What is sensitivity? What is speaker sensitivity? Myth: Sensitive people are talented and smart

English sensitivity).

1. In comparative psychology and zoopsychology, Ch. is understood as the ability for an elementary form of mental reflection - sensation. It is with Ch., according to the hypothesis of A. N. Leontyev and A. V. Zaporozhets, that the development of the psyche in phylogenesis begins. In contrast to irritability in the concept of "Ch." the signaling criterion is used: Ch. - reflection by the body of such influences that are not directly biologically significant (for example, due to their energy weakness), but can signal the presence (change) of other environmental conditions that are vital (necessary or dangerous) ). Ch. allows you to direct (lead) the body to vital components of the environment or away from unfavorable and dangerous components of the environment. To provide Ch., special organs (receptors) are required that respond to biologically insignificant influences; a creature deprived of such organs must lose all reactions (including metabolic) to signal stimuli. Thanks to Ch., such behavioral effects arise as an anticipatory reaction (a reaction to an event that has not yet occurred) and a disproportionality of the reaction energy compared to the weak power of signal, biologically neutral stimuli. (B.M.)

2. In classical psychophysics, Ch. is the reciprocal of the threshold. Like the rapids, Ch.m.b. absolute, difference (differential), etc.

Psychophysical theories that deny the threshold principle of operation of sensory systems (see Classical theory of sensory continuity) use not a threshold as a measure of frequency, but some other indicators (see Coefficient dr, Sensory threshold, Psychophysical model of signal detection theory).

3. Ch. (in the biological sense) - the ability of a living organism to “perceive” adequate and inadequate irritations, responding to them. image: movement, conscious sensation, vegetative reaction, etc.; in a narrow sense - the ability of sense organs and analyzers to respond to the appearance of a stimulus or its change.

A distinction is made between absolute and differential. Part 1 is understood as the ability to “perceive” stimuli of minimal magnitude (detection); 2nd - as the ability to “perceive” changes in a stimulus or distinguish between nearby stimuli. (K.V. Bardin.)

SENSITIVITY

the body’s ability to remember and respond to environmental influences that do not have direct biological significance, but cause a psychological reaction in the form of sensations.

SENSITIVITY

1. In psychophysics, a quantity inversely proportional to the threshold of sensation. Accordingly, absolute and differential (difference) sensitivity differ. 2. In differential psychology and characterology - increased readiness for affective reactions. 3. General ability to sense - the ability of organisms to actively respond to irritations, to reflect influences that are biologically neutral, but objectively related to biotic properties. Appears in phylogeny when organisms begin to respond to environmental factors that perform a signaling function in relation to influences that have direct biological significance. Here reflection, according to A. N. Leontyev, has two aspects: in the objective sense - a response to a given agent, primarily motor; in the subjective - internal experience, sensation of a given object. Sensitivity as the ability to have sensations is the basis of personality. The levels of development of various kinds of sensitivity are the makings of the development of abilities. The classification of types of sensitivity coincides with the existing classifications of sensations. Thus, types of sensitivity are distinguished, differing in the degree of detail of the sensory analysis performed. Considering the nature of the stimulus, we can talk about sensitivity to the action of mechanical, optical, chemical, temperature and other stimuli. The sensitivity of the body can be assessed not only on the basis of sensations, but also by changes in the course of various psychophysiological processes. The results usually result in slightly different metrics; for example, visual sensitivity, determined by the reaction of changes in integral rhythms of the brain, turns out to be higher than sensitivity assessed on the basis of the subject’s verbal report. The emergence of new theoretical concepts (signal detection theory) in psychophysics has made it possible to create generalized definitions of sensitivity, independent of the concept of sensation threshold.

SENSITIVITY

The body’s ability to perceive irritations coming from the external environment or from internal organs and tissues. The physiological basis of Ch. is the activity of analyzers, that is, the process of transmitting impulses that arise in connection with the influence of stimuli to the central nervous system. The classification of types of perception is based on a taxonomy of types of reception and associated subjective experiences. In this regard, a distinction is made between exteroceptors, which perceive stimuli from the outside, and interoceptors, which perceive stimuli arising in the body itself. With more differentiated discrimination, they distinguish pain (nociceptive), visceral, gustatory, deep (proprioceptive), directional (based on some properties of the environment, orientation in space is formed, a certain direction is highlighted), discriminatory (discriminatory), differential (the ability to perceive differences in intensity stimuli), interoceptive, cutaneous, olfactory, proprioceptive, light, auditory, temperature, exteroceptive, electrodermal, complex (integrative perception of stimuli by receptors of various modalities).

According to H. Head, there are also phylogenetically more ancient protopathic (Greek protos - first, primary, pathos - disease, suffering) and phylogenetically new epicritic (Greek epikrisis - judgment, decision) Part. The first is characterized by an increase in the threshold of perception, a qualitative difference in perception from normal, diffuse nature of sensations caused by external stimuli; the quality of irritation is not differentiated clearly enough, but with a certain intensity of irritation they cause a sharp feeling of unpleasantness. Epicritic pain is characterized by a lower threshold of irritation, the ability to perceive light touch, precise localization of external irritation, and more perfect recognition of the quality of the external stimulus. The specified types of Ch., according to M.I. Astvatsaturov, form the basis of the forms of emotions (see Emotions of form according to Astvatsaturov).

SENSITIVITY

sensibility) - the ability to distinguish between stimuli, susceptibility (see Stimulus). All cells of the nervous system have some kind of sensitivity - this is their distinguishing feature from other cells.

Sensitivity

Absolute sensitivity

Differential sensitivity.

SENSITIVITY

the ability of a living organism to perceive adequate and inadequate stimuli, responding to them in some way: movement, conscious sensation, autonomic reaction, etc.; in a narrow sense - the ability of sense organs (analyzers) to respond to the appearance of a stimulus or its change. There are absolute and differential frequencies. The first is understood as the ability to perceive stimuli of minimal magnitude; it is estimated by the value E, the reciprocal of the lower absolute threshold I, i.e. E = 1/1. The second is understood as the ability to perceive changes in a stimulus or distinguish between close stimuli and is determined by the value of the differential threshold. The classification of types of sensations coincides with existing classifications of sensations. In this regard, they talk about visual, auditory, tactile, temperature, vibration, and other types of frequency. The body’s frequency can be assessed not only on the basis of sensations, but also by changes in the course of various psychophysiological processes. As a rule, different indicators are obtained as a result. Thus, visual frequency, determined by the reaction of changes in the integral rhythms of the brain, turns out to be higher than frequency, assessed on the basis of a verbal report. In recent years, thanks to the emergence of new theoretical concepts (the theory of signal detection), more generalized definitions of frequency have appeared, independent of the concept of sensation threshold .

Various sense organs that give us information about the state of the external world around us may be more or less sensitive to the phenomena they display, i.e. may reflect these phenomena with greater or less accuracy. Sensitivity of the senses determined by the minimal stimulus that, under given conditions, is capable of causing sensation.

The minimum strength of the stimulus that causes a barely noticeable sensation is called lower absolute threshold sensitivity. Lesser irritants, so-called subliminal, do not cause sensations. The lower threshold of sensations determines the level absolute sensitivity of this analyzer. There is an inverse relationship between absolute sensitivity and the threshold value: the lower the threshold value, the higher the sensitivity of a given analyzer. This relationship can be expressed by the formula E-1/P, where ^-sensitivity, R- threshold value.

Analyzers have different sensitivities. Humans have very high sensitivity visual and auditory analyzers. As the experiments of S.I. Vavilov (1891-1951) showed, the human eye is capable of seeing light when only 2-8 quanta of radiant energy enter. This allows you to see a burning candle on a dark night at a distance of up to 27 km from the eye.

The auditory cells of the inner ear detect movements whose amplitude is less than 1% of the diameter of a hydrogen molecule. This allows us to hear the ticking of a clock in complete silence at a distance of up to 6 m. The threshold of one human olfactory cell for the corresponding odorous substances does not exceed eight molecules. This allows you to sense the presence of perfume with just one drop of it in a room consisting of six rooms. To create a taste sensation, it takes at least 25 thousand times more molecules than to create an olfactory sensation.

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

The magnitude of absolute thresholds depends on the nature of the activity, age, functional state of the body, strength and duration of irritation.

In addition to the magnitude of the absolute threshold, sensations are characterized by a relative, or differential, threshold. The minimum difference between two stimuli that causes a barely noticeable difference in sensation is called discrimination threshold, or difference threshold. German physiologist E. Weber (1795-1878), testing a person’s ability to determine the heavier of two objects in the right and left hand, he established that differential sensitivity is relative and not absolute. This means that the ratio of the barely noticeable difference to the magnitude of the original stimulus is a constant value. The stronger the intensity of the original stimulus, the more it must be increased in order to notice a difference, i.e. the greater the magnitude of the subtle difference.

The differential threshold of sensations for the same organ is a constant value and is expressed by the following formula: dJ/J = C, where Y is the initial value of the stimulus, adJ- its increase, causing a barely noticeable sensation of change in the magnitude of the stimulus, C is a constant. The value of the differential threshold for different modalities is different: for vision it is approximately 1/100, for hearing - 1/10, for tactile sensations - 1/30. This law is called the Weber-Booger law, and it is only valid for the middle ranges.

Based on Weber's experimental data, the German physicist G. Fechner (1801-1887) expressed the dependence of the intensity of sensations on the strength of the stimulus with the following formula: E=klogJ+ C, where E- magnitude of sensations, /-strength of stimulus, ki S - constants determined by a given sensory system. According to the Weber-Fechner law, the magnitude of sensations is directly proportional to the logarithm of the intensity of the stimulus. In other words, the sensation changes much more slowly than the strength of irritation increases. An increase in the strength of stimulation in geometric progression corresponds to an increase in sensation in arithmetic progression.

The sensitivity of analyzers, determined by the magnitude of absolute thresholds, is not constant and changes under the influence of physiological and psychological conditions. A change in the sensitivity of the sense organs under the influence of a stimulus is called sensory adaptation. There are three types of this phenomenon.

• 1. Adaptation Howcomplete disappearance of sensation during prolonged action of the stimulus. A common fact is the distinct disappearance of olfactory sensations soon after we enter a room with an unpleasant odor. However, complete visual adaptation up to the disappearance of sensations does not occur under the influence of a constant and motionless stimulus. This is explained by compensation for the immobility of the stimulus due to the movement of the eye itself. Constant voluntary and involuntary movements of the receptor apparatus provide continuity and variability of sensations. Experiments in which conditions were artificially created to stabilize the image relative to the retina (the image was placed on a special suction cup and moved with the eye) showed that the visual sensation disappeared after 2-3 s.
• 2. Dulling of sensations under the influence of a strong stimulus is called negative adaptation. For example, when we get from a dimly lit room into a brightly lit space, we are initially blinded and unable to discern any details around us. After some time, the sensitivity of the visual analyzer decreases sharply, and we begin to see normally. Another type of negative adaptation can be observed when immersing a hand in cold water: the intensity of sensations caused Kholodov once jellyfish, soon decreases.
• 3. An increase in sensitivity under the influence of a weak stimulus is called positive adaptation. In the visual analyzer, this is a dark adaptation, when the sensitivity of the eye increases under the influence of being in the dark. A similar form of auditory adaptation is adaptation to silence.

Adaptation is of great biological importance: it allows us to detect weak stimuli and protect the senses from excessive irritation in the case of strong stimuli.

The intensity of sensations depends not only on the strength of the stimulus and the level of adaptation of the receptor, but also on the stimuli currently affecting other sense organs. A change in the sensitivity of the analyzer under the influence of other senses is called interaction of sensations, at the same time, we can observe both an increase and a decrease in sensitivity. The general pattern is that weak stimuli acting on one analyzer increase the sensitivity of another, and vice versa - strong stimuli reduce the sensitivity of other analyzers when they interact. For example, by accompanying the reading of a book with quiet, calm music, we increase the sensitivity and receptivity of the visual analyzer, but if the music is too loud, the reaction will be the opposite.

We can observe the interaction of sensations in a phenomenon called synesthesia, in this case, the properties of various sensory systems merge, which allows a person to hear “color music”, see “warm colors”, etc.

Increased sensitivity as a result of the interaction of analyzers and exercises is called sensitization. The possibilities for training the senses and improving them are very great. There are two areas that determine increased sensitivity of the senses:

sensitization, which spontaneously results from the need to compensate for sensory defects: blindness, deafness. For example, some people who are deaf develop vibration sensitivity so strongly that they can even listen to music;

sensitization caused by activity, specific requirements of the profession. For example, the olfactory and gustatory sensations of tasters of tea, cheese, wine, tobacco, etc. reach a high degree of perfection.

Thus, sensations develop under the influence of living conditions and the requirements of practical activity.

Sensitivity is the body’s ability to respond to signals from the external environment, its own organs and tissues. Irritation is perceived by receptors. A receptor is a sensor located in the skin, ovarian membranes, muscles, ligaments, internal. org. and systems. 3 types of receptors: 1) exteroceptors - perceive pain, temperature and tactile irritations of the skin and mucous membranes; 2) proprioceptors - provide information about the relative position of body parts. Located in the musculoskeletal system; 3) interoreceptors - react to pressure and chemicals. in the blood and gastrointestinal tract contents. Location in internal organs and systems. Types of general sensitivity: 1) superficial (pain, temperature, tactile); 2) deep (muscular-articular, vibration, pressure, mass); 3) complex types of sensitivity (two-dimensional-spatial); 4) interoceptive (vessels and internal organs).

The structure of the sensory pathways: sensory impulses are carried out by peripheral nerves. These nerves, with the exception of the intercostal ones, form plexuses: cervicobrachial, lumbosacral. The cells of the first neurons of all types of sensitivity are located in the intervertebral node. Their dendrites, as part of peripheral nerves, follow to the receptors of the trunk and limbs. The axons of the first neurons go to the spinal cord as part of the dorsal root. In the spinal cord, fibers of different types of sensitivity diverge. Conductors of deep sensitivity enter the posterior cord of the spinal cord on their side, rise to the medulla oblongata and end on the cells of the second neuron. The axon of the second neuron passes to the opposite side and rises to the thalamus, where the third neuron is located. The conductors of superficial sensitivity as part of the dorsal root enter the dorsal horn of the spinal cord, where the second neuron is located. The axon of the second neuron passes to the opposite side and rises in the lateral funiculus to the thalamus. Starting from the thalamus, the pathways of deep superficial sensitivity are common; the axon of their 3 neurons ends in the posterior central gyrus. The projection zones of the posterior central gyrus correspond in location and area to the anterior central gyrus: in its upper part there is the leg and torso, in the middle part there is the arm, in the lower part there is the face and head.

7.Syndromes of sensory disorders, their diagnostic significance.

Main types of sensitivity disorders:

1) anesthesia - complete loss of one or another type of sensitivity (tactile, pain, temperature);

2) hypoesthesia - decreased sensitivity, decreased intensity of sensations;

3) hyperesthesia - increased sensitivity to various types of stimuli;

4) hyperpathy - perverted sensitivity, characterized by an increase in the threshold of perception;

5) paresthesia - sensations of “crawling goosebumps”, burning, numbness, which occur spontaneously without causing irritation;

6) dysesthesia - perverted perception of irritation, in which the sensation does not correspond to the irritated receptor;

7) pain is the most common manifestation of irritation of sensory neurons.

By character: whining, dull, shooting. Sensory tract lesion syndromes:

1) peripheral - with damage to peripheral nerves and nerve plexuses. Manifested by hypoesthesia or anesthesia of all types of sensitivity in the area of ​​innervation of the nerve or plexus;

2) segmental - with damage to the dorsal roots, dorsal horns or sensory nuclei of the cranial nerves.

3) conductive - occurs below the lesion of the sensory pathways in the brain and spinal cord.

Classification of sensations

According to the nature of reflection and location of receptors:

1. Extroceptive, reflecting the properties and phenomena of the external environment and having receptors on the surface of the body.

2. Introceptive, having receptors in the internal organs and tissues of the body and reflecting the state of the internal organs.

3. Proprioceptive, receptors cat. are located in muscles and ligaments and provide information about the movement of our body and its position.

The subclass of proprioceptors representing sensitivity to movement is called kinesthetic and kinesthetic.

Extroceptors (2 groups) – contact And distant receptors.

• Contact– transmit irritation through direct contact.
• Distant– react to a stimulus coming from a distant object.

General properties of sensations.

Feel- This is a form of reflection of adequate stimuli.

1. Quality is the main feature of a given sensation, distinguishing it from other types of sensations.

2. The intensity of sensations is its quantitative characteristic and is determined by the strength of the current stimulus.

3. The duration of a sensation is its temporal characteristic. It determines the functional state of the sense organs, but the main thing is the duration of the stimulus.

4. Spatial localization of the stimulus - spatial analysis, carried out by distant receptors, gives us information about the localization of the stimulus in space.

Sensitivity and its measurement

The sensitivity of a sense organ is determined by the minimum stimulus that, under given conditions, is capable of causing sensation. The minimum strength of the stimulus that causes a barely noticeable sensation is called the lower threshold of sensation.

Lower The sensation threshold determines the level of absolute sensitivity of a given analyzer. There is an inverse relationship between absolute sensitivity and threshold value: the lower the threshold value, the higher the sensitivity of a given analyzer.

E = 1/P (E – sensitivity, P – threshold value of the stimulus)

Upper The absolute threshold of sensitivity is the maximum strength of the stimulus at which a sensation adequate to the current stimulus still occurs.

The magnitude of absolute thresholds changes depending on various conditions: the nature of the Activity, the age of the person, the strength and duration of the stimulus.

The minimum difference between two stimuli that causes a barely noticeable difference in sensation is called n the threshold of discrimination or difference threshold. The discrimination threshold is characterized by a relative value for a given analyzer. Fechner expressed the dependence of the intensity of sensations on the strength of the stimulus: S = KlgJ + C; S is the intensity of sensations, J is the strength of the stimulus, K and C are constants. Weber-Fechner law. The intensity of the sensation is proportional to the logarithm of the stimulus strength. As the strength of the stimulus increases in geometric progression, the intensity of sensations increases in arithmetic progression.

The higher the threshold, the lower the difference sensitivity.

Our analyzing systems are capable of influencing each other to a greater or lesser extent. In this case, the interaction of sensations manifests itself in two opposite processes: an increase and decrease in sensitivity. Weak stimuli increase sensitivity, while strong stimuli reduce the sensitivity of analyzers. Increased sensitivity as a result of the interaction of analyzers and exercise - sensitization. Synesthesia is the occurrence, under the influence of stimulation of one analyzer, of a sensation characteristic of another analyzer.

The psyche begins with sensations. Sensation is the process of primary information processing at the level of individual properties of objects and phenomena. This level of information processing is called sensory. It lacks a holistic understanding of that phenomenon, cat. caused sensations.

Since sensation can be considered the primary, elementary mental experience, scientists first of all wanted to understand how physical stimulation is converted into sensation. Fechner G.T. became the founder of experimental research on the problem of the relationship between the physical and mental.

There are several types of classifications:

I. Wundt– by receptor type (mechano, chemo, photo). It is based on the fact that there is a specific sensitivity to effects not only at the level of receptors, but also at the level of the central unit of analyzers.

Despite its mechanistic nature, this classification is important for psychology.

Classification Ch. Sherrington, which distinguishes the types according to the location of the sensory receptors and is divided into:

1. Exteroceptive– reflect the properties of objects and phenomena of the external environment. Receptors on the surface of the body. Are differentiated. The basis of cognitive processes. A) contact – direct contact with objects (gustatory, tactile); B) distant - reaction to distant stimuli (visual, auditory, olfactory). Pain sensations are common to all analyzers.

2. Interoceptive(organic) – sensations that arise when metabolic processes in the body are reflected with the help of specialized receptors. Undifferentiated. They are the basis for emotional processes.

3. Proprioceptive(kinesthetic) - reflecting the movement and relative position of body parts with the help of receptors located in muscles, ligaments, tendons, joint capsules. The basis of volitional regulatory processes.

II. Evolutionary classification. Head. This is actually a psychological classification.

There are two types of sensitivity:

1. Protopathic(ancient), its peculiarity is the affective coloring of sensations, weak differentiation (example: chemoreception, pain reception, smells), diffuse.

2. Epicritic sensitivity - appears in the later stages of evolution; characterizes – non-affective coloring, allows you to localize the object of sensation in space.

Despite the variety of sensations that arise during the operation of the senses, one can find a number of fundamentally common features in their structure and functioning. In general, we can say that analyzers are a set of interacting formations of the peripheral and central nervous system that receive and analyze information about phenomena occurring both inside and outside the body. It is also necessary to remember about the regulatory function.

Properties of sensations:

1. Quality- the main feature of sensations that distinguishes it from others.

2. Intensity– quantitative characteristic, determined by the strength of the stimuli.

3. Duration– temporal characteristic, determined by the duration of the stimulus and its intensity.

The ability to display the phenomena of the surrounding world with a more or less accurate degree is called sensitivity. The minimum strength of stimuli that causes barely noticeable sensations is called the lowest absolute threshold of sensitivity. The magnitude of absolute thresholds varies.

Phenomena arising from the interaction of sensations:

1. Adaptation is a change in the sensitivity of the analyzer through exposure or training.

2. Sensitization– change in the sensitivity of one analyzer when exposed to another analyzer.

3. Synesthesia- this is the occurrence of a sensation in one analyzing system that is characteristic of another analyzing system and during stimulation of another analyzing system.

According to Petrovsky:

• Feeling- this is the simplest mental process, consisting of reflecting individual properties of objects and phenomena of the material world, as well as internal states of the body under the direct influence of stimuli on the corresponding receptors.
• Functions– receive information about the state of the external and internal environment using the senses.
• Interaction– the sense organs are closely connected with the organs of movement (a motionless eye is as blind as a motionless hand ceases to be an instrument of cognition). The organs of movement are involved in the process of receiving information (both functions are merged in one organ - the hand).

The sensation arises as a reaction of the nervous system to a particular stimulus and has a reflex character. The physiological basis of sensations is a nervous process that occurs when a stimulus acts on an analyzer adequate to it.

An independent type of sensation is temperature. There are external-internal sensations: temperature, pain, taste, vibration, muscle-articular, static-dynamic. Pain sensations are characteristic of different analyzers.

2. Protopathic and epicritic sensitivity. The physiologist Head, interpreting his observations of the sequential restoration of sensitivity after nerve transection, hypothesized two different types of sensitivity - protopathic and epicritic. Protopathic sensitivity is more primitive and affective, less differentiated and localized. Epicritic sensitivity is more subtly differentiating, objectified and rational; the second controls the first. For each of them there are special nerve fibers that regenerate at different rates. Head considered the fibers conducting protopathic sensitivity to be phylogenetically older, primitive in structure and therefore restored earlier, while epicritic sensitivity is conducted by fibers of a phylogenetically younger system and more complexly constructed. The highest centers of protopathic sensitivity are localized, according to Head, in the thalamus, and epicritic sensitivity - in phylogenetically later cortical formations. Under normal conditions, protopathic sensitivity is controlled by epicritic sensitivity through the inhibitory effect of the cortex on the thalamus and underlying areas with which protopathic sensitivity is associated.

3. Interaction of sensations . The intensity of sensations depends not only on the stimulus, but also on the level of adaptation of the receptors to the stimuli currently affecting other sense organs. The interaction of sensations is a change in the sensitivity of the analyzer under the influence of irritation of other senses. Numerous facts of changes in sensitivity caused by the interaction of sensations are known. Thus, the sensitivity of the visual analyzer changes under the influence of auditory stimulation. Weak sound stimuli increase the color sensitivity of the visual analyzer. At the same time, there is a sharp deterioration in the distinctive sensitivity of the eye when loud noise (for example, an aircraft engine) is used as an auditory stimulus. Visual sensitivity also increases under the influence of certain olfactory stimuli. However, with a pronounced negative emotional connotation of the smell, a decrease in visual sensitivity is observed. Similarly, with weak light stimuli, auditory sensations increase; under the influence of intense light stimuli, auditory sensitivity worsens. Facts of increased visual, auditory, tactile and olfactory sensitivity under the influence of weak painful stimuli are described. A change in the sensitivity of any analyzer can also occur with subthreshold stimulation of other analyzers. Thus, evidence was obtained of a decrease in visual sensitivity under the influence of skin irradiation with ultraviolet rays (Ya.P. Lazarev). One of the forms of interaction of sensations is the phenomenon of contrast. It manifests itself in a change in sensitivity under the influence of previous (or concomitant) irritation. Thus, due to contrast, the sensation of sour after the sensation of sweet, the sensation of cold after hot, etc., is intensified. Thus, all our analyzer systems are capable of influencing each other to a greater or lesser extent. In this case, the interaction of sensations, like adaptation, manifests itself in two opposite processes: an increase and decrease in sensitivity. The general pattern here is that weak stimuli increase, and strong ones decrease, the sensitivity of the analyzers during their interaction. The physiological mechanism for the interaction of sensations is the processes of irradiation and concentration of excitation in the cortex of the brain, where the central sections of the analyzers are represented. According to I.P. Pavlov, a weak stimulus causes an excitation process in the PD cortex, which easily radiates (spreads). As a result of the irradiation of the excitation process, the sensitivity of the other analyzer increases. When exposed to a strong stimulus, a process of excitation occurs, which, on the contrary, tends to concentrate. According to the law of mutual induction, this leads to inhibition in the central sections of other analyzers and a decrease in the sensitivity of the latter. A change in the sensitivity of analyzers can be caused by exposure to second-signal stimuli. Thus, evidence was obtained of changes in the electrical sensitivity of the eyes and tongue in response to the presentation of the words “sour as lemon” to the test subject. These changes were similar to those observed when the tongue was actually irritated with lemon juice. Knowing the patterns of changes in the sensitivity of the sense organs, it is possible, by using specially selected side stimuli, to sensitize one or another receptor, i.e., increase its sensitivity. Sensitization can also be achieved as a result of exercise. It is known, for example, how pitch hearing develops in children involved in music. (See also about the interaction of analyzers in paragraph 2.12). Synesthesia is a form of interaction of sensations in which, under the influence of stimulation of one analyzer, sensations characteristic of another analyzer arise. Synesthesia is observed in a wide variety of sensations. The most common is visual-auditory synesthesia, when the subject experiences visual images when exposed to sound stimuli. Synesthesia varies from person to person, but it is fairly consistent across individuals. Some composers (N.A. Rimsky-Korsakov, A.N. Scriabin, etc.) possessed the ability of color hearing; we find a vivid manifestation of this kind of synesthesia in the work of the Lithuanian artist M.K. Ciurlionis, in his symphonies of colors. Less common are cases of auditory sensations arising when exposed to visual stimuli, gustatory sensations in response to auditory stimuli, etc. (for example, patient Sh. described by A.R. Luria). Not all people have synesthesia, although it is quite widespread. No one doubts the possibility of using such expressions as “sharp taste”, “flashy color”, “sweet sounds”, “velvety voice”, etc. The phenomena of synesthesia are another evidence of the constant interconnection of the analyzer systems of the human body, the integrity man's sensory reflection of the objective world. The mediation of some sensations by others. The interaction of receptors is also expressed in the relationship of sensations that always occurs in the process of perception of any object or phenomenon. Thus, during tactile recognition of the shape of an object, when vision is turned off for some reason, tactile sensations are mediated by visual representations. In the sense of touch itself, there is an interaction between the actual skin sensations of touch and muscular, kinesthetic sensations, to which temperature sensations are also mixed when sensing the surface of an object. When you feel the tart, caustic, etc. taste of some food, tactile sensations and mild pain are added to the actual taste sensations, interacting with them. This interaction also occurs within one type of sensation. In the field of vision, for example, distance affects color, sensations of depth affect shape, etc. Of all forms of interaction, this last one is the most important, because without it there is no perception of reality at all.

4.Perception: definition, types and properties

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

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

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

Detection is the initial phase of the development of any sensory process. At this stage, the subject can only answer the simple question of whether there is a stimulus. The next operation of perception is discrimination, or perception itself. Its final result is the formation of a perceptual image of the standard. In this case, the development of perceptual action proceeds along the line of isolating specific sensory content in accordance with the characteristics of the presented material and the task facing the subject.

When the perceptual image is formed, an identification action can be carried out. Comparison and identification are required for identification.

Identification is the identification of a directly perceived object with an image stored in memory, or the identification of two simultaneously perceived objects. Recognition also includes categorization (assigning an object to a certain class of objects previously perceived) and retrieving the corresponding standard from memory.

Thus, perception is a system of perceptual actions; mastering them requires special training and practice.

Depending on the degree to which the individual’s activity is purposeful, perception is divided into unintentional (involuntary) and intentional (voluntary).

Unintentional perception can be caused both by the characteristics of surrounding objects (their brightness, unusualness), and by the correspondence of these objects to the interests of the individual. In unintentional perception there is no predetermined goal. There is also no volitional activity in it, which is why it is called involuntary. Walking, for example, down the street, we hear the noise of cars, people talking, see shop windows, perceive various smells and much more.

Intentional perception from the very beginning is regulated by the task - to perceive this or that object or phenomenon, to become familiar with it. So, for example, intentional perception would be looking at the electrical circuit of the machine being studied, listening to a report, watching a thematic exhibition, etc. It can be included in any activity (in a labor operation, in completing an educational task, etc.), but it can act as an independent activity - observation.

Observation is an arbitrary systematic perception, which is carried out with a specific, clearly conscious purpose with the help of voluntary attention. The most important requirements that observation must satisfy are clarity of the observer’s task and planned and systematic conduct. A significant role is played by the fragmentation of the task, the formulation of particular, more specific tasks.

If a person systematically practices observation and improves the culture of observation, then he develops such a personality trait as observation.

Observation is the ability to notice characteristic but subtle features of objects and phenomena. It is acquired in the process of systematically doing what you love and is therefore associated with the development of a person’s professional interests.

The relationship between observation and observation reflects the relationship between mental processes and personality traits.

17. Basic properties of perception

People perceive the same information differently, subjectively, depending on their interests, needs, abilities, etc. The dependence of perception on the content of a person’s mental life, on the characteristics of his personality is called apperception. The influence of a person’s past experience on the process of perception is manifested in experiments with distorting glasses: in the first days of the experiment, when the subjects saw all the surrounding objects upside down, the exception was those objects whose inverted image, as people knew, was physically impossible. Thus, an unlit candle was perceived to be upside down, but as soon as it was lit, it was seen to be normally oriented vertically, i.e. the flame was directed upward.

Perceptual properties:

Integrity, i.e. perception is always a holistic image of an object. However, the ability of holistic visual perception of objects is not innate, as evidenced by data on the perception of people who became blind in infancy and whose vision was restored in adulthood: in the first days after the operation, they did not see the world of objects, but only vague outlines, spots of varying brightness and quantities, i.e. there were single sensations, but there was no perception, they did not see whole objects. Gradually, over several weeks, these people developed visual perception, but it remained limited to what they had previously learned through touch. Thus, perception is formed in the process of practice, i.e. perception is a system of perceptual actions that must be mastered.

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

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

Meaningfulness of perception - perception is closely connected with thinking, with understanding the essence of objects.

Selectivity of perception - manifests itself in the preferential selection of some objects over others.

The Swiss psychologist Rorschach found that even meaningless inkblots are always perceived as something meaningful (a dog, a cloud, a lake) and only some mental patients tend to perceive random inkblots as such. That is, perception proceeds as a dynamic process of searching for an answer to the question: “What is this?”

Types of perception. There are: perception of objects, time, perception of relationships, movements, space, perception of a person

The sensitivity of a flaw detector, generally defined as the ability of a flaw detector to detect reflectors of a given size, is the most important parameter that mainly determines the reliability and reproducibility of testing.

Carrying out testing at an arbitrary sensitivity level of a flaw detector can lead to missing dangerous defects or to unnecessary rejection of products as a result of recording echo signals from small non-dangerous defects or even from structural inhomogeneities. Therefore, detection of defects, assessment of their sizes and rejection of products must be carried out at strictly defined levels of sensitivity.

There are several types of sensitivity: real, absolute, limiting, rejection, search and conditional.

Real sensitivity is determined by the minimum sizes of real defects that can be detected in products of this type with the selected flaw detector setting. Due to different reflective properties, the actual sensitivity to cracks will differ from the actual sensitivity to inclusions, etc. The numerical expression of real sensitivity is determined based on a static analysis of identified defects in a given product, which were measured during autopsy.

Absolute sensitivity characterizes the maximum achievable sensitivity of the electroacoustic and electrical paths of the flaw detector to acoustic signals. It can be measured by the amount of sensitivity reserve before the appearance of noise with the gain and power controls fully engaged in relation to the reference bottom signal from a plane located at a distance from the converter. This characteristic is necessary to assess the potential capabilities of a flaw detector with a given transducer (size of the minimum detectable defect and sound depth). Modern flaw detectors have an absolute sensitivity of about 80-100 dB.

Ultimate sensitivity is determined by the smallest area of ​​a flat-bottomed hole, coaxial with the acoustic axis of the transducer, located in a given test sample at a given depth and reliably detected with a given flaw detector setting. This level is often called the control sensitivity, and the artificial reflector by which it is adjusted is called the control reflector. Limit sensitivity is the main control parameter and is usually regulated by relevant regulatory documents.

The equivalent area (diameter) is the area (diameter) of a flat-bottomed hole that lies at the same depth as the real defect and gives the same amplitude of the echo signal.

The maximum sensitivity extended to the entire volume of the controlled product is called level of fixation(control level) or level of rejection. The level of fixation is determined by the equivalent area of ​​the defect, which must be detected throughout the entire volume of the controlled product; rejection level - the equivalent area of ​​a defect that is unacceptable in a given product. Fixation and rejection levels are established in the control standards for this product.

Rejection sensitivity characterized by the maximum area of ​​a flat-bottomed reflector, the maximum permissible according to the current technical conditions for this product. Usually its level is 3.5-6 dB (1.5-2 times) lower than the level of maximum sensitivity.

Search sensitivity determines the gain level of the flaw detector when searching for defects. The need for its introduction is due to the fact that the maximum sensitivity of the flaw detector during the scanning process is significantly lower than when the transducer is in a stationary position. Search sensitivity is usually 5-8 dB higher than the maximum sensitivity level.

Adjustment for maximum sensitivity (at a given depth), fixation and rejection levels are performed based on artificial defects. It is not necessary to produce defects such as a flat-bottomed hole. You can use other reflectors or a bottom signal and perform recalculation using acoustic path formulas or DGS diagrams.

The conditional sensitivity of a flaw detector with a transducer is determined by the maximum depth (mm) of the location of the reflector - a side hole with a diameter of 2 mm, confidently detected by the flaw detector in a standard sample SO-1 made of plexiglass (Fig. 4.1, a) or by the difference (dB) between the readings of the attenuator N x , for which the sensitivity is determined, and the reading N 0, at which a reflector with a diameter of 6 mm at a depth of 44 mm in the standard CO-2 sample is still reliably detected (Fig. 4.1, b).

Conditional sensitivities for CO-1 and CO-2 can be compared experimentally.

A certain value of the maximum sensitivity corresponds to a certain value of the conditional one. The maximum sensitivity can be reproduced by conditional sensitivity if the values ​​of f 1 , a 0 , 2a, t of the converters correspond to the values ​​for which the conditional sensitivity was set. Often, the fixation level is adjusted based on artificial defects in the laboratory and the conditional sensitivity is determined there, and then the fixation level is reproduced at the control site using small samples of CO-1 or CO-2.

Sensitivity standardization using test samples is the most common method. With this method, sensitivity standardization is carried out using a test sample or directly on a controlled product, in which there is a flat-bottomed hole or other reflector of equivalent area, regulated by the relevant regulatory documents.

The sensitivity of any type of flaw detector can be measured in a direct way. The method is the simplest and automatically takes into account the influence of many factors on the parameters of the acoustic path. But it is very expensive, since it requires the production of a large set of test samples with different reflectors. The test sample is made of steel of the same grade as the product being tested. Mandatory conditions are that the quality of the surface of the test sample matches the quality of the surface of the controlled product and the conduct of heat treatment, if it is provided for the controlled product. The dimensions of the sample must be such that the echo signal from the reflector is not superimposed by false signals from the walls and corners of the sample. These false signals must be scanned significantly further than the reference echo signal.

Artificial reference reflectors are made on the test sample at a distance of at least 20 mm from one of the edges, corresponding to the required maximum or rejection sensitivity. It is impossible to adjust sensitivity using samples with real defects. This is explained by the impossibility of accurately determining the size and shape of real defects and reproducing them when replicating samples.

The choice of reflector type is determined by its reflective properties, manufacturability and the ability to maintain specified dimensions: GOSTs 21397-81, 24507-80 and 14782-86 provide for the use of the following standard reflectors: flat-bottomed hole, side cylindrical reflector, segment reflector and corner reflector.

A flat-bottomed hole is made in the test sample so that its axis coincides with the axis of the ultrasonic beam (Fig. 4.2a). When setting up the PC converter, the hole axis must be perpendicular to the sample surface. This reference reflector has a significant advantage - a steep monotonic dependence of the increment in the amplitude of the echo signal on the diameter of the reflector.

A side cylindrical reflector (side hole) is the most easily manufactured type of reflector (Fig. 4.2, b). The main advantages of the side reflector are ease of manufacture, good reproducibility of results and the ability to be used for any type of transducer.

In chemical engineering, a segmented reflector is widely used to adjust the sensitivity of a flaw detector when inspecting welds (Fig. 4.2c). It is made using a milling cutter on the surface of the sample. The reflective surface of a segment with radius b c must be perpendicular to the refracted acoustic axis of the transducer. Unfortunately, due to the influence of the bottom surface, such a reflector can only be used at a=(52±5)°.

The height h of the segment reflector must be greater than the ultrasonic wavelength; The h/b ratio of the segment reflector must be more than 0.4.

The corner reflector (notch) well imitates cracks and lack of penetration on the surface (Fig. 4.2d). Analysis of the reflection of ultrasonic waves from models of defects in the form of corner reflectors showed that the field reflected from the notch is formed mainly as a result of double reflection of waves from the defect and the surface of the product (corner effect).

The maximum sensitivity from a flat-bottomed hole to the maximum sensitivity from a notch is recalculated using the formula S з =S p /N, where N is the coefficient determined from the graph N=f(e) (Fig. 4.3). The N coefficient is practically independent of the material.

Notches are squeezed out with a specially sharpened tool - a striker.

The width b and height h of the corner reflector must be greater than the ultrasonic wavelength: the h/b ratio must be more than 0.5 and less than 4.0.

Rice. 4.3. Dependence N = f (e) for steel,

aluminum and its alloys, titanium and its alloys.

If testing is carried out not all of the deposited metal in one pass, but in layers (sequentially upper, middle and lower), then the reflector should be located at the depth of the lower boundary of the corresponding layer.

The standardization method using DGS diagrams (amplitude - distance - diameter) is that the maximum sensitivity, expressed through the equivalent area of ​​the reflector, is set as a fraction of the reference echo signal received from a dihedral angle, an infinite plane or a cylindrical surface, etc. . Its application does not require a set of samples of different thicknesses. In addition, such standardization can be carried out at several points of the product, which makes it possible to average the reference level and get rid of random errors.

Two types of ARD diagrams are used. A generalized dimensionless DGS diagram is a family of curves reflecting the dependence of the signal amplitude P/P 0 in dB on the diameter of the disk reflector d, the distance to it r, the diameter of the piezoelectric element D and the ultrasound frequency f. It is built in dimensionless parameters: . The generalized DGS diagram (Fig. 4.4) is the basis for constructing specialized DGS diagrams for a specific converter by moving from dimensionless parameters to directly measured d and r.

As an example, we will use a DGS diagram to determine the amplitude of the signal from a defect with a diameter of d=6 mm located in a steel sample at a depth of r = 100 mm perpendicular to the axis of a normal finder with a diameter of D=12 mm (radius a=6 mm) at a frequency of 2.5 MHz.

Wavelength mm.

Near zone length mm.

Given distance.

Reduced defect diameter.

At the intersection of the vertical and the curve we find

Neg. dB=0.053.

To take into account the attenuation of ultrasound, you need to multiply the resulting value by. Let the attenuation coefficient be equal to 0.00125 neper/mm, then, moving to decibels, we get:

Neg. dB.

Thus, taking into account the attenuation of neg. dB = 0,0415.