms of the same properties.

The main properties of sensation:

- quality - this is a property that characterizes the basic information displayed by this sensation and distinguishes it from other types of sensation.

- intensity- this is a quantitative characteristic and depends on the strength of the acting stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions. The intensity depends on the strength or amount of the acting stimulus. The intensity depends on the state of the receptors.

- duration- this is a temporal characteristic of the sensation that has arisen, which is determined by the time of action of the stimulus and its intensity.

- spatial localization of the stimulus- this is that any sensation allows us to receive information about the location of the stimulus in space. Any sensation has the property of spatial localization of the stimulus.

Feelings have a latent (latent) period. When exposed to a stimulus, sensation occurs later. This period varies. There is a certain period that continues after the stimulus has ceased to affect the senses. It is called consistent way of feeling. It can be positive or negative, depending on the situation.

FEDERAL AGENCY FOR EDUCATION

State educational institution of higher professional education

AMUR STATE UNIVERSITY (GOUVPO "AmSU")

Department of Psychology and Pedagogy

on the topic: Types of sensations and their mechanisms

by discipline Sociology

Executor

group student

Supervisor

Blagoveshchensk

Introduction

1. General concept of sensation

2. Types of sensations and their mechanisms

2.1 Systematic classification of sensations

2.1.1 Exteroceptive sensations

2.1.1.1 Distant sensations

2.1.1.1.1 Visual sensations

2.1.1.1.2 Auditory sensations

2.1.1.1.3 Olfactory sensations

2.1.1.2 Contact sensations

2.1.1.2.1 Taste sensations

2.1.1.2.2 Temperature sensations

2.1.1.2.3 Sensations of touch, pressure

2.1.1.2.4 Tactile sensations

2.1.2 Interoceptive sensations

2.1.2.1 Organic sensations

2.1.2.2 Feelings of pain

2.1.3 Proprioceptive sensations

2.1.3.1 Feelings of balance

2.1.3.2 Motion sensations

2.2 Structural-genetic classification of sensations

2.2.1 Protopathic sensations

2.2.2 Epicritical sensations

Conclusion

Bibliographic list

INTRODUCTION

The main source of our knowledge about the external world and about our own body is sensations. They constitute the main channels through which information about the phenomena of the external world and the state of the body reaches the brain, giving a person the opportunity to navigate in the environment and in his body. If these channels were closed and the sense organs did not bring the necessary information, no conscious life would be possible.

Feelings in their quality and variety reflect the variety of properties of the environment for a person. The sense organs, or human analyzers, are adapted from birth for the perception and processing of various types of energy in the form of stimuli-stimuli (physical, chemical, mechanical and other influences).

Types of sensations reflect the uniqueness of the stimuli that generate them. These stimuli evoke corresponding sensations of different quality: visual, auditory, sensations of touch, pressure, pain, heat, cold, gustatory, olfactory, organic sensations, sensations of balance and movement.

1. GENERAL CONCEPT OF SENSATION

The simplest of cognitive mental processes is sensation. The process of sensation arises as a result of the impact on the sense organs of various material factors, which are called stimuli, the process of exposure itself is irritation. Irritation causes a process of excitation, which passes through the centripetal or afferent nerves to the cerebral cortex, where sensations arise. Thus, sensation is a sensory reflection of objective reality.

The essence of sensation is the reflection of the individual properties of the object. Each stimulus has its own characteristics, depending on which it can be perceived by certain sense organs. This is the process of reflecting the individual properties of the object.

The physiological basis of sensations is the activity of anatomical structures named by I.P. Pavlov's analyzers. Each analyzer consists of three parts: 1) a peripheral section called a receptor; 2) conducting nerve pathways; 3) the cortical sections of the analyzer, in which the processing of nerve impulses coming from the peripheral sections takes place. The cortical part of each analyzer includes an area that is a projection of the periphery (i.e., a projection of the sense organ) in the cerebral cortex, since certain parts of the cortex correspond to certain receptors. For the sensation to arise, it is necessary to use all the components of the analyzer. If any part of the analyzer is destroyed, the occurrence of the corresponding sensations becomes impossible.

The analyzer is an active organ that reflexively rebuilds itself under the influence of stimuli, so sensation is not a passive process, it always includes motor components. Numerous studies have found that sensation is closely related to movement, which sometimes manifests itself in the form of a vegetative reaction (vasoconstriction, galvanic skin reflex), sometimes in the form of muscle reactions (eye rotation, neck muscle tension). Thus, sensations are not passive processes at all - they are active, or reflex in nature.

Sensations are not only the source of our knowledge of the world, but also of our feelings and emotions. The simplest form of emotional experience is the so-called sensual, or emotional, tone of sensation, i.e. a feeling that is directly related to a feeling.

Feelings connect a person with the outside world and are both the main source of information about him and the main condition for mental development. However, despite the obviousness of these provisions, they have been repeatedly questioned. Representatives of the idealistic trend in philosophy and psychology expressed the idea that the true source of conscious activity is not sensations, but the internal state of consciousness, the ability of rational thinking, inherent in nature and independent of the influx of information coming from the outside world. These views formed the basis of the philosophy of rationalism. The bottom line was the assertion that consciousness and reason are the primary, inexplicable property of the human spirit. Idealist philosophers and many psychologists who are supporters of the idealistic concept have made attempts to reject the position that a person's sensations connect him with the external world, and to prove the opposite: sensations separate a person from the external world with an insurmountable wall. A similar position was put forward by D. Berkeley, D. Hume, E. Mach. These provisions lead to the following statement: a person cannot perceive the objective world, and the only reality is subjective processes that reflect the activity of his sense organs, which create subjectively perceived “elements of the world”. Opposite positions are taken by representatives of the materialistic trend, who consider it possible to objectively reflect the external world. In the process of historical development, especially perceiving organs were formed that specialized in reflecting special types of objectively existing forms of the movement of matter: auditory receptors that reflect sound vibrations; visual receptors that reflect certain ranges of electromagnetic oscillations, etc. The high specialization of various organs is based not only on the structural features of the peripheral part of the analyzer - receptors, but also on the highest specialization of neurons that are part of the central nervous apparatus, which receive signals perceived by peripheral sensory organs.

It should be noted that human sensations are a product of historical development, and therefore they are qualitatively different from the sensations of animals. In animals, the development of sensations is limited by biological, instinctive needs. In humans, on the contrary, the ability to feel is not limited by biological needs. Labor created for him a wider range of needs than for animals, and in activities aimed at satisfying these needs, human abilities, including the ability to feel, constantly developed. Therefore, a person can feel a much larger number of properties of the objects surrounding him than an animal.

2. TYPES OF SENSATIONS AND THEIR MECHANISMS

There are various approaches to the classification of sensations. It has long been customary to distinguish five (by the number of organs) of the main types of sensations, highlighting smell, taste, touch, hearing and vision. 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 believes that the classification can be carried out according to two main 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.

2.1 Systematic classification of sensations

Consider a systematic classification of sensations. This classification was proposed by the English physiologist C. Sherrington. Considering the largest and most significant groups of sensations, he divided them into three main types: interoceptive, proprioceptive and exteroceptive.

2.1.1 Exteroceptive sensations

The largest group of sensations are exteroceptive sensations. They bring information from the outside world to a person and are the main group of sensations that connects a person with the external environment. The whole group is conventionally divided into two subgroups: contact and distant.

2.1.1.1 Distant sensations

Distant sensations reflect the qualities of objects that are 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, occupies an intermediate position, since olfactory sensations occur at a distance from the object, but at the same time, the molecules characterizing 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.

2.1.1.1.1 Visual sensations

The role of visual sensations in the knowledge of the world is especially great. They provide a person with rich and finely differentiated data of a huge range. Vision gives us the most perfect, genuine perception of objects. Visual sensations are most differentiated from affectivity; the moment of sensual contemplation is especially strong in them. Visual perceptions are objectified perceptions of a person. Therefore, they are of great importance for knowledge and for practical action.

Closely related to each other. Both are so-called sensory reflections of objective reality that exists independently of consciousness and as a result of its influence on the sense organs: this is their unity. But perception- awareness of a sensual given object or phenomenon; in perception, we usually have a world of people, things, phenomena that are filled with a certain meaning for us and are involved in diverse relationships. These relationships create meaningful situations, witnesses and participants of which we are. Feeling on the other hand, it is a reflection of a separate sensory quality or undifferentiated and unobjectified impressions from the environment. In this last case sensations and perceptions are distinguished as two different forms or two different relations of consciousness to objective reality. Sensations and perceptions are thus one and different. They make up: sensory-perceptual level of mental reflection. At the sensory-perceptual level, we are talking about those images that arise from the direct impact of objects and phenomena on the senses.

The concept of sensations

The main source of our knowledge about the external world and about our own body is sensations. They constitute the main channels through which information about the phenomena of the external world and about the states of the body reaches the brain, giving a person the opportunity to navigate in the environment and in his body. If these channels were closed and the sense organs did not bring the necessary information, no conscious life would be possible. There are known facts that a person deprived of a constant source of information falls into a sleepy state. Such cases: take place when a person suddenly loses sight, hearing, smell, and when his conscious sensations are limited by some pathological process. A result close to this is achieved when a person is placed for some time in a light and soundproof chamber that isolates him from external influences. This state first induces sleep and then becomes intolerable for the subjects.

Numerous observations have shown that impaired information flow in early childhood, associated with deafness and blindness, causes severe delays in mental development. If children born deaf-deaf or deprived of hearing and sight at an early age are not taught special techniques that compensate for these defects due to touch, their mental development will become impossible and they will not develop independently.

As will be described below, the high specialization of various sense organs is based not only on the structural features of the peripheral part of the analyzer - “receptors”, but also on the highest specialization of neurons that are part of the central nervous apparatus, which reach the signals perceived by the peripheral sense organs.

The reflex nature of sensations

So, sensations are the initial source of all our knowledge about the world. Objects and phenomena of reality that act on our senses are called stimuli, and the effect of stimuli on the senses is called irritation. Irritation, in turn, causes excitation in the nervous tissue. Sensation arises as a reaction of the nervous system to a particular stimulus and, like any mental phenomenon, has a reflex character.

The physiological mechanism of sensations is the activity of special nervous apparatuses called.

Each analyzer consists of three parts:

1. the peripheral section, called the receptor (the receptor is the perceiving part of the analyzer, its main function is the transformation of external energy into a nervous process);
2. afferent or sensory nerves (centripetal), conducting excitation to the nerve centers (the central section of the analyzer);
3. cortical sections of the analyzer, in which the processing of nerve impulses coming from the peripheral sections takes place.

The cortical part of each analyzer includes an area that is a projection of the periphery in the cerebral cortex, since certain areas of the cortical cells correspond to certain cells of the periphery (receptors). For a sensation to arise, the work of the entire analyzer as a whole is necessary. The analyzer is not a passive energy receiver. This is an organ that reflexively rebuilds under the influence of stimuli.

Physiological studies show that sensation is not at all a passive process, it always includes motor components in its composition. So, observations with a microscope of a skin area, carried out by the American psychologist D. Neff, made it possible to make sure that when it is irritated with a needle, the moment the sensation occurs is accompanied by reflex motor reactions of this skin area. Subsequently, numerous studies found that each sensation includes movement, sometimes in the form of a vegetative reaction (vasoconstriction, galvanic skin reflex), sometimes in the form of muscle reactions (eye rotation, neck muscle tension, motor reactions of the hand, etc. .). Thus, sensations are not passive processes at all - they are active. In pointing out the active character of all these processes, the reflex theory of sensations consists.

Classification of sensations

It has long been customary to distinguish five main types (modalities) of sensations: smell, taste, touch, sight and hearing. This classification of sensations according to the main modalities is correct, although not exhaustive. A.R. Luria believes that the classification of sensations can be carried out according to at least two main 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 the level of their construction, on the other).

Systematic classification of sensations

Singling out the largest and most significant groups of sensations, they can be divided into three main types; interoceptive, proprioceptive and exterocentric sensations. The former combine signals that reach us from the internal environment of the body; the latter provide information about the position of the body in space and the position of the musculoskeletal system, provide regulation of our movements; finally, others provide signals from the outside world and provide the basis for our conscious behavior. Consider the main types of sensations separately.

Interoceptive sensations

Interoceptive sensations, signaling the state of the internal processes of the body, bring irritation to the brain from the walls of the stomach and intestines, the heart and circulatory system and other internal organs. This is the oldest and most elementary group of sensations. Interoceptive sensations are among the least conscious and most diffuse forms of sensation and always retain their proximity to emotional states.

proprioceptive sensations

Proprioceptive sensations provide signals about the position of the body in space and form the afferent basis of human movements, playing a decisive role in their regulation. Peripheral receptors for proprioceptive sensitivity are found in muscles and joints (tendons, ligaments) and have the form of special nerve bodies (Paccini bodies). The excitations that arise in these bodies reflect the sensations that occur when muscles are stretched and the position of the joints changes. In modern physiology and psychophysiology, the role of proprioception as the afferent basis of movements in animals was studied in detail by A. A. Orbeli, P. K. Anokhin, and in humans, by N. A. Bernshtein. The described group of sensations includes a specific type of sensitivity, called a sense of balance, or a static sensation. Their peripheral receptors are located in the semicircular canals of the inner ear.

exteroreceptive sensations

The third and largest group of sensations are exteroreceptive sensations. They bring information from the outside world to a person and are the main group of sensations that connects a person with the external environment. The whole group of exteroceptive sensations is conventionally divided into two subgroups: contact and distant sensations.

Contact sensations are caused by an impact directly applied to the surface of the body and the corresponding perceived organ. Taste and touch are examples of contact sensation.

Distant sensations are caused by stimuli acting on the sense organs at some distance. These senses include the sense of smell and, especially, hearing and sight.

Genetic classification of sensations

Genetic classification allows us to distinguish two types of sensitivity:

1. protopathic(more primitive, affective, less differentiated and localized), which includes organic feelings (hunger; thirst, etc.);
2. epicritical(more subtly differentiating, objectified and rational), which includes the main human senses.

Epicritical sensitivity is genetically younger and controls protopathic sensitivity.

General properties of sensations

Different types of sensations are characterized not only by specificity, but also by properties common to them. These properties include: quality, intensity, duration and spatial localization.

Quality- this is the main feature of this sensation, which distinguishes it from other types of sensations and varies within the limits of this type of sensations. The qualitative variety of sensations reflects the infinite variety of forms of motion of matter.

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

Duration sensation is its temporal characteristic. It is also determined by the functional state of the sense organ, but mainly by the duration of the stimulus and its intensity.

When a stimulus is exposed to a sensory organ, sensation does not occur immediately, but after some time - the so-called latent (hidden) period of sensation. The latent period of various types of sensations is not the same: for example, for tactile sensations it is 130 ms; for pain - 370, and for taste - only 50 ms.

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 its action. The presence of positive successive images explains why we do not notice the breaks between successive frames of the film: they are filled with traces of previous frames - successive images from them. The sequential image changes in time, the positive image is replaced by a negative one. With colored light sources, the sequential image turns into a complementary color.