All sensations can be characterized in terms of their properties. Moreover, properties can be not only specific, but also common to all types of sensation. The main properties of sensations include: quality, intensity, duration and spatial localization, absolute and relative thresholds of sensations.
Quality - this is a property that characterizes the basic information displayed by a given sensation, distinguishing it from other types of sensations and varying within this type of sensation. For example, taste sensations provide information about some of the chemical characteristics of an object:
sweet or sour, bitter or salty. The sense of smell also provides us with information about the chemical characteristics of the object, but of a different kind: the smell of flowers, the smell of almonds, the smell of hydrogen sulfide, etc.
It should be borne in mind that very often, when talking about the quality of sensations, they mean the modality of sensations, since it is the modality that reflects the main quality of the corresponding sensation.
Intensity sensation is its quantitative characteristic and depends on the strength of the acting stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions. For example, if you have a runny nose, the intensity of perceived odors may be distorted.
Duration Feelings are a temporal characteristic of the sensation that has arisen. It is also determined by the functional state of the sense organ, but mainly by the time of action of the stimulus and its intensity. It should be noted that sensations have a so-called patent (hidden) period. When a stimulus is applied to the sense organ, the sensation does not occur immediately, but after some time. The latent period of different types of sensations is not the same. For example, for tactile sensations, it is 130 ms, for pain - 370 ms, and for taste - only 50 ms.
The sensation does not arise simultaneously with the beginning of the action of the stimulus and does not disappear simultaneously with the termination of its action. This inertia of sensations is manifested in the so-called aftereffect. A visual sensation, for example, has a certain inertia and does not disappear immediately after the cessation of the action of the stimulus that caused it. The trace from the stimulus remains in the form of a consistent image. Distinguish between positive and negative series
Fechner Gustav Theodor(1801 -1887) - German physicist, philosopher and psychologist, founder of psychophysics. Fechner is the author of the programmatic work "Elements of Psychophysics" (1860). In this work, he put forward the idea of creating a special science - psychophysics. In his opinion, the subject of this science should be the regular correlations of two types of phenomena - mental and physical - functionally interconnected. The idea put forward by him had a significant impact on the development of experimental psychology, and the research that he conducted in the field of sensations allowed him to substantiate several laws, including the basic psychophysical law. Fechner developed a number of methods for indirect measurement of sensations, in particular three classical methods for measuring thresholds. However, after studying the successive images caused by the observation of the sun, he partially lost his sight, which forced leave him psychophysics and philosophy. Fechner was a comprehensively developed person. So, he published several satirical works under the pseudonym "Doctor Mises".
images. positive serial image corresponds to the initial irritation, consists in maintaining a trace of irritation of the same quality as the current stimulus.
Negative serial image consists in the appearance of a quality of sensation that is opposite to the quality of the irritant. For example, light-darkness, heaviness-lightness, heat-cold, etc. The appearance of negative sequential images is explained by a decrease in the sensitivity of this receptor to a certain effect.
And finally, sensations are characterized spatial localization irritant. The analysis carried out by the receptors gives us information about the localization of the stimulus in space, that is, we can tell where the light comes from, the heat comes from, or which part of the body is affected by the stimulus.
All of the above properties to some extent reflect the qualitative characteristics of sensations. However, the quantitative parameters of the main characteristics of sensations are no less important, in other words, the degree sensitivity. The human sense organs are surprisingly fine working apparatuses. Thus, Academician S. I. Vavilov experimentally established that the human eye can distinguish a light signal of 0.001 candles at a distance of a kilometer. The energy of this stimulus is so small that it would take 60,000 years to heat 1 cm3 of water by 1°C with its help. Perhaps no physical device has such sensitivity.
There are two types of sensitivity: absolute sensitivity and sensitivity to difference. By absolute sensitivity is meant the ability to sense weak stimuli, and by difference sensitivity is the ability to sense subtle differences between stimuli. However not any irritation causes sensation. We do not hear the ticking of the clock in the other room. We do not see stars of the sixth magnitude. In order for a sensation to arise, the strength of the stimulus must have a certain amount.
12.Adaptation and sensitization of sensations
adaptation called a decrease or increase in the sensitivity of the analyzers as a result of continuous or prolonged exposure to stimuli. Due to adaptation, sensations that were sharp and strong at the initial stimulation of the receptor, then, with the continuous action of the same stimulation, weaken and may even disappear altogether. An example is adaptation to long-acting odors. In other cases, adaptation is expressed, on the contrary, in an increase in sensitivity. For example, during the transition from light to darkness, we do not distinguish objects around us. However, after some time, this feeling becomes possible.
Sensitization is called an increase in the sensitivity of analyzers due to an increase in the excitability of the cerebral cortex under the influence of certain stimuli. For example, the intake of caffeine or any other stimulants enhances the nervous activity of the cortex, in connection with which the sensitivity of the analyzers also increases: auditory, visual, tactile and other sensations begin to flow more clearly than under normal conditions.
The sensitivity of some analyzers may increase under the influence of the simultaneous activity of other analyzers. For example, when the eye is irritated with light of optimal intensity, at which the visual function is carried out easily and quickly, sensitivity to sounds also increases at the same time; visual acuity and color sensitivity increase with simultaneous prolonged exposure to moderate sounds, sensations of cold increase auditory and visual sensitivity; on the contrary, hot temperatures and a stuffy atmosphere lead to their decrease (S. V. Kravkov). Rhythmic auditory sensations contribute to an increase in musculoskeletal sensitivity: we feel and perform our movements better if physical exercises are accompanied by music.
The physiological basis of sensitization of sensations is the processes of interconnection of analyzers. The cortical parts of some analyzers are not isolated from others; they take part in the general activity of the brain. In this regard, the movement of nervous processes in the central sections of some analyzers, according to the laws of irradiation and mutual induction, is reflected in the activity of other analyzers.
This relationship is strengthened when the functions of different analyzers are involved in some common activity. For example, musculo-motor and auditory analyzers can be organically connected with the performance of movements (the nature of the sound corresponds to the nature of the movements), and then one of them enhances the sensitivity of the other.
The sensitivity of the analyzers sometimes also increases due to the fact that they have not been affected by the corresponding stimuli for a long time. For example, the sensitivity of the eye to light after a 30-40 minute stay in the dark can increase 20,000 times.
13. Interaction of sensations and synesthesia
The individual sense organs that we have just described do not always work in isolation. They can interact with each other, and this interaction can take two forms.
On the one hand, individual sensations can influence each other moreover, the work of one sense organ can stimulate or inhibit the work of another sense organ. On the other hand, there are deeper forms of interaction in which the sense organs work together causing a new, maternal kind of sensitivity, which in psychology is called synesthesia.
Let us dwell separately on each of these forms of interaction. Research conducted by psychologists (in particular, the Soviet psychologist S. V. Kravkov), showed that the work of one sense organ does not remain without influence on the course of the work of other sense organs.
So, it turned out that sound stimulation (for example, whistling) can sharpen the work of visual sensation, increasing its sensitivity to light stimuli. In the same way, some odors also affect, increasing or decreasing light and auditory sensitivity. A similar influence of some sensations on other sensations, apparently, occurs at the level of the upper parts of the trunk and the thalamus, where the fibers that conduct excitations from various sense organs approach each other and the transfer of excitations from one system to another can be carried out especially successfully. The phenomena of mutual stimulation and mutual inhibition of the functioning of the sense organs are of great practical interest in situations where it becomes necessary to artificially stimulate or suppress their sensitivity (for example, during flight at dusk in the absence of automatic control).
Another form of interaction between the sense organs is their joint work, in which the qualities of sensations of one type (for example, auditory) are transferred to another type of sensations (for example, visual). This phenomenon of the transfer of qualities from one modality to another is called synesthesia.
Psychology is well aware of the facts of "colored hearing", which turns on in many people and is especially clearly manifested in some musicians (for example, in Scriabin). So, it is widely known that we regard high sounds as “light”, and low ones as “dark”. The same applies to odors: some odors are known to be rated as "light" and others as "dark".
These facts are not random or subjective, their regularity was shown by a German psychologist Hornbostel, who presented the subjects with a series of odors and offered to correlate them with a series of tones and with a series of light shades. The results showed great consistency, and, most interestingly, the odors of substances whose molecules included a large number of carbon atoms were associated with darker shades, and the odors of substances whose molecules included few carbon atoms were associated with light shades. This shows that synesthesia is based on objective (still insufficiently studied) properties of agents affecting a person.
It is characteristic that the phenomenon of synesthesia is not distributed equally among all people. It is especially clearly manifested in people with increased excitability of subcortical formations. It is known that it prevails in hysteria, can increase markedly during pregnancy and can be artificially induced by the use of a number of pharmacological substances (for example, mescaline).
In some cases, the phenomena of synesthesia are manifested with exceptional distinctness. One of the subjects with exceptional severity of synesthesia - the famous mnemonist Sh. was studied in detail by Soviet psychology. This person perceived the weight of the voice as colored and often said that the voice of the person addressing him was "yellow and crumbly." The tones he heard caused him visual sensations of various shades (from bright yellow to dark silver or purple). Perceived colors were perceived by him as "voiced" or "muffled", "salty" or crispy. Similar phenomena in more obliterated forms occur quite often in the form of a direct tendency to "color" numbers, days of the week, names of months in different colors.
The phenomenon of synesthesia is of great interest for psychopathology, where its assessment can acquire diagnostic value.
The described forms of interaction of sensations are the most elementary and, apparently, proceed mainly at the level of the upper trunk and subcortical formations. There are, however, also more complex forms of sensory interaction or, as IP Pavlov called them, analyzers. It is known that we almost never perceive tactile, visual and auditory stimuli in isolation: perceiving objects of the external world, we see them with the eye, feel them by touch, sometimes perceive their smell, sound, etc. Naturally, this requires the interaction of the senses (or analyzers) and is provided by their synthetic work. This synthetic work of the sense organs proceeds with the closest participation of the cerebral cortex and, above all, those “tertiary” zones (“overlapping zones”), in which neurons belonging to different modalities are represented. These "overlap zones" (we talked about them above) provide the most complex forms of joint work of analyzers that underlie object perception. We will turn to the psychological analysis of the main forms of their work below.
The main properties of sensations include:
quality,
intensity,
duration,
spatial localization,
absolute and relative thresholds of sensations.
All sensations can be characterized in terms of their properties. Moreover, properties can be not only specific, but also common to all types of sensations. The main properties of sensations include: quality, intensity, duration and spatial localization, absolute and relative thresholds of sensations.
Quality- this is a property that characterizes the basic information displayed by this sensation, distinguishing it from other types of sensations and varying within this type of sensation. For example, taste sensations provide information about certain chemical characteristics of an object: sweet or sour, bitter or salty. The sense of smell also provides us with information about the chemical characteristics of the object, but of a different kind: the smell of flowers, the smell of almonds, the smell of hydrogen sulfide, etc.
Feeling intensity- a quantitative characteristic and depends on the strength of the acting stimulus and the functional state of the receptor, which determines the degree of readiness of the receptor to perform its functions. For example, if you have a runny nose, the intensity of perceived odors may be distorted.
Duration of sensation- This is a temporal characteristic of the sensation that has arisen. It is also determined by the functional state of the sense organ, but mainly by the time of action of the stimulus and its intensity. It should be noted that sensations have a so-called latent (hidden) period. When a stimulus is applied to the sense organ, the sensation does not occur immediately, but after some time. The latent period of different types of sensations is not the same. For example, for tactile sensations, it is 130 ms, for pain - 370 ms, and for taste - only 50 ms. The sensation does not arise simultaneously with the beginning of the action of the stimulus and does not disappear simultaneously with the termination of its action. The visual sensation has some inertia and does not disappear immediately after the cessation of the action of the stimulus that caused it. The trace from the stimulus remains in the form of a consistent image. Distinguish between positive and negative sequential images.
positive serial image corresponds to the initial irritation, consists in maintaining a trace of irritation of the same quality as the current stimulus.
Negative serial image consists in the appearance of a quality of sensation that is opposite to the quality of the irritant. For example, light-darkness, heaviness-lightness, heat-cold, etc. The appearance of negative sequential images is explained by a decrease in the sensitivity of this receptor to a certain effect.
Spatial localization of the stimulus. The analysis carried out by the receptors gives us information about the localization of the stimulus in space, i.e. we can tell where the light is coming from, where the heat is coming from, or what part of the body is affected by the stimulus.
Quantitative parameters the main characteristics of sensations, in other words, the degree of sensitivity. The human sense organs are surprisingly fine working apparatuses.
There are two types of sensitivity:
absolute sensitivity - the ability to feel weak stimuli;
difference sensitivity - the ability to sense subtle differences between stimuli.
However, not every irritation causes a sensation. In order for a sensation to arise, the force of irritation must have a certain value.
Absolute threshold of sensation - the minimum value of the stimulus at which a sensation first occurs. Stimuli, the strength of which lies below the absolute threshold of sensation, do not give sensations, but this does not mean that they do not have any effect on the body. Thus, studies by the Russian physiologist G. V. Gershuni and his collaborators showed that sound stimuli below the threshold of sensation can cause a change in the electrical activity of the brain and dilation of the pupil. The zone of influence of irritants that do not cause sensations was called by G.V. Gershuni "subsensory area".
The beginning of the study of the thresholds of sensations was laid by the German physicist, psychologist and philosopher G.T. Fechner, who believed that the material and the ideal are two sides of a single whole. Therefore, he set out to find out where the boundary between the material and the ideal lies. Fechner approached this problem as a naturalist. In his opinion, the process of creating a mental image can be represented by the following scheme:
Fechner Gustav Theodor (1801 -1887)- German physicist, philosopher and psychologist, founder of psychophysics. Fechner is the author of the programmatic work "Elements of Psychophysics" (I860). In this work, he put forward the idea of creating a special science - psychophysics. In his opinion, the subject of this science should be the regular correlations of two types of phenomena - mental and physical - functionally interconnected. The idea put forward by him had a significant impact on the development of experimental psychology, and the research that he conducted in the field of sensations allowed him to substantiate several laws, including the basic psychophysical law. Fechner developed a number of methods for indirect measurement of sensations, in particular three classical methods for measuring thresholds. However, after studying the successive images caused by observing the sun, he partially lost his sight, which forced him to leave psychophysics and take up philosophy.
Irritation - "Excitation -" Sensation - "Judgment (physics) (physiology) (psychology) (logic)
The most important thing in Fechner's idea was that for the first time he included elementary sensations in the circle of interests of psychology. Before Fechner, it was believed that the study of sensations, if anyone was interested, should be dealt with by physiologists, doctors, even physicists, but not psychologists. For psychologists, this is too primitive.
According to Fechner, the desired boundary passes where sensation begins, i.e., the first mental process occurs. The magnitude of the stimulus at which sensation begins, Fechner called lower absolute threshold . To determine this threshold, Fechner developed methods that are actively used in our time. Fechner based his research methodology on two statements, called the first and second paradigms of classical psychophysics.
Human sensory system is a measuring device that responds appropriately to physical stimuli.
Psychophysical characteristics in humans, they are distributed according to the normal law, that is, they randomly differ from some average value, similar to anthropometric characteristics.
The paradigms are already outdated and, to a certain extent, contradict modern principles of the study of the psyche, but Fechner's research was inherently innovative.
Today, researchers understand that it is impossible to single out and study in an experiment one, even the most primitive, mental system from the integral structure of the human psyche. In turn, the activation in the experiment of all mental systems from the lowest to the highest leads to a very wide variety of reactions of the subjects, which requires an individual approach to each subject.
Different analyzers have different sensitivities. We have already talked about the sensitivity of the eye. The sensitivity of our sense of smell is also very high. The threshold of one human olfactory cell for the corresponding odorous substances does not exceed eight molecules. It takes at least 25,000 times more molecules to produce a taste sensation than it does to produce an olfactory sensation.
The absolute sensitivity of the analyzer equally depends on both the lower and the upper threshold of sensation.
The value of absolute thresholds , both lower and upper, varies depending on different conditions:
the nature of the activity,
person's age,
functional state of the receptor,
the strength and duration of the action of irritation, etc.
sensitivity to difference. Relative, or differential sensitivity - to a change in the stimulus. If we put a weight of 100 grams on our hand, and then add another gram to this weight, then no person will be able to feel this increase. In order to feel an increase in weight, you need to add three to five grams.
To feel the minimum difference in the characteristics of the acting stimulus, it is necessary to change the strength of its impact by a certain amount.
Discrimination Threshold - the minimum difference between stimuli, which gives a barely noticeable difference in sensations.
The values of constants were calculated for the perception of changes in various stimuli.
In 1760, the French physicist P. Bouguer, using the material of light sensations, established a very important fact regarding the value of the thresholds of discrimination: in order to feel a change in illumination, it is necessary to change the light flux by a certain amount.
Later, in the first half of the XIX century. German scientist M. Weber, exploring the sensation of heaviness, came to the conclusion that when comparing objects and observing the differences between them, we perceive not the differences between the objects, but the ratio of the difference to the size of the compared objects.
MeaningconstantsWeberforvariousbodiesfeelings
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Feel |
Constant value |
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1. Feeling the change in pitch | |
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2.Sensation of light brightness change | |
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3. Feeling the change in the weight of objects | |
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4. Feeling the change in sound volume | |
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5.Sensation of pressure change on the surface of the skin | |
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6. Sensation of a change in the taste of saline solution |
Closely related to each other. Both are so-called sensory reflections of objective reality that exists independently of consciousness and as a result of its influence on the sense organs: this is their unity. But perception- awareness of a sensual given object or phenomenon; in perception, we usually have a world of people, things, phenomena that are filled with a certain meaning for us and are involved in diverse relationships. These relationships create meaningful situations, witnesses and participants of which we are. Feeling on the other hand, it is a reflection of a separate sensory quality or undifferentiated and unobjectified impressions from the environment. In this last case sensations and perceptions are distinguished as two different forms or two different relations of consciousness to objective reality. Sensations and perceptions are thus one and different. They make up: sensory-perceptual level of mental reflection. At the sensory-perceptual level, we are talking about those images that arise from the direct impact of objects and phenomena on the senses.
The concept of sensations
The main source of our knowledge about the external world and about our own body is sensations. They constitute the main channels through which information about the phenomena of the external world and about the states of the body reaches the brain, giving a person the opportunity to navigate in the environment and in his body. If these channels were closed and the sense organs did not bring the necessary information, no conscious life would be possible. There are known facts that a person deprived of a constant source of information falls into a sleepy state. Such cases: take place when a person suddenly loses sight, hearing, smell, and when his conscious sensations are limited by some pathological process. A result close to this is achieved when a person is placed for some time in a light and soundproof chamber that isolates him from external influences. This state first induces sleep and then becomes intolerable for the subjects.
Numerous observations have shown that impaired information flow in early childhood, associated with deafness and blindness, causes severe delays in mental development. If children born deaf-deaf or deprived of hearing and sight at an early age are not taught special techniques that compensate for these defects due to touch, their mental development will become impossible and they will not develop independently.
As will be described below, the high specialization of various sense organs is based not only on the structural features of the peripheral part of the analyzer - “receptors”, but also on the highest specialization of neurons that are part of the central nervous apparatus, which reach the signals perceived by the peripheral sense organs.
The reflex nature of sensations
So, sensations are the initial source of all our knowledge about the world. Objects and phenomena of reality that act on our senses are called stimuli, and the effect of stimuli on the senses is called irritation. Irritation, in turn, causes excitation in the nervous tissue. Sensation arises as a reaction of the nervous system to a particular stimulus and, like any mental phenomenon, has a reflex character.
The physiological mechanism of sensations is the activity of special nervous apparatuses called.
Each analyzer consists of three parts:- the peripheral section, called the receptor (the receptor is the perceiving part of the analyzer, its main function is the transformation of external energy into a nervous process);
- afferent or sensory nerves (centripetal), conducting excitation to the nerve centers (the central section of the analyzer);
- cortical sections of the analyzer, in which the processing of nerve impulses coming from the peripheral sections takes place.
The cortical part of each analyzer includes an area that is a projection of the periphery in the cerebral cortex, since certain areas of the cortical cells correspond to certain cells of the periphery (receptors). For a sensation to arise, the work of the entire analyzer as a whole is necessary. The analyzer is not a passive energy receiver. This is an organ that reflexively rebuilds under the influence of stimuli.
Physiological studies show that sensation is not at all a passive process, it always includes motor components in its composition. So, observations with a microscope of a skin area, carried out by the American psychologist D. Neff, made it possible to make sure that when it is irritated with a needle, the moment the sensation occurs is accompanied by reflex motor reactions of this skin area. Subsequently, numerous studies found that each sensation includes movement, sometimes in the form of a vegetative reaction (vasoconstriction, galvanic skin reflex), sometimes in the form of muscle reactions (eye rotation, neck muscle tension, motor reactions of the hand, etc. .). Thus, sensations are not passive processes at all - they are active. In pointing out the active character of all these processes, the reflex theory of sensations consists.
Classification of sensations
It has long been customary to distinguish five main types (modalities) of sensations: smell, taste, touch, sight and hearing. This classification of sensations according to the main modalities is correct, although not exhaustive. A.R. Luria believes that the classification of sensations can be carried out according to at least two main principles − systematic and genetic(in other words, according to the principle of modality, on the one hand, and according to the principle of complexity or the level of their construction, on the other).
Systematic classification of sensations
Singling out the largest and most significant groups of sensations, they can be divided into three main types; interoceptive, proprioceptive and exterocentric sensations. The former combine signals that reach us from the internal environment of the body; the latter provide information about the position of the body in space and the position of the musculoskeletal system, provide regulation of our movements; finally, others provide signals from the outside world and provide the basis for our conscious behavior. Consider the main types of sensations separately.
Interoceptive sensationsInteroceptive sensations, signaling the state of the internal processes of the body, bring irritation to the brain from the walls of the stomach and intestines, the heart and circulatory system and other internal organs. This is the oldest and most elementary group of sensations. Interoceptive sensations are among the least conscious and most diffuse forms of sensation and always retain their proximity to emotional states.
proprioceptive sensationsProprioceptive sensations provide signals about the position of the body in space and form the afferent basis of human movements, playing a decisive role in their regulation. Peripheral receptors for proprioceptive sensitivity are found in muscles and joints (tendons, ligaments) and have the form of special nerve bodies (Paccini bodies). The excitations that arise in these bodies reflect the sensations that occur when muscles are stretched and the position of the joints changes. In modern physiology and psychophysiology, the role of proprioception as the afferent basis of movements in animals was studied in detail by A. A. Orbeli, P. K. Anokhin, and in humans, by N. A. Bernshtein. The described group of sensations includes a specific type of sensitivity, called a sense of balance, or a static sensation. Their peripheral receptors are located in the semicircular canals of the inner ear.
exteroreceptive sensationsThe third and largest group of sensations are exteroreceptive sensations. They bring information from the outside world to a person and are the main group of sensations that connects a person with the external environment. The whole group of exteroceptive sensations is conventionally divided into two subgroups: contact and distant sensations.
Contact sensations are caused by an impact directly applied to the surface of the body and the corresponding perceived organ. Taste and touch are examples of contact sensation.
Distant sensations are caused by stimuli acting on the sense organs at some distance. These senses include the sense of smell and, especially, hearing and sight.
Genetic classification of sensations
Genetic classification allows us to distinguish two types of sensitivity:- protopathic(more primitive, affective, less differentiated and localized), which includes organic feelings (hunger; thirst, etc.);
- epicritical(more subtly differentiating, objectified and rational), which includes the main human senses.
Epicritical sensitivity is genetically younger and controls protopathic sensitivity.
General properties of sensations
Different types of sensations are characterized not only by specificity, but also by properties common to them. These properties include: quality, intensity, duration and spatial localization.
Quality- this is the main feature of this sensation, which distinguishes it from other types of sensations and varies within the limits of this type of sensations. The qualitative variety of sensations reflects the infinite variety of forms of motion of matter.
Intensity sensation is its quantitative characteristic and is determined by the strength of the acting stimulus and the functional state of the receptor.
Duration sensation is its temporal characteristic. It is also determined by the functional state of the sense organ, but mainly by the duration of the stimulus and its intensity.
When a stimulus is exposed to a sensory organ, sensation does not occur immediately, but after some time - the so-called latent (hidden) period of sensation. The latent period of various types of sensations is not the same: for example, for tactile sensations it is 130 ms; for pain - 370, and for taste - only 50 ms.
Just as a sensation does not arise simultaneously with the beginning of the action of the stimulus, it does not disappear simultaneously with the termination of its action. The presence of positive successive images explains why we do not notice the breaks between successive frames of the film: they are filled with traces of previous frames - successive images from them. The sequential image changes in time, the positive image is replaced by a negative one. With colored light sources, the sequential image turns into a complementary color.
A person receives a variety of information about the state of the external and internal environment with the help of the senses, in the form of sensations.
Sensations are a cognitive process, a reflection in the human mind of individual properties of objects that directly affect our senses.
Feelings are the source of our knowledge about the world and ourselves. The ability to sense is present in all living beings with a nervous system. The vital role of sensations is to promptly and quickly bring information about the state of the external and internal environment to the central nervous system.
For a sensation to occur, the stimulus must act on the sense organs. Material agents of various nature (physical, chemical) act as an irritant. The emergence of sensations is ensured by the work of analyzers, of which a person has five: visual, auditory, tactile-kinesthetic (provides a distinction between touch and movement), olfactory, and gustatory.
Analyzer- the nervous apparatus, which performs the function of analysis and synthesis of stimuli emanating from the external and internal environment of the body. Analyzers receive the impact of certain stimuli from the external and internal environment and process them into sensations.
Analyzers consist of the following parts:
receptors, or sense organs that convert the energy of external influences into nerve signals;
Nerve pathways through which these signals are transmitted to the brain and back to the receptors;
cortical areas of the brain.
In the cerebral cortex, each analyzer is assigned a separate area. Each receptor is adapted to receive only certain types of exposure (light, sound, etc.), i.e. has a specific excitability to certain physical and chemical agents.
Types of sensations reflect the uniqueness of the stimuli that give rise to them.
Feelings can be classified in different ways. According to the leading modality (qualitative characteristic), there are:
· visual sensations - are caused by exposure to light, i.e. electromagnetic waves that are emitted or reflected by various physical bodies. The receptor is the retina of the eye. Light waves differ in length, amplitude and shape. Length is the number of oscillations of a light wave per second. The larger the number of oscillations, the shorter the wavelength, and, conversely, the smaller the number of oscillations, the longer the wavelength. The wavelength of light determines the color tone. Colors have different psychological meanings. The amplitude of the light wave oscillations determines the brightness of the color. The shape of the light wave, resulting from mixing light waves of different wavelengths together, determines the saturation of the color.
· auditory sensations - are caused by sound waves, i.e. rhythmic fluctuations in the air. There is a special physical unit by which the frequency of air oscillations per second is estimated - hertz - numerically equal to one oscillation per second. The higher the frequency of air vibrations, the higher the sound we perceive. On average, a person hears sounds in the frequency range from 16 Hz to 20 kHz. Sound below the human hearing range is called infrasound; from 20 kHz to 1 GHz - by ultrasound, from 1 GHz and above - by hypersound. The loudness of the perceived sound depends on its strength or intensity, i.e. amplitude and frequency of air oscillations. To assess the loudness of the perceived sound, a unit is adopted - decibel. The average loudness values of various sounds are presented in table No. 2.
Table number 2
Average loudness values of various sounds
· olfactory sensations are a reflection of smells. They arise due to the penetration of particles of odorous substances that spread in the air into the upper part of the nasopharynx, where they act on the peripheral endings of the olfactory analyzer, embedded in the nasal mucosa.
· taste sensations play an important role in the process of eating, in distinguishing between different types of food. Taste sensations have four main modalities: sweet, salty, sour and bitter. All other varieties of taste sensations are a diverse combination of the four main ones. The olfactory analyzer plays an important role in the emergence of certain taste sensations.
· tactile sensation or skin sensitivity is the most common type of sensitivity. The familiar feeling that occurs when an object touches the surface of the skin is the result of a complex combination of 4 others: pressure, pain, heat and cold. For each of them there is a specific number of receptors, unevenly located in different parts of the skin surface. The strength and quality of sensations are themselves relative. For example, when the surface of one area of the skin is simultaneously exposed to warm water, its temperature is perceived differently, depending on what kind of water we act on the neighboring area of the skin. If it is cold, then in the first area of the skin there is a feeling of warmth, and if it is hot, then a feeling of cold. Temperature receptors have, as a rule, two threshold values: they respond to high and low impacts, but do not respond to medium ones.
These sensations are called exteroceptive and constitute a single group according to the type of analyzers, the receptors of which are located on the surface of the body or near it. Exteroceptive sensations are divided into contact and distance. Contact sensations are caused by direct contact with the surface of the body (taste, touch), distant sensations are caused by stimuli that act on the sense organs at some distance (vision, hearing). Olfactory sensations occupy an intermediate position between them.
To proprioceptive sensations include a sense of balance, provided by the work of the vestibular apparatus, and a kinesthetic sensation, which carries information about the state of the muscular system. kinesthetic sensations(from the Greek kinesis - “movement”) come from muscles, ligaments and tendons; allow you to perform and coordinate movements. They are formed automatically, enter the brain and regulate movements at a subconscious level.
Signals from internal organs are called visceral sensations and are interoceptive. These include hunger, thirst, nausea, and internal pain.
In addition, a person has several specific types of sensations that carry information about time, acceleration, vibration. Vibrating sensations occupy an intermediate place between tactile and auditory sensitivity.
Feeling properties. Feelings have the following properties.
1. Modality- a qualitative characteristic of sensations is a property that allows you to distinguish one type of sensation from another.
2. Intensity- this is a quantitative characteristic of sensations, which is determined by the strength of the acting stimulus and the functional state of the receptor.
3. Duration is a temporal characteristic of sensations. It is determined by the functional state of the sense organ, the time of exposure to the stimulus and its intensity.
4. Sensitivity is the ability of the nervous system to respond to stimuli. Sensitivity is characterized by two thresholds - lower and upper. The lower threshold is the minimum amount of stimulus that can cause a subtle sensation. The upper one is the maximum value of the stimulus at which pain sensation occurs. High sensitivity corresponds to low thresholds, and vice versa, low sensitivity corresponds to high ones. The threshold for the occurrence of sensation in different people is not the same. The value of the threshold varies with age and depends on the state of health and mental state of the person. Sensitivity can be increased or decreased by pharmacological means. An important role in changing the sensitivity is played by the fitness of the analyzer. For example, musicians develop auditory sensitivity (“musical ear”), tasters develop olfactory and gustatory sensitivity.
5. Adaptation is the adaptation of the sense organ to external conditions. Through adaptation, the receptor gets used to the sensation. For example, when moving from bright light to darkness, we do not see objects at first, but gradually begin to distinguish their outlines (dark adaptation).
6. Synesthesia- this is the appearance under the influence of irritation of a certain analyzer of a sensation characteristic of another analyzer. For example, in some people, the sounds of music can cause a sensation of color (the so-called "color hearing") or a combination of colors gives rise to musical associations.
7. Compensation- this is the property of sensations to increase any sensitive system when another is disturbed (for example, hearing becomes aggravated with loss of vision).
Which are manifested in the reflection of a separate property of objects. This includes various phenomena of the surrounding world and the internal states of the human body during the direct impact of material stimuli on receptors. Types of sensations will help determine the most common human stimuli.
The role of sensations in life
The role of sensations in human life can hardly be overestimated, because they are a unique source of all knowledge about the world. People feel the surrounding reality with the help of the senses, because they are the only channels through which the outside world penetrates the human consciousness.
Various types of sensations are capable of reflecting certain properties of the environment to one degree or another. This includes sounds, lighting, taste and many other factors, thanks to which a person has the opportunity to navigate in the world around him.
The physiological basis of sensations is the nervous processes that, by their nature, appear during the action of a stimulus on an adequate analyzer. It, in turn, consists of receptors, nerve pathways and a central section. Here, a variety of signals are processed that come directly from the receptors to the cerebral cortex. It is safe to say that due to the receipt of impulses and stimuli into the brain, a person can quickly respond and perceive various types of sensations.
How do sensations arise?
Human sensations arise only when a certain stimulus appears. It is worth noting that the provision of a certain effect on the receptor can lead to the appearance of an irritant. It transforms all processes into nervous excitation, which is transmitted to the central parts of the analyzer.
At this moment, a person can feel the taste, light, and many other factors. In this case, there should be a response of the body to a particular stimulus. It is transmitted from the brain to the sense organs by means of the centrifugal nerve. A person can move his own gaze and perform many other actions every second, perceiving irritable signals.
Basic classification of sensations
The main role of sensations in human life is to timely bring all the necessary information to the central nervous system. It is possible to single out the most common classification in which types of sensations are presented.
Feelings:
Exteroceptive: a) contact - temperature, tactile and taste; b) distant - visual, auditory and olfactory.
Proprioceptive: a) musculo-motor.
Interoceptive - they indicate the current state of all internal organs.
Certain sensations are able to reflect the properties of objects, phenomena of the external world, reflecting the state of the body, tactile, pain, as well as sensations of various origins. It is thanks to these possibilities that a person can distinguish colors and light.
Taste sensations
It can be said with certainty that taste sensations are determined by the various properties of surrounding things. They do not have a complete or objective classification. If we take into account the main complex of sensations that arise due to taste substances, then several main irritants can be distinguished - these are sour, salty, sweet and bitter foods.
Taste sensations often include olfactory sensations, and in some cases this may include a reaction to pressure, heat, cold, or pain. If we talk about caustic, astringent, tart taste qualities, then they are due to a whole range of different sensations. Thanks to a complex complex, a person is able to feel the taste of the food consumed.
Taste buds are able to express themselves during exposure to different taste regions. It turns out that a single substance has a relatively small molecular weight.
The value of the properties of sensations
The main properties of sensations should be reduced to adaptation or adaptations of various stimuli. All this happens until the moment when the reaction of a person is equal to the minimum indicators. These include sensitization, contrast, and interaction with various stimuli.
Varieties and properties of sensations can manifest themselves to varying degrees, that is, they depend on the individual physical and biological characteristics of a particular subject. But it is worth noting that all of these properties are significant in the field of a psychological point of view. It is worth noting that sensitization and adaptation are widely used today in psychotherapy in order to develop the ability of each person to more vividly and emotionally perceive various positive elements.
Exteroceptive and tactile sensations
All human sensations can be divided into exteroceptive and tactile. It should be noted that exteroceptive sensations provide the human body with all the necessary information that comes exclusively from the environment. In turn, people get a visual image with the help of the presence of a sufficient number of cells, which are called "koloboks" and "rods".
The "rods" help to provide fairly good vision at dusk, and the "koloboks" are responsible for color vision. The ear can respond to pressure fluctuations in the atmosphere, which are perceived as sound.
The taste buds, which are located on the papillae of the tongue, are able to perceive several main tastes - sour, salty, sweet and bitter. Human tactile sensations appear during the interaction of any mechanical stimulus and receptors. They are found on the skin of the fingers, palms, lips and many other organs.
Proprioceptive sensations provide important information about the current state of the muscles. They are able to quickly respond to the degree of contraction and muscle relaxation. It should be noted that proprioceptive sensations inform a person about the state of internal organs, their chemical composition, the presence of biological, useful or harmful substances.
Features of pain
Pain is an important biologically active protective device. It arises with the help of the destructive force of irritation. It is worth noting that pain can serve as an alarm about a possible danger to the human body. The sensitivity of pain is distributed over the surface of the skin, as well as in the internal organs. The distribution process is partial and uneven.
There are areas where a small number of pain receptors are located. Experimental studies were carried out, which made it possible to consider the distribution of pain points as dynamic and mobile. Pain sensations are the result of impacts exceeding the prescribed limit of intensity and frequency of impulses. Also, it all depends on the duration of a particular stimulus.
According to Frey's theory, different pain sensitivity has an independent, peripheral and central nervous apparatus.
Touch and pressure
Presented are characterized by the features of touch and pressure. Therefore, it is possible to accurately determine their localization, which is developed as a result of experience during the participation of vision and muscle joints. It should be noted that a large number of receptors are characterized by rapid adaptation. That is why a person feels not only force pressure, but also a change in intensity.
Common sense characteristics
It should be noted that intensity is the main characteristic of human sensations, which is determined by the quantity and strength of the acting stimulus. Certain sense organs have a special sensitivity to the displayed phenomena. Sensitivity can be described as the threshold of sensation.
The duration of sensation is a temporal characteristic that can be determined by the periodic effects of the stimulus on duration and intensity. But it is worth noting that many other features must be taken into account. During the impact of the stimulus on any sense organ, a certain sensation may not occur immediately, but after some time. This phenomenon can be characterized as latent or latent sensation time.
Olfactory sensations
The sense of smell is a type of chemical sensitivity. It is worth noting that in animals, the sense of smell and taste are one, they simply differentiate after a certain period of time. A few years ago, it was generally accepted that the sense of smell does not play a particularly important role in human life. If you look from the point of view of the knowledge of the external world, then sight, hearing and touch are in the first place and are more important.
But it is worth noting that the smell has a direct impact on the various functions of the autonomic nervous system. Also, with the help of this feeling, you can create a positive or negative emotional background that can color the general well-being of a person.
Touch
During touch, each person cognizes the material world, performs the process of movement, which can also turn into conscious purposeful feeling. It is in this way that a person in practice has the opportunity to know any objects.
Sensations of touch and pressure are typical traditional psychophysiological phenomena. They are associated with the thresholds of skin sensitivity, therefore they play only a subordinate role in the human mind, as well as its objective reality. The sense organs - skin, eyes, ears - allow a person to fully experience the world.
