Scientific electronic library. Characteristics of sensations, types and properties of sensations
A brief excursion into the development of the concept of sensations
Feel- “the law of specific energy of the sensory organ,” that is, the sensation does not depend on the nature of the stimulus, but on the organ or nerve in which the process of irritation occurs. The eye sees, the ear hears. The eye cannot see, but the ear cannot see. 1827
The objective world is fundamentally unknowable. The result of the sensation process is a partial, that is, partial image of the world. Everything we perceive is a process of specificity of influence on the senses. “Mental processes” Wekker L.M.
Power-law dependence of changes in sensations when the intensity of stimuli changes (Stevens' law)
The lower and upper absolute thresholds of sensation (absolute sensitivity) and thresholds of discrimination (relative sensitivity) characterize the limits of human sensitivity. Along with this, there is a distinction operational sensation thresholds— the magnitude of the difference between the signals at which the accuracy and speed of their discrimination reaches a maximum. (This value is an order of magnitude greater than the discrimination threshold.)
2. Adaptation. The sensitivity of the analyzer is not stable, it varies depending on different conditions.
Thus, when entering a poorly lit room, we initially do not distinguish objects, but gradually the sensitivity of the analyzer increases; being in a room with any odors, after a while we stop noticing these odors (the sensitivity of the analyzer decreases); when we move from a poorly lit space to a brightly lit one, the sensitivity of the visual analyzer gradually decreases.
A change in the sensitivity of the analyzer as a result of its adaptation to the strength and duration of the current stimulus is called adaptation(from lat. adaptatio- device).
Different analyzers have different speed and range of adaptation. Adaptation to some stimuli occurs quickly, to others - more slowly. The olfactory and tactile senses adapt faster (from the Greek. taktilos- touch) analyzers. The auditory, gustatory and visual analyzers adapt more slowly.
Full adaptation to the smell of iodine occurs in a minute. After three seconds, the pressure sensation reflects only 1/5 of the force of the stimulus. (Searching for glasses pushed onto the forehead is one example of tactile adaptation.) For complete dark adaptation of the visual analyzer, 45 minutes are needed. However, visual sensitivity has the largest range of adaptation - it changes 200,000 times.
The phenomenon of adaptation has expedient biological significance. It helps to reflect weak stimuli and protects analyzers from excessive exposure to strong ones. Adaptation, as getting used to constant conditions, provides an increased orientation to all new influences. Sensitivity depends not only on the strength of external stimuli, but also on internal states.
3. Sensitization. Increasing the sensitivity of analyzers under the influence of internal (mental) factors is called sensitization(from lat. sensibilis- sensitive). It can be caused by: 1) the interaction of sensations (for example, weak taste sensations increase visual sensitivity. This is explained by the interconnection of analyzers, their systemic work); 2) physiological factors (the state of the body, the introduction of certain substances into the body; for example, vitamin “A” is essential to increase visual sensitivity); 3) the expectation of a particular influence, its significance, a special attitude towards distinguishing between stimuli; 4) exercise, experience (thus, tasters, by specially exercising their taste and olfactory sensitivity, distinguish between different types of wines and teas and can even determine when and where the product was made).
In people deprived of any type of sensitivity, this deficiency is compensated (compensated) by increasing the sensitivity of other organs (for example, increasing auditory and olfactory sensitivity in the blind). This is the so-called compensatory sensitization.
Strong stimulation of some analyzers always reduces the sensitivity of others. This phenomenon is called desensitization. Thus, increased noise levels in “loud workshops” reduce visual sensitivity; desensitization of visual sensitivity occurs.
Rice. 4. . The inner squares produce sensations of varying intensities of gray. In reality they are the same. Sensitivity to the properties of phenomena depends on adjacent and sequential contrasting influences.
4. . One of the manifestations of the interaction of sensations is their contrast(from lat. contrast- sharp contrast) - increased sensitivity to some properties under the influence of other, opposite, properties of reality. Thus, the same gray figure appears dark on a white background, but white on a black background (Fig. 4).
5. Synesthesia. An associative (phantom) foreign-modal sensation that accompanies a real one (the sight of a lemon causes a sour sensation) is called synesthesia(from Greek synaisthesis- shared feeling).
Rice. 5.
Features of certain types of sensations.
Visual sensations. Colors perceived by humans are divided into chromatic (from the Greek. chroma- color) and achromatic - colorless (black, white and intermediate shades of gray).
For visual sensations to occur, electromagnetic waves must act on the visual receptor—the retina (a collection of photosensitive nerve cells located at the bottom of the eyeball). The central part of the retina is dominated by nerve cells called cones, which provide the sense of color. At the edges of the retina, rods, sensitive to changes in brightness, predominate (Fig. 5, 6).
Rice. 6. . Light penetrates the light-sensitive receptors - rods (reacting to changes in brightness) and cones (reacting to different lengths of electromagnetic waves, i.e. chromatic (color) influences), bypassing the ganglion and bipolar cells, which carry out the primary elementary analysis of nerve impulses traveling already from the retina. For visual stimulation to occur, it is necessary that the electromagnetic energy falling on the retina be absorbed by its visual pigment: rod pigment - rhodopsin and cone pigment - iodopsin. Photochemical transformations in these pigments give rise to the visual process. At all levels of the visual system, this process: manifests itself in the form of electrical potentials, which are recorded by special devices - an electroretinograph.
Light (electromagnetic) rays of different lengths cause different color sensations. Color is a mental phenomenon - human sensations caused by different frequencies of electromagnetic radiation (Fig. 7). The eye is sensitive to the region of the electromagnetic spectrum from 380 to 780 nm (Fig. 8). The 680 nm wavelength gives the sensation of red; 580 - yellow; 520 - green; 430 - blue; 390 - purple flowers.
Electromagnetic radiation.
Rice. 7. Electromagnetic spectrum and its visible part (NM - nanometer - one billionth of a meter)
Rice. 8. .
Rice. 9. . Opposite colors are called complementary colors - when mixed they form white. Any color can be obtained by mixing two bordering colors. For example: red - a mixture of orange and purple).
The mixing of all perceived electromagnetic waves gives the sensation of white color.
There is a three-component theory of color vision, according to which the entire variety of color sensations arises as a result of the work of only three color-perceiving receptors - red, green and blue. Cones are divided into groups of these three colors. Depending on the degree of excitation of these color receptors, different color sensations arise. If all three receptors are excited to the same extent, the sensation of white color occurs.
Rice. 10. .
Our eye is sensitive to different parts of the electromagnetic spectrum unequal sensitivity. It is most sensitive to light rays with a wavelength of 555 - 565 nm (light green color tone). The sensitivity of the visual analyzer in twilight conditions moves towards shorter waves - 500 nm (blue color). These rays begin to appear lighter (Purkinje phenomenon). The rod apparatus is more sensitive to ultraviolet color.
In conditions of sufficiently bright lighting, the cones are turned on and the rod apparatus is turned off. In low light conditions, only the sticks are activated. Therefore, in twilight lighting we do not distinguish chromatic color, the coloring of objects.
Rice. eleven. . Information about events in the right half of the visual field enters the left occipital lobe from the left side of each retina; information about the right half of the visual field is sent to the left occipital lobe from the right parts of both retinas. Redistribution of information from each eye occurs as a result of the crossing of part of the optic nerve fibers in the chiasm.
Visual stimulation is characterized by some inertia. This is the reason for the persistence of a trace of light stimulation after the cessation of exposure to the stimulus. (This is why we do not notice the breaks between frames of the film, which turn out to be filled with traces from the previous frame.)
People with weakened cone apparatus have difficulty distinguishing chromatic colors. (This disadvantage, described by the English physicist D. Dalton, is called color blindness). Weakening of the rod apparatus makes it difficult to see objects in dim light (this deficiency is called “night blindness.”)
For the visual analyzer, the difference in brightness is essential - contrast. The visual analyzer is capable of distinguishing contrast within certain limits (optimum 1:30). Strengthening and weakening contrasts is possible through the use of various means. (To identify subtle relief, shadow contrast is enhanced by lateral lighting and the use of light filters.)
The color of each object is characterized by those rays of the light spectrum that the object reflects. (A red object, for example, absorbs all rays of the light spectrum except red, which are reflected by it.) The color of transparent objects is characterized by the rays that they transmit. Thus, the color of any object depends on what rays it reflects, absorbs and transmits.
Rice. 12.: 1 - chiasmus; 2 - visual thalamus; 3 - occipital lobe of the cerebral cortex.
In most cases, objects reflect electromagnetic waves of different lengths. But the visual analyzer does not perceive them separately, but collectively. For example, exposure to red and yellow colors is perceived as orange, and a mixture of colors occurs.
Signals from photoreceptors - light-sensitive formations (130 million cones and rods) arrive to 1 million larger (ganglionic) neurons of the retina. Each ganglion cell sends its process (axon) to the optic nerve. Impulses traveling to the brain along the optic nerve receive primary processing in the diencephalon. Here the contrast characteristics of the signals and their time sequence are enhanced. And from here, nerve impulses enter the primary visual cortex, localized in the occipital region of the cerebral hemispheres (Brodmann fields 17 - 19) (Fig. 11, 12). Here, individual elements of the visual image are highlighted - points, angles, lines, directions of these lines. (Established by Boston researchers and 1981 Nobel Prize winners Hubel and Wiesel.)
Rice. 13. Optograph, taken from the retina of a dog's eye after its death. This indicates the screen principle of the functioning of the retina.
The visual image is formed in the secondary visual cortex, where sensory material is compared (associated) with previously formed visual standards - the image of the object is recognized. (0.2 seconds pass from the beginning of the stimulus to the appearance of the visual image.) However, already at the level of the retina, a screen display of the perceived object occurs (Fig. 13).
Auditory sensations. There is an opinion that we receive 90% of information about the world around us through vision. This can hardly be calculated. After all, what we see with the eye must be covered by our conceptual system, which is formed integratively, as a synthesis of all sensory activity.
Rice. 14. Deviations from normal vision - myopia and farsightedness. These deviations can usually be compensated for by wearing glasses with specially selected lenses.
The work of the auditory analyzer is no less complex and important than the work of the visual analyzer. The main flow of speech information goes through this channel. A person perceives sound 35 - 175 ms after it reaches the auricle. Another 200 - 500 ms is necessary for maximum sensitivity to a given sound to occur. It also takes time to turn the head and appropriately orient the auricle in relation to the source of the weak sound.
From the tragus of the auricle, the oval auditory canal deepens into the temporal bone (its length is 2.7 cm). Already in the oval passage, the sound is significantly enhanced (due to resonant properties). The oval passage is closed by the tympanic membrane (its thickness is 0.1 mm and its length is 1 cm), which constantly vibrates under the influence of sound. The eardrum separates the outer ear from the middle ear - a small chamber with a volume of 1 cm³ (Fig. 15).
The middle ear cavity is connected to the inner ear and the nasopharynx. (The air coming from the nasopharynx balances the external and internal pressure on the eardrum.) In the middle ear, sound is amplified many times over by a system of ossicles (the malleus, incus and stapes). These ossicles are supported by two muscles that tighten when sounds are too loud and weaken the ossicles, protecting the hearing aid from injury. With weak sounds, the muscles increase the work of the bones. The sound intensity in the middle ear increases 30 times due to the difference between the area of the eardrum (90 mm2), to which the malleus is attached, and the area of the base of the stapes (3 mm2).
Rice. 15. . Sound vibrations from the external environment pass through the ear canal to the eardrum, located between the outer and middle ear. The eardrum transmits vibrations and the bony mechanism of the middle ear, which, acting on a lever principle, amplifies the sound by about 30 times. As a result, slight changes in pressure at the eardrum are transmitted in a piston-like motion to the oval window of the inner ear, which causes fluid movement in the cochlea. Acting on the elastic walls of the cochlear canal, the movement of the fluid causes an oscillatory movement of the auditory membrane, or more precisely, a certain part of it that resonates at the corresponding frequencies. At the same time, thousands of hair-like neurons transform the oscillatory movement into electrical impulses of a certain frequency. The round window and the Eustachian tube extending from it serve to equalize pressure with the external environment; entering the nasopharynx area, the Eustachian tube opens slightly during swallowing movements.
The purpose of the auditory analyzer is to receive and analyze signals transmitted by vibrations of an elastic medium in the range of 16-20,000 Hz (sound range).
The receptor section of the auditory system is the inner ear, the so-called cochlea. It has 2.5 turns and is divided transversely by a membrane into two isolated channels filled with fluid (perilymph). Along the membrane, which narrows from the lower curl of the cochlea to its upper curl, there are 30 thousand sensitive formations - cilia - they are sound receptors, forming the so-called organ of Corti. The primary separation of sound vibrations occurs in the cochlea. Low sounds affect long cilia, high sounds affect short ones. The vibrations of the corresponding sound cilia create nerve impulses that enter the temporal part of the brain, where complex analytical and synthetic activity is carried out. The most important verbal signals for humans are encoded in neural ensembles.
The intensity of the auditory sensation—loudness—depends on the intensity of the sound, that is, on the amplitude of vibrations of the sound source and on the pitch of the sound. The pitch of the sound is determined by the frequency of vibrations of the sound wave, the timbre of the sound is determined by overtones (additional vibrations in each main phase) (Fig. 16).
The pitch of a sound is determined by the number of vibrations of the sound source in 1 second (1 vibration per second is called a hertz). The organ of hearing is sensitive to sounds in the range from 20 to 20,000 Hz, but the greatest sensitivity lies in the range of 2000 - 3000 Hz (this is the pitch corresponding to the cry of a frightened woman). A person does not feel the sounds of the lowest frequencies (infrasounds). The sound sensitivity of the ear begins at 16 Hz.
Rice. 16. . The intensity of a sound is determined by the amplitude of the vibration of its source. Height - vibration frequency. Timbre - additional vibrations (overtones) in each “time” (middle picture).
However, subthreshold low-frequency sounds affect a person’s mental state. Thus, sounds with a frequency of 6 Hz cause dizziness, a feeling of fatigue, depression in a person, and sounds with a frequency of 7 Hz can even cause cardiac arrest. Getting into the natural resonance of the work of internal organs, infrasounds can disrupt their activity. Other infrasounds also selectively affect the human psyche, increasing suggestibility, learning ability, etc.
Sensitivity to high-frequency sounds in humans is limited to 20,000 Hz. Sounds lying beyond the upper threshold of sound sensitivity (i.e. above 20,000 Hz) are called ultrasounds. (Animals have access to ultrasonic frequencies of 60 and even 100,000 Hz.) However, since sounds up to 140,000 Hz are found in our speech, it can be assumed that they are perceived by us at a subconscious level and carry emotionally significant information.
The thresholds for distinguishing sounds by their height are 1/20 of a semitone (that is, up to 20 intermediate steps differ between the sounds produced by two adjacent piano keys).
In addition to high-frequency and low-frequency sensitivity, there are lower and upper thresholds of sensitivity to sound intensity. With age, sound sensitivity decreases. Thus, to perceive speech at the age of 30, a sound volume of 40 dB is required, and to perceive speech at the age of 70, its volume must be at least 65 dB. The upper threshold of hearing sensitivity (in terms of volume) is 130 dB. Noise above 90 dB is harmful to humans. Sudden loud sounds that hit the autonomic nervous system and lead to a sharp narrowing of the lumen of blood vessels, increased heart rate and an increase in the level of adrenaline in the blood are also dangerous. The optimal level is 40 - 50 dB.
Tactile sensation(from Greek taktilos- touch) - sensation of touch. Tactile receptors (Fig. 17) are most numerous on the tips of the fingers and tongue. If on the back two points of contact are perceived separately only at a distance of 67 mm, then at the tip of the fingers and tongue - at a distance of 1 mm (see table).
Spatial thresholds of tactile sensitivity.
Rice. 17. .
| High sensitivity zone | Low sensitivity zone |
| Tip of the tongue - 1 mm | Sacrum - 40.4 mm |
| Terminal phalanges of fingers - 2.2 mm | Buttock - 40.5 mm |
| Red part of lips - 4.5 mm | Forearm and lower leg - 40.5 mm |
| Palmar side of the hand - 6.7 mm | Sternum - 45.5 mm |
| Terminal phalanx of the big toe - 11.2 mm | Neck below the back of the head - 54.1 mm |
| The back side of the second phalanges of the toes is 11.2 mm | Lumbar - 54.1 mm |
| The back side of the first phalanx of the big toe is 15.7 mm | Back and middle of neck - 67.6 mm |
| Shoulder and hip - 67.7 mm |
The threshold of spatial tactile sensitivity is the minimum distance between two point touches at which these impacts are perceived separately. The range of tactile discrimination sensitivity is from 1 to 68 mm. High sensitivity zone - from 1 to 20 mm. Low sensitivity zone - from 41 to 68 mm.
Tactile sensations combined with motor ones form tactile sensitivity, which underlies objective actions. Tactile sensations are a type of skin sensation, which also includes temperature and pain sensations.
Kinaesthetic (motor) sensations.
Rice. 18. (according to Penfield)
Actions are associated with kinesthetic sensations (from the Greek. kineo- movement and aesthesia- sensitivity) - sensation of the position and movement of parts of one’s own body. Labor movements of the hand were of decisive importance in the formation of the brain and the human psyche.
Based on muscle-joint sensations, a person determines compliance or non-compliance
their movements to external circumstances. Kinaesthetic sensations perform an integrating function throughout the human sensory system. Well-differentiated voluntary movements are the result of the analytical and synthetic activity of a large cortical zone located in the parietal region of the brain. The motor area of the cerebral cortex is especially closely connected with the frontal lobes of the brain, which perform intellectual and speech functions, and with the visual areas of the brain.
Rice. 19. .
Muscle spindle receptors are especially numerous in the fingers and toes. When moving various parts of the body, arms, fingers, the brain constantly receives information about their current spatial position (Fig. 18), compares this information with the image of the final result of the action and carries out appropriate correction of movement. As a result of training, images of intermediate positions of various parts of the body are generalized into a single general model of a specific action - the action is stereotyped. All movements are regulated based on motor sensations, based on feedback.
Motor physical activity of the body is essential for optimizing brain function: proprioceptors of skeletal muscles send stimulating impulses to the brain and increase the tone of the cerebral cortex.
Rice. 20.: 1. Limits of permissible vibrations for individual parts of the body. 2. Limits of permissible vibrations acting on the entire human body. 3. Boundaries of weakly felt vibrations.
Static sensations- sensations of the position of the body in space relative to the direction of gravity, a sense of balance. The receptors for these sensations (gravitoreceptors) are located in the inner ear.
Receptor rotational body movements are cells with hair endings located in semicircular canals inner ear, located in three mutually perpendicular planes. When the rotational movement accelerates or decelerates, the fluid filling the semicircular canals exerts pressure (according to the law of inertia) on the sensitive hairs, in which a corresponding excitation is caused.
Moving into space in a straight line reflected in otolithic apparatus. It consists of sensitive cells with hairs, above which are located otoliths (pads with crystalline inclusions). Changing the position of the crystals signals the brain the direction of the rectilinear movement of the body. The semicircular canals and otolithic apparatus are called vestibular apparatus. It is connected to the temporal region of the cortex and to the cerebellum through the vestibular branch of the auditory nerve (Fig. 19). (Strong overexcitation of the vestibular apparatus causes nausea, since this apparatus is also connected with internal organs.)
Vibration sensations arise as a result of reflection of vibrations from 15 to 1500 Hz in an elastic medium. These vibrations are reflected by all parts of the body. Vibrations are tiring and even painful for humans. Many of them are unacceptable (Fig. 20).
Rice. 21. . The olfactory bulb is the brain center of smell.
Olfactory sensations arise as a result of irritation by particles of odorous substances in the air of the mucous membrane of the nasal cavity, where the olfactory cells are located.
Substances that irritate the olfactory receptors penetrate into the nasopharyngeal cavity from the nose and nasopharynx (Fig. 21). This allows you to determine the smell of a substance both from a distance and if it is in the mouth.
Rice. 22. . Relative concentration of taste receptors on the surface of the tongue.
Taste sensations. The entire variety of taste sensations consists of a combination of four tastes: bitter, salty, sour and sweet. Taste sensations are caused by chemicals dissolved in saliva or water. Taste receptors are nerve endings located on the surface of the tongue - taste buds. They are located unevenly on the surface of the tongue. Certain areas of the surface of the tongue are most sensitive to individual taste influences: the tip of the tongue is more sensitive to sweet, the back to bitter, and the edges to sour (Fig. 22).
The surface of the tongue is sensitive to touch, that is, it participates in the formation of tactile sensations (the consistency of food affects the taste sensations).
Temperature sensations arise from irritation of skin thermoreceptors. There are separate receptors for the sensation of heat and cold. On the surface of the body they are located in some places more, in others - less. For example, the skin of the back and neck is most sensitive to cold, and the tips of the fingers and tongue are most sensitive to hot. Different areas of the skin themselves have different temperatures (Fig. 23).
Painful sensations are caused by mechanical, temperature and chemical influences that have reached above-threshold intensity. Pain sensations are largely associated with subcortical centers, which are regulated by the cerebral cortex. Therefore, they can be inhibited to some extent through a second signaling system.
Rice. 23. (according to A.L. Slonim)
Expectations and fears, fatigue and insomnia increase a person’s sensitivity to pain; with deep fatigue, the pain dulls. Cold intensifies and warmth reduces pain. Pain, temperature, tactile sensations and pressure sensations are skin sensations.
Organic sensations- sensations associated with interoceptors located in the internal organs. These include feelings of satiety, hunger, suffocation, nausea, etc.
This classification of sensations was introduced by the famous English physiologist C.S. Sherrington (1906);
There are three types of visual sensations: 1) photopic - daytime, 2) scotopic - nighttime and 3) mesopic - twilight. The greatest photopic visual acuity is located in the central visual field; it corresponds to the central, foveal region of the retina. In scotopic vision, maximum light sensitivity is provided by the paramolecular regions of the retina, which are characterized by the greatest concentration of rods. They provide the greatest light sensitivity.
Sources and literature
- Enikeev M.I. Psychological encyclopedic dictionary. M., 2010.
- Zinchenko T.P., Kondakov I.M. Psychology. Illustrated Dictionary. M. 2003.
Entry text:
1. Psychology of sensations.
1. Psychology of sensations.
The simplest mental process from which a person’s cognition of the surrounding world begins is sensation. In the evolution of living beings, sensations arose on the basis of primary irritability, which is the property of living matter to selectively respond to biologically significant changes in the environment. Subsequently, these functions were taken over by the nervous system. A stimulus (visual, auditory, etc.) affects the sense organs, resulting in nerve impulses that enter the brain along nerve pathways and are processed there to form individual sensations. Sensation is the primary “building” material on the basis of which a holistic reflection in consciousness of the complexity and versatility of the surrounding world, the image of one’s bodily and mental “I” is built. Sensations are essentially subjective images of the objective world - the external and internal states of the body.
Sensation is a mental process of reflecting individual properties of objects and phenomena during their direct impact on the senses.
Since the time of Aristotle, five types (modalities) of sensations have traditionally been distinguished that inform a person about changes in the environment: touch, taste, smell, hearing and vision.
It has now been established that there are also many other types of sensations, and the body is equipped with very complex mechanisms that ensure the interaction of the senses with each other. Thus, the sense of touch, along with tactile sensations (touch sensations), includes a completely independent type of sensation - temperature, which is a function of a special temperature analyzer. Vibration sensations occupy an intermediate position between tactile and auditory sensations. The sensations of balance and acceleration associated with the functions of the vestibular apparatus play a large role in a person’s orientation. Pain sensations that signal the destructive power of the stimulus are also common to different analyzers.
Depending on the type and location of the receptors, all sensations are usually divided into three groups:
1) exteroceptive (exteroceptive), reflecting the properties of objects and phenomena of the external environment and having receptors on the surface of the body;
2) interoceptive (interoceptive), having receptors located in the internal organs and tissues of the body and reflecting the state of the internal environment of the body;
3) proprioceptive (proprioceptive), whose receptors are located in muscles, ligaments, joints and provide information about the movement and position of the body. Motion sensitivity is also often called kinesthesia, and the corresponding receptors are kinesthetic.
Exteroceptive sensations can be divided into two more groups: contact(e.g. tactile, gustatory) and distant(e.g. visual, auditory). Contact receptors transmit irritation upon direct contact with an object, and distant receptors react to irritation emanating from a distant object.
For most created by the end of the 19th century. Psychological laboratories are characterized by reducing the main problems of experimental research to the study of elementary mental processes - sensations and perceptions. Until the beginning of the 20th century. The leading centers of world experimental psychology were the laboratories of V. Wundt in Germany (1879) and V.M. Bekhterev in Russia (1886 - in Kazan, 1894 - in St. Petersburg). The work of scientists in these laboratories on studying the mechanisms of perception prepared the subsequent experimental study of emotions, associations and memory, and then thinking.
2. General patterns of sensations
Sensations are a form of reflection of adequate stimuli. Thus, an adequate stimulator of visual sensation is electromagnetic waves in the range of 380-770 mmk. Auditory sensations arise under the influence of sound waves with a frequency of 16 to 20,000 Hz. Other sensations also have their own specific stimuli. However, different types of sensations are characterized not only by specificity, but also by properties common to all of them. These properties include quality, intensity, duration and spatial location.
Quality- this is the main feature of a given sensation, distinguishing it from other types of sensations and varying within a given type of sensation (one modality). Auditory sensations, for example, differ in pitch, timbre, and volume, while visual sensations differ in saturation and color tone.
Intensity sensation is its quantitative characteristic and is determined both by the strength of the stimulus and the functional state of the receptor.
Duration sensations are also determined by the intensity of the effect on the receptor, its functional state, but mainly by the time of action on the receptor.
When a stimulus is applied, the sensation does not occur immediately, but after some time. For painful sensations, the latent period is 370 ms, for tactile sensations - 130, and the taste sensation occurs within 50 ms after the application of a chemical irritant to the tongue.
Just as a sensation does not arise simultaneously with the onset of the stimulus, it does not disappear immediately after the cessation of its effect. This inertia of sensations is called aftereffect. For example, the trace of a stimulus in the visual analyzer remains in the form sequential image, first positive and then negative. A positive sequential image does not differ in lightness and color from the original image (in cinema, this property of the visual analyzer is used to create the illusion of movement), and then a negative image appears, and color sources of color are replaced by complementary colors.
If you look at the red color first, then the white surface will appear green. If the original color was blue, then the sequential image will be yellow, and if you initially look at a black surface, then the sequential image will be white.
Auditory sensations can also be accompanied by sequential images. For example, everyone is well aware of the phenomenon of “ringing in the ears” after exposure to deafening sounds.
A similar effect is typical for the muscular system. Stand in the doorway and strongly “push” the doorframes away from you with your hands; After this, moving to the side and relaxing the muscles of your arms, you will feel that your arms are rising up by themselves.
Academician D.N. Uznadze (1963) asked subjects to touch a large ball with their right hand and a small ball with their left, and then balls of the same size 10-15 times. It turned out that the ball felt with the right hand seemed smaller in contrast, and the ball felt with the left hand seemed larger.
3. Basic characteristics of sensations
1. Sensitivity range . A stimulus is capable of causing a sensation only when it reaches a certain magnitude or strength.
The lower absolute threshold of sensation(J0) is the minimum force (intensity, duration, energy or area) of impact that causes a barely noticeable sensation. The lower J0, the higher the sensitivity of the analyzer to the stimulus. For example, the lower limit (threshold) of sensitivity for pitch of sound is 15 Hz, for light - 0.001 light. etc.
Stimuli of lesser strength are called subliminal(subsensory), and signals about them are not transmitted to the cerebral cortex. If the light intensity is reduced so much that a person can no longer tell whether he saw a flash of light, then a galvanic skin response is nevertheless recorded by hand at that moment. This suggests that the light signal, although not realized, was processed by the nervous system. The operation of a “lie detector” is based on this procedure.
The transition from a subthreshold sensation occurs abruptly: if the impact has almost reached the threshold value, then a barely noticeable increase in its strength is enough for the stimulus to immediately become completely felt. Subthreshold impulses are not indifferent to the body. This is confirmed by numerous facts obtained in clinics of nervous diseases and psychiatry, when it is weak, subthreshold stimuli coming from the external or internal environment that create a dominant focus in the cerebral cortex and contribute to the emergence of “deceptions of the senses” - hallucinations.
Some scientists note the similarity between subliminal perception (sensation) and extrasensory perception, when we are also talking about signals that are too weak to reach the level of consciousness, but are still picked up by some people at a certain time and in a certain state. Extrasensory perception includes clairvoyance (the ability to see things that cannot be seen at a distance), telepathy (obtaining information about a person who is far away, transmitting thoughts), precognition (the ability to guess the future).
The border zone of psychology, studying the so-called psi phenomena, arose in the early 1930s (L.L. Vasiliev in the USSR and J. Rhine in the USA), although in scientific circles this work began to be openly discussed only in recent decades. The Parapsychological Association, which studied “anomalous” phenomena, was admitted to the American Association for Scientific Progress in 1969. This area, recently recognized as a scientific discipline, is called parapsychology in Germany and the USA, metapsychology in France, and bioinformatics in Russia. Its new general name is psychology. The main difficulty in fully recognizing the results in this area is that it is not always possible to reproduce the phenomena being studied, which is certainly necessary for facts that claim to be scientific.
Upper absolute threshold of sensation(Jmax) is the maximum value of the stimulus that the analyzer is capable of adequately perceiving. Impacts exceeding Jmax cease to be differentially felt or cause pain; Jmax is much more variable between individuals and ages than J0. The interval between J0 and Jmax is called sensitivity range.
2. Differential (difference) sensitivity threshold . With the help of our senses, we can not only ascertain the presence or absence of a particular stimulus, but also distinguish between stimuli by their strength and quality. The minimum magnitude of the difference in the strength of two homogeneous stimuli that a person is able to feel is called threshold of discrimination(aJ). The lower the difference threshold value, the higher the ability of this analyzer to differentiate irritation.
The German physiologist E. Weber established that an increase in the intensity of a stimulus, capable of causing a barely noticeable increase in the intensity of sensation, always constitutes a certain part of the initial value of the stimulus. Thus, an increase in pressure on the skin is already felt if the load is increased by only 3% (3 g should be added to a weight weighing 100 g, and 6 g should be added to a weight weighing 200 g, etc.). This dependence is expressed by the following formula: dJ/J = const, where J is the strength of the stimulus, dJ is its barely noticeable increase (discrimination threshold), const is a constant value (constant), different for different sensations (pressure on the skin - 0.03, vision - 0.01, hearing - 0.1, etc.).
3. Operational signal discernibility threshold - this is the value of discrimination between signals at which the accuracy and speed of discrimination reach their maximum. The operational threshold is 10-15 times higher than the differential threshold.
4. Psychophysical Weber-Fechner law - describes the dependence of the intensity of sensation (E) on the strength of the stimulus (J).
German physicist, psychologist and philosopher G.T. Fechner (1801-1887) expressed this dependence, which was first discovered by E. Weber, with the following formula (basic psychophysical law): E = k . logJ + c (the intensity of the sensation increases in proportion to the logarithm of the stimulus strength), where k is the proportionality coefficient; c is a constant that is different for sensations of different modalities.
The American scientist S. Stevens believes that the basic psychophysical law is better expressed not by a logarithmic, but by a power function. However, in any case, the strength of sensation increases significantly more slowly than the magnitude of physical stimuli. These patterns are associated with the characteristics of the electrochemical processes occurring in the receptors when converting the effect into a nerve impulse.
5. Time threshold - the minimum duration of exposure to the stimulus required for the occurrence of sensations. For vision it is 0.1-0.2 s, and for hearing - 50 ms.
6. Spatial threshold - determined by the minimum size of a barely perceptible stimulus. For example, visual acuity is expressed by the ability of the eye to distinguish small details of objects. Their sizes are expressed in angular values, which are related to linear sizes by the formula tgC/2=h/2L, where C is the angular size of the object, h is the linear size, L is the distance from the eye to the object. With normal vision, the spatial threshold of visual acuity is 1", but the minimum acceptable dimensions of image elements for confident identification of objects should be 15" for simple objects, and at least 30-40 for complex ones.
7. Latent period of reaction - the period of time from the moment the signal is given to the moment the sensation occurs. It is different for sensations of different modalities. For example, for vision it is 160-240 ms. It should also be remembered that after the end of the stimulus, the sensations do not disappear immediately, but gradually (the inertia of vision is 0.1-0.2 s), therefore the duration of the signal and the interval between appearing signals must be no less than the time the sensations persist.
When designing modern technology, engineers need to know and take into account the psychological capabilities of a person to receive information. The main characteristics of analyzers can be found in the relevant manuals and reference books on engineering psychology.
4. Changes in sensitivityand processes of interaction between analyzers
There are two main forms of change in the sensitivity of the analyzer - adaptation and sensitization.
Adaptation called a change in the sensitivity of the analyzer under the influence of its adaptation to the current stimulus. It can be aimed at either increasing or decreasing sensitivity. For example, after 30-40 minutes of being in the dark, the sensitivity of the eye increases by 20 thousand times, and subsequently by 200 thousand times. The eye adapts (adapts) to the dark within 4-5 minutes - partially, 40 minutes - enough and 80 minutes - completely. Such an adaptation, which leads to an increase in the sensitivity of the analyzer, is called positive.
Negative adaptation accompanied by a decrease in the sensitivity of the analyzer. So, in the case of constant stimuli, they begin to be felt weaker and disappear. For example, it is a common fact for us that the olfactory sensations noticeably disappear soon after we enter an atmosphere with an unpleasant odor. The intensity of the taste sensation also weakens if the corresponding substance is kept in the mouth for a long time. Close to what is described is the phenomenon of dulling of sensation under the influence of a strong stimulus. For example, if you come out of the darkness into bright light, then after “blinding” the sensitivity of the eye sharply decreases, and we begin to see normally.
The phenomenon of adaptation is explained by the action of both peripheral and central mechanisms. When mechanisms regulating sensitivity act on the receptors themselves, they speak of sensory adaptation. In the case of more complex stimulation, which, although captured by receptors, is not so important for activity, central regulation mechanisms come into play at the level of the reticular formation, which blocks the transmission of impulses so that they do not “clutter” consciousness with excess information. These mechanisms underlie habituation-type adaptation to stimuli ( habituations).
Sensitization - increased sensitivity to the effects of a number of stimuli. Physiologically it is explained by an increase in the excitability of the cerebral cortex to certain stimuli as a result of exercise or interaction of analyzers. According to I.P. Pavlov, a weak stimulus causes an excitation process in the cerebral cortex, which easily spreads (irradiates) throughout the cortex. As a result of the irradiation of the excitation process, the sensitivity of other analyzers increases. On the contrary, under the influence of a strong stimulus, an excitation process occurs, which tends to concentrate, and, according to the law of mutual induction, this leads to inhibition in the central sections of other analyzers and a decrease in their sensitivity. Thus, when a quiet tone of equal intensity is sounded and at the same time the rhythmic impact of light on the eye, it will seem that the tone also changes its intensity. Another example of the interaction of analyzers is the well-known fact of increased visual sensitivity with a weak taste sensation of sour in the mouth. Knowing the patterns of changes in the sensitivity of the sensory organs, it is possible to sensitize a particular analyzer by using specially selected side stimuli. Sensitization can also be achieved as a result of exercise. These data have important practical applications, for example, in cases where it is necessary to compensate for sensory defects (blindness, deafness) at the expense of other, intact analyzers or in the development of pitch hearing in children involved in music.
Thus, the intensity of sensations depends not only on the strength of the stimulus and the level of adaptation of the receptor, but also on the stimuli currently acting on other sense organs. A change in the sensitivity of the analyzer under the influence of irritation of other sense organs is called interaction of sensations. The interaction of sensations, like adaptation, appears in two opposite processes: an increase and a decrease in sensitivity. Weak stimuli, as a rule, increase, and strong ones decrease, the sensitivity of analyzers
The interaction of analyzers is also manifested in the so-called synesthesia . With synesthesia, the sensation occurs under the influence of irritation characteristic of another analyzer. Visual-auditory synesthesia most often occurs when visual images (“color hearing”) appear under the influence of auditory stimuli. Many composers possessed this ability - N.A. Rimsky-Korsakov, A.N. Scriabin et al. Auditory-gustatory and visual-gustatory synesthesia, although they are much less common, we are not surprised by the use in speech of expressions like: “sharp taste”, “sweet sounds”, “screaming color”, etc.
5. Disorders of sensations
Sensory disturbances are very numerous. However, in most cases, all observed sensation disorders can be classified into one of three main groups: hyperesthesia, hypoesthesia and paresthesia.
Hyperesthesia - increased sensitivity to real ordinary or even weak influences. In these cases, both external and intero- and proprioceptive stimuli cause an extremely intense reaction due to a sharp decrease in the lower absolute thresholds of sensations. For example, the sound of a typewriter deafens the patient (acoustic hyperesthesia), a burning candle blinds (optical hyperesthesia), and a shirt adjacent to the body irritates so much that it seems to be made “of barbed wire” (hyperesthesia of the skin sense), etc. Such mental hyperesthesia is observed in neuroses, intoxication with certain substances, in the initial stages of clouding of consciousness, and in acute psychoses.
Hypesthesia - decreased sensitivity to real stimuli, increased lower absolute thresholds of sensations. In this case, the patient almost does not react to an injection, to a fly crawling on his face, etc. Reduced sensitivity to temperature stimuli can lead to accidents - burns and frostbite. In extreme cases of hypoesthesia, the analyzer is completely unable to respond to stimulation, and this phenomenon is called anesthesia. Anesthesia usually occurs with a complete anatomical interruption of one of the peripheral nerve trunks or destruction of the central part of the analyzer. Loss of sensation usually extends to tactile, pain and temperature sensitivity (total anesthesia) or only to certain types of it (partial anesthesia). Neurologists distinguish radicular anesthesia, in which sensitivity in the zone of innervation of a certain dorsal root of the spinal cord is completely impaired, and segmental, in which disorders occur in the innervation zone of a certain segment of the spinal cord. In the latter case, anesthesia can be as follows: total, so dissociated, in which the absence of pain and temperature sensitivity is combined with the preservation of proprioceptive sensitivity or vice versa. In some diseases, such as leprosy (leprosy), specific damage to skin receptors occurs with a subsequent weakening and loss of temperature, then pain, and then tactile sensitivity (proprioceptive sensitivity is preserved for the longest time during leprosy anesthesia).
At mental hypoesthesia and anesthesia the corresponding analyzer is anatomically and physiologically formally preserved. Thus, hypoesthesia and anesthesia can be instilled in a person in a hypnotic sleep. Mental amblyopia (blindness), mental anosmia (insensitivity to smells), mental ageusia (loss of the sense of taste), mental acusia (deafness), mental tactile and pain anesthesia are often found in hysterical neurotic disorders. Within the framework of hysterical anesthesia, disorders of pain sensitivity of the “stockings” and “gloves” type are described, i.e., from the point of view of neurologists, patients develop areas of insensitivity to pain with clear boundaries that do not correspond to the zones of innervation of certain roots or nerves.
Paresthesia . If hypoesthesia and hyperesthesia can be qualified as quantitative disorders of sensitivity, then paresthesia is associated with qualitative changes (distortion) of information coming from the receptor to the cortical part of the analyzer. Probably everyone knows about the sensations that arise from prolonged compression of a nerve by an uncomfortable position - “I rested my arm,” “I spent my time on my leg.” When conduction along the nerve is disrupted, sensations of “crawling goosebumps”, skin tightening, tingling, burning appear (these are peculiar fluctuations in the modality of sensation). Paresthesia is often a sign of neurological or vascular damage.
They are close to paresthesia and senesthopathy, but occupy an intermediate position with visceral hallucinations, since they are even less associated with any real irritation of the peripheral part of the analyzer.
Senestopathies, “psychosomatic sensations”, or “sensations” - vague, often migrating, very unpleasant and painful sensations that are projected inside the body (inside the bodily “I”): squeezing and stretching, rolling and trembling, “suction”, “sticking” etc. They never have a clear localization, and patients are not even able to describe them correctly. Senestopathies occur in many mental illnesses. They can be constant or episodic. Sometimes they occur in the form of attacks, acute attacks, which allows us to talk about senestopathic crises. They are often accompanied by panic reactions, autonomic disorders, fear of madness, expressive postures and gestures. There are different approaches to assessing the clinical significance of senestopathy and their classification. So, A.K. Anufriev (1978) distinguishes five types of senestopathy for latent depression: cardiovascular, central neurological, abdominal, musculoskeletal, and skin-subcutaneous.
List of used literature
1. Ananyev B.G. Theory of sensations. – L.: Lenizdat, 1961.
2. Luria A.R. Sensation and perception. – M.: Education, 1978.
3. Sidorov P.I., Parnyakov A.V. Clinical psychology. – 3rd ed., revised. and additional – M.: GEOTAR-Media, 2008.
Sensations are the source of our knowledge about the world and ourselves. All living beings with a nervous system have the ability to sense sensations. Conscious sensations are present only in living beings that have a brain and cerebral cortex. On the one hand, sensations are objective, since they always reflect an external stimulus, and on the other hand, sensations are subjective, since they depend on the state of the nervous system and the individual characteristics of a person.
Objects and phenomena of reality that affect our senses are called irritants. Stimuli cause excitation in nervous tissue. The sensation arises as a reaction of the nervous system to a particular stimulus and, like any mental phenomenon, has a reflex nature.
Sensations can be classified on different grounds. According to the leading modality (qualitative characteristics of sensations), the following sensations are distinguished: visual, auditory, olfactory, gustatory, tactile, motor, internal (sensations of the internal state of the body).
Visual sensations are a reflection of both achromatic (white, black and intermediate shades of gray) and chromatic (various shades of red, yellow, green, blue) colors. Visual sensations are caused by exposure to light, i.e. electromagnetic waves emitted (or reflected) by physical bodies to the visual analyzer. The external perceptive “device” is the retina of the eye.
Auditory sensations are a reflection of sounds of different heights (high - low), strength (loud - quiet) and different qualities (musical sounds, noises). They are caused by the influence of sound waves created by vibrations of bodies.
Olfactory sensations are a reflection of smells. Olfactory sensations arise due to the penetration of particles of odorous substances spreading in the air into the upper part of the nasopharynx, where they affect the peripheral endings of the olfactory analyzer, embedded in the nasal mucosa.
Taste sensations are a reflection of certain chemical properties of flavoring substances dissolved in water or saliva. The sense of taste plays an important role in the eating process, in distinguishing between different types of food.
Tactile sensations are a reflection of the mechanical properties of objects that are detected when touching them, rubbing them, or hitting them. These sensations also reflect the temperature of environmental objects and external pain.
Said sensations are called exteroceptive and form a single group based on the type of analyzers located on or near the surface of the body. Exteroceptive sensations are divided into contact and distant. Contact sensations are caused by direct touching the surface of the body (taste, touch), distant- irritants acting on the senses at some distance (vision, hearing). Olfactory sensations occupy an intermediate position between them.
The next group consists of sensations that reflect the movements and states of the body itself. They are called motor or proprioceptive. Motor sensations reflect the position of the limbs, their movements and the degree of effort applied. Without them, it is impossible to perform movements normally and coordinate them. Feel provisions(equilibrium) along with motor sensations play an important role in the process of perception (for example, stability).
In addition, there is a group of organic sensations - internal (interoceptive). These sensations reflect the internal state of the body. These include feelings of hunger, thirst, nausea, internal pain, etc.
Different types of sensations are common to them properties . These properties include:
quality- an essential feature of sensations that allows one to distinguish one type of sensation from another (for example, auditory from visual), as well as various variations of sensations within a given type (for example, by color, saturation);
intensity - a quantitative characteristic of sensations, which is determined by the strength of the current stimulus and the functional state of the receptor;
duration - temporal characteristics of sensations. It is determined by the functional state of the sense organs, the time of exposure to the stimulus and its intensity.
The quality of sensations of all types depends on the sensitivity of the appropriate type of analyzers.
The intensity of sensations depends not only on the strength of the stimulus and the level of adaptation of the receptors, but also on the irritations currently affecting other sense organs. A change in the sensitivity of analyzers under the influence of irritation of other sense organs is called interaction of sensations. The interaction of sensations is manifested in an increase and decrease in sensitivity: weak stimuli increase the sensitivity of the analyzers, and strong ones decrease it.
The interaction of sensations is manifested in the phenomena of sensitization and synesthesia. Sensitization(Latin sensibilis - sensitive) - increased sensitivity of nerve centers under the influence of a stimulus. Sensitization can develop not only through the use of side stimuli, but also through exercise. Thus, musicians develop high auditory sensitivity, tasters develop olfactory and gustatory sensations. Synesthesia- this is the occurrence, under the influence of irritation of a certain analyzer, of a sensation characteristic of another analyzer. Thus, when exposed to sound stimuli, a person may experience visual images.
3. Perception: concept, types. Basic properties of perception.
Perception- This is a reflection of integral objects and phenomena with their direct impact on the senses. In the course of perception, individual sensations are ordered and combined into holistic images of things. Unlike sensations, which reflect individual properties of the stimulus, perception reflects the object as a whole, in the totality of its properties.
Representatives of Gestalt psychology interpret perception as a kind of holistic configuration - Gestalt. Integrity, according to Gestalt psychology, is always the selection of a figure from the background. Details, parts, properties can only be separated from the whole image later. Gestalt psychologists have established many laws of perceptual organization, completely different from the laws of associations, according to which elements are connected into a coherent structure (laws of proximity, isolation, good form, etc.). They convincingly proved that the holistic structure of the image influences the perception of individual elements and individual sensations. The same element, being included in different images of perception, is perceived differently. For example, two identical circles appear different if one is surrounded by large circles and the other by small ones, etc.
The main ones are identified features (properties) perception:
1) integrity and structure - perception reflects a holistic image of an object, which, in turn, is formed on the basis of generalized knowledge about the individual properties and qualities of the object. Perception is capable of capturing not only individual parts of sensations (individual notes), but also a generalized structure woven from these sensations (the entire melody);
2) constancy- preservation of certain properties of the image of an object that seem constant to us. (When the conditions of perception change.) Thus, an object known to us (for example, a hand), distant from us, will seem to us exactly the same size as the same object that we see close. The property of constancy is involved here: the properties of the image approach the true properties of this object. Our perceptual system corrects the inevitable errors caused by the infinite diversity of the environment and creates adequate images of perception. When a person puts on glasses that distort objects and enters an unfamiliar room, he gradually learns to correct the distortions caused by the glasses, and finally ceases to notice these distortions, although they are reflected on the retina. So, the constancy of perception that is formed during life in the process of objective activity is a necessary condition for a person’s orientation in a changing world;
3) objectivity of perception - this is an act of objectification, i.e., attributing information received from the external world to this world. There is a certain system of actions that provides the subject with the discovery of the objectivity of the world, and the main role is played by touch and movement. Objectivity also plays a big role in regulating behavior. Thanks to this quality, we can distinguish, for example, a brick from a block of explosives, although they will be similar in appearance;
4) meaningfulness. Although perception arises as a result of the direct impact of a stimulus on receptors, perceptual images always have a certain semantic meaning. Perception is thus related to with thinking and speech. We perceive the world through the prism of meaning. To consciously perceive an object means mentally naming it and attributing the perceived object to a certain group, class of objects, and generalizing it in words. For example, when we look at a watch, we do not see something round, shiny, etc., we see a specific object - a watch.
5) activity. During the process of perception, the motor components of the analyzers are involved (hand movements during touch, eye movements during visual perception, etc.). In addition, it is necessary to be able to actively move your body during the process of perception;
6) property of apperception. The perceptual system actively “builds” the image of perception, selectively using not all, but the most informative properties, parts, elements of the stimulus. In this case, information from memory and past experience is also used, which is added to sensory data (apperception). During the process of formation, the image itself and the actions to build it are constantly adjusted through feedback, and the image is compared with the reference one. Influence installations perception is reflected in Gogol’s comedy “The Inspector General”.
Thus, perception depends not only on irritation, but also on the perceiving object itself - a specific person. Perception is always affected by the personality characteristics of the perceiver, his attitude towards what is perceived, needs, aspirations, emotions at the time of perception, etc. Perception is thus closely related to the content of a person’s mental life.
Classification of perception.
At the core one of the classifications of perception, as well as sensations, lie differences in analyzers involved in perception. In accordance with which analyzer plays the predominant role in perception, visual, auditory, tactile, kinesthetic, olfactory and gustatory perceptions are distinguished.
Typically, the perception process is carried out by a number of analyzers interacting with each other. Motor sensations are involved to one degree or another in all types of perceptions. An example is tactile perception, which involves tactile and kinesthetic analyzers. Similarly, the motor analyzer is also involved in auditory and visual perception.
Different types of perception are rarely found in their pure form; they are usually combined, and as a result complex types of perceptions arise. Thus, a student’s perception of text in a lesson includes visual, auditory and kinesthetic perception.
basis second classification are forms of existence of matter. Distinguishes the perception of space, time and movement.
Perception of space This is the perception of shape, size, relative position of objects, their relief, distance and direction. In the perception of the spatial properties of things, tactile and kinesthetic sensations play a certain role, but the basis is visual data.
Two mechanisms play a significant role in the perception of magnitude: accommodation and convergence. The perception of depth and distance is achieved through binocularity. Perception of the direction in which objects are located is possible not only with the help of the visual, but also with the help of the auditory, motor and olfactory analyzer.
Perception of time- reflection of the objective duration, speed and sequence of phenomena of reality. This type of perception is based on a rhythmic change of excitation and inhibition in the central nervous system. Kinesthetic and auditory sensations are involved in the perception of time.
The perception of time is determined by the content that fills it. So, busy with interesting activities, we do not notice the passage of time. While idle, we, on the contrary, do not know how to kill time. However, when we remember, we will evaluate the first interval as longer than the second. This phenomenon reveals the law of the filled time period. The perception of time is also influenced by a person's emotions. The waiting time for a desired event is tedious, but for an unwanted, painful event, it is reduced.
Motion perception- this is a reflection of the change in position that objects occupy in space. There are two ways to perceive movement:
1. When the image of an object on the retina remains more or less motionless.
2. The eye remains relatively motionless, and the image of the object is mixed on the retina.
There are real and apparent movements.
An example of apparent movement is stroboscopic movement, on the principle of which cinema is based. It is known that the visual sensation does not disappear immediately, so we do not see flickering, but see a stable image.
Illusions of perception
The Ebbinghaus illusion (1902).
Which circle is bigger? The one surrounded by small circles
or the one that is surrounded by large ones?
They are identical.
Muller-Lyer illusion (Franz Muller-Lyer, 1889)
(transferring the properties of a whole figure to its individual parts) 
Which of the horizontal segments is longer?
...................................
Wife or mother-in-law (two picture options). 
Who do you see here?
A young girl or a sad old woman?
They are closely related to each other. Both one and the other are the so-called sensory reflection of objective reality, existing independently of consciousness and due to its influence on the senses: this is their unity. But perception- awareness of a sensory given object or phenomenon; in perception, a world of people, things, and phenomena are usually spread out before us, filled with a certain meaning for us and involved in diverse relationships. These relationships create meaningful situations, of which we are witnesses and participants. Feeling same - a reflection of a separate sensory quality or undifferentiated and non-objectified impressions of 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: the 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 our own body is sensations. They constitute the main channels through which information about the phenomena of the external world and the states of the body reaches the brain, giving a person the opportunity to navigate the environment and his body. If these channels were closed and the senses did not bring the necessary information, no conscious life would be possible. There are known facts that indicate that a person deprived of a constant source of information falls into a sleepy state. Such cases: occur 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, isolating him from external influences. This state first induces sleep and then becomes difficult for the subjects to bear.
Numerous observations have shown that disruption of the flow of information in early childhood, associated with deafness and blindness, causes sharp delays in mental development. If children born blind-deaf or deprived of hearing and vision at an early age are not taught special techniques that compensate for these defects through the sense of touch, their mental development will become impossible and they will not develop independently.
As will be described below, the high specialization of the various sense organs is based not only on the structural features of the peripheral part of the analyzer - the “receptors”, but also on the highest specialization of the neurons that make up the central nervous apparatus, which receive signals perceived by the peripheral sense organs.
Reflex nature of sensations
So, sensations are the initial source of all our knowledge about the world. Objects and phenomena of reality that affect our senses are called stimuli, and the impact of stimuli on the senses is called irritation. Irritation, in turn, causes excitation in the nervous tissue. The sensation arises as a reaction of the nervous system to a particular stimulus and, like any mental phenomenon, has a reflex nature.
The physiological mechanism of sensations is the activity of special nervous apparatus called.
Each analyzer consists of three parts:- a peripheral section called the receptor (the receptor is the perceiving part of the analyzer, its main function is the transformation of external energy into a nervous process);
- afferent or sensory nerves (centripetal), conducting excitation to the nerve centers (central section of the analyzer);
- the cortical sections of the analyzer, in which the processing of nerve impulses coming from the peripheral sections occurs.
The cortical part of each analyzer includes an area that represents a projection of the periphery in the cerebral cortex, since certain cells of the periphery (receptors) correspond to certain areas of the cortical cells. For sensation to arise, the entire analyzer as a whole must work. The analyzer is not a passive receiver of energy. This is an organ that reflexively rearranges itself under the influence of stimuli.
Physiological studies show that sensation is not at all a passive process; it always includes motor components. Thus, observations using a microscope of an area of skin carried out by the American psychologist D. Neff made it possible to verify that when it is irritated by a needle, the moment the sensation occurs is accompanied by reflexive motor reactions of this area of the skin. Subsequently, numerous studies have established that each sensation includes movement, sometimes in the form of a vegetative reaction (vasoconstriction, galvanic skin reflex), sometimes in the form of muscle reactions (turning the eyes, tension in the neck muscles, motor reactions of the hand, etc. .). Thus, sensations are not passive processes at all - they are active. The reflex theory of sensations consists of indicating the active nature of all these processes.
Classification of sensations
It has long been customary to distinguish between 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 basic principles - systematic And genetic(in other words, according to the principle of modality, on the one hand, and according to the principle of complexity or level of their construction, on the other).
Systematic classification of sensations
By identifying the largest and most significant groups of sensations, they can be divided into three main types; interoceptive, proprioceptive and exteroceptive sensations. The first combine signals reaching 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, still others provide signals from the external world and create the basis for our conscious behavior. Let's consider the main types of sensations separately.
Interoceptive sensationsInteroceptive sensations, signaling the state of the internal processes of the body, bring to the brain irritations from the walls of the stomach and intestines, the heart and circulatory system and other internal organs. This is the most ancient and most elementary group of sensations. Interoceptive sensations are among the least conscious and most diffuse forms of sensations and always retain their proximity to emotional states.
Proprioceptive sensationsProprioceptive sensations provide signals about the position of the body in space and constitute the afferent basis of human movements, playing a decisive role in their regulation. Peripheral receptors of proprioceptive sensitivity are located in muscles and joints (tendons, ligaments) and have the form of special nerve bodies (Paccini bodies). The excitations that arise in these bodies reflect the sensations that occur when muscles are stretched and the position of 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. Bernstein. The described group of sensations includes a specific type of sensitivity called the feeling of balance, or static sensation. Their peripheral receptors are located in the semicircular canals of the inner ear.
Exteroreactive 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 connect a person with the external environment. The entire 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. Examples of contact sensation are taste and touch.
Distant sensations are caused by stimuli acting on the sense organs at some distance. These senses include smell and especially hearing and vision.
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.);
- epicritic(more subtly differentiating, objectified and rational), which includes the basic human senses.
Epicritic sensitivity is younger in genetic terms, and it 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 a given sensation, distinguishing it from other types of sensations and varying within a given type of sensation. The qualitative diversity of sensations reflects the infinite variety of forms of matter movement.
Intensity sensation is its quantitative characteristic and is determined by the strength of the current stimulus and the functional state of the receptor.
Duration sensations are its temporary characteristics. It is also determined by the functional state of the sensory organ, but mainly by the time of action of the stimulus and its intensity.
When a stimulus acts on a sense organ, the sensation does not arise immediately, but after some time - the so-called latent (hidden) period of sensation. The latent period of different 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 onset of the stimulus, it does not disappear simultaneously with the cessation of its action. The presence of positive sequential images explains why we do not notice breaks between successive frames of a film: they are filled with traces of the frames that acted before - sequential images from them. The consistent image changes over time, the positive image is replaced by a negative one. With colored light sources, the sequential image turns into a complementary color.
Cognition of the environment and one’s own states begins in a person with such a mental process as sensation. It is sensations that allow a person to navigate the environment, distinguish sounds, colors, smells, taste of products, and also estimate the weight and size of objects. However, sensation is not capable of giving a person a complete picture of the reflected objects. With the help of sensations, a living being is able to obtain knowledge about the individual properties of certain objects.
V.M. Kozubovsky gives the following definition: “Sensation is a mental cognitive process of reflecting individual properties of the real external world and the internal state of a person, which directly affect the senses at a given (current) moment. When sensing, primary information processing occurs precisely at the sensory level, that is, at the level of individual properties of objects and phenomena.”
It is worth noting that sensations are characteristic of all living beings that have a nervous system. Sensations are a sensory reflection of objective reality, as they arise due to the influence of various stimuli on the sense organs. It is precisely in the fact that a really existing external stimulus is reflected through the means of sensations that the objectivity of sensations is expressed. However, sensations are also characterized by subjectivity, which is due to the dependence of sensations on individual characteristics and the current mental state of a person.
The physiological basis of sensations are analyzers, that is, channels through which a person receives information about the external environment and his own internal state. Together, the analyzers form the human sensory system.
Sensations originate from the physical process of irritation, which occurs when various factors influence a person’s sense organs: vision, smell, etc. The appearance of sensations directly depends on the functioning of the brain, however, in order for the brain to perceive certain stimuli, they must be transmitted to it in in the form of electrical signals. Translation of signals of various modalities into electrical form is carried out using receptors.
Each receptor works with certain signals: the visual one reacts to light stimuli, the auditory one to sound stimuli, etc. In this case, not only information about the presence of the stimulus is transmitted to the brain, but also about its characteristics. Coding of signal characteristics is realized through the conversion of physical stimuli into electrical signals with certain parameters. So, for example: the sensation of touching the hand corresponds to a sequential series of rectangular electrical impulses, with a light touch corresponding to a small number of impulses in a series, and strong pressure - a large number.
After encoding, the electrical signal enters the receptive zones of the cerebral cortex via afferent nerves, with each receptor having a specific receptive zone. The movement of signals is ensured by the physiological process of excitation - the property of nerve cells (neurons) to respond to irritation. When excited, the cell moves from a state of physiological rest to activity.
In the cerebral cortex, an electrical signal causes the simplest emotional experiences of sensations that arrive at the periphery of the body through excitation through efferent nerves. Thus, a response of the body occurs, which can take the form of movement or an internal process.
For example, birdsong and the sound of the sea surf balance the nervous system and promote relaxation. The body also reacts to the sensations of smells. The Japanese company Shieido successfully uses odors to increase the stress resistance of their employees. On the website “World of Psychology and Self-Development” you can study in more detail such areas in psychology as color therapy, music therapy and aromatherapy.
In psychology, the following properties of sensations are distinguished:
- Intensity of sensation characterizes a person’s subjective sensory experience and expresses the degree of sensation experienced, which depends on the strength of the stimulus and the functional state of the receptor.
- Duration of sensation - this is the period of time during which the sensation of the impact of the stimulus persists after its cessation.
- Latent (hidden) period of sensation - the period of time from the moment the stimulus begins to act until the moment the sensation begins.
- Aftereffect of sensation - the period of time from the end of the stimulus until the sensation disappears. So, due to the aftereffect of sensations, we do not notice breaks between frames when watching a film.
- Spatial localization of the stimulus - the property of sensation to provide a person with the ability to determine the spatial position of the stimulus acting on the receptors (the direction of the sound, the location of the pain point on the body, etc.)
Sensations are classified according to their characteristics, that is, depending onwhat properties need to be emphasized:
- by type of modality (visual, auditory, olfactory, skin and taste sensations);
— according to the level of awareness, they are divided into conscious and unconscious (for example, sensations of balance);
- Based on the location of the receptors, interoceptive, exteroceptive and proprioceptive are distinguished.
Interoceptive sensations– these are sensations that signal the state of the internal processes of the body and are associated with internal receptors located on the walls of the internal organs (feelings of hunger, thirst, pain, etc.)
Information from the external environment of a person is provided exteroceptive sensations, which arise both through direct contact with a source of irritation (contact), and through a source located at some distance (distant). It is worth noting that olfactory sensations are sometimes neutral, since the source of the odor is located at a distance, and the molecules carrying the odor have direct contact with human receptors.
There are other classifications of sensations. It is interesting that in psychology the prevailing hypothesis is the existence of a magnetic sensation, which helps some species of animals (dolphins, pigeons, bees, etc.) navigate in the Earth’s magnetic field.
In the following articles you will learn more about different types of sensations.
