Lecture
Это продолжение увлекательной статьи про ощущение.
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which increases with the proper training of the subjects. In his experiments, subjects who had undergone preliminary training, trained to act in a situation of a psychophysical experiment, took part. Therefore, in the law of Stevens z = 1, which shows the full awareness of the subject.
Thus, the law proposed by Yu. M. Zabrodin removes the contradiction between the laws of Stevens and Fechner. Therefore, it is not by chance that he received the name of the generalized psychophysical law.
However, no matter how the contradiction between the laws of Fechner and Stevens is resolved, both versions fairly accurately reflect the essence of the change in sensations as the magnitude of the stimulation changes. First, sensations change disproportionately to the strength of physical stimuli acting on the senses. Secondly, the power of sensation grows much slower than the magnitude of physical stimuli. That is the meaning of psychophysical laws.
Speaking about the properties of sensations, we cannot but dwell on a number of phenomena associated with sensations. It would be wrong to assume that the absolute and relative sensitivity remain unchanged and their thresholds are expressed in constant numbers. Studies show that sensitivity can vary within very large limits. For example, in the dark our vision sharpens, and with strong illumination its sensitivity decreases. This can be observed when moving from a dark room to light or from a brightly lit room into darkness. In both cases, the person is temporarily "blind", it takes some time for the eyes to adjust to bright light or darkness. This suggests that, depending on the environment (light), a person’s visual sensitivity varies dramatically. As studies have shown, this change is very large and the sensitivity of the eye in the dark sharpens 200,000 times.
The described changes in sensitivity, depending on environmental conditions, are associated with the phenomenon of sensory adaptation. Sensory adaptation is the change in sensitivity that occurs as a result of the adaptation of the sense organ to the stimuli acting on it. As a rule, adaptation is expressed in that when sufficiently strong stimuli act on the senses, the sensitivity decreases, and when the stimuli are weak or in the absence of stimuli, the sensitivity increases.
. Such a change in sensitivity does not occur immediately, but requires a certain time. Moreover, the temporal characteristics of this process are not the same for different senses. So, in order for vision in a dark room to acquire the necessary sensitivity, about 30 minutes must pass. Only after that a person acquires the ability to navigate well in the dark. Adaptation of the auditory organs is much faster. A person's hearing adapts to the surrounding background in as little as 15 seconds. Just as quickly, a change in the sensitivity of touch occurs (a faint touch of the skin ceases to be perceived after a few seconds).
The phenomena of thermal adaptation (addiction to changes in ambient temperature) are well known. However, these phenomena are clearly expressed only in the middle range, and addiction to extreme cold or extreme heat, as well as to pain stimuli, is almost not found. Known and phenomena of adaptation to odors.
Adaptation of our sensations mainly depends on the processes occurring in the receptor itself. Thus, for example, under the influence of light, the visual purple in the rods of the retina of the eye decomposes (fades). In the dark, on the contrary, visual purple is restored, which leads to increased sensitivity. However, the phenomenon of adaptation is associated with the processes occurring in the central parts of the analyzers, in particular, with a change in the excitability of the nerve centers. With prolonged irritation, the cerebral cortex responds with internal protective inhibition, reducing sensitivity. The development of inhibition causes increased excitation of other foci, contributing to an increase in sensitivity in new conditions. In general, adaptation is an important process, indicating the greater plasticity of the body in its adaptation to environmental conditions.
There is another phenomenon that we must consider. All kinds of sensations are not isolated from each other, so 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 that are currently acting on other senses. The change in the sensitivity of the analyzer under the influence of irritation of other organs of the senses is called the interaction of sensations.
Two types of interaction of sensations should be distinguished: 1) interaction between sensations of the same type and 2) interaction between sensations of different types.
The interactions between sensations of different types can be illustrated by the research of academician P. P. Lazarev, who found that lighting the eyes makes audible sounds louder. Similar results were obtained by Professor S. V. Kravkov. He found that no sense organ can work without affecting the functioning of other organs. So, it turned out that sound irritation (for example, whistle) can aggravate the work of visual sensation, increasing its sensitivity to light stimuli. Some odors also influence in a similar way, raising or lowering light and auditory sensitivity. All our analyzer systems are able to more or less influence each other. At the same time, the interaction of sensations, as well as adaptation, is manifested in two opposite processes -
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Names
Luria Alexander Romanovich (1902-1977) - Russian psychologist who dealt with many problems in various areas of psychology. It is considered to be the founder of domestic neuropsychology. Full member of the USSR Academy of Pedagogical Sciences, Doctor of Psychology and Medicine, professor, author of over 500 scientific papers. He worked with L. S. Vygotsky to create a cultural-historical concept for the development of higher mental functions, with the result that in 1930. together with Vygotsky wrote the work "Studies on the history of behavior." Exploring in the 1920s. affective states of a person, created an original psycho-physiological method of conjugated motor reactions designed for the analysis of affective complexes. Repeatedly organized expeditions to Central Asia and personally participated in them. Based on the material collected in these expeditions, he made a number of interesting generalizations concerning the intercultural differences in the human psyche.
The main contribution of A. R. Luria to the development of psychological science lies in the development of the theoretical foundations of neuropsychology, which was expressed in his theory of the systemic dynamic localization of higher mental functions and their disorders in brain damage. He conducted research on the neuropsychology of speech, perception, attention, memory, thinking, voluntary movements and actions.
increase and decrease of sensitivity. The general pattern is that weak stimuli increase, and strong - reduce the sensitivity of the analyzers during their interaction.
A similar picture can be observed in the interaction of sensations of the same species. For example, a point in the dark is easier to see on a light background. As an example of the interaction of visual sensations, we can cite the phenomenon of contrast, expressed in the fact that the color changes in the opposite direction with respect to the colors surrounding it. For example, gray on a white background will look darker, and surrounded by black - lighter.
As follows from the above examples, there are ways to increase the sensitivity of the senses. Sensitization due to the interaction of analyzers or exercise is called sensitization. A. R. Luria identifies two sides of sensitization sensitization. The first one is long-term, permanent, and depends mainly on the steady changes occurring in the body, therefore the age of the subject is clearly associated with a change in sensitivity. Studies have shown that the sensitivity of the sensory organs increases with age, reaching a maximum by the age of 20-30, in order to gradually decline in the future. The second side of sensitization-type sensitization is temporary and depends on both physiological and psychological emergency effects on the subject's condition.
The interaction of sensations is also found in a phenomenon called synesthesia - the appearance, under the influence of irritation of one analyzer, of a sensation characteristic of other analyzers. In psychology, the facts of “colored hearing” are well known, which are common to many people, and especially
many musicians (for example, Scriabin). So, it is widely known that we regard high sounds as “light” and low sounds as “dark”.
In some people, synesthesia is manifested with exceptional clarity. One of the subjects with exceptionally pronounced synesthesia — the well-known mnemonist Sh. —Was studied in detail by A. R. Luria. This person perceived all voices colored and quite often said that the voice of the person applying to him, for example, was “yellow and crumbly”. The tones that he heard caused him visual sensations of various shades (from bright yellow to purple). Perceived colors were felt by him as “voiced” or “deaf”, as “salty” or “crispy”. Similar phenomena in more erased forms are quite common in the form of a direct tendency to “paint” numbers, days of the week, names of months in different colors. The phenomena of synesthesia are another evidence of the constant interrelation of the analyzer systems of the human body, the integrity of the sensory reflection of the objective world.
The feeling begins to develop immediately after the birth of the child. A short time after birth, the baby begins to respond to stimuli of all kinds. However, there are differences in the degree of maturity of individual feelings and in the stage of their development.
Immediately after birth, the child is more developed skin sensitivity. When a baby is born, it shivers due to the difference in mother's body temperature and air temperature. The newborn child also reacts to touch, with the lips and the entire area of the mouth being the most sensitive. It is likely that the newborn can feel not only warmth and touch, but also pain.
Already at the time of birth, the child's taste sensitivity is highly developed. Newborns react differently to the introduction of quinine or sugar into their mouths. A few days after birth, the baby distinguishes the mother’s milk from the sweetened water, and the latter from the plain water.
From the moment of birth, the child already has a fairly well developed olfactory sensitivity. By the smell of mother's milk, a newborn baby determines whether the mother is in the room or not. If the child eats the mother's milk for the first week, then he will turn away from cow's milk, only by feeling its smell. However, olfactory sensations that are not related to nutrition develop long enough. They are poorly developed in most children, even at the age of four or five.
Vision and hearing pass through a more complex path of development, which is explained by the complexity of the structure and organization of the functioning of these sense organs and their lesser maturity at the time of birth. In the first days after birth, the child does not respond to sounds, even very loud ones. This is explained by the fact that the ear canal of a newborn is filled with amniotic fluid, which dissolves only after a few days. Usually, the child begins to respond to sounds during the first week, sometimes this period is delayed up to two or three weeks.
The first reactions of the child to the sound have the character of general motor excitation: the child throws up arms, moves his legs, makes a loud cry. Sound sensitivity is initially low, but increases in the first weeks of life. After two or three months, the child begins to perceive the direction of the sound, turns his head toward the sound source. In the third or fourth month, some children begin to respond to singing and music.
With regard to the development of speech hearing, the child first begins to respond to the intonation of speech. This is observed in the second month of life, when the gentle tone affects the child soothingly. Then the child begins to perceive the rhythmic side of speech and the general sound pattern of the words. However, the distinction of speech sounds comes to the end of the first year of life. From this moment begins the development of proper speech hearing. First, the child has the ability to distinguish vowels, and at a later stage, he begins to distinguish consonants.
The most slowly the child develops vision. The absolute sensitivity to light in newborns is low, but increases markedly in the first days of life. Since the onset of visual sensations, the child reacts to light with various motor responses. The distinction of colors grows slowly. It is established that the child begins to distinguish color in the fifth month, after which he begins to show interest in all sorts of bright objects.
The child, starting to feel the light, at first cannot “see” objects. This is explained by the fact that the movements of the child’s eyes are not coordinated: one eye can look in one direction, the other in another, or it can even be closed at all. The child begins to control the movement of the eyes only at the end of the second month of life. Objects and faces, he begins to distinguish only in the third month. From this moment begins the long development of the perception of space, the shape of the object, its size and removal.
In relation to all types of sensitivity, it should be noted that absolute sensitivity reaches a high level of development already in the first year of life. The ability to distinguish sensations develops somewhat more slowly. A child of preschool age, this ability is developed incomparably lower than that of an adult. The rapid development of this ability is noted in school years.
It should also be noted that the level of development of sensations in different people is not the same. This is largely due to human genetic characteristics. Nevertheless, sensations within certain limits can be developed. The development of sensation is carried out by the method of constant training. It is thanks to the possibility of developing sensations that, for example, children are taught music or drawing.
Skin sensations. We will begin our acquaintance with the main types of sensations with the sensations we receive from the effects of various stimuli on receptors located on the surface of human skin. All sensations
which a person receives from skin receptors, can be combined under one name - skin sensations. Однако к категории этих ощущений необходимо отнести и те ощущения, которые возникают при воздействии раздражителей на слизистую оболочку рта и носа, роговую оболочку глаз.
Кожные ощущения относятся к контактному виду ощущений, т. е. они возникают при непосредственном контакте рецептора с предметом реального мира. При этом могут возникать ощущения четырех основных видов: ощущения прикосновения, или тактильные ощущения; ощущения холода; ощущения тепла; ощущения боли.
Каждый из четырех видов кожных ощущений имеет специфические рецепторы. Одни точки кожи дают только ощущения прикосновения (тактильные точки), другие — ощущения холода (точки холода), третьи — ощущения тепла (точки тепла), четвертые — ощущения боли (точки боли) (рис. 7.2).
Fig. 7.2. Кожные рецепторы и их функции
Normal stimuli for tactile receptors are touches that cause skin deformation, for cold objects - exposure to objects of lower temperature, for thermal ones - effects of higher temperature objects, for painful conditions - any of the listed effects, provided that the intensity is high enough. The location of the corresponding receptor points and the absolute sensitivity thresholds are determined using an esthesiometer. The simplest device is a hair esthesiometer (Fig. 7.3), consisting of horsehair and a device that allows you to measure the pressure exerted by this hair on any point of the skin. With a weak touch of hair to the skin, sensations arise only when directly hitting a tactile point. Locate cold and heat points in the same way, only a thin metal tip filled with water, the temperature of which can vary, is used instead of hair.
The existence of cold points can be seen without the device. To do this, it is enough to hold the tip of the pencil down the eyelid. As a result, from time to time there will be a feeling of cold.
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Attempts have been made to determine the number of skin receptors. There are no exact results, but it is approximately established that the contact points are about one million, the pain points are about four million, the cold points are about 500 thousand, the heat points are about 30 thousand.
The points of certain types of sensations on the surface of the body are uneven. For example, at the fingertips, the touch points are twice as large as the points of pain, although the total number of the latter is much greater. On the cornea, on the contrary, there are no points of contact at all, but only points of pain, so any contact with the cornea causes a sensation of pain and a protective reflex of closing the eyes.
Uneven distribution of skin receptors over the body surface causes uneven sensitivity to touch, pain, etc. Thus, the fingertips are more sensitive to touch and the back, abdomen and the outer side of the forearm are less sensitive. The sensitivity to pain is quite different. Most sensitive to back pain, cheek and least sensitive fingertips. As for the temperature regimes, the most sensitive are those parts of the body that are usually covered with clothes: the waist, chest.
Tactile sensations carry information not only about the stimulus, but also about the localization of its effects. In different parts of the body, the accuracy of determining the localization of exposure is different. It is characterized by the magnitude of the spatial threshold of tactile sensations. If we touch the skin
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Fig. 7.3. Hair esthesiometer |
modernly at two points, we will not always feel these touches as separate, - if the distance between the touch points is not large enough, both sensations will merge into one. Therefore, the minimum distance between the places of contact, which allows you to distinguish between the touch of two spatially separate objects, is called the spatial threshold of tactile sensations .
Usually, a circular esthesiometer (Fig. 7.4), which is a compass with sliding legs, is used to determine the spatial threshold of tactile sensations. The smallest threshold of spatial differences in skin sensations is observed on the more sensitive to touch parts.
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Fig. 7.4. Circular esthesiometer
kah body. So, the spatial threshold of tactile sensations is 67 mm on the back, 45 mm on the forearm, 30 mm on the back of the hand, 9 mm on the palm, and 2.2 mm on the fingertips. The lowest spatial threshold is also
tilting sensations located at the tip of the tongue —1.1 mm. It is here that touch receptors are most densely located.
Taste and olfactory sensations. Taste taste receptors are taste bulbs consisting of sensitive taste cells connected to nerve fibers (Fig. 7.5). In an adult person, the taste buds are located mainly on the tip, on the edges and on the back of the upper surface of the tongue. The middle of the upper surface and the entire lower surface of the tongue is not sensitive to taste. Taste bulbs are also available on the palate, tonsils and the back of the throat. In children, the area of distribution of taste bulbs is much wider than in adults. Stimuli for taste buds are dissolved flavors.
Olfactory receptors are olfactory cells that are immersed in the mucous membrane of the so-called olfactory region (Fig. 7.6). Irritants for the smell receptors are various odorous substances,
Fig. 7.6. Olfactory receptors
penetrating nose with air. In an adult, the area of the olfactory region is approximately 480 mm 2. In a newborn, it is much larger. This is due to the fact that in newborns the leading sensations are taste and olfactory sensations. It is thanks to them that the child receives the maximum amount of information about the world, and they also provide the newborn with the satisfaction of its basic needs. In the process of development, olfactory and gustatory sensations give way to other, more informative sensations, and first of all to vision.
It should be noted that the taste sensations in most cases are mixed with olfactory. The variety of taste largely depends on the admixture of olfactory sensations. For example, in case of a cold, when the olfactory sensations are “turned off”, in some cases the food seems tasteless. In addition, tactile and temperature sensations from receptors located in the area of the mucous membrane in the mouth are mixed with the taste sensations. Thus, the peculiarity of "acute" or "knitting" poorness is mainly associated with tactile sensations, and the characteristic taste of mint is largely dependent on the irritation of cold receptors.
If we exclude all these impurities of tactile, temperature and olfactory sensations, then the actual taste sensations will be reduced to four main types: sweet, sour, bitter, salty. The combination of these four components allows you to get a variety of taste options.
Experimental studies of taste sensations were carried out in the laboratory of P. P. Lazarev. To obtain the taste sensations were used: sugar, oxalic acid, salt and quinine. It was found that with the help of these substances, most taste sensations can be imitated. For example, the taste of ripe peach gives a combination in certain proportions of sweet, sour and bitter.
It has also been established experimentally that different parts of the tongue have different sensitivities to the four flavors. For example, sweetness is maximal at the tip of the tongue and minimal at the back of it, while sensitivity to bitter is, on the contrary, maximal at the back and minimal at the tip of the tongue.
In contrast to taste, olfactory sensations cannot be reduced to combinations of basic odors. Therefore, there is no strict classification of odors. All smells are tied to a particular item that possesses them. For example, a flower smell, a smell of a rose, a smell of a jasmine, etc. As well as for flavoring sensations, impurity of other sensations play a big role in receiving a smell:
taste (especially from the irritation of taste receptors located in the back of the throat), tactile and temperature. The sharp pungent odors of mustard, horseradish, ammonia contain an admixture of tactile and painful sensations, and the refreshing smell of menthol contains an admixture of sensations of cold.
You should also pay attention to the fact that the sensitivity of olfactory and taste receptors increases with the state of hunger. After a few hours of fasting, the absolute sensitivity to sweets is greatly enhanced, and, to a lesser extent, the sensitivity to sour increases. This suggests that olfactory and gustatory sensations are significant
least related to the need to meet the biological needs such as the need for food.
Individual differences in taste sensations in humans are small, but there are exceptions. So, there are people who are able, to a much greater extent than the majority of people, to distinguish between the components of smell or taste. Taste and olfactory sensations can be developed with the help of constant training. This is taken into account in the development of the profession taster.
Auditory sensations. Stimuli to the organ of hearing are sound waves, that is, the longitudinal ripple of air particles that spreads in all directions from the oscillating body, which is the source of sound.
All sounds that the human ear perceives can be divided into two groups: musical (sounds of singing, sounds of musical instruments, etc.) and noises (all sorts of squeaks, rustles, knocks, etc.). There is no strict boundary between these groups of sounds, since musical sounds contain noises, and noises can contain elements of musical sounds. Human speech, as a rule, simultaneously contains sounds of both groups.
In sound waves, the frequency, amplitude, and shape of a collar *** are distinguished. Accordingly, the auditory sensations have the following three sides: pitch, which is a reflection of the frequency of the ***; sound volume, which is determined by the amplitude of the ripple of the waves; timbre, which is a reflection of the form of the collation of *** waves.
The pitch of the sound is measured in hertz, i.e., in the amount of cola *** of the sound wave per second. The sensitivity of the human ear has its limits. The upper limit of hearing in children is 22,000 hertz. By old age, this limit drops to 15,000 hertz and even lower. Therefore, older people often do not hear the high-pitched sounds, such as the chirping of grasshoppers. The lower limit of human hearing - 16-20 hertz.
The absolute sensitivity is highest in relation to the sounds of an average frequency of a cola *** *** - 1000-3000 hertz, and the ability to distinguish the pitch of different people varies considerably. The highest threshold of discrimination is observed in musicians and tuners of musical instruments. B.N. Teplova’s experiments show that in people of a given profession the ability to distinguish the pitch of a sound is determined by a parameter of 1/20 or even 1/30 semitones. This means that between two adjacent keys of the piano, the tuner can hear 20-30 intermediate steps of height.
The loudness of the sound is called the subjective intensity of the auditory sensation. Why subjective? We cannot speak about the objective characteristics of sound, because, as follows from the basic psychophysical law, our sensations are not proportional to the intensity of the stimulation acting, but to the logarithm of this intensity. Secondly, the human ear has a different sensitivity to sounds of different heights. Therefore, there may exist and with the highest intensity affect our body sounds that we absolutely can not hear. Thirdly, there are individual differences between people regarding absolute sensitivity to sound stimuli. However, practice determines the need to measure the sound volume. Units are decibels. For one unit of measurement, the intensity of the sound emanating from the ticking of the clock is taken at a distance of 0.5 m from the human ear. So, the volume of ordinary human speech at a distance of 1 meter
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Helmholtz Herman (1821-1894) - German physicist, physiologist and psychologist. Being a physicist by training, he sought to introduce physical methods of research into the study of a living organism. In his work “On Conservation of Strength”, Helmholtz mathematically substantiated the law of conservation of energy and the proposition that a living organism is a physico-chemical environment in which this law is exactly implemented. He first measured the rate of excitation along nerve fibers, which marked the beginning of the study of reaction time.
Helmholtz made a significant contribution to the theory of perception. In particular, in the psychology of perception, he developed the concept of unconscious inferences, in accordance with which actual perception is determined by the familiar methods already existing in humans, by which constancy of the visible world is preserved and in which muscular sensations and movements play a significant role. Based on this concept, I attempted to explain the mechanisms of space perception. Following MV Lomonosov, he developed a three-component theory of color vision. Developed a resonance theory of hearing. In addition, Helmholtz made a significant contribution to the development of world psychological science. So his
V. Wundt, I. M. Sechenov and others were employees and students.
will be 16-22 decibels, noise on the street (without a tram) - up to 30 decibels, noise in the boiler room - 87 decibels, etc.
The timbre is the specific quality that distinguishes the sounds of the same pitch and intensity from different sources from different sources. Very often the timbre is referred to as the “coloring” of the sound.
The differences in timbre between the two sounds are determined by the variety of forms of the sound ***. In the simplest case, the shape of the sound ring will correspond to a sine wave. Such sounds are called "simple". They can be obtained only with the help of special devices. Close to a simple sound is the sound of a tuning fork - an instrument used to tune musical instruments. In everyday life, we do not meet with simple sounds. The sounds surrounding us are made up of various sound elements, so the form of their sound, as a rule, does not correspond to a sinusoid. But nevertheless, musical sounds arise when sound collars have the form of a strict periodic sequence, while in noise they do the opposite. The form of a sound ring *** is characterized by the absence of strict periodization.
It should also be borne in mind that in everyday life we perceive a multitude of simple sounds, but we do not distinguish this diversity, because all these sounds merge into one. So, for example, two sounds of different pitch are often, as a result of their merging, perceived by us as one sound with a specific timbre. Therefore, the combination of simple sounds in one complex gives the originality of the form of a sound ring *** and determines the timbre of the sound. The timbre of the sound depends on the degree of fusion of sounds. The simpler the form of a sound ring ***, the more pleasant the sound. Therefore, it is customary to allocate a pleasant sound - consonance and unpleasant sound - dissonance.
Fig. 7.7. The structure of the hearing sense receptors
The best explanation of the nature of the auditory sensations is given by the Helmholtz resonance theory of hearing. As is known, the end device of the auditory nerve is the organ of Corti, resting on the main membrane, running along the entire spiral bone canal, called the cochlea (Fig. 7.7). The main membrane consists of a large number (about 24,000) of transverse fibers, the length of which gradually decreases from the tip of the cochlea to its base. According to the Helmholtz resonance theory, each such fiber is tuned, like a string, to a specific frequency of ***. When the sound snakes of a certain frequency reach the cochlea, a certain group of fibers of the main membrane resonates and only those cells of the organ of Corti that are resting on these fibers are excited. Shorter fibers, lying at the base of the cochlea, respond to higher sounds, longer fibers that lie at its apex, to lower ones.
It should be noted that the laboratory workers IP Pavlova, who studied the physiology of hearing, came to the conclusion that the Helmholtz theory quite accurately reveals the nature of the auditory sensations.
Visual sensations. Irritant for the organ of vision is light, that is, electromagnetic waves having a length of 390 to 800 millimeters (millimicron is one millionth of a millimeter). Waves of a certain length make a person feel a certain color. So, for example, the sensations of red light are caused by waves with a length of 630-800 nanometers, yellow - by waves from 570 to 590 nanometers, green - by waves from 500 to 570 microns, blue - by waves from 430 to 480 nanometers.
Everything that we see has color, so the visual sensations are the sensations of color. All colors are divided into two large groups: achromatic colors and chromatic colors . To achromatic include white, black and gray. All other colors (red, blue, green, etc.) are considered chromatic.
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From the history of psychology Theory of hearing
It should be noted that the Helmholtz resonance theory of hearing is not the only one. So, in 1886. British physicist E. Rutherford put forward the theory, which he tried to explain the principles of encoding the height and intensity of sound. His theory contained two statements. First, in his opinion, the sound wave causes the entire eardrum (membrane) to vibrate, and the frequency of vibrations corresponds to the frequency of the sound. Secondly, the frequency of vibrations of the membrane sets the frequency of nerve impulses transmitted through the auditory nerve. Thus, a tone with a frequency of 1000 hertz causes the membrane to vibrate 1000 times per second, as a result of which the fibers of the auditory nerve are discharged with a frequency of 1000 pulses per second, and the brain interprets this as a certain height. Since this theory assumed that pitch depends on changes in sound over time, it was called time theory (in some literature it is also called frequency theory). It turned out that Rutherford’s hypothesis was not able to explain all the phenomena of auditory sensations. For example, it was found that nerve fibers can transmit no more than 1000 pulses per second, and then it is unclear how a person perceives pitch with a frequency of more than 1000 hertz. In 1949 V. Weaver attempted to modify the theory of Rutherford. He suggested that frequencies above 1000 hertz are encoded by different groups of nerve fibers, each of which is activated at a slightly different pace. If, for example, one group of neurons generates 1000 pulses per second as well. then 1 millisecond later, another group of neurons starts to emit 1000 pulses per second, then a combination of pulses from these two groups will produce 2000 pulses per second. However, some time later it was established that this hypothesis is capable of explaining the perception of sound coils ***, the frequency of which does not exceed 4000 hertz, and we can hear higher sounds. Since the Helmholtz theory can more accurately explain how the human ear perceives sounds of different heights, it is now more recognized. In fairness, it should be answered that the main idea of this theory was expressed by the French anatomist Joseph Guichard Duvernier, who in 1683. suggested that the frequency is encoded by mechanical pitch, by resonance. Exactly how membrane *** crosses occur, was not known until 1940, when Georg von Bekeshi managed to measure its movements. He established that the membrane behaves not as a piano with separate strings, but as a sheet that was shaken at one end. When a sound wave enters the ear, the entire membrane begins to shake (vibrate), but at the same time the place of the most intensive movement depends on the pitch. High frequencies cause vibration at the near end of the membrane; as the frequency rises, the vibration shifts to the oval window. For this and for a number of other studies of hearing, von Békésy received in 1961. Nobel Prize. At the same time, it should be noted that this theory of locality explains many, but not all, phenomena of perception of the pitch of a sound. In particular, the main difficulties associated with the tones of low frequencies. The fact is that at frequencies below 50 hertz all parts of the basilar membrane vibrate about the same. This means that all receptors are activated equally, which means that we have no way of distinguishing frequencies below 50 hertz. In fact, we lay down to distinguish the frequency of only 20 hertz. Thus, at present, there is no complete explanation of the mechanisms of auditory sensations. |
Sunlight, like the light of any artificial source, consists of waves of different lengths. At the same time, any object or physical body will be perceived in a strictly defined color (combination of colors). The color of a particular object depends on which waves and in what proportion are reflected by this object. If an object uniformly reflects all the waves, that is, it is characterized by the absence of selectivity of reflection, then its color will be achromatic. If it is characterized by the selective reflection of waves, i.e., it reflects
mainly waves of a certain length, and the rest absorbs, then the object will be painted in a certain chromatic color.
Achromatic colors differ from each other only in lightness. Lightness depends on the reflection coefficient of the object, i.e. on how much of the incident light it reflects. The higher the reflection coefficient, the brighter the color. For example, white writing paper, depending on its grade, reflects from 65 to 85% of the light falling on it. Black paper, in which photo paper is wrapped, has a reflection coefficient of 0.04, i.e., it reflects only 4% of the incident light, and a good black velvet reflects only 0.3% of the light incident on it — its reflection coefficient is 0.003.
Chromatic colors are characterized by three properties: lightness, color tone and saturation. The color tone depends on which particular wavelengths prevail in the light flux reflected by this object. Saturation is the degree of expression of a given color tone, i.e. the degree of color difference from gray, the same with it in lightness. The saturation of the color depends on how prevailing in the light flux are those wavelengths that determine its color tone.
It should be noted that our eye has a different sensitivity to light waves of different lengths. As a result, the colors of the spectrum with an objective equality of intensity seem to be different in lightness. It seems to us that the brightest light is yellow, and the darkest is blue, because the eye’s sensitivity to waves of this length is 40 times lower than the eye’s sensitivity to yellow. It should be noted that the sensitivity of the human eye is very high. For example, between black and white, a person can distinguish about 200 transition colors. However, it is necessary to separate the concepts of "eye sensitivity" and "visual acuity."
Visual acuity is called the ability to distinguish between small and distant objects. The smaller the objects that the eye is able to see in specific conditions, the higher its visual acuity. Visual acuity is characterized by a minimum gap between two points, which from a given distance are perceived separately from each other, rather than merge into one. This value can be called the spatial threshold of view.
In practice, all the colors we perceive, even those that appear to be uniform, are the result of a complex interaction of light waves of various lengths. Waves of different lengths simultaneously hit our eye, and the waves are mixed, with the result that we see one particular color. The works of Newton and Helmholtz established the laws of color mixing. Of these laws, two are of most interest to us. First, for each chromatic color, you can choose a different chromatic color, which, when mixed with the first, gives an achromatic color, that is, s. white or gray. These two colors are called optional. And secondly, by mixing two non-complementary colors, a third is obtained — an intermediate color between the first two. One very important point follows from the above laws: all color tones can be obtained by mixing three respectively chosen chromatic colors. This position is extremely important for understanding the nature of color vision.
194 • Part II. Mental processes
In order to comprehend the nature of color vision, let's take a closer look at the theory of three-color vision, the idea of which in 1756. was put forward by Lomonosov, 50 years later expressed by T. Jung, and 50 years later, developed in more detail by Helmholtz. According to the Helmholtz theory, it is assumed that the eye has three of the following physiological apparatus: the red-sensing, the green-sensing, and the violet-sensing. Isolated excitement of the first gives a feeling of red. The isolated sensation of the second apparatus gives the sensation of green, and the excitation of the third — the violet. However, as a rule, the light acts simultaneously on all three vehicles or on at least two of them. In this case, the excitation of these physiological apparatus with different intensity and in different proportions in relation to each other gives all the known chromatic colors. The sensation of white appears with the uniform excitation of all three apparatuses.
This theory well explains many phenomena, including a disease of partial color blindness, in which a person does not distinguish individual colors or color shades. Most often noted the inability to distinguish between shades of red or green. This disease was named after the English chemist Dalton, who suffered from it.
The ability to see is determined by the presence in the eye of the retina, which is a branching of the optic nerve entering the back of the eyeball. There are two types of retina in the retina: cones and rods (so named because of their shape). Rods and cones are the end apparatuses of the nerve fibers of the optic nerve. In the retina of the human eye, there are about 130 million rods and 7 million cones, which are unevenly distributed across the retina. Cones fill the central fossa of the retina, i.e. the place where the image of the object falls on which we are looking at. To the edges of the retina, the number of cones decreases. The rods are bigger at the edges of the retina, they are practically absent in the middle (Fig. 7.8).
Cones have low sensitivity. To cause their reaction, you need a strong enough light. Therefore, with the help of cones, we see in bright light. They are also called the apparatus of day vision. The rods are more sensitive, and with their help we see them at night, which is why they are called night vision devices. However, it is only with the help of cones that we distinguish colors, since they determine the ability to cause chromatic sensations. In addition, cones provide the necessary visual acuity.
There are people who do not have a cone apparatus, and they see everything around them only in gray. This disease is called color blindness. And vice versa, there are cases when the rod apparatus is not functioning. Such people do not see in the dark. Their disease is called hemeralopia (or "night blindness").
Concluding our consideration of the nature of visual sensations, we need to dwell on several more phenomena of vision. Thus, the visual sensation does not stop at the same instant as the action of the stimulus ceases. It lasts some more time. This is because visual arousal has a certain inertia. This continuation of sensation for some time is called a positive sequential way.
Chapter 7. Sensation • 195
Fig. 7.8. Reception receptors
In order to observe this phenomenon in practice, sit near the lamp in the evening and close your eyes for two or three minutes. Затем откройте глаза и в течение двух-трех секунд смотрите на лампу, после чего снова закройте глаза и прикройте их рукой (чтобы свет не проникал сквозь веки). Вы увидите на темном фоне светлый образ лампы. Следует отметить, что именно благодаря этому явлению мы смотрим кино, когда мы не замечаем движения пленки из-за положительного последовательного образа, возникающего после засветки кадра.
Другой феномен зрения связан с отрицательным последовательным образом. Суть данного феномена состоит в том, что после воздействия света в течение некоторого времени сохраняется ощущение противоположного по светлоте воздействующего раздражителя. Например, положите перед собой два чистых белых листа бумаги. На середину одного из них положите квадратик красной бумаги. В середине красного квадратика нарисуйте маленький крестик и в течение 20-30 секунд смотрите на него, не отрывая взора. Затем переведите взгляд на чистый белый лист бумаги. Через некоторое время вы увидите на нем образ красного квадратика. Только цвет у него будет другой — голубовато-зеленый. Через несколько секунд он начнет бледнеть и вскоре исчезнет. Образ квадратика и есть отрицательный последовательный образ. Почему образ квадратика зеленовато-голубой? Дело в том, что этот цвет является дополнительным по отношению к красному цвету, т. е. их слияние дает ахроматический цвет.
The question may arise: why under normal conditions do we not notice the occurrence of negative consecutive images? Just because our eyes are constantly moving and certain parts of the retina do not have time to get tired.
196 • Part II. Mental processes
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From the history of psychology
Color vision theory Considering the problem of color vision, it should be noted that in the world science the three-color theory of vision is not the only one. There are other points of view on the nature of color vision. So, in 1878. Ewald Göring observed that all colors can be described as consisting of one or two of the following sensations: red, green, yellow and blue. Hering also noted that a person never perceives anything as reddish green or yellowish blue; a mixture of red and green would rather look yellow, and a mixture of yellow and blue would rather be white. It follows from these observations that red and green form an opponent pair - just like yellow and blue - and that the colors included in the opponent pair cannot be perceived at the same time. The concept of "opponent pairs" was further developed in studies in which the subject first looked at the colored light, and then at the neutral surface. As a result, when examining a neutral surface, the subject saw a color on it that was an additional original color. These phenomenological observations prompted Hering to propose a different theory of color vision, called the theory of opponent colors. Goering believed that in the visual system there are two types of color sensitive elements. One type reacts to red or green, the other to blue or yellow. Each element reacts oppositely to its two opponent colors: for a red-green element, for example, the reaction force increases on presentation of red and decreases on presentation of green. Since an element cannot react in two directions at once, upon presenting two opponent colors, yellow color is simultaneously perceived. The theory of opponent colors with a certain degree of objectivity can explain a number of facts. In particular, according to a number of authors, she explains why we see precisely those colors that we see. For example, we perceive only one tone — red or green, yellow or blue — when the balance is shifted only for one type of opponent pair, and we perceive combinations of tones when the balance is shifted for both types of opponent pairs. Objects are never perceived as red-green or yellow-blue because the element cannot react in two directions at once. In addition, this theory explains why the subjects, who first looked at the colored light, and then at the neutral surface, say that they see additional colors; if, for example, the subject first looks at red, then the red component of the pair becomes tired, as a result of which the green component comes into play. . Thus, in the scientific literature one can come across two theories of color vision — the three-color (trichromatic) and the theory of opponent colors — and each of them can explain some facts, and some cannot. For many years, these two theories in the works of many authors were considered alternative or competitive, until the researchers proposed a compromise theory — a two-stage one. According to the two-stage theory, those three types of receptors, which are considered in the three-chromatic theory, provide information for opponent pairs located at a higher level of the visual system. This hypothesis was expressed when color-component neurons were detected in the thalamus, one of the intermediate links between the retina and the visual cortex. Studies have shown that these nerve cells have spontaneous activity, which rises in response to one wavelength range and decreases in response to another. For example, some cells located at a higher level of the visual system are excited more quickly when the retina is stimulated with blue light than when it is stimulated with yellow light; such cells constitute the biological basis of the blue-yellow opponent pair. Consequently, targeted research has established the presence of three types of receptors, as well as color-component neurons located in the thalamus. This example clearly shows how complex a person is. It is likely that many seemingly true judgments about mental phenomena can be questioned over time, and these phenomena will have a completely different explanation.
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Chapter 7. Sensation • 197
Fig. 7.9. Balance sensory receptors
Proprioceptive sensations. As you remember, the proprioceptive sensations include the sensations of movement and balance. Receptors for balance sensations are located in the inner ear (Fig.7.9). The latter consists of three parts:
vestibule, semicircular canals and cochlea. Equilibrium receptors are on the verge of.
The movement of fluid irritates the nerve endings located on the inner walls of the semicircular tubes of the inner ear, which is the source of a sense of balance. It should be noted that the feeling of balance in normal conditions, we get not only from these receptors. For example, when we have our eyes open, the position of the body in space is determined also by means of visual information, as well as motor and skin sensations, through the information about movement or vibration information transmitted by them. But in some special conditions, for example when diving into water, we can receive information about the position of the body only with the help of a sense of balance.
It should be noted that the signals coming from the equilibrium receptors do not always reach our consciousness. In most cases, our body reacts to a change in the position of the body automatically, that is, at the level of unconscious regulation.
Receptors of kinesthetic (motor) sensations are found in the muscles, tendons and articular surfaces. These sensations give us an idea of the size and speed of our movement, as well as the position in which this or that part of our body is located. Motor sensations play a very important role in coordinating our movements. In doing this or that movement, we, or rather our brain, constantly receive signals from receptors located in the muscles and on the surface of the joints. If a person has disturbed the processes of formation of sensations of movement, then, having closed his eyes, he cannot walk, because he cannot maintain balance in movement. This disease is called ataxia, or movement disorder.
Touch. It should also be noted that the interaction of motor and skin sensations allows for a more detailed study of the subject. This process - the process of combining skin and motor sensations - is called touch. A detailed study of the interaction of these types of sensations produced interesting experimental data. Thus, various figures were
продолжение следует...
Часть 1 7. Sensation-Mental processes
Часть 2 7.4. Sensory adaptation and interaction of sensations - 7. Sensation-Mental
Часть 3 Iii. Conditions of sensation - 7. Sensation-Mental processes
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General psychology
Terms: General psychology