exteroceptive sensations. Sensations in human life Relationship between visually perceived wavelength
Abstract on the topic:
"FEEL"
INTRODUCTION
PHYSIOLOGICAL MECHANISMS
THEORIESSENSATIONS
CLASSIFICATION OF TYPES OF SENSATIONS
PROPERTIES AND REGULARITIES
DEVELOPMENT
SENSING DISTURBANCES
INDIVIDUAL CHARACTERISTICS
STUDY METHODS
LIST OF USED LITERATURE
INTRODUCTION
Feeling - the process of reflecting individual properties of objects of the objective world, both the external environment and one's own organism, arising from their direct impact on receptors (sense organs).
This is the process of primary information processing, characteristic of both animals and humans.
With the help of sensations, the subject reflects light, color, sounds, noises, heat, cold, smells, tastes. Sensations are a prerequisite for the creation of images and their knowledge.
Functions
Signal- notification of the organism about vital objects or properties of the surrounding world.
Reflective (shaped)- construction of a subjective image of the property necessary for orientation in the world.
Regulatory- adaptation in the surrounding world, regulation of behavior and activities.
PHYSIOLOGICAL MECHANISMS
Sensation is the result of nervous processes occurring in special nervous devices - analyzers. This process is nothing but a reflex (see Fig. 11).
Analyzer - complex set of anatomical structures. 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) conducting nerve pathways; 3) 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 takes place. For the sensation to arise, it is necessary to use all the components of the analyzer.
Reflex(lat.reflexus- reflection) - special sensitive nerve formations that perceive irritations from the external or internal environment and process them into nerve signals.
Receptors(from lat.recipere- receive, accept) - special sensory formations that perceive and transform stimuli from the external or internal environment and transmit information about the acting stimulus to the nervous system.
THEORIESSENSATIONS
Receptive. According to this theory, the sensory organ (receptor) passively responds to stimuli. This passive response is the corresponding sensations, that is, the sensation is a purely mechanical imprint of external influence in the corresponding sense organ. At present, this theory is recognized as untenable, since the active nature of sensations is denied.
Dialectical-materialistic. According to this theory, “sensation is a real direct connection of consciousness with the external world, it is the transformation of the energy of external irritation into a fact of consciousness” (V. L. Lenin).
Reflex. Within the framework of the reflex concept of I.M. Sechenov and I.P. Pavlova, studies have been conducted that have shown that, in terms of its physiological mechanisms, sensation is a holistic reflex that combines direct and feedback peripheral and central sections of the analyzer.
CLASSIFICATION OF TYPES OF SENSATIONS
By modality (types of analyzers), sensations are distinguished: visual, auditory, tactile (tactile, temperature and pain), olfactory and gustatory. There are also intermodal sensations.
According to the nature of the reflection and the location of the receptors, the classification of sensations was presented by the English physiologist C. Sherrington (1906). Based on the anatomical location of the receptors, sensations are divided into three classes: interoceptive(receptors are located in the internal environment of the body), proprioceptive(receptors are located in muscles, tendons and joint bags) and ex-steroceptive(receptors are located on the surface of the body). The exteroceptive include: contact (taste, touch) and distant (smell, hearing, vision). A.R. Luria completes the last row with two categories: intermodal(intermediate) and non-specific types of sensations.
By origin (X. Head's genetic classification) there are: protopathic and epicritical Feel.
Modality(modal - related to location) - a qualitative characteristic of sensations and perceptions, indicating their belonging to certain sense organs, for example, visual, auditory, tactile, etc.
visual sensations - sensations, the stimulus for which is electromagnetic radiation with a wavelength of approximately 380 to 780 billionths of a meter, and the receptors are light-sensitive cells of the retina.
Visual sensations serve to reflect light, color, darkness. Color occurs when the eye receptor is exposed to waves of different wavelengths from this range. Perceived colors are divided into chromatic (for example, the colors of the rainbow: red, orange, yellow, green, cyan, indigo, violet) and achromatic (white, black, gray). The color tone contains about 150 transitions, depending on the length of the light wave acting on the eye. Vision receptor - special cells of the retina: "rods" and "cones". "Rods" are characterized by high sensitivity to low light intensity and are night (twilight) vision apparatus, and the "cones" have a lower sensitivity and are a day vision apparatus.
Achromatic colors -white, black, grey. Achromatic vision uses "rods".
Chromatic colors- red, orange, yellow, green, blue, indigo, violet. In chromatic vision, "cones" operate.
auditory sensations - sensations stimulated by sound waves of various amplitudes and frequencies. Sound waves are longitudinal vibrations of air particles propagating in all directions from an oscillating body that serves as a sound source. All sounds that the human ear perceives can be divided into two groups: musical (sounds of singing, sounds of musical instruments, etc.) and noises (squeaks, rustles, knocks, etc.).
Musical sounds are formed due to periodic rhythmic oscillations of sound waves, and noises are formed as a result of irregular oscillations.
Human speech, as a rule, simultaneously contains the sounds of both groups.
Sounds are simple or complex, consisting of several tones. One of these tones is the main one, which determines the strength and pitch of the sound, the other is the accompanying (overtone), which determines the originality (timbre) of the sound.
Timbre- a specific quality that distinguishes sounds of the same height and intensity from different sources from each other.
vestibular sensations - based on information coming from the semicircular canaliculi of the inner ear. One of the primary functions of the vestibular sense system is to provide a stable basis for visual observation. Due to the existence of a reflex mechanism that compensates for each movement of the head with the opposite movement of the eyes, we have a fairly stable picture of the world (does not jump, does not tremble).
vestibular apparatus- an analyzer that allows you to evaluate the position in space and change the direction of movement.
Feelings are tactile(or skin) - include three different types of sensations that have their own analyzers: tactile (touch and pressure), temperature (heat and cold) and pain.
Skin sensations are caused by the action of the mechanical and thermal properties of an object on the surface of the skin. They occur when receptors are stimulated located in the skin in the form of endings of nerve plexuses or in the form of special nerve formations - Meisner bodies located on its surface, devoid of hair, and Pacini bodies located in the deep layers of the skin.
Feelings tactile - provide information about what is in contact with the subject's body. It is a feeling of touch and pressure. Sometimes there is a tickling sensation.
Temperature sensations - sensations of warmth or cold. There are more cold cells on the skin surface (8-23 per 1 sq. cm) than thermal ones (0-3 per 1 sq. cm), and they are closer to the surface (by 0.17 mm) than thermal ones (by 0, 3 mm). Therefore, the body reacts faster to cold than to heat.
Feelings of pain - some scientists believe that there are specialized pain receptors located on the entire surface of the skin. Their number is large (about 100 per 1 sq. cm), and they are located at a depth of 0.1 mm from the skin surface. According to others, pain occurs in response to excessive stimulation of any skin receptor. Pain signals a possible physical danger.
Olfactory sensations - a type of sensitivity that gives rise to specific sensations of smell. Olfactory sensations are caused by the action of chemicals on the receptor cells of the nasal cavity and nasopharynx. The odor classification system known as "Hanning's Prism" (floral, fruity, spicy, resinous, burnt, putrid) forms the corners of a prism with intermediate qualities located on the planes.
There are other classifications as well. In practice, a comparison of this smell with a known standard (lilac, hay, etc.) is often used. The sense of smell is one of the most ancient, simple, but vital senses. It provides the individual with information about the presence of various chemicals in the air and acts on the subconscious.
Taste sensations - reflecting the quality of food, providing the individual with information about whether a given substance can be ingested. Taste sensations (often along with smell) are caused by the action of chemical properties of substances dissolved in saliva or water on taste buds (taste buds) located on the surface of the tongue, back of the throat, palate and epiglottis. The taste classification system is represented by the Hanning Tetrahedron (Fig. 13), in which there are four main tastes (sweet, sour, salty, bitter). They are located in the corners of the tetrahedron (four-cornered pyramid), and all other taste sensations are located on the planes of the Tetrahedron and represent them as combinations of two or more basic taste sensations.
Different parts of the tongue are differently sensitive to different substances: the tip of the tongue is most sensitive to sweet, its edges to sour, the region of the root of the tongue to bitter, the edges of the tongue and the middle to salty.
Interoceptive sensations - unite signals that reach us from the internal environment of the body, sensitivity to their own metabolic processes (hunger, thirst, suffocation, etc.). Usually they close at the subsensory (unconscious) subcortical level and are realized only in the event of a significant violation of the normal state of the body, violation of the necessary constancy of its internal environment (homeostasis). They arise due to receptors located on the walls of the stomach and intestines, the heart and the circulatory system and other internal organs. Interoceptive sensations are among the least conscious and most diffuse forms of sensations and always retain their proximity to emotional states. They are often referred to as organic.
Sat - an integral part of the word, meaning "under", below, lower, younger, in a small amount.
homeostasis(Greek homoios - similar, similar, statis - standing, immobility) - mobile, but stable balance of any system (biological, mental). The system counteracts external and internal factors that disturb this balance. The concept was introduced by the American physiologist W.B. Cannon. For example, a decrease in temperature (a factor that disturbs the equilibrium of the system) initiates a number of processes, such as trembling, etc., which cause and maintain a high temperature until a normal temperature is reached, that is, equilibrium (homeostasis).
Proprioceptive sensations("deep sensitivity") - sensations that transmit information about the position of the body in space and the position of the musculoskeletal system, provide regulation of our movements. These sensations form the basis of human movements, playing a decisive role in their regulation. This group of sensations includes a sense of balance, or static sensation, as well as a motor, or kinesthetic, sensation. Peripheral receptors for this sensitivity are found in muscles and joints (tendons, ligaments) and are called Paccini bodies. Peripheral balance receptors are located in the semicircular canals of the inner ear.
Feelings kinesthetic(Greek kinema - movement, aisthesis - sensation, feeling) - a reflection of the position and movement in space of the body or its parts, the direction and volume of movements in various positions, the resistance and severity of environmental objects. It is carried out through impulses coming from proprioceptors located in muscles, tendons, ligaments, joints. It plays an important role in keeping the body in balance in various positions.
Sensations exteroceptive - according to C. Sherrington's classification, these are sensations that provide signals from the outside world and create the basis for our conscious behavior. Everyone goes up here 5 modalities of sensations.
Feelings are intermodal(intermediate) - sensations that occupy an intermediate place between modalities. For example, the vibrational system occupies a middle position between touch and sight. Intermodal sensations also include sensations of super-strong smells and tastes, super-strong sounds and light. All these influences cause mixed sensations, located between the olfactory, auditory or visual and pain sensations.
Vibratory sensations - sensitivity to vibrations caused by a moving body. Vibrational feeling is an intermediate, transitional form between tactile and auditory sensitivity. With normal hearing, it does not particularly appear, but with damage to the auditory organ, this function of it is clearly manifested.
Feelings are non-specific these include, for example, the photosensitivity of the skin - the ability to feel color shades with the skin of the hand or fingertips. This also includes the little-studied "sense of distance", which allows the blind to determine the emerging obstacle at a distance. It is assumed that the "sense of distance" is associated either with the sensation of heat waves on the skin of the face, or with the reflection of sound waves from an obstacle (like a radar). However, these forms of sensitivity are still poorly understood.
Photosensitivity of the skin -the ability to feel color shades with the skin of the hand or fingertips (described by A.N. Leontiev and others).
Feeling protopathic(gr.protos- first, primarypathos- illness, suffering) - phylogenetically these are more ancient sensations, primitive and undifferentiated, mixed with emotions and localized. More often this concept is used in relation to skin sensitivity. These include organic sensations (hunger, thirst, etc.).
Feelings are epicritical(Greek Epikrisis - judgment, decision) - phylogenetically new sensations. They are characterized by a lower threshold of irritation, the ability to feel light touches, accurate localization of external irritation, and more perfect recognition of the quality of an external stimulus. These include all the basic types of human sensations.
PROPERTIES AND REGULARITIES
Sensitivity and its measurement
The intensity of sensations varies from person to person. To measure the intensity of sensations in science, the following concepts have been introduced: absolute sensitivity, lower and upper thresholds of absolute sensitivity, thresholds of sensitivity, relative sensitivity and threshold of relative sensitivity. There is an inverse relationship between absolute sensitivity and its threshold:
and similar - for relative sensitivity.
Far from any difference between the stimuli is felt. Its value should be in a certain relation to the initial, initial strength of the stimulus. The ratio of the increase in the strength of the stimulus to the initial strength is constant for each modality of sensation (Weber's law), and the smallest value of this ratio represents the discrimination threshold:
Different sense organs have different thresholds, both absolute and relative. Their values are calculated and summarized in special tables.
There is also a general dependence of the intensity of sensation on the strength of the stimulus, which is expressed in the basic psychophysiological law of Weber - Fechner.
This law says:
Feeling intensity (S) is proportional to the logarithm of the strength of the stimulus (I) and is expressed by the formula: S = k/ nI + C, where k is a proportionality factor depending on the modality of the stimulus, and C is the constant of integration. It follows that the intensity of sensation grows much more slowly than the strength of the stimulus.
This law is valid only in the comfort zone. Each type of sensation has its own thresholds. They are presented in figurative form in Table 2.
table 2
Average values of absolute sensation thresholds for different human senses
|
sense organs |
The value of the absolute threshold of sensation, presented in the form of conditions under which there is a barely noticeable sensation of this modality |
| Vision | The ability to feel the light of one burning candle in complete darkness at a distance of 48 km from the eye |
| Hearing | Distinguishing the ticking of a watch in complete silence at a distance of up to 6 m |
| Taste | Feeling the presence of one spoonful of sugar in 8 liters of water. |
| Smell | The feeling of having one drop of perfume in a room of 6 rooms |
| Touch | Sensation of air movement produced by the fall of a fly wing on the surface of the skin from a height of 1 cm |
Sensitivity - the ability to respond to relatively weak or slightly different influences.
Sensitivity absolute(E) - the ability to feel barely noticeable, weak irritations.
(lower) (RA) - the minimum value of the stimulus of any modality, at which a sensation first occurs.
Sensitivity absolute threshold(upper) is the maximum intensity of the stimulus at which it is still perceived in its modality or is not perceived at all.
Relative sensitivity(difference, differential) is the ability to feel slight differences between stimuli of the same modality.
Sensitivity relative threshold(difference or differential) - this is the minimum difference between stimuli, which gives a barely noticeable difference in sensations.
Weber - Fechner law - the law of psychophysics, stating that the strength of sensation is proportional to the logarithm of the magnitude (intensity) of the impact on the senses of the stimulus ( S = kIn+ С, whereS- intensity of sensation, k - coefficient of proportionality, depending on the modality of the stimulus, C - constant of integration). The main meaning of this pattern is that the intensity of sensations does not increase in proportion to the change in stimuli, but much more slowly.
Sensitivity change
Sensitivity can vary depending on various conditions: the nature of the activity, age, functional state, the characteristics of the receptor, the strength and duration of the stimulus. There are two forms of sensitivity change: adaptation, sensitization. Adaptation consists in a change in sensitivity with weak stimuli, for example, when moving from a bright room to a dark one, light sensitivity increases and decreases during the reverse transition. Worse, a person adapts to auditory and pain stimuli. All types of sensations are interconnected, therefore sensations also depend on the stimuli that are currently affecting other analyzers. A change in the sensitivity of the analyzer under the influence of irritation of other sense organs is sensitization.
Adaptation(lat.adaptatio- adaptation) - adaptation to external conditions.
Adaptation(sensory) - a change in sensitivity that occurs as a result of the adaptation of the sense organ to the stimuli acting on it. It is known that in the dark our vision becomes sharper, and in strong light, its sensitivity decreases. Adaptation also exists in the auditory sphere (changes in auditory sensations in conditions of silence and noise), in the sphere of smell (under the influence of strong odors), touch (in extreme cold or heat) and taste.
Sensitization - increased sensitivity as a result of the interaction of analyzers or exercises. For example, an increase in visual acuity under the influence of weak auditory or olfactory stimuli. Significant increases in sensitivity due to the nature of the activity are known (violinists have a high sensitivity to sounds, textile workers learn to distinguish more than 60 shades of black, etc.).
Interaction of sensations
Synesthesia(Greek syn - with, together, aesthesis - feeling, feeling. - co-sensations) - the emergence under the influence of irritation of one analyzer of sensations characteristic of other analyzers. The quality of sensations of one kind is transferred to another. They are normal (“color hearing”) in many people, and especially in musicians (for example, in Scriabin), for example, low-frequency sounds give a feeling of softness or abundance, while high-frequency sounds are perceived as fragile and sharp, blue is perceived as cold, while red is like warm. In mental pathology, for example, there are synesthetic functional and reflex hallucinations.
contrast phenomenon- a change in the intensity and quality of sensation under the influence of the previous and accompanying stimulus, for example, after a cold, a weak thermal stimulus seems hot, or the same figure appears lighter on a black background, and darker on a white one.
Duration of sensations
Sensations have the ability to maintain intensity over time. They do not appear immediately, but after some time - a latent period (hidden, invisible). These periods are different for different analyzers, for example, for tactile sensations - 130 m / s, and for pain - 50 m / s. But sensations do not disappear immediately after irritation. There is inertia - for some time the image is preserved, it is called consistent. If you look at the sun for a long time, and then look at a white wall, then the disk of the sun will be visible on it in full accordance with the original (in color and lightness) - a positive image or a changed (negative) one.
latent period(from Latin latens - hidden, secret) - the time between the onset of the stimulus and the appearance of a visible reaction to this stimulus.
Consistent image- sensations do not disappear immediately after the cessation of the stimulus. A trace remains from the stimulus - a consistent image.
Spatial localization
Thanks to the binocularity of vision, hearing, we see and hear images of sensations in a certain place in space. Localization of tactile sensations is developed in experience due to the joint activity of vision and muscular sensation. The sensations of touch, pressure and pain are different in different parts of the body. The sensation of taste is localized in different parts of the tongue: sweet - the tip of the tongue, sour - the edges of the tongue, bitter - the base of the tongue, salty - the edges and middle of the tongue. Sense of smell - the left side of the nose is more sensitive.
Spatial localization stimulus (for hearing) - a point in space from which the sound comes. The main role in the localization of sound is played by the fact that: a) the ear, which is closer to the sound source, experiences the stimulus somewhat earlier than the other ear; b) the head creates a "barrier" that partially blocks the sound so that the ear closest to the source receives a more intense stimulus; c) two ears perceive different phases of sound waves.
The term "localization" is used in relation to hearing (determining the location of the sound source in the environment), vision (determining the position of the stimulus in the field of vision), tactile sensations (determining the location of stimulation on the skin).
Feelings of man and animals
According to the ideas developed in Soviet psychology, sensations arise in phylogenesis on the basis of elementary irritability as sensitivity to stimuli that have no direct ecological significance, thereby reflecting an objective relationship between biotic and abiotic environmental factors. In contrast to the sensations of animals, human sensations are mediated by his practical activity, by the entire process of the historical development of society. In favor of the historical understanding of sensations as a process of development of the entire world history (K. Marx), there are numerous data on the possibility of wide restructuring of sensitivity under the influence of objective labor activity, as well as on the dependence of the perception of individual properties of objects on socially developed systems of sensory qualities, such as systems of native phonemes. language, the scale of musical sounds or the basic tones of the light spectrum.
Biotic- important for life, viable.
abiotic- incompatible with life, unviable.
DEVELOPMENT
Sensations begin to develop immediately after birth. However, not all types of sensitivity develop in the same way. Immediately after birth, the child develops tactile, gustatory and olfactory sensitivity (the child reacts to environmental temperature, touch, pain; determines the mother by the smell of mother's milk; distinguishes mother's milk from cow's milk or water). However, the development of these sensations continues for a long time (slightly developed at 4-5 years).
Less mature at the time of birth are visual and auditory sensations. Auditory sensations begin to develop faster (reacts to sound - in the first weeks of life, to direction - after two or three months, and to singing and music - in the third or fourth month). Speech hearing develops gradually. First, the child reacts to the intonation of speech (in the second month), then to the rhythm, and the ability to distinguish sounds (first vowels, and then consonants) appears by the end of the first year of life.
The absolute sensitivity to light in an infant is low, but increases markedly in the first days of life. Distinguishing colors occurs only in the fifth month.
In general, the absolute sensitivity of all species reaches a high level of development in the first year of life. Relative sensitivity develops more slowly (rapid development occurs at school age).
Feelings within certain limits can be developed by constant training. Thanks to the possibility of developing sensations, for example, children are taught (music, drawing).
SENSING DISTURBANCES
Among violations of sensations, quantitative and qualitative changes are distinguished.
Quantitative disorders include: loss or decrease in the ability to feel various types of stimuli and an increase in this ability. Loss of sensation extends, as a rule, to tactile, pain, temperature sensitivity, but can cover all types of sensitivity.
This is usually associated with various diseases of the individual. Synesthesia is a quality sensory disorder. Another type of pathology of sensations is manifested in various, unpleasant sensations: numbness, tingling, burning, crawling, etc. With various pathological diseases, there may be changes in pain sensitivity. They consist in different pain sensitivity and endurance to pain.
INDIVIDUAL CHARACTERISTICS
Individual differences in sensations is a little studied area of psychology. It is known that the sensitivity of different sense organs depends on many factors. Influence features of the central nervous system (in individuals with a strong nervous system, sensitivity is lower); emotionality (the emotional ones have a more developed sense of smell); age (hearing acuity is greatest at 13 years old, vision - at 20-30 years old, old people hear low-frequency sounds quite well, and high ones are worse); gender (women are more sensitive to high sounds, and men to low ones); the nature of the activity (steelworkers distinguish the subtlest shades of a hot metal flow, etc.).
STUDY METHODS
experimental
Methods for studying sensations are associated with experiments, mainly physiological or psychophysiological.
Pain sensations have one feature, which can be noticed by easily pricking a finger. First, there is a relatively weak, but precisely localized pain sensation. After 1-2 seconds it becomes more intense. For the first time, G. Head managed to share this “double feeling” in 1903. His sensory nerve was cut for experimental purposes. Then it was already known that the nerves are able to recover. Immediately after the transection, all types of sensitivity disappeared in the experimental area, which were restored at an unequal rate. After 8-10 weeks, the first signs of recovery appeared, after 5 months pain sensitivity was restored, but very peculiar. A light injection, even a touch from an assistant, caused an excruciating, almost unbearable feeling of pain. The subject was screaming, shaking all over, clutching at the one who irritated. At the same time, if he was blindfolded, he could not tell where the sensation of pain arises. And only five years later the pain fully recovered. Thus arose the doctrine of protopathic and epicriticalsensitivity. Protopathic sensitivity (from the Greek.protos- first andpathos- suffering)
represents the most ancient primitive undifferentiated sensitivity of a low level, and epicpytic (from the Greek. epikriticos - making a decision) is a highly sensitive and finely differentiated type of sensitivity that arose at later stages of phylogenesis.
Diagnostic
Diagnostic methods for studying sensations are mainly related to the measurement of sensitivity thresholds and require the presence of special equipment.
LIST OF USED LITERATURE
GamezoM. B., GerasimovB. C., Mashurtseva D.A., Orlova L.M.
General psychology: Educational and methodical manual / Under the general. ed. M.V. Gamezo. - M.: Os-89, 2007. - 352 p.
Sensation is an elementary act of the cognitive process, a function of reflecting individual qualities and properties of the surrounding reality. Phylo- and ontogenetically sensation is one of the earliest functions of the central nervous system. sensation pathology.
Psychopathology. Somatoform mental disorders and somatic diseases. Perceptual disturbances in various mental illnesses. Gnostic disorders. Selectivity, volume, stability, switchability of attention and its violation.
Skin sensitivity is subdivided by classical physiology of the sense organs into four different types. Receptions are usually distinguished: 1) pain, 2) heat, 3) cold, and 4) touch (and pressure).
Date: 09/01/98. Lesson number: 1. Topic: "Feeling". Type of lesson: A lesson in mastering new knowledge by students (according to the typology of Onischuk V.A.) Purpose: To give an idea of the concept of sensation as the first step
Sensations, perceptions, representations, memory as sensory forms of cognition. Sensory organization of the personality, the concept of sensation, the principles of information processing by the brain. The activity of nerve receptors, the classification of sensations. Sight, taste, hearing, smell.
Feelings as the main source of knowledge about the outside world and about one's own body, a reflection of the human psyche, individual properties of objects and phenomena. The main types of sensations are smell, taste, touch, hearing and sight. The origin of knowledge from sensations and reflection.
The concept and psychological nature of sensations, their varieties. Characteristic properties and physiological mechanisms of the development of sensations. Characteristics of the types of sensations: visual and auditory analyzers, musical and speech sensations, smell and taste.
INTERNATIONAL INSTITUTE OF THE MARKET TOGLYATTI BRANCH
Sensation as the simplest element of sensory cognition and human consciousness. Varieties of sensations, their significance in human life. The essence of sensitivity, its thresholds. Types of perception and their specificity. Differences between hallucinations and illusions.
The concept of sensation and its physiological basis. Types and classification of sensations: visual, auditory, vibrational, olfactory, gustatory, skin and others. Definition of perception as a psychological process, its properties. Types and ways of thinking.
Properties of distance, selectivity and objectivity of auditory sensations, their role in the life of the blind. Determination of the threshold of auditory sensitivity. The need for special training of auditory sensations. Dependence of auditory sensations on atmospheric conditions.
The ability to sense is present in all living beings with a nervous system. As for conscious sensations, they exist only in living beings that have a brain and a cerebral cortex.
Basic psychophysical law. Based on Weber's law, Fechner made the assumption that subtle differences in sensations can be considered equal, since they are all infinitesimal quantities, and taken as a unit of measure, with which one can numerically express the intensity of sensations ...
The concept, mechanisms and physiological basis of sensations. Systematic classification of sensations: interoceptive (pain), proprioceptive (balance and movement), exteroceptive (distant, contact). Structural-genetic classification of sensations.
Topic: "" PLAN: Introduction 1. Receptors. 2. Classification of sensations. 3. Organic sensations. 4. Statistical sensations. 5. Kinetic sensations.
The concept, essence, classification, types and patterns of sensations, their role in human life and activity. Moral and psychological climate of the labor collective, features of its formation. Ethical norms and rules of conduct in public places.
Types of sensations. Already the ancient Greeks distinguished five sense organs and their corresponding sensations: visual, auditory, tactile, olfactory and gustatory. Modern science has significantly expanded our understanding of the types of human sensations. Currently, there are about two dozen different analyzer systems that reflect the impact of the external and internal environment on receptors.
visual sensations - it is the sensation of light and color. Everything we see has some color. Only a completely transparent object that we cannot see can be colorless. Colors come in achromatic(white and black and shades of gray in between) and chromatic(various shades of red, yellow, green, blue).
Visual sensations arise as a result of the action of light rays (electromagnetic waves) on the sensitive part of our eye. The light-sensitive organ of the eye is the retina, which contains two types of cells - rods and cones, so named for their external shape. There are a lot of such cells in the retina - about 130 rods and 7 million cones.
In daylight, only cones are active (for rods, such light is too bright). As a result, we see colors, i.e. there is a sensation of chromatic colors - all colors of the spectrum. In low light (at dusk), the cones stop working (there is not enough light for them), and vision is carried out only by the rod apparatus - a person sees mostly gray colors (all transitions from white to black, i.e. achromatic colors).
Color has a different effect on the well-being and performance of a person, on the success of educational activities. Psychologists note that the most acceptable color for painting the walls of classrooms is orange-yellow, which creates a cheerful, upbeat mood, and green, which creates an even, calm mood. Red excites, dark blue depresses, and both tire the eyes. In some cases, people experience violations of normal color perception. The reasons for this may be heredity, diseases and eye injury. The most common is red-green blindness, called color blindness (after the English scientist D. Dalton, who first described this phenomenon). Colorblind people do not distinguish between red and green, do not understand why people designate a color with two words. Such a feature of vision as color blindness should be taken into account when choosing a profession. Color-blind people cannot be drivers, pilots, they cannot be painters and fashion designers, etc. A complete lack of sensitivity to chromatic colors is very rare. The less light, the worse a person sees. Therefore, one should not read in poor lighting, at dusk, so as not to cause excessive eye strain, which can be harmful to vision, contribute to the development of myopia, especially in children and schoolchildren.
auditory sensations occur with the help of the organ of hearing. There are three types of auditory sensations: speech, music And noises. In these types of sensations, the sound analyzer identifies four qualities: sound power(loud-weak), height(high Low), timbre(the peculiarity of a voice or musical instrument), sound duration(playing time) and tempo-rhythmic features successive sounds.
Rumor to speech sounds called phonemic. It is formed depending on the speech environment in which the child is brought up. Mastering a foreign language involves the development of a new system of phonemic hearing. The developed phonemic hearing of the child significantly affects the accuracy of written speech, especially in elementary school. Ear for music the child is brought up and formed, as well as speech hearing. Here, the early introduction of the child to the musical culture of mankind is of great importance.
Noises they can cause a certain emotional mood in a person (the sound of rain, the rustle of leaves, the howling of the wind), sometimes they serve as a signal of approaching danger (the hissing of a snake, the menacing barking of a dog, the rumble of a moving train) or joy (the clatter of a child’s feet, the steps of an approaching loved one, the thunder of fireworks) . In school practice, one often encounters the negative effect of noise: it tires the human nervous system.
vibration sensations reflect vibrations of an elastic medium. A person receives such sensations, for example, when touching the lid of a sounding piano with his hand. Vibratory sensations usually do not play an important role for a person and are very poorly developed. However, they reach a very high level of development in many deaf people, with which they partially replace the missing hearing.
Olfactory sensations. The ability to smell is called the sense of smell. The organs of smell are special sensitive cells that are located deep in the nasal cavity. Separate particles of various substances enter the nose along with the air that we inhale. This is how we get olfactory sensations. In modern man, olfactory sensations play a relatively minor role. But deaf-deaf people use their sense of smell, as sighted people use sight with hearing: they identify familiar places by smell, recognize familiar people, receive danger signals, etc. A person’s olfactory sensitivity is closely related to taste, helps to recognize the quality of food. Olfactory sensations warn a person about an air environment dangerous for the body (smell of gas, burning). The incense of objects has a great influence on the emotional state of a person. The existence of the perfume industry is entirely due to the aesthetic need of people for pleasant smells.
Taste sensations arise with the help of the organs of taste - taste buds located on the surface of the tongue, pharynx and palate. There are four types of basic taste sensations: sweet, bitter, sour, salty. The variety of taste depends on the nature of the combinations of these sensations: bitter-salty, sour-sweet, etc. A small number of qualities of taste sensations does not mean, however, that taste sensations are limited. Within the limits of salty, sour, sweet, bitter, a whole range of shades arise, each of which gives a new originality to taste sensations. Taste sensations of a person are highly dependent on the feeling of hunger, tasteless food seems tastier in a state of hunger. Taste sensations are very dependent on olfactory ones. With a severe cold, any, even the most beloved, dish seems tasteless. The tip of the tongue feels sweet best. The edges of the tongue are sensitive to sour, and its base to bitter.
Skin sensations - tactile (sensation of touch) and temperature(feelings of warmth or cold). On the surface of the skin there are different types of nerve endings, each of which gives a feeling of either touch, or cold, or heat. The sensitivity of different parts of the skin to each type of irritation is different. Touch is most felt on the tip of the tongue and on the fingertips, the back is less sensitive to touch. The most sensitive to the effects of heat and cold are the skin of those parts of the body that are usually covered by clothing, the lower back, abdomen, and chest. Temperature sensations have a very pronounced emotional tone. So, average temperatures are accompanied by a positive feeling, the nature of the emotional coloring for heat and cold is different: cold is experienced as an invigorating feeling, warmth as a relaxing one. The temperature of high indicators, both in the direction of cold and heat, causes negative emotional experiences.
Visual, auditory, vibrational, gustatory, olfactory and skin sensations reflect the influence of the external world, therefore the organs of all these sensations are located on the surface of the body or near it. Without these sensations, we could not know anything about the world around us. Another group of sensations tells us about the changes, condition and movement in our own body. These feelings include motor, organic, balance sensations, tactile, pain. Without these sensations, we would not know anything about ourselves.
Motor (or kinesthetic) sensations - These are sensations of movement and position of body parts. Thanks to the activity of the motor analyzer, a person gets the opportunity to coordinate and control his movements. Receptors for motor sensations are located in the muscles and tendons, as well as in the fingers, tongue and lips, since it is these organs that carry out precise and subtle working and speech movements.
The development of kinesthetic sensations is one of the important tasks of education. Labor, physical education, drawing, drawing, reading lessons should be planned taking into account the possibilities and prospects for the development of the motor analyzer. For mastering movements, their aesthetic expressive side is of great importance. Children master movements and, consequently, their bodies in dancing, rhythmic gymnastics and other sports that develop the beauty and ease of movement. Without the development of movements and their mastery, educational and labor activity is impossible. The formation of speech movement, the correct motor image of the word increases the culture of students, improves the literacy of written speech. Teaching a foreign language requires the development of such motor speech movements that are not typical for the Russian language.
organic sensations tell us about the work of our body, our internal organs - the esophagus, stomach, intestines and many others, in the walls of which the corresponding receptors are located. While we are full and healthy, we do not notice any organic sensations at all. They appear only when something is disturbed in the work of the body. For example, if a person has eaten something that is not very fresh, the work of his stomach will be disrupted, and he will immediately feel it: there will be pain in the abdomen.
Hunger, thirst, nausea, pain, sexual sensations, sensations related to the activity of the heart, breathing, etc. These are all organic sensations. Without them, we would not be able to recognize any disease in time and help our body cope with it.
“There is no doubt,” said I.P. Pavlov, “that not only the analysis of the external world is important for the organism, it also needs signaling upwards and analysis of what is happening in itself.”
tactile sensations- a combination of skin and motor sensations when touching objects that is, when touched by a moving hand. A small child begins to explore the world with touch, feeling objects. This is one of the important sources of obtaining information about the objects surrounding it.
In people deprived of sight, touch is one of the most important means of orientation and cognition. As a result of practice, it reaches great perfection. Such people can thread a needle, do modeling, simple design, even sewing, cooking. The combination of skin and motor sensations arising from the palpation of objects, i.e. when touched by a moving hand, is called touch. The organ of touch is the hand.
Feelings of balance reflect the position occupied by our body in space. When we first sit on a two-wheeled bicycle, stand on skates, roller skates, water skis, the most difficult thing is to keep our balance and not fall. The sense of balance is given to us by an organ located in the inner ear. It looks like a snail shell and is called labyrinth. When the position of the body changes, a special fluid (lymph) oscillates in the labyrinth of the inner ear, called vestibular apparatus. The organs of balance are closely connected with other internal organs. With a strong overexcitation of the balance organs, nausea, vomiting (the so-called sea or air sickness) are observed. With regular training, the stability of the balance organs increases significantly. The vestibular apparatus gives signals about the movement and position of the head. If the labyrinth is damaged, a person can neither stand, nor sit, nor walk, he will fall all the time.
Pain have a protective value: they signal to a person about the trouble that has arisen in his body. If there was no sensation of pain, a person would not even feel serious injuries. Complete insensitivity to pain is a rare anomaly, and it brings a person serious trouble. Pain sensations are of a different nature. First, there are “pain points” (special receptors) located on the surface of the skin and in the internal organs and muscles. Mechanical damage to the skin, muscles, diseases of internal organs give a feeling of pain. Secondly, sensations of pain arise under the action of a superstrong stimulus on any analyzer. Blinding light, deafening sound, intense cold or heat radiation, a very pungent odor also cause pain.
There are various classifications of sensations. The classification according to the modality of sensations (the specificity of the sense organs) is widespread - this is the division of sensations into visual, auditory, vestibular, tactile, olfactory, gustatory, motor, visceral. There are intermodal sensations - synesthesia. Ch. Sherrington's classification is well-known, distinguishing the following types of sensations:
exteroceptive sensations (arising from the action of external stimuli on receptors located on the surface of the body, from the outside);
proprioceptive (kinesthetic) sensations (reflecting the movement and relative position of body parts with the help of receptors located in muscles, tendons, articular bags);
interoceptive (organic) sensations - arising from the reflection of metabolic processes in the body with the help of specialized receptors.
Despite the variety of sensations that arise during the operation of the sense organs, one can find a number of fundamentally common features in their structure and functioning. In general, it can be said that analyzers are a set of interacting formations of the peripheral and central nervous systems that receive and analyze information about phenomena occurring both inside and outside the body.
The classification of sensations is made on several grounds. By the presence or absence of direct contact of the receptor with the stimulus that causes sensation, distant and contact reception are distinguished. Vision, hearing, smell are related to distant reception. These types of sensations provide orientation in the nearest environment. Taste, pain, tactile sensations - contact.
By location on the surface of the body, in muscles and tendons or inside the body, respectively, exteroception (visual, auditory, tactile, etc.), proprioception (sensations from muscles, tendons) and interoception (sensation of hunger, thirst) are distinguished.
According to the time of occurrence during the evolution of the animal world, ancient and new sensitivity are distinguished. So, distant reception can be considered new in comparison with contact, but in the structure of the contact analyzers themselves, more ancient and newer functions are distinguished. Pain sensitivity is more ancient than tactile.
Consider the basic patterns of sensations. These include thresholds, adaptation, sensitization, interaction, contrast, and synesthesia.
Thresholds of sensitivity. Sensations arise when exposed to a stimulus of a certain intensity. The psychological characteristic of the "dependence" between the intensity of sensation and the strength of stimuli is expressed by the concept of the threshold of sensations, or the threshold of sensitivity.
In psychophysiology, two types of thresholds are distinguished: the threshold of absolute sensitivity and the threshold of sensitivity to discrimination. That smallest stimulus strength at which a barely noticeable sensation first occurs is called the lower absolute threshold of sensitivity. That greatest strength of the stimulus, at which there is still a sensation of this type, is called the upper absolute threshold of sensitivity.
Thresholds limit the zone of sensitivity to stimuli. For example, of all electromagnetic vibrations, the eye is capable of reflecting wavelengths from 390 (violet) to 780 (red) millimicrons;
There is an inverse relationship between sensitivity (threshold) and the strength of the stimulus: the greater the force needed to create a sensation, the lower the sensitivity of a person. Sensitivity thresholds are individual for each person.
An experimental study of sensitivity to discrimination made it possible to formulate the following law: the ratio of the surplus strength of the stimulus to the main one is a constant value for this type of sensitivity. So, in the sensation of pressure (tactile sensitivity), this increase is equal to 1/30 of the weight of the original stimulus. This means that 3.4 g must be added to 100 g in order to feel a change in pressure, and 34 g to 1 kg. For auditory sensations, this constant is 1/10, for visual sensations, 1/100.
Adaptation- adaptation of sensitivity to a constantly acting stimulus, manifested in a decrease or increase in thresholds. In life, the phenomenon of adaptation is well known to everyone. The first minute a person enters the river, the water seems cold to him. Then the feeling of cold disappears, the water seems warm enough. This is observed in all types of sensitivity, except for pain. Staying in absolute darkness increases the sensitivity to light in 40 minutes by about 200,000 times. The interaction of sensations. (The interaction of sensations is a change in the sensitivity of one analyzer system under the influence of the activity of another analyzer system. The change in sensitivity is explained by cortical connections between analyzers, to a large extent by the law of simultaneous induction). The general pattern of the interaction of sensations is as follows: weak stimuli in one analyzer system increase sensitivity in another. An increase in sensitivity as a result of the interaction of analyzers, as well as systematic exercises, is called sensitization.
Which are manifested in the reflection of a separate property of objects. This includes various phenomena of the surrounding world and the internal states of the human body during the direct impact of material stimuli on receptors. Types of sensations will help determine the most common human stimuli.
The role of sensations in life
The role of sensations in human life can hardly be overestimated, because they are a unique source of all knowledge about the world. People feel the surrounding reality with the help of the senses, because they are the only channels through which the outside world penetrates the human consciousness.
Various types of sensations are capable of reflecting certain properties of the environment to one degree or another. This includes sounds, lighting, taste and many other factors, thanks to which a person has the opportunity to navigate in the world around him.
The physiological basis of sensations is the nervous processes that, by their nature, appear during the action of a stimulus on an adequate analyzer. It, in turn, consists of receptors, nerve pathways and a central section. Here, a variety of signals are processed that come directly from the receptors to the cerebral cortex. It is safe to say that due to the receipt of impulses and stimuli into the brain, a person can quickly respond and perceive various types of sensations.
How do sensations arise?
Human sensations arise only when a certain stimulus appears. It is worth noting that the provision of a certain effect on the receptor can lead to the appearance of an irritant. It transforms all processes into nervous excitation, which is transmitted to the central parts of the analyzer.
At this moment, a person can feel the taste, light, and many other factors. In this case, there should be a response of the body to a particular stimulus. It is transmitted from the brain to the sense organs by means of the centrifugal nerve. A person can move his own gaze and perform many other actions every second, perceiving irritable signals.
Basic classification of sensations
The main role of sensations in human life is to timely bring all the necessary information to the central nervous system. It is possible to single out the most common classification in which types of sensations are presented.
Feelings:
Exteroceptive: a) contact - temperature, tactile and taste; b) distant - visual, auditory and olfactory.
Proprioceptive: a) musculo-motor.
Interoceptive - they indicate the current state of all internal organs.
Certain sensations are able to reflect the properties of objects, phenomena of the external world, reflecting the state of the body, tactile, pain, as well as sensations of various origins. It is thanks to these possibilities that a person can distinguish colors and light.
Taste sensations
It can be said with certainty that taste sensations are determined by the various properties of surrounding things. They do not have a complete or objective classification. If we take into account the main complex of sensations that arise due to taste substances, then several main irritants can be distinguished - these are sour, salty, sweet and bitter foods.
Taste sensations often include olfactory sensations, and in some cases this may include a reaction to pressure, heat, cold, or pain. If we talk about caustic, astringent, tart taste qualities, then they are due to a whole range of different sensations. Thanks to a complex complex, a person is able to feel the taste of the food consumed.
Taste buds are able to express themselves during exposure to different taste areas. It turns out that a single substance has a relatively small molecular weight.
The value of the properties of sensations
The main properties of sensations should be reduced to adaptation or adaptations of various stimuli. All this happens until the moment when the reaction of a person is equal to the minimum indicators. These include sensitization, contrast, and interaction with various stimuli.
Varieties and properties of sensations can manifest themselves to varying degrees, that is, they depend on the individual physical and biological characteristics of a particular subject. But it is worth noting that all of these properties are significant in the field of a psychological point of view. It is worth noting that sensitization and adaptation are widely used today in psychotherapy in order to develop the ability of each person to more vividly and emotionally perceive various positive elements.
Exteroceptive and tactile sensations
All human sensations can be divided into exteroceptive and tactile. It should be noted that exteroceptive sensations provide the human body with all the necessary information that comes exclusively from the environment. In turn, people get a visual image with the help of the presence of a sufficient number of cells, which are called "koloboks" and "rods".
The "rods" help to provide fairly good vision at dusk, and the "koloboks" are responsible for color vision. The ear can respond to pressure fluctuations in the atmosphere, which are perceived as sound.
The taste buds, which are located on the papillae of the tongue, are able to perceive several main tastes - sour, salty, sweet and bitter. Human tactile sensations appear during the interaction of any mechanical stimulus and receptors. They are found on the skin of the fingers, palms, lips and many other organs.
Proprioceptive sensations provide important information about the current state of the muscles. They are able to quickly respond to the degree of contraction and muscle relaxation. It should be noted that proprioceptive sensations inform a person about the state of internal organs, their chemical composition, the presence of biological, useful or harmful substances.
Features of pain
Pain is an important biologically active protective device. It arises with the help of the destructive force of irritation. It is worth noting that pain can serve as an alarm about a possible danger to the human body. The sensitivity of pain is distributed over the surface of the skin, as well as in the internal organs. The distribution process is partial and uneven.
There are areas where a small number of pain receptors are located. Experimental studies were carried out, which made it possible to consider the distribution of pain points as dynamic and mobile. Pain sensations are the result of impacts exceeding the prescribed limit of intensity and frequency of impulses. Also, it all depends on the duration of a particular stimulus.
According to Frey's theory, different pain sensitivity has an independent, peripheral and central nervous apparatus.
Touch and pressure
Presented are characterized by the features of touch and pressure. Therefore, it is possible to accurately determine their localization, which is developed as a result of experience during the participation of vision and muscle joints. It should be noted that a large number of receptors are characterized by rapid adaptation. That is why a person feels not only force pressure, but also a change in intensity.
Common sense characteristics
It should be noted that intensity is the main characteristic of human sensations, which is determined by the quantity and strength of the acting stimulus. Certain sense organs have a special sensitivity to the displayed phenomena. Sensitivity can be described as the threshold of sensation.
The duration of sensation is a temporal characteristic that can be determined by the periodic effects of the stimulus on duration and intensity. But it is worth noting that many other features must be taken into account. During the impact of the stimulus on any sense organ, a certain sensation may not occur immediately, but after some time. This phenomenon can be characterized as latent or latent sensation time.
Olfactory sensations
The sense of smell is a type of chemical sensitivity. It is worth noting that in animals, the sense of smell and taste are one, they simply differentiate after a certain period of time. A few years ago, it was generally accepted that the sense of smell does not play a particularly important role in human life. If you look from the point of view of the knowledge of the external world, then sight, hearing and touch are in the first place and are more important.
But it is worth noting that the smell has a direct impact on the various functions of the autonomic nervous system. Also, with the help of this feeling, you can create a positive or negative emotional background that can color the general well-being of a person.
Touch
During touch, each person cognizes the material world, performs the process of movement, which can also turn into conscious purposeful feeling. It is in this way that a person in practice has the opportunity to know any objects.
Sensations of touch and pressure are typical traditional psychophysiological phenomena. They are associated with the thresholds of skin sensitivity, therefore they play only a subordinate role in the human mind, as well as its objective reality. The sense organs - skin, eyes, ears - allow a person to fully experience the world.
Signaling about what is happening at a given moment in the environment around us and in our own body. It gives people the opportunity to navigate in the conditions that surround them, and to match their actions and actions with them. That is, sensation is the knowledge of the environment.
Feelings - what is it?
Sensations are a reflection of certain properties that are inherent in an object, with their direct impact on human or animal senses. With the help of sensations, we gain knowledge about objects and phenomena, such as, for example, shape, smell, color, size, temperature, density, taste, etc., we catch various sounds, comprehend space and make movements. Sensation is the first source that gives a person knowledge about the world around him.
If a person were deprived of absolutely all sense organs, then by no means would he be able to cognize the environment. After all, sensation is what gives a person material for the most complex psychological processes, such as imagination, perception, thinking, and so on.
So, for example, those people who are blind from birth will never be able to imagine what blue, red or any other color looks like. And a person suffering from deafness from birth has no idea how his mother’s voice sounds, the purring of a cat and the murmur of a stream.
So, sensation is in psychology that which is generated as a result of irritation of certain sense organs. Then irritation is an effect on the sense organs, and stimuli are phenomena or objects that in one way or another affect the sense organs.
Sense organs - what is it?
We know that sensation is a process of knowing the environment. And with the help of what do we feel, and therefore, cognize the world?
Even in ancient Greece, there were five sense organs and sensations corresponding to them. We know them from school. These are auditory, olfactory, tactile, visual and gustatory sensations. Since sensation is a reflection of the world around us, and we use not only these sense organs, modern science has significantly increased information about the possible types of feelings. In addition, the term "sense organs" today has a conditional interpretation. "Sense organs" is a more accurate name.
Sensory nerve endings are the main part of any sense organ. They are called receptors. Millions of receptors have such sense organs as tongue, eye, ear and skin. When the stimulus acts on the receptor, a nerve impulse occurs, which is transmitted along the sensory nerve to certain areas of the cerebral cortex.
In addition, there is a sensory experience that is generated within. That is, not as a result of physical impact on the receptors. Subjective sensation - this is such an experience. One example of this sensation is tinnitus. In addition, the feeling of happiness is also a subjective feeling. Thus, we can conclude that subjective sensations are individual.
Types of sensations
Sensation is a reality in psychology that affects our sense organs. To date, there are about two dozen different sensory organs that reflect the impact on the human body. All types of sensations are the result of exposure to receptors of various stimuli.
Thus, sensations are divided into external and internal. The first group is what our sense organs tell us about the world, and the second is what our own body signals to us. Let's consider them in order.
External sensations include visual, gustatory, olfactory, tactile and auditory.
visual sensations
It is the feeling of color and light. All objects that surround us have some kind of color, while a completely colorless object can only be one that we do not see at all. There are chromatic colors - various shades of yellow, blue, green and red, and achromatic - these are black, white and intermediate shades of gray.
As a result of the impact of light rays on the sensitive part of our eye (the retina), visual sensations arise. In the retina there are two types of cells that react to color - these are rods (about 130) and cones (about seven million).
The activity of cones occurs only in the daytime, and for rods, on the contrary, such light is too bright. Our vision of color is the result of the work of cones. At dusk, the sticks are active, and a person sees everything in black and white. By the way, hence the well-known expression that at night all cats are gray.
Of course, the less light, the worse a person sees. Therefore, in order to prevent excessive eye strain, it is strongly recommended not to read at dusk and in the dark. Such strenuous activity adversely affects vision - the development of myopia is possible.
auditory sensations
There are three types of such sensations: musical, speech and noise. The auditory analyzer in all these cases identifies four qualities of any sound: its strength, pitch, timbre and duration. In addition, he perceives the tempo-rhythmic features of sounds perceived sequentially.
Phonemic hearing is the ability to perceive speech sounds. Its development is determined by the speech environment in which the child is brought up. A well-developed phonemic ear significantly affects the accuracy of written speech, especially during the period of education in elementary school, while a child with a poorly developed phonemic ear makes many mistakes when writing.
The musical ear of the baby is formed and develops in the same way as speech or phonemic. The early introduction of the child to musical culture plays a huge role here.
A certain emotional mood of a person can create various noises. For example, the sound of the sea, rain, the howl of the wind or the rustle of leaves. Noises can signal danger, such as the hiss of a snake, the sound of an approaching car, the menacing bark of a dog, or they can signal joy, such as fireworks or the steps of a loved one. School practice often talks about the negative impact of noise - it tires the nervous system of the student.
Skin sensations
Tactile sensation is the sensation of touch and temperature, that is, the feeling of cold or heat. Each type of nerve endings on the surface of our skin allows us to feel the temperature of the environment or touch. Of course, the sensitivity of different areas of the skin is different. For example, the chest, lower back and stomach are more susceptible to the sensation of cold, and the tip of the tongue and fingertips are most susceptible to touch, the back is least susceptible.
Temperature sensations have a very pronounced emotional tone. Thus, average temperatures are accompanied by a positive feeling, despite the fact that the emotional coloring of heat and cold differ significantly. Warmth is regarded as a relaxing feeling, while cold, on the contrary, is invigorating.
Olfactory sensations
Sense of smell is the ability to smell odors. In the depths of the nasal cavity there are special sensitive cells that contribute to the recognition of odors. Olfactory sensations in modern man play a relatively small role. However, for those who are deprived of any sense organ, the rest work more intensively. For example, deaf-blind people are able to recognize people and places by smell, receive signals of danger using their sense of smell.
The sense of smell can also signal to a person that danger is nearby. For example, if the smell of burning or gas is in the air. The emotional sphere of a person is greatly influenced by the smells of the objects around him. By the way, the existence of the perfume industry is entirely due to the aesthetic need of a person for pleasant smells.
Taste and olfactory sensations are closely related to each other, since the sense of smell helps to determine the quality of food, and if a person has a runny nose, then all the dishes offered will seem tasteless to him.
Taste sensations
They arise due to irritation of the taste organs. These are the taste buds, which are located on the surface of the pharynx, palate and tongue. There are four main types of taste sensations: bitter, salty, sweet and sour. The range of nuances that emerge within these four senses gives each dish a unique taste.
The edges of the tongue are susceptible to sour, its tip to sweet, and its base to bitter.
It should be noted that taste sensations are largely influenced by the feeling of hunger. If a person is hungry, then tasteless food seems much more pleasant.
Internal sensations
This group of sensations makes a person aware of what changes are taking place in his own body. Interoceptive sensation is an example of an internal sensation. It tells us that we experience hunger, thirst, pain, and so on. In addition, motor, tactile sensations and a sense of balance are also distinguished. Of course, interoceptive sensation is an extremely important ability for survival. Without these sensations, we would not know anything about our own organism.
Motor sensations
They determine that a person feels the movement and position in space of parts of his body. With the help of the motor analyzer, a person has the ability to feel the position of his body and coordinate its movements. Receptors for motor sensations are located in the tendons and muscles of a person, as well as in the fingers, lips, tongue, because these organs need to make subtle and precise working and speech movements.
organic sensations
This type of sensation tells how the body works. Inside organs, such as the esophagus, intestines, and many others, there are corresponding receptors. While a person is healthy and full, he does not feel any organic or interoceptive sensations. But when something is disturbed in the body, they appear in full. For example, abdominal pain appears if a person has eaten something that is not too fresh.
tactile sensations
This type of feeling is due to the fusion of two sensations - motor and skin. That is, tactile sensations appear when probing an object with a moving hand.
Equilibrium
This sensation reflects the position that our body occupies in space. In the labyrinth of the inner ear, which is also called the vestibular apparatus, when the position of the body changes, the lymph (a special fluid) fluctuates.
The organ of balance is closely connected with the work of other internal organs. For example, with a strong excitation of the balance organ, a person may experience nausea or vomiting. In another way, it is called air sickness or sea sickness. The stability of the balance organs increases with regular training.
Pain
The feeling of pain has a protective value, as it signals that something is unfavorable in the body. Without this kind of sensation, a person would not even feel serious injuries. Complete insensitivity to pain is considered an anomaly. It does not bring a person anything good, for example, he does not notice that he cuts his finger or put his hand on a hot iron. Of course, this leads to permanent injuries.
A brief digression into the development of the concept of sensations
Feel- “the law of the specific energy of the sense organ”, that is, sensation does not depend on the nature of the stimulus, but on the organ or nerve in which the process of irritation occurs. The eye sees, the ear hears. The eye cannot see, but the ear cannot see. 1827
The objective world is fundamentally unknowable. The result of the sensation process is a partial, that is, a partial image of the world. All that we perceive is the process of specific impact on the senses. "Mental processes" Vecker L.M.
Power dependence of the change in sensations with a change in the intensity of stimuli (Stevens law)
The lower and upper absolute thresholds of sensations (absolute sensitivity) and the thresholds of discrimination (relative sensitivity) characterize the limits of human sensitivity. In addition to this, there are operational thresholds of sensations— the magnitude of the difference between the signals, at which the accuracy and speed of their discrimination reach a maximum. (This value is an order of magnitude greater than the difference threshold value.)
2. Adaptation. The sensitivity of the analyzer is not stable, it changes depending on various conditions.
So, entering a poorly lit room, at first we do not distinguish objects, but gradually the sensitivity of the analyzer increases; being in a room with any smells, after a while we stop noticing these smells (the sensitivity of the analyzer decreases); when we get from a poorly lit space into a brightly lit one, the sensitivity of the visual analyzer gradually decreases.
A change in the sensitivity of the analyzer as a result of its adaptation to the strength and duration of the acting stimulus is called adaptation(from lat. adaptatio- fixture).
Different analyzers have different speed and range of adaptation. To some stimuli, adaptation occurs quickly, to others - more slowly. Olfactory and tactile adapt faster (from the Greek. taktilos- touch) analyzers. Auditory, gustatory and visual analyzers adapt more slowly.
Full adaptation to the smell of iodine occurs in a minute. After three seconds, the sensation of pressure reflects only 1/5 of the strength of the stimulus. (Searching for glasses shifted to the forehead is one example of tactile adaptation.) Full dark adaptation of the visual analyzer takes 45 minutes. However, visual sensitivity has the largest range of adaptation - it changes 200,000 times.
The phenomenon of adaptation has expedient biological significance. It contributes to the reflection of weak stimuli and protects the analyzers from excessive exposure to strong ones. Adaptation, like getting used to constant conditions, provides an increased orientation to all new influences. Sensitivity depends not only on the strength of the impact of external stimuli, but also on internal states.
3. Sensitization. Increasing the sensitivity of analyzers under the influence of internal (mental) factors is called sensitization(from lat. sensibilis- sensitive). It can be caused by: 1) the interaction of sensations (for example, weak taste sensations increase visual sensitivity. This is due to the interconnection of analyzers, their systemic work); 2) physiological factors (the state of the body, the introduction of certain substances into the body; for example, vitamin A is essential to increase visual sensitivity); 3) the expectation of a particular impact, its significance, a special setting to distinguish between stimuli; 4) exercise, experience (thus, tasters, by specially exercising taste and olfactory sensitivity, distinguish between various varieties of wines, teas and can even determine when and where the product was made).
In people deprived of any kind of sensitivity, this deficiency is compensated (compensated) by increasing the sensitivity of other organs (for example, increased auditory and olfactory sensitivity in the blind). This so-called compensatory sensitization.
Strong excitation of some analyzers always lowers the sensitivity of others. This phenomenon is called desensitization. So, the increased noise level in "loud shops" lowers visual sensitivity; visual desensitization occurs.
Rice. 4. . The inner squares produce sensations of varying intensities of gray. In reality they are the same. Sensitivity to the properties of phenomena depends on adjacent and successive contrast effects.
4. . One of the manifestations of the interaction of sensations is their contrast(from lat. contraste- a sharp contrast) - an increase in sensitivity to one property under the influence of other, opposite, properties of reality. So, the same gray figure appears dark on a white background, and white on a black one (Fig. 4).
5. Synesthesia. An associative (phantom) non-modal sensation that accompanies a real one (the sight of a lemon causes a sensation of sourness) is called synesthesia(from Greek. synaisthesis shared feeling).
Rice. 5.
Features of certain types of sensations.
visual sensations. The colors perceived by a person are divided into chromatic (from the Greek. chroma- color) and achromatic - colorless (black, white and intermediate shades of gray).
For the appearance of visual sensations, the impact of electromagnetic waves on the visual receptor, the retina of the eye (an accumulation of photosensitive nerve cells located at the bottom of the eyeball), is necessary. In the central part of the retina, nerve cells predominate - cones, which provide a sense of color. At the edges of the retina, rods sensitive to brightness changes predominate (Fig. 5, 6).
Rice. 6. . To light-sensitive receptors - rods (reacting to changes in brightness) and cones (reacting to different wavelengths of electromagnetic waves, i.e. to chromatic (color) influences), light penetrates, bypassing ganglion and bipolar cells, which carry out the primary elementary analysis of nerve impulses going already from the retina. For the occurrence of visual excitation, it is necessary that the electromagnetic energy that enters the retina be absorbed by its visual pigment: rod pigment - rhodopsin and cone pigment - iodopsin. Photochemical transformations in these pigments give rise to the visual process. At all levels of the visual system, this process: manifests itself in the form of electrical potentials, which are recorded by special devices -, electroretinograph,.
Light (electromagnetic) beams of different lengths cause different color sensations. Color - a mental phenomenon - human sensations caused by different frequencies of electromagnetic radiation (Fig. 7). The eye is sensitive to the part of the electromagnetic spectrum from 380 to 780 nm (Fig. 8). The wavelength of 680 nm gives the impression of red; 580 - yellow; 520 - green; 430 - blue; 390 - purple flowers.
electromagnetic radiation.
Rice. 7. electromagnetic spectrum and its visible part (NM - nanometer - one billionth of a meter)
Rice. 8. .
Rice. 9. . Opposite colors are called complementary colors - when mixed, they form white. Any color can be obtained by mixing two border colors with it. For example: red - a mixture of orange and purple).
The mixture of all perceived electromagnetic waves gives the sensation of white.
There is a three-component theory of color vision, according to which the whole variety of color sensations arises as a result of the work of only three color-perceived receptors - red, green and blue. Cones are divided into groups of these three colors. Depending on the degree of excitation of these color receptors, various color sensations arise. If all three receptors are excited to the same extent, then there is a sensation of white color.
Rice. 10. .
To different parts of the electromagnetic spectrum, our eye has unequal sensitivity. It is most sensitive to light rays with a wavelength of 555 - 565 nm (light green color tone). The sensitivity of the visual analyzer at dusk moves towards shorter wavelengths - 500 nm (blue color). These rays begin to appear lighter (Purkinje phenomenon). The rod apparatus is more sensitive to ultraviolet color.
In conditions of sufficiently bright lighting, the cones turn on, the rod apparatus turns off. In low light, only sticks are included in the work. Therefore, in twilight lighting, we do not distinguish the chromatic color, the color of objects.
Rice. eleven. . Information about events in the right half of the visual field enters the left occipital lobe from the left side of each retina; information about the right half of the visual field is sent to the left occipital lobe from the right parts of both retinas. The redistribution of information from each eye occurs as a result of the crossing of part of the optic nerve fibers in the chiasm.
Visual excitations are characterized by some inertia. This is the reason for the preservation of a trace of light irritation after the cessation of exposure to the stimulus. (Therefore, we do not notice gaps between frames of the film, which turn out to be filled with traces from the previous frame.)
People with weakened cone apparatus have difficulty distinguishing chromatic colors. (This drawback, described by the English physicist D. Dalton, is called color blind). The weakening of the rod apparatus makes it difficult to see objects in twilight lighting (this drawback is called "night blindness".)
For the visual analyzer, the difference in brightness is essential - contrast. The visual analyzer is capable of distinguishing contrast within certain limits (optimum 1:30). Strengthening and weakening of contrasts is possible through the use of various means. (To reveal a subtle relief, shadow contrast is enhanced by side lighting, the use of filters.)
The color of each object is characterized by those rays of the light spectrum that the object reflects. (A red object, for example, absorbs all rays of the light spectrum, except for the red, which is reflected by it.) The color of transparent objects is characterized by the rays that they transmit. Thus, The color of any object depends on which rays it reflects, absorbs and transmits..
Rice. 12.: 1 - chiasm; 2 - visual tubercle; 3 - occipital lobe of the cerebral cortex.
In most cases, objects reflect electromagnetic waves of various lengths. But the visual analyzer perceives them not separately, but in total. For example, exposure to red and yellow colors is perceived as orange, and a mixture of colors occurs.
Signals from photoreceptors - light-sensitive formations (130 million cones and rods) go to 1 million larger (ganglion) retinal neurons. Each ganglion cell sends its own process (axon) to the optic nerve. Impulses traveling to the brain along the optic nerve receive primary processing in the diencephalon. Here, the contrast characteristics of the signals and their temporal sequence are enhanced. And from here, nerve impulses enter the primary visual cortex, localized in the occipital region of the cerebral hemispheres (fields 17-19 according to Brodmann) (Fig. 11, 12). Here, individual elements of the visual image are distinguished - points, angles, lines, directions of these lines. (Established by Boston researchers, 1981 Nobel Prize winners Hubel and Wiesel.)
Rice. 13. optogram taken from the retina of a dog's eye after her death. This indicates the screen principle of functioning of the retina.
The visual image is formed in the secondary visual cortex, where the sensory material is compared (associated) with previously formed visual standards - the image of the object is recognized. (It takes 0.2 seconds from the beginning of the stimulus to the appearance of a visual image.) However, a screen display of the perceived object occurs already at the level of the retina (Fig. 13).
auditory sensations. There is an opinion that we receive 90% of information about the world around us through vision. It can hardly be calculated. After all, what we see with the eye should be covered by our conceptual system, which is formed integratively, as a synthesis of all sensory activity.
Rice. 14. Deviations from normal vision - nearsightedness and farsightedness. These deviations can usually be compensated for with glasses with specially selected lenses.
The work of the auditory analyzer is no less complex and important than the work of the visual analyzer. This channel is the main flow of speech information. A person feels sound 35 - 175 ms after he has reached the auricle. Another 200 - 500 ms is necessary for maximum sensitivity to a given sound. It also takes time to turn the head and properly orient the auricle in relation to the source of a weak sound.
From the tragus of the auricle, the oval auditory canal deepens into the temporal bone (its length is 2.7 cm). Already in the oval passage, the sound is significantly amplified (due to the resonant properties). The oval passage is closed by the tympanic membrane (its thickness is 0.1 mm, and its length is 1 cm), which constantly vibrates under the influence of sound influences. The tympanic membrane separates the outer ear from the middle ear - a small chamber with a volume of 1 cm³ (Fig. 15).
The middle ear cavity is connected to the inner ear and the nasopharynx. (The air coming from the nasopharynx balances the external and internal pressure on the tympanic membrane.) In the middle ear, sound is repeatedly amplified by the system of bones (hammer, anvil and stirrup). These ossicles are supported in weight by two muscles that tighten when sounds are too loud and weaken the ossicles, protecting the hearing aid from injury. With weak sounds, the muscles increase the work of the bones. The intensity of sound in the middle ear increases 30 times due to the difference between the area of the tympanic membrane (90 mm2) to which the malleus is attached and the area of the base of the stirrup (3 mm2).
Rice. 15. . Sound vibrations of the external environment pass through the ear canal to the tympanic membrane, located between the outer and middle ear. The tympanic membrane transmits vibrations and the bony mechanism of the middle ear, which, acting on a lever principle, amplifies the sound by about 30 times. As a result of this, slight changes in pressure at the eardrum are transmitted by a piston-like movement to the oval window of the inner ear, which causes the movement of fluid in the cochlea. Acting on the elastic walls of the cochlear canal, the movement of the fluid causes an oscillatory movement of the auditory membrane, more precisely, of a certain part of it, resonating at the appropriate frequencies. At the same time, thousands of hair-like neurons transform the oscillatory movement into electrical impulses of a certain frequency. The round window and the Eustachian tube coming from it serve to equalize the pressure with the external environment; leaving the nasopharynx, the Eustachian tube opens slightly during swallowing movements.
The purpose of the auditory analyzer is to receive and analyze signals transmitted by vibrations of an elastic medium in the range of 16-20,000 Hz (sound range).
The receptor part of the auditory system - the inner ear - the so-called cochlea. It has 2.5 turns and is divided transversely by a membrane into two isolated channels filled with liquid (relymph). Along the membrane, which narrows from the lower coil of the cochlea to its upper coil, there are 30 thousand sensitive cilia formations - they are sound receptors, forming the so-called organ of Corti. In the cochlea, the primary dissection of sound vibrations occurs. Low sounds affect long eyelashes, high sounds affect short ones. The vibrations of the corresponding sound cilia create nerve impulses that enter the temporal part of the brain, where complex analytical and synthetic activity is carried out. The most important verbal signals for a person are encoded in neural ensembles.
The intensity of the auditory sensation - loudness - depends on the intensity of the sound, that is, on the amplitude of the vibrations of the sound source and on the pitch of the sound. The pitch of the sound is determined by the oscillation frequency of the sound wave, the timbre of the sound is determined by overtones (additional oscillations in each main phase) (Fig. 16).
The pitch of a sound is determined by the number of oscillations of the sound source in 1 second (1 oscillation per second is called hertz). The organ of hearing is sensitive to sounds in the range from 20 to 20,000 Hz, but the highest sensitivity lies in the range of 2000 - 3000 Hz (this is the pitch corresponding to the cry of a frightened woman). A person does not feel the sounds of the lowest frequencies (infrasounds). The sound sensitivity of the ear starts at 16 Hz.
Rice. 16. . The intensity of sound is determined by the amplitude of the vibration of its source. Height - vibration frequency. Timbre - additional vibrations (overtones) in each "time" (middle figure).
However, subthreshold low-frequency sounds affect the mental state of a person. So, sounds with a frequency of 6 Hz cause a person to feel dizzy, tired, depressed, and sounds with a frequency of 7 Hz can even cause cardiac arrest. Getting into the natural resonance of the work of internal organs, infrasounds can disrupt their activity. Other infrasounds also selectively affect the human psyche, increasing its suggestibility, learning ability, etc.
Human sensitivity to high frequency sounds is limited to 20,000 Hz. Sounds that lie beyond the upper threshold of sound sensitivity (that is, over 20,000 Hz) are called ultrasounds. (Ultrasonic frequencies of 60 and even 100,000 Hz are available to animals.) However, since sounds up to 140,000 Hz are found in our speech, we can assume that they are perceived by us at a subconscious level and carry emotionally significant information.
The thresholds for distinguishing sounds by their height are 1/20 of a semitone (that is, up to 20 intermediate steps differ between the sounds produced by two adjacent piano keys).
In addition to high-frequency and low-frequency sensitivity, there are lower and upper thresholds for sensitivity to sound intensity. Sound sensitivity decreases with age. So, for the perception of speech at the age of 30, a sound volume of 40 dB is required, and for the perception of speech at the age of 70, its volume must be at least 65 dB. The upper threshold of auditory sensitivity (in terms of volume) is 130 dB. Noise above 90 dB is harmful to humans. Sudden loud sounds are also dangerous, hitting the autonomic nervous system and leading to a sharp narrowing of the lumen of blood vessels, an increase in heart rate and an increase in the level of adrenaline in the blood. The optimal level is 40 - 50 dB.
Tactile sensation(from Greek. taktilos- touch - the feeling of being touched. Tactile receptors (Fig. 17) are most numerous at the fingertips and tongue. If on the back two touch points are perceived separately only at a distance of 67 mm, then on the tip of the fingers and tongue - at a distance of 1 mm (see table).
Spatial thresholds of tactile sensitivity.
Rice. 17. .
| High sensitivity zone | Low sensitivity zone |
| Tip of the tongue - 1 mm | Sacrum - 40.4 mm |
| End phalanxes 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.
