Physiological bases of sensations and perception. Psychology of sensations. The anatomical and physiological basis of sensation are

Sensations arise only when objects directly impact the sense organs. A sense organ is an anatomical and physiological apparatus located on the periphery of the body or in internal organs and specialized for receiving the effects of certain stimuli from the external environment and internal organs. The main part of each sense organ is the endings of nerves, which are called receptors. A receptor is a part of an analyzer whose function is to transform external energy into a nervous process. Sensory organs such as the eye and ear, which combine dozens of receptor endings. The receptor, the nerves that conduct information about subdivisions, and the area in the cerebral cortex, which represent a single morphological structure. IP. Pavlov called it an analyzer.

Each analyzer is a nervous mechanism, which consists of three parts: 1) a peripheral section - a receptor, 2) an afferent or sensory nerve (centripetal), which conducts excitation to the nerve center three (central section of the analyzer), 3) cortical sections of the analyzer, in which process nerve impulses coming from peripheral parts. The cork part of the analyzer includes a long section, which is a projection of the periphery in the cerebral cortex, since certain parts of the cortical cells correspond to certain cells of the periphery (receptors). For sensation to arise, the entire analyzer as a whole must work.

Objects and phenomena of reality that affect our senses are called stimuli. The effect of stimuli on the sense organs is called irritation. Irritation causes excitement in the nervous tissue. Viidchuttya arises as a reaction of the nervous system to a particular stimulus and is of a reflex nature. The action of the stimulus on the receptor leads to the emergence of a nerve impulse, which is transmitted along afferent nerves to certain areas of the cerebral cortex. Reaction - the response is transmitted along the efferent (motor) nerve to the organ that responds to the senses. So, when a person touches a hot object with his hand, the signal goes to the brain and through the efferent nerves to the muscles, as a result of which they contract.

23 Types of sensations

Even the ancient Greeks distinguished five sense organs and their corresponding sensations: visual, auditory, tactile, olfactory and gustatory. Modern science has significantly expanded our understanding of the types of sensations. OR. Luria believes that the classification of sensations can be carried out using less than 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 and level of their construction, on the other).

Systematic classification of sensations

Based on the location of receptors on the surface of the body or inside the body, the following types of sensations are distinguished:

1) exteroceptive;

2) interoceptive;

3) proprioceptive

exteroceptive sensation- this is the largest group of sensations. They provide signals from the outside world and create the basis for our consciousness. Exteroceptive sensations include visual, auditory, olfactory, sensory, tactile (tactile), thermal (temperature) and pain sensations.

interoceptive sensation- these are organic sensations, they signal the state of the internal processes of the body, bring to the brain irritations 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. They are among the least conscious and most diffuse forms of sensations and are always closely related to emotional states.

proprioceptive sensations provide signals about the position of the body in space and form the basis of human movements, playing an important role in their regulation. Peripheral receptors of proprioceptive sensitivity are located in muscles and joints (tendons, ligaments) and have the form of special nerve bodies (Paccini bodies). The excitation that occurs in these bodies reflects the sensations that occur when calculating muscle tension and changing the position of joints. This group of sensations includes a specific type of sensitivity called the sense of balance, or static sensation, their peripheral receptors are located in the canals of the inner ear. Proprioceptive sensations include kinesthetic and static sensations.

Exteroceptive sensations are usually divided depending on the presence or absence of direct contact of the receptor with the stimulus causing the sensation into:

1) contact;

2) sufficient

Contact sensations are caused by the impact directly applied to the surface of the body of the corresponding organ of perception. Examples of contact sensations are taste, touch

distant sensations are caused by stimuli acting on the sense organs at some distance. These include olfactory sensations, hearing and vision

Genetic classification allows us to distinguish two types of sensitivity:

1) protopathic (more primitive, affective, less differentiated and localized), which includes organic sensations (hunger, thirst, etc.);

2) epicritic (more subtly differentiated, objectified and rational), to which the main human senses belong. The sensitivity of the younger one in genetic terms is epicritical, and it controls protopathic sensitivity.

Let us dwell in more detail on the characteristics of certain types of sensations

Visual sensations play a large role in human interaction with the environment. The visual apparatus is the eye, a sensory organ with a complex anatomical structure. What is the physical cause of visual sensations? The human eye perceives only a small part of electromagnetic waves. Light waves that are reflected by an object are refracted as they pass through the lens and are focused on the retina in the form of an image. The retina is connected through the optic nerve to the cerebral hemispheres. The retina has a complex structure. One of the layers included in its composition is the layer of rods and cones, which are the final formations of the optic nerve. Rods and cones perform different functions. Rods are the organ of vision in the dark, and since under such conditions a person does not feel spectral colors, they are called non-color vision organs. Cones are the organ of “daytime” vision; they are characterized by less sensitivity to light. Since during the day a person perceives different kinds of colors, the cones are called the organ of color vision.

Visual sensations include the sensation of light and color

Auditory sensations, reflecting a wide variety of properties of sounding objects and phenomena, help a person navigate the environment and regulate his actions. They are caused by sounds acting on the auditory analyzer at a distance through air vibrations and sound waves. Therefore, auditory sensations belong to distant sensations.

The sensory endings of the auditory nerve are located in the inner ear. The outer ear (pinna) collects sound vibrations and transmits them to the inner ear at the cochlea. Excitation of the nerve endings of the curls occurs according to the principle of resonance, the endings of the auditory nerve, different in length and thickness, begin to move according to a certain number of oscillations per second.

Auditory sensations include the sense of language, music and noise. With the help of auditory sensations, the following qualities of sound are distinguished: strength (loud - quiet), height (high - low), timbre (the originality of a voice or musical instrument), duration (sounding time), as well as a dark-rhythmic pattern of sounds that are consistently perceived.

Auditory sensations are also of great importance in the perception of oral speech. Phonemic hearing, or sensitivity to speech sounds, is formed in the process of acquiring and using language. Its development affects the ease of written speech, especially in the primary grades.

Hearing sensitivity is closely related to vibration sensitivity. It is believed that in the human body there are no special receptors designed to sense vibration, and all organs and tissues of the human body are capable of reflecting vibrations.

Olfactory sensations do not have the same significance in a person’s life as visual and auditory ones, since they are not associated with orientation in the environment; their role is that they signal a person about the freshness of food, cleanliness of air, etc. In those cases, when their development is stimulated by the conditions of professional activity, they achieve significant perfection (perfumers, firefighters, etc..).

The irritants that cause olfactory sensations are microscopic particles of odorous substances that enter the nasal cavity with air, dissolve in the nasal fluid and affect the receptor. Olfactory sensations are very often combined with other senses - taste, tactile, temperature, etc. and become complex. The connection of an olfactory sensation with others can be of a conditioned reflex nature (the sight of a rose can enhance our sense of its smell).

Taste sensations are closely related to olfactory sensations; they are united by a common role in nutrition processes. The organ of taste is the tongue. Taste sensations include sour, sweet, bitter and salty. Other flavors result from the mixing of basic flavors. Taste sensations increase a person’s appetite and also perform a protective function, signaling poor quality food. The dynamics of taste sensations are closely related to the body's need for food. In a state of hunger, sensitivity increases, and when satiated, it decreases.

Skin sensations include tactile, temperature and pain sensations

Tactile sensations arise due to the impact of mechanical stimuli on the surface of the skin. The condition for their occurrence is contact with an irritant that causes deformation of the skin; tactile sensitivity is unevenly distributed throughout the body. The largest concentration of tactile receptors is on the palms, fingertips and lips.

Tactile sensations are sensations of touch and pressure. They signal the presence of a particular irritant that collides with the surface of the body. Tactile sensations reflect important properties of the object of the objective world: equality, roughness, hardness, softness, dryness, moisture, etc.

Temperature sensations are divided into sensations of cold and warmth. They signal changes in the temperature environment, the danger of cooling the body or overheating, and help regulate the exchange between the body and the environment. In addition, temperature sensations give a person information about the thermal properties of objects and phenomena in the environment.

The nature of temperature sensations depends on the nature of the current stimulus. If the temperature of an object is lower than body temperature, then a feeling of cold occurs, if higher, a feeling of warmth occurs. Temperature sensations are local in nature, since we attribute them to a specific area of ​​the skin that is affected by the irritant.

Painful sensations occur when exposed to various types of irritants (mechanical, thermal, chemical, electrical, etc.), which cause damage or destruction of body tissues. They play an important role as components of protective reflexes, signal the harm of the stimulus to the body and the need to interrupt contact with it, and have a pronounced negative emotional connotation. Painful sensations carry certain information about the stimulus; they reflect its intensity, quality (stabbing, cutting, burning pain), and location. The spatial localization of pain is not always precise, which is explained by the irradiation of excitation processes.

Static sensations reflect the position of the body in space and its balance. Static sensation receptors are located in the vestibular apparatus of the inner ear. This type of sensation is of great importance for the vitality of the body, since it ensures that the body maintains balance. Regulation of the body's balance is reflexive in nature. The normal operation of the static analyzer is necessary to display space using other types of sensations, in particular visual and rukhovovogo.

kinesthetic sensation (from the Greek “kinesis” - movement and “aisthesis” - sensation) is the sensation of the movements and position of parts of one’s own body. Receptors for kinesthetic sensations are located in muscles and tendons. Irritation in these receptors occurs during contraction and stretching of muscles and ligaments, and friction of joints. The result of these sensations is knowledge about the strength, speed, and trajectory of movement of parts of the body.

In combination with other senses, kinesthetic sensations become specific and differentiated; in combination with visual sensations, they become important in a person’s cognition of the spatial properties of things. The combination of kinesthetic sensation with tactile sensation appears in the form of touch.

During training, it is necessary to pay attention to the development of kinesthetic sensations, which is the focus of labor, drawing, physical education lessons, as well as dancing, rhythmic gymnastics and other sports. At the same time, it is important to take into account the peculiarities of the development of this type of sensation in certain age periods.

Organic sensations are sensations associated with the activity of internal organs. These sensations, merging, form the organic feeling (well-being) of a person. This is the so-called senesthesia (general sensation), which reflects the general state of the body based on signals coming from various organs of the body. An example is the feeling of general malaise that occurs in a patient. Organic sensations include feelings of hunger, thirst, satiety, nausea, changes in the activity of the heart, stomach, and pain.

Organic sensations are caused by impulses from internal states, as well as changes in the chemical formula of the blood. They are characterized by insufficient clarity, vagueness and uncertainty of localization; a characteristic feature of organic sensations is their emotional coloring (positive or negative).

The physiological basis of sensations is the activity of complex complexes of anatomical structures, named by I.P. Pavlov analyzers . Each analyzer consists of three parts:

1) a 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) nerve pathways;

3) the cortical sections of the analyzer (they are also called the central sections of the analyzers), in which the processing of nerve impulses coming from the peripheral sections occurs.

The cortical part of each analyzer includes an area that represents a projection of the periphery (i.e., a projection of the sensory organ) in the cerebral cortex, since certain receptors correspond to certain areas of the cortex. For sensation to occur, all components of the analyzer must be used. If any part of the analyzer is destroyed, the occurrence of the corresponding sensations becomes impossible. Thus, visual sensations cease when the eyes are damaged, when the integrity of the optic nerves is damaged, and when the occipital lobes of both hemispheres are destroyed.

Analyzer - this is an active organ, reflexively rearranged under the influence of stimuli, therefore sensation is not a passive process, it always includes motor components. Thus, the American psychologist D. Neff, observing an area of ​​skin with a microscope, became convinced that when it is irritated by a needle, the moment the sensation occurs is accompanied by reflexive motor reactions of this area of ​​the skin. Subsequently, numerous studies have established 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 (turning the eyes, tension in the neck muscles, motor reactions of the hand, etc.) .d.). Thus, sensations are not at all passive processes - they are active, or reflexive, in nature.

3. Classification of types of sensations.

There are different approaches to classifying sensations. It has long been customary to distinguish between five (based on the number of sense organs) main types of sensations: smell, taste, touch, vision and hearing. This classification of sensations according to the main modalities is correct, although not exhaustive. B. G. Ananyev spoke about eleven types of sensations. A. R. Luria believes 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, with one sides, andBy principle difficulties or the level of their construction - on the other).

Let's consider systematic classification sensations (Fig. 1). 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 Feel. The first combine signals reaching us from the internal environment of the body; the latter transmit information about the position of the body in space and the position of the musculoskeletal system, and ensure the regulation of our movements; finally, still others provide signals from the external world and create the basis for our conscious behavior. Let's consider the main types of sensations separately.

Interoceptive sensations signaling the state of the internal processes of the body arise due to receptors located on the walls of the stomach and intestines, the heart and circulatory system and other internal organs. This is the most ancient and most elementary group of sensations. Receptors that perceive information about the state of internal organs, muscles, etc. are called internal receptors. Interoceptive sensations are among the least conscious and most diffuse forms of sensations and always retain their proximity to emotional states. It should also be noted that interoceptive sensations are often called organic.

Proprioceptive sensations transmit signals about the position of the body in space and form the afferent basis of human movements, playing a decisive role in their regulation. The described group of sensations includes a sense of balance, or static sensation, as well as a motor, or kinesthetic, sensation.

Peripheral receptors of proprioceptive sensitivity are located in muscles and joints (tendons, ligaments) and are called Paccini corpuscles.

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. Bernstein.

Peripheral receptors for the sensation of balance are located in the semicircular canals of the inner ear.

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

Rice. 1. Systematic classification of the main types of sensations

Contact sensations are caused by the direct impact of an object on the senses. Examples of contact sensation are taste and touch. Distant Feel reflect the qualities of objects located at some distance from the senses. Such sensations include hearing and vision. 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 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.

Since sensation arises as a result of the action of a certain physical stimulus on the corresponding receptor, the primary classification of sensations considered by us proceeds, naturally, from the type of receptor that gives the sensation of a given quality, or “modality”. However, there are sensations that cannot be associated with any specific modality. Such sensations are called intermodal. These include, for example, vibration sensitivity, which connects the tactile-motor sphere with the auditory sphere.

The sensation of vibration is the sensitivity to vibrations caused by a moving body. According to most researchers, the vibration sense is an intermediate, transitional form between tactile and auditory sensitivity. In particular, the school of L. E. Komendantov believes that tactile-vibration sensitivity is one of the forms of sound perception. With normal hearing, it does not appear particularly prominent, but with damage to the auditory organ, this function is clearly manifested. The main position of the “auditory” theory is that tactile perception of sound vibration is understood as diffuse sound sensitivity.

Vibration sensitivity acquires particular practical significance in cases of damage to vision and hearing. It plays a big role in the lives of deaf and deaf-blind people. Deaf-blind people, thanks to the high development of vibration sensitivity, learned about the approach of a truck and other types of transport at a great distance. In the same way, through the vibrational sense, deaf-blind people know when someone enters their room. Consequently, sensations, being the simplest type of mental processes, are actually very complex and have not been fully studied.

It should be noted that there are other approaches to the classification of sensations. For example, the genetic approach proposed by the English neurologist H. Head. 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) epicritic (more subtly differentiating, objectified and rational), which includes the main types of human sensations. Epicritic sensitivity is younger in genetic terms, and it controls protopathic sensitivity.

The famous Russian psychologist B.M. Teplov, considering the types of sensations, divided all receptors into two large groups: exteroceptors (external receptors), located on the surface of the body or close to it and accessible to external stimuli, and interoceptors (internal receptors), located deep within tissues such as muscles, or on surfaces of internal organs. The group of sensations that we called “proprioceptive sensations” was considered by B.M. Teplov as internal sensations.

All sensations can be characterized in terms of their properties. Moreover, the properties can be not only specific, but also common to all types of sensation. The main properties of sensations include: quality, intensity, duration, spatial localization, absolute and relative thresholds of sensations.

Quality - this is a property that characterizes the basic information displayed by a given sensation, distinguishes it from other types of sensations and varies within a given type of sensation. For example, taste sensations provide information about certain chemical characteristics of an object: sweet or sour, bitter or salty. The sense of smell also provides us with information about the chemical characteristics of an object, but of a different kind: flower smell, almond smell, hydrogen sulfide smell, etc.

It should be borne in mind that very often, when they talk about the quality of sensations, they mean the modality of sensations, since it is the modality that reflects the main quality of the corresponding sensation.

Intensity sensation is its quantitative characteristic and depends on the strength of the current stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions. For example, if you have a runny nose, the intensity of perceived odors may be distorted.

Duration Feel - this is a temporary characteristic of the sensation that has arisen. It is also determined by the functional state of the sensory organ, but mainly by the time of action of the stimulus and its intensity. It should be noted that sensations have a so-called latent (hidden) period. When a stimulus acts on a sense organ, the sensation does not occur immediately, but after some time. The latent period of different types of sensations is not the same. For example, for tactile sensations it is 130 ms, for pain - 370 ms, and for taste - only 50 ms.

The sensation does not appear simultaneously with the onset of the stimulus and does not disappear simultaneously with the cessation of its effect. This inertia of sensations manifests itself in the so-called aftereffect. A visual sensation, for example, has some inertia and does not disappear immediately after the cessation of the action of the stimulus that caused it. The trace of the stimulus remains in the form of a consistent image. There are positive and negative sequential images. Positive consistent image corresponds to the initial irritation, consists in maintaining a trace of irritation of the same quality as the actual stimulus.

Negative sequential image consists in the emergence of a quality of sensation opposite to the quality of the stimulus that acts. For example, light-darkness, heaviness-lightness, warmth-cold, etc. The emergence of negative sequential images is explained by a decrease in the sensitivity of a given receptor to a certain influence.

And finally, sensations are characterized by spatial localization irritant. The analysis carried out by the receptors gives us information about the localization of the stimulus in space, that is, we can tell where the light comes from, the heat comes from, or what part of the body the stimulus affects.

All the properties described above, to one degree or another, reflect the qualitative characteristics of sensations. However, no less important are the quantitative parameters of the main characteristics of sensations, in other words, the degree sensitivity .

4. Patterns of sensations.

So far we have been talking about the qualitative difference in types of sensations. However, quantitative research, in other words, their measurement, is no less important.

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

Stimuli of lesser strength, so-called subthreshold, do not cause sensations, and signals about them are not transmitted to the cerebral cortex. At each individual moment, from an infinite number of impulses, the cortex perceives only vitally relevant ones, delaying all others, including impulses from internal organs. This position is biologically expedient. It is impossible to imagine the life of an organism in which the cerebral cortex would equally perceive all impulses and provide reactions to them. This would lead the body to inevitable death. It is the cerebral cortex that guards the vital interests of the body and, raising the threshold of its excitability, transforms irrelevant impulses into subthreshold ones, thereby relieving the body of unnecessary reactions.

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

The lower threshold of sensations determines the level of absolute sensitivity of this analyzer. There is an inverse relationship between absolute sensitivity and the threshold value: the lower the threshold value, the higher the sensitivity of a given analyzer. This relationship can be expressed by the formula:

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

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

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

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

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

With the help of our senses, we can not only ascertain the presence or absence of a particular stimulus, but also distinguish between stimuli by their strength and quality. The minimum difference between two stimuli that causes a barely noticeable difference in sensation is called discrimination threshold or difference threshold . The German physiologist E. Weber (1795-1878), testing a person’s ability to determine the heavier of two objects in the right and left hand, established that difference sensitivity is relative, not absolute. This means that the ratio of the additional stimulus to the main one must be a constant value. So, if there is a load of 100 grams on your hand, then for a barely noticeable sensation of weight gain to occur, you need to add about 3.4 grams. If the weight of the load is 1000 grams, then to create the feeling of a barely noticeable difference you need to add about 33.3 grams. Thus, the greater the magnitude of the initial stimulus, the greater the increase should be to it.

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

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

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

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

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

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

Adaptation, or adaptation, is a change in the sensitivity of the senses under the influence of a stimulus.

Three types of this phenomenon can be distinguished.

1. Adaptation as the complete disappearance of sensation during the prolonged action of a stimulus. We mentioned this phenomenon at the beginning of this chapter, talking about the peculiar mood of the analyzers to changes in stimuli. In the case of constant stimuli, the sensation tends to fade. For example, a light weight resting on the skin soon ceases to be felt. A common fact is the distinct disappearance of olfactory sensations soon after we enter an atmosphere with an unpleasant odor. The intensity of the taste sensation weakens if the corresponding substance is kept in the mouth for some time and, finally, the sensation may fade away completely.

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

2. Adaptation is also called another phenomenon, close to the one described, which is expressed in a dulling of sensation under the influence of a strong stimulus. For example, when you immerse your hand in cold water, the intensity of the sensation caused by the cold stimulus decreases. When we move from a dimly lit room into a brightly lit space, we are initially blinded and unable to discern any details around us. After some time, the sensitivity of the visual analyzer decreases sharply, and we begin to see normally. This decrease in eye sensitivity under intense light stimulation is called light adaptation.

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

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

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

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

Adaptive regulation of the level of sensitivity depending on what stimuli (weak or strong) affects the receptors is of great biological importance. Adaptation helps the sensory organs to detect weak stimuli and protects the sensory organs from excessive irritation in the event of unusually strong influences.

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

Interaction of sensations . The intensity of sensations depends not only on the strength of the stimulus and the level of adaptation of the receptor, but also on the stimuli currently affecting other sense organs. A change in the sensitivity of the analyzer under the influence of irritation of other senses is called the interaction of sensations.

The literature describes numerous facts of changes in sensitivity caused by the interaction of sensations. Thus, the sensitivity of the visual analyzer changes under the influence of auditory stimulation. S.V. Kravkov (1893-1951) showed that this change depends on the volume of auditory stimuli. Weak sound stimuli increase the color sensitivity of the visual analyzer. At the same time, there is a sharp deterioration in the distinctive sensitivity of the eye when, for example, the loud noise of an aircraft engine is used as an auditory stimulus.

Visual sensitivity also increases under the influence of certain olfactory stimuli. However, with a pronounced negative emotional connotation of the smell, a decrease in visual sensitivity is observed. Similarly, with weak light stimuli, auditory sensations increase, and exposure to intense light stimuli worsens auditory sensitivity. There are known facts of increased visual, auditory, tactile and olfactory sensitivity under the influence of weak painful stimuli.

A change in the sensitivity of any analyzer is also observed with subthreshold stimulation of other analyzers. Thus, P.I. Lazarev (1878-1942) obtained evidence of a decrease in visual sensitivity under the influence of skin irradiation with ultraviolet rays.

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

Sensitization . Increased sensitivity as a result of the interaction of analyzers and exercise is called sensitization.

The physiological mechanism for the interaction of sensations is the processes of irradiation and concentration of excitation in the cerebral cortex, where the central sections of the analyzers are represented. According to I.P. Pavlov, a weak stimulus causes an excitation process in the cerebral cortex, which easily irradiates (spreads). As a result of the irradiation of the excitation process, the sensitivity of the other analyzer increases. When exposed to a strong stimulus, a process of excitation occurs, which, on the contrary, tends to concentrate. According to the law of mutual induction, this leads to inhibition in the central sections of other analyzers and a decrease in the sensitivity of the latter.

A change in the sensitivity of analyzers can be caused by exposure to second-signal stimuli. Thus, evidence was obtained of changes in the electrical sensitivity of the eyes and tongue in response to the presentation of the words “sour as lemon” to the test subject. These changes were similar to those observed when the tongue was actually irritated with lemon juice.

Knowing the patterns of changes in the sensitivity of the sensory organs, it is possible, by using specially selected side stimuli, to sensitize one or another receptor, i.e. increase its sensitivity.

Sensitivity and exercise . Sensitization of the senses is possible not only through the use of side stimuli, but also through exercise. The possibilities for training the senses and improving them are very great. There are two areas that determine increased sensitivity of the senses:

1) sensitization, which spontaneously results from the need to compensate for sensory defects (blindness, deafness);

2) sensitization caused by the activity and specific requirements of the subject’s profession.

The loss of vision or hearing is to a certain extent compensated by the development of other types of sensitivity.

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

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

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

Grinders are known to have extraordinary visual acuity. They see gaps from 0.0005 millimeters, while untrained people see only up to 0.1 millimeters. Fabric dyeing specialists distinguish between 40 and 60 shades of black. To the untrained eye they appear exactly the same. Experienced steelmakers are able to quite accurately determine its temperature and the amount of impurities in it by the faint color shades of molten steel.

The olfactory and gustatory sensations of tasters of tea, cheese, wine, and tobacco reach a high degree of perfection. Tasters can pinpoint not only what type of grape a wine is made from, but also where those grapes grew.

Painting places special demands on the perception of shapes, proportions and color relationships when depicting objects. Experiments show that the artist's eye is extremely sensitive to assessing proportions. It distinguishes changes equal to 1/60-1/150 of the size of the object. The subtlety of color sensations can be judged by the mosaic workshop in Rome - it contains more than 20,000 shades of primary colors created by man.

The possibilities for developing auditory sensitivity are also quite large. Thus, playing the violin requires special development of pitch hearing, and violinists have it more developed than pianists. Experienced pilots can easily determine the number of engine revolutions by hearing. They freely distinguish 1300 from 1340 rpm. Untrained people only notice the difference between 1300 and 1400 rpm.

All this is proof that our sensations develop under the influence of living conditions and the requirements of practical work activity.

Despite the large number of similar facts, the problem of exercising the senses has not yet been sufficiently studied. What underlies the exercise of the senses? It is not yet possible to give a comprehensive answer to this question. An attempt has been made to explain the increased tactile sensitivity in blind people. It was possible to isolate tactile receptors - special bodies found in the skin of the fingers of blind people. For comparison, the same study was conducted on the skin of sighted people of various professions. It turned out that blind people have an increased number of tactile receptors. Thus, if in the skin of the nail phalanx of the first finger in sighted people the number of corpuscles on average reached 186, then in those born blind it was 270.

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

Synesthesia . The interaction of sensations manifests itself in another type of phenomenon called synesthesia. Synesthesia is the occurrence, under the influence of stimulation of one sensation analyzer, of sensations characteristic of another analyzer. Synesthesia is observed in a wide variety of sensations. The most common is visual-auditory synesthesia, when the subject experiences visual images when exposed to sound stimuli. There is no overlap in these synesthesias among different people, but they are fairly consistent across individuals. It is known that some composers (N.A. Rimsky-Korsakov, A.M. Scriabin, etc.) possessed the ability of color hearing. We find a striking manifestation of this kind of synesthesia in the work of the Lithuanian artist M.K. Churlionis - in his symphonies of colors.

The phenomenon of synesthesia is the basis for the creation in recent years of color music devices that transform sound images into light images, and intensive research into color music. Less common are cases of auditory sensations arising when exposed to visual stimuli, gustatory sensations in response to auditory stimuli, etc. Not all people have synesthesia, although it is quite widespread. No one doubts the possibility of using such expressions as “sharp taste”, “flashy color”, “sweet sounds”, etc. The phenomena of synesthesia are another evidence of the constant interconnection of the analytical systems of the human body, the integrity of the sensory reflection of the objective world.

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

All living beings that have a nervous system have the ability to sense sensations. As for conscious sensations (about, the source and quality of which a report is given), only humans have them.

In the evolution of living beings, sensations arose on the basis of primary irritability, which is the property of living matter to respond to biologically significant environmental influences by changing its internal behavior.

By their origin, from the very beginning, sensations were associated with the activity of the body, with the need to satisfy its biological needs. The vital role of sensations is to promptly convey to the central nervous system (as the main organ of control of human activity and behavior) information about the state of the external and internal environment, the presence of biologically significant factors in it.

Sensation, unlike irritability, carries information about certain qualities of external influence. A person’s sensations, in their quality and diversity, reflect the variety of environmental properties that are significant to him.

Potential energy signals are: light, pressure, heat, chemicals, etc.

Human sense organs, or analyzers, from the moment of birth are adapted to perceive and process various types of energy in the form of stimuli - irritants (physical, mechanical, chemical and others).

An irritant is any factor that affects the body and can cause some kind of reaction in it. It is necessary to distinguish between stimuli that are adequate for a given sense organ and those that are adequate for it. This fact indicates a subtle specialization of the senses to reflect one or another type of energy, certain properties of objects and phenomena of reality.

The specialization of the sense organs is a product of long evolution, and the sense organs themselves are products of adaptation to the influences of the external environment, therefore, in their structure and properties, they are adequate to these influences. In humans, subtle differentiation in the field of sensations is associated with the historical development of human society and with social and labor practice. “Serving” the processes of adaptation of the organism to the environment, the sense organs can successfully perform their function only if they correctly reflect its objective properties. Thus, it is not the specificity of the sense organs that gives rise to the specificity of sensations, but the specific qualities of the external world that give rise to the specificity of the senses.

Sensations are not symbols, hieroglyphs, but reflect the actual properties of objects and phenomena of the material world that affect the sense organs of the subject, existing independently of him. The physiological basis of sensations is the complex activity of the sensory organs, called analyzer activity.

Analyzers are a set of interacting formations of the peripheral and central nervous systems that receive and analyze information about phenomena occurring both inside and outside the body.

The entire human body can be considered as a single and complexly differentiated analyzer of environmental impacts on humans.

The differentiation of analyzers is associated with their specialization in displaying various types of influences. The analyzer consists of three parts:

• 1. The peripheral part of the analyzers consists of receptors in which the primary transformations of external influences into the internal state of a person are carried out.
• 2. Afferent (centripetal) and efferent (centrifugal) nerves, conducting pathways connecting the peripheral part of the analyzer with the central one.
• 3. Subcortical and cortical sections (brain end) of the analyzer, where the processing of nerve impulses coming from peripheral sections occurs. In the cortical section (central) of each analyzer there is the core of the analyzer, i.e., the central part, where the bulk of the receptor cells is concentrated, and the periphery, consisting of scattered cellular elements, which are located in varying quantities in areas of the cortex. The peripheral (receptor) section of the analyzers consists of all sense organs - the eye, ear, nose, skin, as well as special receptor devices located in the internal environment of the body (in the digestive and respiratory organs, in the cardiovascular system, in the genitourinary organs). This section of the analyzer reacts to a specific type of stimulus and processes it into a specific excitation. Receptors can be located on the surface of the body (exteroceptors) and in internal organs and tissues (interoreceptors). Receptors located on the surface of the body respond to external stimuli. Visual, auditory, skin, taste, and olfactory analyzers have such receptors. Receptors located on the surface of the internal organs of the body respond to changes occurring inside the body. Organic sensations are associated with the activity of interoceptors. An intermediate position is occupied by proprioceptors located in muscles and ligaments, which serve to sense the movement and position of body organs, and also participate in determining the properties and qualities of objects, in particular when touching them with the hand. Thus, the peripheral section of the analyzer plays the role of a specialized, perceiving apparatus. Certain cells of the peripheral parts of the analyzer correspond to certain areas of cortical cells. Thus, spatially different points in the cortex represent, for example, different points of the retina of the eye, and the organ of hearing is represented in the cortex by spatially different locations of cells. The same applies to other senses. Numerous experiments carried out using artificial stimulation methods now make it possible to quite definitely establish the localization in the cortex of certain types of sensitivity. Thus, the representation of visual sensitivity is concentrated mainly in the occipital lobes of the cerebral cortex. For sensation to arise, the entire analyzer must work as a single whole. The impact of an irritant on a receptor causes irritation. The beginning of this irritation is the transformation of external energy into a nervous process, which is produced by the receptor. From the receptor, this process travels along the centripetal nerve to the nuclear part of the analyzer, located in the spinal cord or brain. When excitation reaches the cortical cells of the analyzer, we feel the qualities of the stimuli, and after this the body’s response to the irritation occurs. If the signal is caused by a stimulus that threatens to cause damage to the body, or is addressed to the autonomic nervous system, then it is very likely that it will immediately cause a reflex reaction emanating from the spinal cord or other lower center, and this will happen before we are aware of this effect (reflex - automatic response of the body to the action of any internal or external stimulus). Our hand withdraws when burned by a cigarette, our pupil constricts in bright light, our salivary glands begin to secrete saliva if we put a lollipop in our mouth, and all this happens before our brain deciphers the signal and gives the appropriate order. The survival of an organism often depends on the short neural circuits that make up the reflex arc.

There is no clear connection between receptors and the functions they perform. A set of hierarchical mechanisms that solve perceptual tasks of varying complexity is called a perceptual system.

Nature has endowed every person with the ability to understand the world in which he was born and, among other things, the ability to sense and perceive the world around him - people, nature, culture, various objects and phenomena. The path to understanding the environment and one’s own states begins with sensations.

Meaning of sensations:

1. sensations allow a person to navigate the world of sounds, smells, perceive colors, estimate the weight and size of objects, determine the taste of a product, etc.
2. sensations provide material for other more complex mental processes (for example, deaf people will never be able to comprehend the sounds of the human voice, blind people - colors);
3. especially developed sensations are a condition for a person’s success in a particular profession (for example, taster, artist, musician, etc.);
4. Depriving a person of sensations leads to sensory deprivation (sensory hunger - lack of impressions), which can occur both in natural and in laboratory conditions. (according to Lee, sensory deprivation is the main condition for creativity, since 95% of the energy spent on overcoming gravity goes to creative potential);
5. there is the possibility of influencing a person’s condition through sensations (the sound of the surf, birdsong, aromatherapy, music).

Feeling (lat. sensus– perception) is a mental cognitive process of reflection individual properties of the real external world and the internal state of a person, which directly affect the senses At the moment.

The sensation does not give a person a complete picture of the reflected objects. If, for example, a person is blindfolded and asked to touch an unfamiliar object (table, computer, mirror) with the tip of his finger, then the sensation will give him knowledge of only individual properties of the object (for example, that this object is hard, cold, smooth, etc.). P.).

Sensations are a sensory reflection of objective reality, as they arise due to the influence of various factors (stimulants) on the sense organs (vision, hearing, etc.). They are characteristic of all living beings with a nervous system. Moreover, some animals (for example, eagles) have significantly sharper vision than humans, a more subtle sense of smell and hearing (dogs). The eyes of ants detect ultraviolet rays that are inaccessible to the human eye. Bats and dolphins distinguish ultrasounds that humans cannot hear. The rattlesnake can detect minute temperature fluctuations of 0.001 degrees.

Feelings are both objective and subjective. Objectivity lies in the fact that they reflect a really existing external stimulus. Subjectivity is due to the dependence of sensations on individual characteristics and the current mental state of a person. This is exactly what the famous proverb says: “There are no comrades according to taste.”

Associated with the emotional sphere of a person, sensations can give rise to various feelings in him and cause the simplest emotional experiences. For example, the sensation of a sharp sound of car brakes heard somewhere nearby can evoke in a person passing by unpleasant memories of his own experience of driving a car. Negative experiences are generated by sensations of unloved smell, color and taste.

Analyzer structure:

The physiological basis of sensations is laid in the work of special nervous structures, called analyzers by I. Pavlov. Analyzers- these are the channels through which a person receives all information about the world (both about the external environment and about his own, internal state).

Analyzer – a nervous formation that carries out the perception, analysis and synthesis of external and internal stimuli acting on the body.

Each type of analyzer is adapted to highlight a certain property: the eye reacts to light stimuli, the ear to sound stimuli, the olfactory organ to odors, etc.

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. A receptor is a specialized cell designed to perceive a certain stimulus from the external or internal environment and to convert its energy from a physical or chemical form into the form of nervous excitation (impulse).

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

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

Sensation is essentially a mental process that occurs when processing information received by the brain.

Depending on the type of sensitivity, visual, auditory, olfactory, gustatory, skin, motor and other analyzers are distinguished. Each analyzer selects stimuli of a certain type from the entire variety of influences. For example, a hearing analyzer identifies waves generated by vibrations of air particles. The taste analyzer generates an impulse as a result of “chemical analysis” of molecules dissolved in saliva, and the olfactory analyzer generates an impulse as a result of “chemical analysis” of molecules dissolved in saliva, and the olfactory analyzer generates an impulse in the air. The visual analyzer perceives electromagnetic waves, the characteristics of which give rise to a particular visual image.

The concept of perception. Properties of perception.

Classification of main types of perception

1. The concept of sensation. Physiological basis of sensation. Analyzer. Types of sensations.

THE CONCEPT OF SENSATION

Definition of sensations.

Knowledge about the individual properties of objects arises during the activity of any sense organ. For example, when an object is exposed (shown) for 1/100 sec, a person may say that he saw a light or spot of a certain color, but will not be able to say exactly what the object is. Listening to speech in an unfamiliar language, a person perceives individual properties of sound (pitch, volume, timbre), although he does not perceive the content of the speech.

Feeling- reflection of individual properties of objects during their direct impact on the senses.

Sensation is the primary form of orientation of the body in the surrounding world.

Sensation is the initial form of development of cognitive activity.

Organic sensations are correlated with objects of the external world, give rise to desires, and serve as a source of volitional impulse. Movements and actions aimed at achieving a goal are regulated by sensations that are necessary to construct an action. Thus, sensations ensure human life.

Sensations are not the only form of reflection of the world. Higher forms of sensory reflection (perception, representation) cannot be reduced to a sum or combination of sensations. Each of the forms of reflection has a qualitative originality, but without sensations as the initial form of reflection, the existence of any kind of cognitive activity is impossible.

Without sensations, human mental activity is impossible.

Physiological bases of sensations.

Sensation can only arise when an object impacts a sensory organ.

A sense organ is an anatomical and physiological apparatus located on the periphery of the body or in the internal organs. It is adapted to receive the effects of certain stimuli from the external and internal environment. The main part of each sense organ is the endings of the sensory nerve, which are called receptors. Sense organs such as the eye and ear combine dozens of receptor endings. The impact of a stimulus on the receptor leads to the generation of a nerve impulse, which is transmitted along the sensory nerve to certain areas of the cerebral cortex. The response is transmitted along the efferent (motor) nerve.

Receptor, conductive nerves and areas in the cortex of the g.m. are called an analyzer.

The sensation is always associated with a response: either with movement or with the restructuring of vegetative processes.

So, the physiological mechanism of sensations can be characterized as a mechanism of conditioned reflex activity of analyzers, arising on the basis of a limited number of unconditioned reflexes. The primary signaling mechanisms of human sensations include the activity of the second signaling system.

TYPES OF SENSATIONS Classification of sensations.

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

Classification of sensations is made on several grounds.

Based on the presence or absence of direct contact of the receptor with the stimulus causing the sensation, they are distinguished distant (z vision, hearing, smell ) And contact ( taste, pain, tactile ) reception.

According to their location on the surface of the body, in the muscles and tendons or inside the body, they are distinguished accordingly exteroception(visual, auditory, tactile, etc.), proprioception(sensations from muscles, tendons) and interoception(feeling of hunger, thirst).

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

Patterns of sensations. Sensory organization of personality.

Let's consider the basic patterns of sensations. These include sensory thresholds, adaptation, sensitization, interaction, contrast, and synesthesia.

Sensitivity thresholds.

The concept of the threshold of sensations, or sensitivity threshold, expresses the psychological characteristic of the “dependence” between the intensity of sensation and the strength of stimuli.

In psychophysiology There are two types of thresholds: absolute sensitivity threshold and discrimination sensitivity threshold.

That smallest stimulus strength at which a barely noticeable sensation first occurs is called lower absolute threshold of sensitivity.

The greatest strength of the stimulus at which a sensation of this type still exists is called upper absolute threshold of sensitivity.

Thresholds limit the zone of sensitivity to stimuli. For example, of all electromagnetic oscillations, the eye is capable of reflecting waves with a length from 390 (violet) to 780 (red) millimicrons;

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

Threshold of sensitivity to discrimination- that smallest increase in the strength of the current stimulus at which a barely noticeable difference occurs in the strength or quality of sensations.

Thus, in the sensation of pressure (tactile sensitivity), this increase is equal to 1/30 of the weight of the original stimulus. This means that you need to add 3.4 g to 100 g to feel a change in pressure, and 34 g to 1 kg. For auditory sensations, this constant is equal to 1/10, for visual sensations it is 1/100. (check out Weber's research).

Adaptation- adaptation of sensitivity to a constantly acting stimulus, manifested in a decrease or increase in thresholds.

In life, the phenomenon of adaptation is well known to everyone. The first minute a person enters the river, the water seems cold to him. Then the feeling of cold disappears, the water seems quite warm. This is observed in all types of sensitivity, except pain.

Staying in absolute darkness increases sensitivity to light by about 200 thousand times over 40 minutes.

Interaction of sensations- this is a change in the sensitivity of one analyzing system under the influence of the activities of another analyzing system.

This is explained by cortical connections between the analyzers.

The general pattern of interaction between sensations is as follows: weak stimuli in one analyzing system increase sensitivity in another.

Increasing sensitivity as a result of the interaction of analyzers, as well as systematic exercises, is called sensitization.

Contrast of sensations– a change in the intensity and quality of sensations under the influence of a previous or accompanying stimulus.

With the simultaneous action of two stimuli, a simultaneous contrast occurs. This contrast is clearly visible in visual sensations. The same figure appears lighter on a black background, and darker on a white background.

The phenomenon of sequential contrast is widely known. After a cold one, a weak thermal stimulus seems hot.

Consistent image- the physiological mechanism of its occurrence is as follows: the cessation of the action of the stimulus does not cause an instant cessation of the process of irritation in the receptor and excitation in the cortical parts of the analyzer.

Synesthesia- excitation by emerging sensations of one modality of sensations of another modality.

Synesthesia can be considered as a special case of the interaction of sensations, which is expressed not in a change in the level of sensitivity, but in the fact that the impact of sensations of a given modality is enhanced through the stimulation of sensations of other modalities. Synesthesia enhances the sensual tone of sensations.

(So ​​the sound becomes colored, etc.)

SENSORY ORGANIZATION OF PERSONALITY – the level of development of individual sensitivity systems characteristic of an individual and the way they are combined into complexes.

In the animal world, the predominant level of development of sensitivity of any one modality is a generic characteristic. All representatives of one species (for example, eagles) have good vision, and all representatives of another (for example, dogs) have a sense of smell. A feature of the human sensory organization is that it develops during life and is influenced by activity.

3. The concept of perception. Properties of perception.

THE CONCEPT OF PERCEPTION

General characteristics of perception.

Perception - This is a reflection of objects and phenomena in the totality of their properties and parts with their direct impact on the senses.

Perception depends on certain relationships between sensations, in addition to which it includes a person’s past experience in the form of ideas and knowledge.

The process of perception occurs in connection with other mental processes of the individual: thinking (we are aware of what is in front of us), speech (we name the object of perception), feelings (we relate in a certain way to what we perceive), will (to one degree or another voluntarily organize the process of perception).

The main characteristics of perception are constancy, objectivity, integrity and generality.

Constancy- this is the relative independence of the image from the conditions of perception, manifested in its immutability: the shape, color and size of objects are perceived by us as constant, despite the fact that the signals coming from these objects to the senses are constantly changing.

An important characteristic of perception is its objectivity. The objectivity of perception is manifested in the fact that the object is perceived by us as a separate physical body isolated in space and time.

This ratio is the basis of the orienting function of our behavior and activity.

Any image integral This means the internal organic relationship between the parts and the whole in the image.

The perception of the whole affects the perception of its parts. Several rules for grouping parts into a whole were formulated by Wertheimer.

1. Rule of similarity: the more similar parts of a picture are to each other, the more likely they are to be perceived as being located together. Similarity in size, shape, and arrangement of parts can act as grouping properties.

2. The rule of common fate. Many elements moving at the same speed and along the same trajectory are perceived holistically, as a single moving object (or when these objects are stationary but the observer is moving).

3. Rule of proximity. In any field containing multiple objects, those that are closest to each other are perceived as a single object.

The whole dominates the parts. There are three forms of such dominance: 1. The same element, being included in different structures, is perceived differently. 2. When replacing individual elements but maintaining the relationships between them, the structure of the image remains unchanged. 3. The structure is perceived as a whole even when some of its parts fall out.

Generality means belonging to a certain class of objects that has a name.

All of the considered properties of perception are not innate and develop throughout a person’s life.