Characteristics of visual sensation corresponding to the intensity of the stimulus. Basic properties and characteristics of sensations. Theories of color vision
Whatever the sensation, it can be described using several characteristics, properties inherent in it. The first one is modality.
Modality is a qualitative characteristic in which the specificity of sensation as the simplest mental signal is manifested in comparison with a nervous signal (L.M. Wekker). First of all, such types of sensations as visual, auditory, olfactory, etc. are distinguished. However, each type of sensation has its own modal characteristics. For visual sensations, these may be color tone, lightness, saturation; for auditory - pitch, timbre, volume; for tactile - hardness, roughness, etc. The characteristics of the sensation may or may not coincide with the physical description of the qualities of the stimulus that correspond to these modal characteristics. An example of a match is hardness and elasticity, and a mismatch is a color tone corresponding to the frequency of electromagnetic oscillations.
Another (spatial) characteristic of sensations is their localization. Sometimes (as, for example, in the case of pain and interoceptive, “internal” sensations) localization is difficult and uncertain. Another problem is to explain the “objectivity” of sensations, their “existence” outside of us, although the physiological processes that cause them occur in the analyzer. This issue is discussed in detail by A.N. Leontyev. It is the objectivity, i.e. relation to reality creates sensation as a mental phenomenon. The ability to “project” sensations externally is probably acquired very early, and practical actions and motor skills play a decisive role in this. First, objective reality acts as an object of adaptation of the organism, carried out in real contacts with it. The “probe problem” is interesting in this regard: when we write or cut something, the sensations are localized at the tip of the pen or knife, i.e. not at all where the probe comes into contact with the skin and affects it.
Intensity- This is a classic quantitative characteristic. The problem of measuring the intensity of sensation is one of the main ones in psychophysics. G. Fechner believed that the subject cannot directly quantify his sensations. However, S. Stevens did not agree with this. He developed the so-called direct methods for assessing the intensity of sensation, for example, when the subject must evaluate in some units (points, percentages, etc.) the magnitude of the stimulus in comparison with the sample.
The basic psychophysical law reflects the relationship between the magnitude of the sensation and the magnitude of the acting stimulus. Such variants of the basic psychophysical law are known as the logarithmic law of G. Fechner, the power law of S. Stevens, as well as the one proposed by Yu.M. Zabrodin generalized psychophysical law. Fechner's and Stevens' laws turn out to be special cases of the latter.
The next (temporary) characteristic of sensation is its duration. The sensation occurs later than the stimulus begins to act, and does not disappear immediately with its cessation. The period from the onset of the stimulus to the onset of sensation is called the latent (hidden) period of sensation. It is not the same for different types of sensations (for tactile - 130 ms, for pain - 370 ms, for taste - 50 ms) and can change dramatically in diseases of the nervous system.
After the cessation of the stimulus, its trace remains for some time in the form of a consistent image, which can be either positive (corresponding to the characteristics of the stimulus) or negative (having opposite characteristics, for example, painted in an additional color). We usually do not notice positive consistent images because of their short duration. Visual sequential images are best studied, although they also occur in sensations of other modalities. Sequential images are mainly determined by processes on the periphery of the analyzer, but also depend on neurodynamics in its central section. For example, its duration in the visual sphere increases sharply in patients suffering from hallucinations.
The ability of analyzers to reflect individual properties of stimuli or subtle differences between them characterizes thresholds of sensations. Lower absolute threshold- this is the minimum amount of stimulus that causes a sensation. Upper absolute threshold They call the maximum magnitude of the stimulus at which the sensation disappears or changes qualitatively (for example, turns into pain). The minimal change in the intensity of a stimulus or its other property that causes a change in sensation is difference(or differential) threshold. The value inversely proportional to the threshold of sensation is called sensitivity. The presence of thresholds protects us from information overload and some biologically harmful effects.
The quotient of dividing the difference threshold by the initial value of the stimulus, from which it increases or decreases, is sometimes called relative threshold. This value (in contrast to the difference threshold) is constant over a wide range of stimulus changes for sensations of a certain modality. For example, for the sensation of pressure it is approximately , for the intensity of sound - 
, and for luminous intensity - 
. The latter means that to 100 identical light bulbs you need to add one more of the same to make the change in lighting noticeable.
It is necessary to distinguish the physiological threshold from the threshold of conscious sensation. It is overcome when the impact energy is sufficient for brain stimulation. Threshold of conscious sensation always higher than physiological: 1 photon is enough to excite the receptor in the retina, but the luminous point can be visible only under the influence of 5-8 photons. Between these thresholds lies a subthreshold zone, or an area of subsensory stimuli that are not felt, but cause a number of objectively recorded reactions (for example, such as the galvanic skin or cochlear-pupillary reflex). Physiological threshold- this value is quite stable, since it is mainly determined genetically.
Psychophysics is the study and measurement of sensation thresholds, the founder of which is considered to be G. Fechner (1860). A heated debate has developed around the concept of a lower absolute threshold. The threshold concept considered the sensory range to be discrete. The lower absolute threshold is considered as zero on the scale of sensations, and, starting from this limit, the stimulus always causes a sensation. This view was contradicted by the facts of the inconstancy of the experimentally obtained threshold value. The concept of continuity of the sensory series arose, according to which the theoretical concept of the threshold as a specific point on a continuum should be abandoned. Change operational threshold, obtained during the measurement process was explained by the constantly changing ratio between favorable and unfavorable factors influencing the threshold. At the same time, an arbitrarily weak stimulus can sometimes cause a sensation. K.V. Bardeen analyzes in detail different approaches to solving the threshold problem. The best solution now is probably the psychophysical model of the signal detection theory, according to which the sensory effect of the stimulus is always summed up with the conditioned intrinsic excitation in the sensory system. To decide whether there was a signal against the background noise, the subject uses a criterion that is chosen depending on a number of factors (for example, the cost of errors such as “missing a signal” and “false alarm”).
When measuring thresholds of sensations, they can vary significantly at different times in the same person. This is due to many factors. Some of them - emergency - change thresholds quickly, but not for long. Others - long-term - cause a gradual and steady change in sensation thresholds. An example of the first factors would be sensory adaptation, and the second would be age. In addition, all these factors are sometimes divided into external (influence of the environment) and internal (changes in the body).
Sensory adaptation- this is a change in sensation thresholds under the action of a constant stimulus. With full adaptation, there is no sensation at all. Thus, overstimulation of the analyzers is avoided and sensitivity to very weak influences is ensured. Adaptation is especially pronounced in tactile, temperature, olfactory and visual sensations. For example, after being in the dark for an hour, light sensitivity increases approximately 200,000 times. There is practically no adaptation to sound and pain. Adaptation occurs with negative acceleration, i.e. the first time is the fastest. It depends on the intensity of the stimulus and the area on which it acts.
Sensitivity increases under the action of a weak near-threshold (or threshold) stimulus of the corresponding modality. This phenomenon was studied by A.I. Bronstein and named by him sensitization, although often this term used in a different meaning. For example, A.R. Luria refers to sensitization as cases of increased sensitivity under the influence of physiological or psychological changes in the body.
Sensation thresholds are influenced by motivation, biological or social significance of the stimulus. For example, when creating an interesting play situation, children demonstrate higher visual acuity compared to its measurement under normal laboratory conditions. A very faintly luminous dot becomes visible only after it is given a signal value (in the experiment of G.V. Gershuni, the subjects, having noticed the dot, could avoid an electric shock).
Sensation thresholds can be significantly lowered with special exercises and training. A.N. Leontyev, using the subjects' singing of the sounds presented to them to distinguish sounds, ensured that within a few hours of training the thresholds were reduced by 6-8 times. By gaining professional experience, a factor of significance is added to long-term training, so the results are especially impressive. For example, an experienced grinder notices a gap of 0.0005 mm by eye, and a non-professional - 0.01 mm.
With age, under the influence of the growth and maturation of the corresponding brain structures, the child’s sensory thresholds decrease. In particular, it is well known that as we grow older, color discrimination improves significantly and visual acuity increases. During aging, the process goes on reverse direction. Sensitivity to high-frequency sounds is also gradually lost.
Changes in metabolic processes and endocrine disorders (in particular, hyperfunction of the thyroid gland) also affect thresholds. In pregnant women, olfactory sensitivity increases, but the thresholds of visual and auditory sensations increase, which is biologically useful.
Emergency factors include fatigue, which reduces sensitivity, and exposure to certain pharmacological drugs and chemicals.
“Side” stimuli can change the thresholds of sensations, i.e. exposure to another modality. Finally, another way is to create a conditional temporary connection. If the word “darkness” is accompanied by turning on the light, a second-signal conditioned reflex is developed when the pronunciation of this word will increase light sensitivity.
The human brain functions as a single, integral system, therefore the processes occurring in one analyzer depend on the processes in other sense organs. This idea of the integrity of the body (and the nervous system in particular) is analyzed by B.G. Ananyev, discussing the sensory-perceptual organization of a person and calling the brain a single giant analyzer. Let us consider two manifestations of the interaction of sense organs.
As a result of the action of stimuli on one analyzer, the thresholds of sensations of another modality may increase or decrease. This phenomenon was studied by S.V. Kravkov, and, according to his data, it is observed in relation to all types of sensations. For example, strong noise reduces the acuity of central vision, while weak noise increases it. Under the influence of sweet, salty and sour foods, visual sensitivity increases, and under the influence of bitter foods, it decreases. Changes can reach several tens of percent of the original value and persist for a long time. In cases of mental pathology and brain damage (in particular, after a concussion), the interaction of analyzers is often strengthened, weakened or distorted, which is advisable to use for diagnostic purposes. The result of changes in thresholds when exposed to another analyzer is easy to notice without laboratory tests. Also M.V. Lomonosov wrote that in the cold the colors are brighter. The lecturer's voice seems louder in the dark when he uses transparencies.
Several theories have been proposed to explain the mechanisms of this phenomenon: the interaction of processes in closely located afferent nerve fibers of different analyzers; the autonomic nervous system as the main mediator in interanalyzer influences. Another approach assigns a decisive role to intercentral influences in the cerebral cortex, activation of the central parts of the analyzers (for example, sniffing odorless substances also increases visual thresholds). There is no single general theory yet.
Another manifestation of the interaction of analyzers is the phenomenon of synesthesia. In a narrow (strict) meaning, this is the occurrence of sensations of one modality under the action of a stimulus of another modality. True synesthesia is very rare (one case in several thousand people).
Synesthesia is sometimes also called the appearance of integral images-representations under the action of a stimulus of a different modality. Finally, synesthesia is also spoken of when characterizing a stimulus of one modality in terms of the qualities of another modality of sensations (sharp sound, cool color, etc.) or when it is easy to select a stable correspondence between smell and color, smell and sound, etc.
To explain synesthesia, they often refer to the development of stable conditioned temporary connections between analyzers (usually in childhood). This corresponds, in particular, to large qualitative individual differences when different people some kind of zzuk is associated with different colors. At the same time, there is evidence that synesthesia is based on the objective properties of stimuli (as a rule, darker shades of gray are selected for the odors of substances whose molecules have more carbon atoms). It is also known that synesthesia is more pronounced in people with increased excitability of subcortical formations; it can increase during pregnancy and when taking drugs.
One aspect of synesthesia studied by A.P. is interesting. Zhuravlev in line with the so-called phonosemantics. Typical Zuko-color correspondences were established: A - deep red, E - green, I - blue, etc. An analysis of the poems of famous poets showed that in many cases the color palette described in words corresponds well to the color meaning of sound letters, which appear in the text much more often than the average.
4. The founder of the cognitive theory of personality is...
J. Kelly
J. Watson
B. Skinner
K. Rogers
Solution:
The founder of the cognitive theory of personality is J. Kelly. In his opinion, the only thing a person wants to know in life is what happened to him and what will happen to him in the future. The main source of personality development is the environment, the social environment. Cognitive theory of personality emphasizes the influence of intellectual processes on human behavior. In this theory, any person is compared to a scientist who tests hypotheses about the nature of things and makes predictions about future events.
5. In foreign psychology, ______________ (understood as the originality, uniqueness and integrity of a particular personality) is correlated with a special, scientific term “self”.
individuality
personality
Solution:
In foreign psychology, individuality (understood as the originality, uniqueness and integrity of a particular person) is correlated with a special, scientific term “self” (C. Jung, G. Allport, C. Rogers). The Self is the essential core of the individual psyche, the deep structure that ensures the integrity and coherence of human experience.
6. V. Petrovsky, personality as a subject of interpersonal relations reveals itself in three spheres: ____________, interindividual and metaindividual.
intra-individual
extra-individual
hyperindividual
autoindividual
Solution:
V. Petrovsky, personality as a subject of interpersonal relations reveals itself in three spheres: intra-individual, inter-individual and meta-individual. The intra-individual sphere characterizes a person’s individuality (temperament, character, abilities, etc.). The interindividual sphere characterizes a person involved in interindividual connections. The meta-individual sphere characterizes personality as the “ideal representation” of an individual in the life activities of other people.
Topic 5: Cognitive sphere of personality
1. Proprioceptive sensations include...
muscle relaxation and contraction
bright light
bitter taste
loud sound
Solution:
Proprioceptive sensations include sensations of muscle relaxation and contraction. Proprioceptive sensations enable a person to perceive changes in position individual parts body at rest and during movements. Information coming from the proprioceptors allows him to constantly control the posture and accuracy of voluntary movements, dose the force of muscle contractions when counteracting external resistance, for example, when lifting or moving a load.
2. The numerical characteristic of the average attention span of people is equal to __________ units of information.
Solution:
The numerical characteristic of the average attention span of people is 5–9 units of information. Attention is the selective focus of perception on a particular object. A numerical characteristic is usually established through an experiment in which a person is presented with a large amount of information for a very short time. What he manages to notice during this time characterizes his attention span.
3. A corrective test that allows you to study the stability of attention was proposed by a French psychologist...
B. Burdon
Solution:
A corrective test that allows one to study the stability of attention was proposed by the French psychologist B. Bourdon. The essence of this test is that the subject is given a form with a set of letters or other characters written in a line (some of them are repeated), and is instructed to review all the characters in each line within a certain period of time, crossing out in the proposed ways those of them that were previously indicated by the experimenter.
4. The theory of memory, which is based on the concept of connections between individual mental phenomena, is a ___________ theory.
associative
active
semantic
informational
Solution:
The theory of memory, which is based on the concept of connections between individual mental phenomena, is an associative theory. This theory is one of the first psychological theories of memory, which has not lost its scientific significance to this day. It arose in the 17th century, was actively developed in the 18th and 19th centuries, and received primary distribution and recognition in England and Germany. This theory is based on the concept of association, developed by G. Ebbinghaus, G. Müller, A. Pilzecker and others.
5. The characteristic of visual sensation corresponding to the intensity of the stimulus is called...
saturation
brightness
duration
Solution:
The characteristic of visual sensation corresponding to the intensity of the stimulus is called saturation. Visual sensations arise when electromagnetic waves act on the visual receptor – the retina of the eye. Saturation is the degree of difference of a given color from a gray color of the same lightness, or, as they say, the degree of its expression. Color saturation depends on the ratio of the number of light rays characterizing the color of a given surface to the total luminous flux reflected by it. Color saturation depends on the shape of the light wave.
6. The phenomenon characterizing the influence of breaks in activity on memory processes was described by B.V. Zeigarnik as an effect ...
unfinished action
saving
Solution:
The phenomenon characterizing the influence of breaks in activity on memory processes was described by B.V. Zeigarnik as the effect of an unfinished action. B.V. Zeigarnik tested K. Levin’s hypothesis that interrupted tasks, due to persistent motivational tension, are remembered better than completed ones. It was found that the number of remembered interrupted tasks was approximately twice as large as the number of remembered completed ones.
Topic 6: Individual psychological characteristics of personality
1. The type of character accentuation, which is characterized by fearfulness, isolation, shyness, is called ...
sensitive
introverted
neurosthenic
extroverted
Solution:
The type of character accentuation that is characterized by fearfulness, isolation, and shyness is called sensitive. Sensitive teenagers avoid joining large and especially new companies, do not participate in the pranks and risky enterprises of their peers, and prefer to play with small children. They are afraid of tests, and are often embarrassed to answer in front of the class, fearing that a mistake will make them laugh or cause the envy of their classmates with a too good answer. The feeling of inferiority in sensitive adolescents makes the reaction of overcompensation (or overcompensation, that is, an increased desire to overcome one’s shortcomings) especially pronounced. They seek self-affirmation not away from the weak point of their nature, not in areas where their abilities can be revealed, but precisely where they especially feel their inferiority.
2. A stable dominant system of motives, interests, beliefs, ideals, which reflect the dominant needs of a person, is called ________________ personality.
focus
worldview
conviction
dominant
Solution:
A stable dominant system of motives, interests, beliefs, ideals, which reflect the dominant needs of a person, is called the orientation of the individual. Direction is one of the characteristics of a formed personality. The personality is also characterized by activity, the presence of dynamic semantic systems (in the terminology of L. S. Vygotsky) and the degree of awareness of one’s own relationships to various aspects of reality.
3. Neurophysiological theories of temperament go back to the works of...
I. P. Pavlova
K. E. Fabry
K. Galena
Solution:
Neurophysiological theories of temperament go back to the works of I. P. Pavlov. In the classical teachings of I.P. Pavlov, all types of temperament are correlated with certain parameters of the functioning of the central nervous system. The individual psychological characteristics of a person, according to this teaching, are naturally associated with specific aspects of conditioned reflex activity.
4. The stage of personality development according to E. Erikson, which is characterized by hard work, a strong sense of duty and the desire to achieve success, is called ...
latent
locomotor-genital
early adulthood
muscular-anal
Solution:
The stage of personality development according to E. Erikson, which is characterized by hard work, a strong sense of duty and the desire to achieve success, is called latent. The formation of personality in E. Erikson’s concept is understood as a change of stages, at each of which a qualitative transformation occurs inner world person. The latent stage is characterized by the development of cognitive and communication skills, setting oneself and solving real problems.
5. The doctrine of the connection between appearance a person and his belonging to a certain type of personality is called...
physiognomy
palmistry
dermatoglyphics
characterology
Solution:
The study of the connection between a person’s external appearance and his belonging to a certain type of personality is called physiognomy (from the Greek physis - nature, gnomon - knower). main idea This teaching is based on the assumption that the psychological characteristics of a person belonging to one type or another can be determined by external signs.
6. The doctrine, which is based on the assertion that all character traits have their strictly specialized centers in the cerebral hemispheres, is called ...
phrenology
dermatoglyphics
physiognomy
characterology
Solution:
The doctrine, which is based on the assertion that all character traits have their strictly specialized centers in the cerebral hemispheres, is called phrenology. Phrenology is associated with the name of the German doctor F. Gall. The degree of development of qualities is directly dependent on the size of the corresponding parts of the brain. And since, according to Gall, the bones of the skull should exactly correspond to the convexities and depressions of the brain, one look at a person’s skull or simply feeling the “bumps” of the head was supposedly enough to determine his spiritual qualities. Hall compiled special phrenological maps, where the surface of the skull was divided into 27 sections and each of them corresponded to a certain mental quality, for example, caution and foresight, a tendency to cruelty and murder, deceit, constancy, perseverance and stubbornness, etc.
Each type of sensation has its own specific characteristics.Skin sensations
Skin sensations are obtained from the direct impact of various irritants on receptors located on the surface of human skin. All such sensations have common name skin, although, strictly speaking, the category of these sensations also includes those sensations that arise when irritants act on the mucous membrane of the mouth and nose, and the cornea of the eyes.Skin sensations are a contact type of sensation. This is due to the fact that they occur when the receptor comes into direct contact with an object. real world. In this case, four main types of sensations may arise:
Sensations of touch (tactile),
Feelings of cold
Feelings of warmth
Feelings of pain.
Although it is said that skin sensations arise only through direct contact with an object in the real world, there are exceptions. If you hold your hand in some proximity to a hot object, you can feel the heat emanating from it. This warm air transferred from a hot object to your hand. In this case, we can say that we feel an intermediary object (warm air). However, if you put a glass partition that completely separates the hot object, you can still feel the sensation of heat. The fact is that hot objects emit infrared rays, which heat our skin.
Another thing is interesting. People familiar with electronics might assume that one type of receptor is sufficient to perceive heat and cold. The vast majority of temperature sensors (like conventional thermometers) measure temperature in a fairly wide range: from cold to hot. However, nature has equipped us with two types of receptors: for the sensation of cold and for the sensation of warmth. At normal temperatures, the receptors of both types are “silent”. Touching warm objects causes the heat receptors to “speak.” Touching cold - cold receptors.
Each of the four types of skin sensations mentioned above has specific receptors. In experiments, it was shown that some points of the skin provide only sensations of touch (tactile points), others - sensations of cold (cold points), still others - sensations of warmth (heat points), and fourth - sensations of pain (pain points). Tactile receptors are designed in such a way that they respond to touches that cause deformation of the skin. Thermal ones are designed to react to cold or heat. And painful ones react to deformation, and to heat, and to cold, but only with a high intensity of exposure.
To determine the location of receptor points and sensitivity thresholds, a special device, an aesthesiometer, is used. The simplest aesthesiometer consists of horse hair and a sensor that allows you to measure the pressure exerted by this hair. When the hair touches the skin lightly, sensations arise only when it directly hits the tactile point. The location of cold and hot spots is determined in the same way. Only in this case, instead of a hair, a thin metal tip is used, filled with water, the temperature of which can vary.
Still not known total skin receptors in humans. It has been approximately established that there are about one million touch points, about four million pain points, about 500 thousand cold points, about 30 thousand heat points.
Over the surface of the body, the density of receptors is not constant. The proportions of receptors of different species also change. So on the fingertips the number of touch receptors is twice as large as pain points, although the total number of the latter is much greater (see above). On the cornea of the eye, on the contrary, there are no touch points at all, but only pain points, so any touch to the cornea causes a sensation of pain and a protective reflex of closing the eyes.
The density of certain receptors in one place or another is determined by the meaning of the corresponding signals. If for manual operations it is very important to have an accurate understanding of the object being held in the hands, then the density of tactile receptors will be higher here. The back, abdomen and outer forearm contain significantly fewer touch receptors. The back and cheeks are most sensitive to pain and the fingertips are the least sensitive. It is interesting that in relation to temperature, those parts of the body that are usually covered by clothing are most sensitive: the lower back, chest.
The greater the density of receptors in a particular area of the body, the more accurately we can determine the coordinates of the source of a new sensation. Experiments often examine the spatial threshold between touch sites that allows discrimination between the touch of two (or more) spatially separated objects.
To determine the spatial threshold of tactile sensations, a circular aesthesiometer is used, which is a compass with sliding legs. The lowest threshold of spatial differences in skin sensations is observed on areas of the body that are more sensitive to touch. On the back, the spatial threshold of tactile sensations is 67 mm, on the forearm - 45 mm, on the back of the hand - 30 mm, on the palm - 9 mm, at the fingertips 2.2 mm. The lowest spatial threshold of tactile sensations is at the tip of the tongue - 1.1 mm. This is where touch receptors are most densely located. Obviously, this is due to the peculiarity of chewing food.
Taste and olfactory sensations
The taste receptors are the so-called taste buds, consisting of sensitive taste cells connected to nerve fibers. In an adult, taste buds are located mainly at the tip, along the edges and on the back of the upper surface of the tongue. In children, the distribution of taste buds is much wider than in adults. Taste buds are present on the palate, tonsils, and back of the pharynx (more so in children).The middle of the upper surface and the entire lower surface of the tongue are not sensitive to taste.
Chemical substances dissolved in water serve as irritants for taste buds. In the course of evolution, nature has endowed us with the ability to distinguish between the most significant classes of chemicals (acids, salts, sugars, etc.)
The receptors for olfactory sensations are olfactory cells embedded in the mucous membrane of the so-called olfactory region. The olfactory receptors are irritated by various odorous chemicals that enter the nose along with the air. In an adult, the area of the olfactory region is approximately five hundred square millimeters.
In newborns, the olfactory area is much larger, which is due to the fact that in newborns the leading sensations are taste and olfactory sensations. It is thanks to them that the child receives the maximum amount of information about the world around him, and they also provide the newborn with satisfaction of his basic needs.
In the process of further ontogenetic development, olfactory taste sensations give way to other, more informative sensations, and primarily vision.
Taste sensations are closely related to olfactory sensations. Therefore, in most cases they are mixed with each other. Many people, for example, notice that during a severe runny nose, when the olfactory senses are turned off for obvious reasons, food becomes less tasty, one dish begins to taste like another.
Also mixed with taste sensations are tactile and temperature sensations from receptors located in the area of the oral mucosa. The perception of “spicy” or “astringent” food is mainly associated with tactile sensations. The characteristic “chill” taste of mint largely depends on irritation of cold receptors.
If we exclude from the taste sensations the admixtures of tactile, temperature and olfactory sensations, then the taste sensations themselves will be reduced to a combination of four main types:
Sweet,
Gorky,
Salty.
In 1997, Japanese scientists showed that there are also receptors responsible for the perception of lipids, that is, recognizing fatty taste. Thus, it turns out that any taste is a combination of five individual tastes.
The experiments also found that different parts of the tongue have different sensitivity to certain taste qualities. For example, sensitivity to sweet is maximum at the tip of the tongue and minimal at the back of it, and sensitivity to bitter, on the contrary, is maximum at the back and minimal at the tip of the tongue.
Although taste and smell are very similar, there is a huge difference between them. While gustatory sensations can be reduced to a combination of four or five basic tastes, olfactory sensations are not a combination of certain “basic odors.” Therefore, there is no strict classification of odors. And it’s even difficult to imagine in what form such a classification could exist.
Each smell is associated with a specific object or classes of objects that possess it. Examples:
Flower smell,
The smell of a rose
The smell of an animal
The smell of a rat
Gasoline smell
The smell of a new car
The smell of rotten eggs
The smell of fried pies.
In most cases, the unique smell is made up of many chemicals. In some cases, the odor consists predominantly of one substance (dominant). For example, the smell of rotten eggs consists mainly of hydrogen sulfide. Throughout our lives, we learn new smells, learn to distinguish them from others, sometimes we give verbal names to these smells (“the smell of my favorite perfume”) or adopt common names (“the smell of sweat”).
In the reception and recognition of smell, admixtures of other sensations also play a role:
Gustatory (especially from irritation of the taste buds located in the back of the pharynx - next to the air movement channel),
tactile,
Painful,
Temperature
We find the smell of fresh buns delicious not only because it is associated with... delicious buns- its source. But also because it directly irritates the taste buds (chemicals dissolve in the moisture of the mouth and irritate the taste buds). Some pungent odors, such as mustard, contain both tactile and painful sensations. The smell of menthol includes a "chill" sensation due to the fact that it irritates the cold receptors.
Interestingly, the sensitivity of the olfactory and taste receptors increases during a state of hunger. After several hours of fasting, absolute sensitivity to sweets increases significantly, and sensitivity to sour increases, but to a lesser extent. This suggests that olfactory and gustatory sensations are largely related to the need to satisfy such biological needs as the need for food. Nature has endowed us with the senses of taste (to a greater extent) and olfaction (to a lesser extent) mainly so that we have the opportunity to detect potential food and taste it, checking for edibility. It is logical to assume that hunger activates this ability.
Also, taste and olfactory sensations include the mechanism for obtaining pleasure from eating food (especially in a state of hunger). Thus, nature made sure that we get pleasure not from the distant result of eating food (when it is all swallowed and digested), but “in real time.” You need to reinforce your strength every day, and that’s why nature came up with such a powerful incentive.
Auditory sensations
For the organ of hearing, the irritant is sound waves, that is, longitudinal wave-like vibrations of air particles. The source of such wave-like air movement is an oscillating body (and usually a solid one). Sound spreads from this body in all directions. It is worth noting that sound can travel not only through air, but also through all matter: liquid, gaseous, solid. In a vacuum, where there is no matter, sound does not travel.All sounds can be divided into two categories:
Noise (chaotic alternation of sound waves),
Ordered sounds.
With some convention, ordered sounds can be divided into four types:
Sounds inanimate nature(howling wind, dripping water, crunching snow),
Signal sounds of living creatures (meowing, chirping, human speech),
Man-made sounds (speaker squeak, servo hum, caterpillar clang),
The more ordered the sounds, the fewer random elements they contain. The least chaotic sounds are the sounds of music; in a typical piece of music, every note, every overtone, every sequence is not a random element at all.
Sound waves are different:
According to the waveform,
frequency,
amplitude,
Timbre (coloring with additional elements).
Sound waves do not always have a sine wave shape. The sound of a bell, for example, is not shaped like a sine wave. However, by default, when we talk about a sound wave, we mean a sine wave.
The pitch of sound is measured in hertz, i.e. the number of vibrations per second. If the membrane of the source or receiver swung in one direction or the other 100 times, then the pitch of the sound will be 100 Hz. We are not able to perceive sound of every frequency. The highest sound perceived by an adult is 20,000 Hz. For children - 22,000 Hz, for elderly - 15,000 Hz. The lower limit of hearing is 16-20 hertz. We can also perceive lower-frequency sounds, but not with the ear, but with the skin.
The human ear is most sensitive to sounds with a frequency of 1000-3000 Hz. The accuracy of pitch perception develops with experience.
The loudness of a sound determines the subjective intensity of the auditory sensation. One would expect that, for our perception, the loudness of an auditory sensation would be proportional to the pressure exerted on the eardrum. It turned out, however, that the auditory sensation is proportional only to the logarithm of the pressure intensity.
The units of measurement for auditory sensation are decibels. One unit of measurement is the intensity of the sound emanating from the ticking of a clock at a distance of 0.5 meters from the human ear. Thus, the volume of ordinary human speech at a distance of 1 meter will be 16-22 dB, noise on the street (without a tram) - up to 30 dB, noise in a boiler room - 87 dB, noise of a plane taking off - 130 dB (pain threshold).
Timbre is a specific quality that distinguishes sounds of the same pitch and intensity produced by different sources from each other. And vice versa - a quality that can combine sounds of different pitches and intensities. Timbre can be called the color of sound.
In music, the shape of sound vibration, especially in string instruments, corresponds to a sine wave. Such sounds are called “harmonious”. By themselves, they already cause pleasant sensations.
But the fact is that in a sound wave there can be a superposition of several sinusoids. Even a simple string, in addition to the main sine wave, also produces accompanying ones (overtones). If the fundamental frequency of vibration is 100 Hz, then the frequency of the overtones will be: 200 Hz, 300 Hz, 400 Hz, 500 Hz, etc.
Using a tuning fork or special electronic devices or a computer, you can get a simple sound - it consists of a single sine wave and has a constant sound frequency. But in everyday life we do not encounter simple sounds. The sounds around us consist of various sound elements, so the shape of their sound, as a rule, does not correspond to a sine wave.
The combination of simple sounds in one complex one gives originality to the shape of the sound vibration and determines the timbre of the sound. This timbre also depends on the degree of fusion of sounds. How simpler form sound vibration, the more pleasant the sound. Therefore, it is customary to distinguish between a pleasant sound - consonance and an unpleasant sound - dissonance.
IN modern science Helmholtz's resonance theory is used to explain auditory sensations. The terminal apparatus of the auditory nerve is the organ of Corti, which rests on the main membrane running along the entire spiral bone canal called the cochlea. The main membrane consists of approximately 24,000 transverse fibers. The length of these fibers gradually decreases from the apex of the cochlea to its base.
Each such fiber is tuned, like a string, to a certain vibration frequency. When sound vibrations, usually consisting of a combination of different frequencies, reach the cochlea, certain groups of fibers of the main membrane resonate. After this, only those cells of the organ of Corti that rest on these fibers are excited. Shorter fibers lying at the base of the cochlea respond to higher sounds, longer fibers lying at its apex respond to low sounds.
Subsequently, the sound passes through complex processing in specialized brain centers. In the process of this processing: individual independent sequences in sounds are isolated (for example, a person’s voice is separated from the noise of the city), repeating elements are sought out, and identified.
Visual sensations
For the organ of vision, the irritant is light, or more precisely, electromagnetic waves with a length of 390 to 800 nanometers (one billionth of a meter). If the electromagnetic wave is “energetic,” that is, it has a large amplitude of vibration, we perceive bright light, otherwise we perceive weak light.Nature has endowed us with the ability to distinguish light not only by intensity, but also by quality. More precisely, by wavelength. We perceive light with a length of 500 nm differently than 700 nm. Unfortunately (or fortunately), our consciousness does not perceive light in exactly this order: “I see a light spot with a wavelength of 539 nm.” Instead, we perceive light on a scale of names, that is, by color.
The sensations of red light are caused by waves with a length of 630-800 nm, yellow - 570-590 nm, green - 500-570 nm, blue - 430-480 nm.
Visual sensations are sensations of color. Everything we see, we perceive in color. But at the same time, colors are divided into:
Achromatic ("colorless" colors - white, gray and black),
Chromatic (all others).
Gray color includes wavelengths of different lengths. Bright gray is white. Dark gray color - black. But this is kind of in theory. In fact, any chromatic color (for example blue or red) when very dark is perceived as black (low intensity), and when very light (high intensity) is perceived as white.
Chromatic color tone depends on which wavelengths predominate in the light flux reflected by a given object.
The eye has unequal sensitivity to light waves of different lengths. As a result, the colors of the spectrum, with objective equality of intensity, seem to us to be unequal in lightness. The lightest color seems to us to be yellow, and the darkest is blue, because the sensitivity of the eye to waves of this length is 40 times lower than the sensitivity of the eye to yellow color.
Color vision in humans is excellent. For example, between black and white, a person can distinguish about 200 transitional colors. Dozens of shades of red or blue can be distinguished, many of which even have proper names(“blood red”, “ruby”, “scarlet”, etc.).
Visual acuity is the ability to distinguish small and distant objects. The smaller the objects that the eye is able to see under specific conditions, the higher its visual acuity. Visual acuity is characterized by a minimum gap between two points, which from a given distance are perceived separately from each other, and do not merge into one. This value can be called the spatial visual threshold.
In everyday life, the colors we perceive, even those that appear monochromatic, are the result of the addition of many light waves of different lengths. Waves of different lengths simultaneously enter our eye, and the waves mix, resulting in us seeing one specific color. And this is very characteristic feature our vision. For comparison, our hearing analyzes sound waves and sorts them into categories. If hearing worked like vision, then we would perceive any sound as simple - it doesn’t matter whether the metronome is ticking or the stadium is blaring, in both cases we would hear the same thing, only slightly different in intensity.
Newton and Helmholtz established the laws of color mixing. Firstly, for each chromatic color you can choose another chromatic color, which, when mixed with the first one, gives an achromatic color (gray). These two colors are usually called complementary. Secondly, mixing two non-complementary colors produces a third color - an intermediate color between the first two. One very important point follows from the above laws: all color tones can be obtained by mixing three appropriately selected chromatic colors.
If we again compare vision and hearing, it may seem amusingly absurd that the green color is not only a specific and rather narrow part of the spectrum, but also (in another version) a mixture of the blue and yellow parts of the spectrum. And completely different parts of the spectrum: without perceiving “green waves,” we nevertheless still see the color green. It’s like listening to the balalaika playing and the roar of an elephant at the same time, and in the end perceiving the babbling of a stream. However, it is quite clear that nature simply has not come up with a way to make a spectrometer as effective as in the case of hearing. Basically, the problem is that for each perceived point in space it would be necessary to have not three receptors, but tens or hundreds.
The retina is the most important and characteristic element of our vision. It is a branch of the optic nerve entering the eyeball from behind. There are two types of receptors in the retina:
cones,
Sticks.
These receptors got their name because of their shape.
Rods and cones are the terminal devices of the nerve fibers of the optic nerve. The retina of the human eye has about 130 million rods and 7 million cones, which are unevenly distributed across the retina. Cones fill the central fovea of the retina, i.e. the place where the image of the object to which our attention is drawn falls. Toward the edges of the retina, the number of cones decreases.
There are more rods just at the edges of the retina; in the middle they are practically absent.
Cones have low light sensitivity. To provoke their reaction, you need a strong enough light. Therefore, with the help of cones, we see only in bright light or artificial lighting. This is why cones are sometimes called daytime vision devices.
Rods are more sensitive, and with their help we see at night, which is why they are called night vision apparatus.
The most important difference between rods and cones is that we use cones to distinguish colors. There are three types of cones. Each species is responsible for its part of the spectrum.
There is a disease in which the cone apparatus does not work completely. Patients see everything only in shades of gray. They can't see straight ahead. With another disease - “night blindness” - the rod apparatus does not work on the contrary, and then the patient perceives almost nothing in the dark.
Visual stimulation has a certain inertia. This continuation of the sensation over some time is called a positive sequential image. It can be observed simply by closing your eyes.
Proprioceptive sensations
Proprioceptive sensations are sensations of movement and balance. Balance sensory receptors are located in the inner ear. Receptors for kinesthetic (motor) sensations are located in muscles, tendons and joint surfaces. These sensations give us ideas about the magnitude and speed of our movement, as well as the position in which this or that part of our body is located.The fact is that motor sensations play a very important role important role in coordinating our movements. Nature could not be satisfied with the other senses. If there were no proprioceptive sensations, we would have to constantly look at our hands and feet in order to achieve something with them. In the process of performing a particular movement, our brain constantly receives signals from receptors located in the muscles and on the surface of the joints. This helps to correct the movement. Without proprioceptive sensations, it would be difficult to move and maintain balance while moving. The human body consists of a huge number of moving elements and muscles, proprioceptive sensitivity allows you to control this entire huge “orchestra”.
Chapter 7. Sensation
Summary
General concept of sensation. The general place and role of cognitive mental processes in human life. Sensation as a sensory reflection of individual properties of objects. Physiological mechanisms of sensation. The concept of analyzers. Reflexive nature of the analyzer. Teachings about sensation. Law on “specific” energy by I. Muller. The concept of “signs” by G. Helmholtz. The theory of solipsism. Sensation as a product of human historical development.
Types of sensations. A general idea of the classifications of sensations. Systematic classification of sensations by A. R. Lurie." Intercentenary, iroprioceptive and exterocentive sensations. Contact and distant sensations. Genetic classification of sensations:
irotonic and eikritic sensations. Classification of sensations by B. M. Teplov. The concept of modality of sensations. Classification of sensations by modality.
Basic properties and characteristics of sensations. Properties of sensations: quality, intensity, duration, spatial localization. Absolute sensitivity and sensitivity to difference. Absolute and relative thresholds of sensations. “Subsensory area” by G. V. Gershuni. Bouguer-Vsber law. The essence of Weber's constant. Basic psychophysical law of Weber-Fehnsr. Stevens Law. Generalized psychophysical law of Yu. M. Zabrodin.
Sensory adaptation and the interaction of sensations. The concept of sensory adaptation. Interaction of sensations: interaction between sensations of the same type, interaction between sensations of different types. The concept of sensitization. The phenomenon of synesthesia.
Development sensations. Feelings of a newborn. Features of the process of development of vision and hearing. Development of speech hearing. Development of absolute sensitivity. Genetic predisposition and the possibility of developing sensations.
Characteristics of the main types of sensations*. Skin sensations. Taste and olfactory sensations. Auditory sensations. Visual sensations. Proprioceptive sensations. The concept of touch.
7.1. General concept of sensation
We begin to study cognitive mental processes, the simplest of which is sensation. The process of sensation arises as a result of the influence on the sense organs of various material factors, which are called stimuli, and the process of this influence itself is called irritation. In turn, irritation causes another process - excitation, which passes through the centripetal, or a4>ferential, nerves to the cerebral cortex, where sensations arise. Thus, sensation is a sensory reflection of objective reality.
The essence of sensation is the reflection of individual properties of an object. What does "individual properties" mean? Each stimulus has its own characteristics, depending on which it can be perceived by certain organs
* This section is based on chapters from the book: Psychology. / Ed. prof. K. I. Kornilova, prof. A. A. Smirnova, prof. B. M. Teplova. - Ed. 3rd, revised and additional - M.: Uchpedgiz, 1948.
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feelings. For example, we can hear the sound of a mosquito flying or feel its bite. In this example, sound and bite are stimuli that affect our senses. At the same time, you should pay attention to the fact that the process of sensation reflects in consciousness only the sound and only the bite, without in any way connecting these sensations with each other, and, consequently, with the mosquito. This is the process of reflecting individual properties of an object.
The physiological basis of sensations is the activity of complex complexes of anatomical structures, called analyzers by I. P. Pavlov. Each analyzer consists of three parts: 1) a peripheral section called a receptor (the receptor is the perceiving part of the analyzer, its main function is the transformation of external energy into a nervous process); 2) nerve pathways; 3) the cortical sections of the analyzer (they are also called the central sections of the analyzers), in which the processing of nerve impulses coming from the peripheral sections occurs. The cortical part of each analyzer includes an area that represents a projection of the periphery (i.e., a projection of the sensory organ) in the cerebral cortex, since certain receptors correspond to certain areas of the cortex. For sensation to occur, all components of the analyzer must be used. If any part of the analyzer is destroyed, the occurrence of the corresponding sensations becomes impossible. Thus, visual sensations cease when the eyes are damaged, when the integrity of the optic nerves is damaged, and when the occipital lobes of both hemispheres are destroyed.
The analyzer is an active organ, reflexively rearranged under the influence of stimuli, so sensation is not a passive process, it always includes motor components. Thus, the American psychologist D. Neff, observing an area of skin with a microscope, became convinced 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 sensation is closely related to movement, which sometimes manifests itself 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.) .d.). Thus, sensations are not at all passive processes - they are active, or reflexive, in nature.
It should be noted that sensations are not only the source of our knowledge about the world, but also our feelings and emotions. The simplest form of emotional experience is the so-called sensory, or emotional, tone of sensation, that is, a feeling directly related to sensation. For example, it is well known that some colors, sounds, smells can themselves, regardless of their meaning, memories and thoughts associated with them, cause us a pleasant or unpleasant feeling. The sound of a beautiful voice, the taste of an orange, the smell of a rose are pleasant and have a positive emotional tone. The creaking of a knife on glass, the smell of hydrogen sulfide, the taste of quinine are unpleasant and have a negative emotional tone. This kind of simplest emotional experiences play a relatively insignificant role in the life of an adult, but from the point of view of the origin and development of emotions, their significance is very great.
This is interesting
How information is transferred from the receptor to the brain!
A person is able to sense and perceive the objective world thanks to the special activity of the brain. All sense organs are connected to the brain. Each of these organs responds to a certain kind of stimulus; organs of vision - to light influence, organs of hearing and touch - to mechanical influence, organs of taste and smell - to chemical influence. However, the brain itself is not able to perceive these types of influences. It only “understands” electrical signals associated with nerve impulses. In order for the brain to respond to a stimulus, each sensory modality must first convert the corresponding physical energy into electrical signals, which then follow their own paths to the brain. This translation process is carried out special cells in sensory organs called receptors. Visual receptors, for example, are located in a thin layer on inside eyes; Each visual receptor contains a chemical that reacts to light, and this reaction triggers a series of events that results in a nerve impulse. The auditory receptors are thin hair cells located deep in the ear; air vibrations, which are a sound stimulus, bend these hair cells, resulting in a nerve impulse. Similar processes occur in other sensory modalities. A receptor is a specialized nerve cell, or neuron; when excited, it sends an electrical signal to the interneurons. This signal travels until it reaches its receptive zone in the cerebral cortex, with each sensory modality having its own receptive zone. Somewhere in the brain - perhaps in the receptive cortex, or perhaps in some other part of the cortex - an electrical signal causes the conscious experience of a sensation. So, when we feel touch, the sensation “happens” in our brain, not on our skin. Moreover, the electrical impulses that directly mediate the sensation of touch were themselves caused by electrical impulses generated in the touch receptors located in the skin. Likewise, the sensation of bitter taste does not originate in the tongue, but in the brain; but the brain impulses mediating the sensation of taste were themselves caused by electrical impulses from the taste buds of the tongue. The brain perceives not only the impact of the stimulus, it also perceives a number of characteristics of the stimulus, such as the intensity of the impact. Consequently, receptors must have the ability to encode the intensity and qualitative parameters of the stimulus. How do they do it? In order to answer this question, scientists needed to conduct a series of experiments to record the activity of single receptor cells and pathways during the presentation of various input signals, or stimuli, to the subject. This way you can accurately determine which properties of the stimulus a particular neuron responds to. How practically osu Is there such an experiment? Before the experiment begins, the animal (monkey) undergoes surgery, during which thin wires are implanted into certain areas of the visual cortex. Of course, such an operation is performed under sterile conditions and with appropriate anesthesia. Thin wires - microelectrodes - are covered with insulation everywhere except the very tip, which records the electrical activity of the neuron in contact with it. Once implanted, these microelectrodes do not cause pain, and the monkey can live and move quite normally. During the actual experiment, the monkey is placed in a testing device, and microelectrodes are connected to amplification and recording devices. The monkey is then presented with various visual stimuli. By observing which electrode produces a stable signal, we can determine which neuron responds to each stimulus. Since these signals are very weak, they must be amplified and displayed on the screen of an oscilloscope, which converts them into electrical voltage curves. Most neurons produce a number of nerve |
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pulses reflected on the oscilloscope in the form of vertical bursts (spikes). Even in the absence of stimuli, many cells produce rare impulses (spontaneous activity). When a stimulus to which a given neuron is sensitive is presented, a rapid sequence of spikes can be seen. By recording the activity of a single cell, scientists have learned a lot about how sensory organs encode the intensity and quality of a stimulus. The main way to encode stimulus intensity is the number of nerve impulses per unit time, i.e., the frequency of nerve impulses. Let's show this using the example of touch. If someone lightly touches your hand, a series of electrical impulses will appear in the nerve fibers. If the pressure increases, the magnitude of the pulses remains the same, but their number per unit time increases. It's the same with other modalities. In general, the greater the intensity, the higher the frequency of nerve impulses and the greater the perceived intensity of the stimulus. Stimulus intensity can be encoded in other ways. One of them is to encode intensity in the form of a temporal pattern of impulses. At low intensity, nerve impulses follow relatively rarely and the interval between adjacent impulses is variable. At high intensity, this interval becomes quite constant. Another possibility is to encode intensity as the absolute number of neurons activated: the greater the stimulus intensity, the more neurons are involved. Coding the quality of a stimulus is more complex. Trying to explain this process, I. Müller in 1825 suggested that the brain is able to distinguish information from different sensory modalities due to the fact that it travels along different sensory nerves (some nerves transmit visual sensations, others auditory, etc.). Therefore, if we do not take into account a number of Muller’s statements about the unknowability of the real world, we can agree that the neural pathways that begin at different receptors end in different areas of the cerebral cortex. Consequently, the brain receives information about the qualitative parameters of the stimulus thanks to those nerve channels that connect the brain and the receptor. However, the brain is able to distinguish between the effects of one modality. For example, we distinguish red from green or sweet from sour. Apparently, coding here is also associated with specific neurons. For example, there is evidence that a person distinguishes sweet from sour simply because each type of taste has its own nerve fibers. Thus, “sweet” fibers mainly transmit information from sweet receptors, By“acidic” fibers - from sour receptors, and the same with “salty” fibers and “bitter” fibers, However, specificity is not the only possible coding principle. It is also possible that the sensory system uses a specific pattern of nerve impulses to encode quality information. An individual nerve fiber, reacting maximally to, say, sweets, can respond, but to varying degrees, to other types of taste stimuli. One fiber reacts most strongly to sweet foods, weaker to bitter foods, and even weaker to salty foods; so a “sweet” stimulus would activate a large number of fibers with varying degrees of excitability, and then this particular pattern of neural activity would be the code for sweet in the system. A different pattern would be transmitted along the fibers as a bitter code. However, in the scientific literature we can find a different opinion. For example, there is every reason to assert that the qualitative parameters of a stimulus can be encoded through the form of an electrical signal entering the brain. We encounter a similar phenomenon when we perceive the timbre of a voice or the timbre of a musical instrument. If the signal shape is close to a sinusoid, then the timbre is pleasant to us, but if the shape differs significantly from a sinusoid, then we have a feeling of dissonance. Thus, the reflection of the qualitative parameters of the stimulus in sensations is a very complex process, the nature of which is up to has not been fully studied. By: Atkinson R. L., Agkinson R. S., Smith E. E., et al. Introduction to psychology: Textbook for universities / Transl. from English under. ed. V. P. Zinchenko. - M.: Trivola, 1999. |
166 Part II. Mental processes
Sensations connect a person with the outside world and are both the main source of information about it and the main condition for mental development. However, despite the obviousness of these provisions, They have been repeatedly questioned. Representatives of the idealistic trend in philosophy and psychology often expressed the idea that the true source of our conscious activity is not sensations, but the internal state of consciousness, the ability of rational thinking, inherent in nature and independent of the influx of information coming from the outside world. These views formed the basis of philosophy rationalism. Its essence was the assertion that consciousness and reason are the primary, inexplicable properties of the human spirit.
Idealist philosophers and many psychologists who are supporters of the idealistic concept have often made attempts to reject the position that a person’s sensations connect him with the outside world, and to prove the opposite, paradoxical position, namely that sensations are an insurmountable wall separating a person from the outside world. A similar position was put forward by representatives of subjective idealism (D. Berkeley, D. Hume, E. Mach).
I. Müller, one of the representatives of the dualistic trend in psychology, based on the above-mentioned position of subjective idealism, formulated the theory of “specific energy of the senses.” According to this theory, each of the sense organs (eye, ear, skin, tongue) does not reflect the influence of the external world, does not provide information about real processes occurring in the environment, but only receives external influences shocks that excite their own processes. According to this theory, each sense organ has its own “specific energy”, excited by any influence coming from the outside world. So, just press on the eye or influence it electric shock to get a feeling of light; Mechanical or electrical stimulation of the ear is sufficient to produce the sensation of sound. From these provisions it was concluded that the senses do not reflect external influences, but are only excited by them, and a person does not perceive the objective influences of the external world, but only his own subjective states, reflecting the activity of his senses.
A similar point of view was that of G. Helmholtz, who did not reject the fact that sensations arise as a result of the influence of objects on the sense organs, but believed that the mental images arising as a result of this influence have nothing in common with real objects. On this basis, he called sensations “symbols” or “signs” of external phenomena, refusing to recognize them as images, or reflections, of these phenomena. He believed that the impact of a certain object on a sense organ evokes in consciousness a “sign” or “symbol” of the influencing object, but not its image. “For the image is required to have a certain resemblance to the object depicted... The sign is not required to have any similarity to that of which it is a sign.”
It is easy to see that both of these approaches lead to the following statement: a person cannot perceive the objective world, and the only reality is the subjective processes that reflect the activity of his senses, which create the subjectively perceived “elements of the world.”
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Similar conclusions formed the basis of the theory solipsism(from lat. solus - one, ipse - himself) which boiled down to the fact that a person can only know himself and has no evidence of the existence of anything other than himself.
Representatives are in opposing positions materialistic directions that consider an objective reflection of the outside world possible. The study of the evolution of the sense organs convincingly shows that in the process of long historical development, special perceptive organs (sense organs, or receptors) were formed that specialized in reflecting special types of objectively existing forms of movement of matter (or types of energy): auditory receptors that reflect sound vibrations; visual receptors that reflect certain ranges of electromagnetic vibrations. etc. The study of the evolution of organisms shows that in fact we do not have “specific energies of the sense organs themselves,” but specific organs that objectively reflect various types of energy. Moreover, the high specialization of 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 neurons, components of the central nervous apparatus, which receive signals perceived by the peripheral sense organs.
It should be noted that human sensations are a product of historical development, and therefore they are qualitatively different from the sensations of animals. In animals, the development of sensations is entirely limited by their biological, instinctive needs. In many animals, certain types of sensations are striking in their subtlety, but the manifestation of this finely developed ability of sensation cannot go beyond the boundaries of that circle of objects and their properties that have direct vital significance for animals of a given species. For example, bees are able to distinguish the concentration of sugar in a solution much more subtly than the average person, but this limits the subtlety of their taste sensations. Another example: a lizard that can hear the slight rustle of a crawling insect will not react in any way to the very loud knock of stone on stone.
In humans, the ability to feel is not limited by biological needs. Labor created in him an incomparably wider range of needs than in animals, and in activities aimed at satisfying these needs, human abilities were constantly developing, including the ability to feel. Therefore, a person can sense a much larger number of properties of the objects around him than an animal.
7.2. Types of sensations
There are different approaches to classifying sensations. It has long been customary to distinguish between five (based on the number of sense organs) main types of sensations: smell, taste, touch, vision and hearing. This classification of sensations according to the main modalities is correct, although not exhaustive. B. G. Ananyev spoke about eleven types of sensations. A. R. Luria believes that the classification
170 Part II. Mental processes
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Sherrington Charles Scott(1857-1952) - English physiologist and psychophysiologist. In 1885, he graduated from Cambridge University and then worked at such famous universities as London, Liverpool, Oxford and Edinburgh. From 1914 to 1917 he was a research professor in physiology at the Royal Institution in Great Britain. Nobel Prize winner. He became widely known for his experimental research, which he conducted based on the idea of the nervous system as an integral system. He was one of the first to attempt an experimental test of the James-Lange theory and showed that the separation of the visceral nervous system from the central nervous system does not change the general behavior of the animal in response to emotiogenic influence.
Ch. Sherrington belongs to the classification of receptors into exteroceptors, proprioceptors and interoceptors. He also experimentally showed opportunity origin of distant receptors from contact ones.
sensations can be carried out according to at least two basic principles - systematic And genetic (in other words, according to the principle of modality, with one sides and principle difficulties or the level of their construction - on the other).
Let's consider systematic classification sensations (Fig. 7.1). This classification was proposed by the English physiologist C. Sherrington. Considering the largest and most significant groups of sensations, he divided them into three main types: interoceptive, proprioceptive and exteroceptive Feel. The first combine signals reaching us from the internal environment of the body; the latter transmit information about the position of the body in space and the position of the musculoskeletal system, and ensure the 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 sensations signaling the state of the internal processes of the body arise thanks to receptors located on the walls of the stomach and intestines, heart and circulatory system and other internal organs. This is the most ancient and most elementary group of sensations. Receptors that perceive information about the state of internal organs, muscles, etc. are called internal receptors. Interoceptive sensations are among the least conscious and most diffuse forms of sensations and always retain their proximity to emotional states. It should also be noted that interoceptive sensations are often called organic.
Proprioceptive sensations transmit signals about the position of the body in space and form the afferent basis of human movements, playing a decisive role in their regulation. The described group of sensations includes a sense of balance, or static sensation, as well as a motor, or kinesthetic, sensation.
Peripheral receptors of proprioceptive sensitivity are located in muscles and joints (tendons, ligaments) and are called Paccini corpuscles.
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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.
Peripheral receptors for the sensation of balance are located in the semicircular canals of the inner ear.
The third and largest group of sensations are exteroceptive Feel. 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.
Rice. 7.1.
Systematic classification of the main types of sensations
172 Part II. Mental processes
Contact sensations are caused by the direct impact of an object on the senses. Examples of contact sensation are taste and touch. Distant sensations reflect the qualities of objects located at some distance from the sense organs. Such sensations include hearing and vision. It should be noted that the sense of smell, according to many authors, occupies an intermediate position between contact and distant sensations, since formally olfactory sensations arise at a distance from the object, but “at the same time, the molecules characterizing the smell of the object with which the olfactory receptor contacts are undoubtedly belong to this subject.This is the duality of the position occupied by the sense of smell in the classification of sensations.
Since sensation arises as a result of the action of a certain physical stimulus on the corresponding receptor, the primary classification of sensations considered by us proceeds, naturally, from the type of receptor that gives the sensation of a given quality, or “modality”. However, there are sensations that cannot be associated with any specific modality. Such sensations are called intermodal. These include, for example, vibration sensitivity, which connects the tactile-motor sphere with the auditory sphere.
The sensation of vibration is the sensitivity to vibrations caused by a moving body. According to most researchers, the vibration sense is an intermediate, transitional form between tactile and auditory sensitivity. In particular, the school of L. E. Komendantov believes that tactile-vibration sensitivity is one of the forms of sound perception. With normal hearing, it does not appear particularly prominent, but with damage to the auditory organ, this function is clearly manifested. The main position of the “auditory” theory is that tactile perception of sound vibration is understood as diffuse sound sensitivity.
Vibration sensitivity acquires particular practical significance in cases of damage to vision and hearing. It plays a big role in the lives of deaf and deaf-blind people. Deaf-blind people, thanks to the high development of vibration sensitivity, learned about the approach of a truck and other types of transport at a great distance. In the same way, through the vibrational sense, deaf-blind people know when someone enters their room. Consequently, sensations, being the simplest type of mental processes, are actually very complex and have not been fully studied.
It should be noted that there are other approaches to the classification of sensations. For example, the genetic approach proposed by the English neurologist H. Head. Genetic classification allows us to distinguish two types of sensitivity: 1) protopathic (more primitive, affective, less differentiated and localized), which includes organic feelings (hunger, thirst, etc.); 2) epicritic (more subtly differentiating, objectified and rational), which includes the main types of human sensations. Epicritic sensitivity is younger in genetic terms, and it controls protopathic sensitivity.
The famous domestic psychologist B. M. Teplov, considering the types of sensations, divided all receptors into two large groups: exteroceptors (external
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receptors), located on the surface of the body or close to it and accessible to external stimuli, and interoceptors (internal receptors), located deep in tissues, such as muscles, or on surfaces of internal organs. The group of sensations that we called “proprioceptive sensations” was considered by B. M. Teplov as internal sensations.
7.3. Basic properties andsensation characteristics
All sensations can be characterized in terms of their properties. Moreover, the 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 a given sensation, distinguishes it from other types of sensations and varies within a given 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 an object, but of a different kind: flower smell, almond smell, hydrogen sulfide smell, etc.
It should be borne in mind that very often, when they talk 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 current 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 sensations are a temporary characteristic of the sensation that has arisen. 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. It should be noted that sensations have a so-called patent (hidden) period. When a stimulus acts on a 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 appear simultaneously with the onset of the stimulus and does not disappear simultaneously with the cessation of its effect. This inertia of sensations manifests itself in the so-called aftereffect. A visual sensation, for example, has some inertia and does not disappear immediately after the cessation of the action of the stimulus that caused it. The trace of the stimulus remains in the form of a consistent image. There are positive and negative sequential
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Names
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 natural relationships between two types of phenomena - mental and physical - functionally interconnected. The idea he put forward had a significant impact on the development of experimental psychology, and the research 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 indirectly measuring sensation, in particular three classical methods for measuring thresholds. However, after studying sequential images caused by observing the sun, he partially lost his vision, which forced leave him psychophysics and engage in philosophy. Fechner was a comprehensively developed person. Thus, he published several satirical works under the pseudonym “Dr. Mises.”
images. Positive consistent image corresponds to the initial irritation, consists in maintaining a trace of irritation of the same quality as the actual stimulus.
Negative sequential image consists in the emergence of a quality of sensation opposite to the quality of the stimulus that acts. For example, light-darkness, heaviness-lightness, warmth-cold, etc. The emergence of negative sequential images is explained by a decrease in the sensitivity of a given receptor to a certain influence.
And finally, sensations are characterized by 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 what part of the body the stimulus affects.
All the properties described above, to one degree or another, reflect the qualitative characteristics of sensations. However, no less important are the quantitative parameters of the main characteristics of sensations, in other words, the degree sensitivity. Human senses are amazingly fine-working devices. 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 low that it would take 60,000 years to use it to heat 1 cm 3 of water by 1°. Perhaps no other physical device has such sensitivity.
There are two types of sensitivity: absolute sensitivity And sensitivity to difference. Absolute sensitivity refers to the ability to sense weak stimuli, and difference sensitivity refers to the ability to sense weak differences between stimuli. However Not every irritation causes a sensation. We don't hear the ticking of a clock in another room. We don't see sixth magnitude stars. In order for a sensation to arise, the strength of irritation must have a certain amount.
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The minimum magnitude of the stimulus at which sensation first occurs is called the absolute threshold of sensation. Stimuli whose strength lies below the absolute threshold of sensation do not produce sensations, but this does not mean that they do not have any effect on the body. Thus, studies by Russian physiologist G.V. Gershuni and his colleagues showed that sound stimulation below the threshold of sensation can cause changes in the electrical activity of the brain and dilation of the pupil. The zone of influence of stimuli that do not cause sensations was called by G.V. Gershuni the “subsensory area.”
The study of sensation thresholds was started 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 border between the material and the ideal lies. Fechner approached this problem as a natural scientist. In his opinion, the process of creating a mental image can be represented by the following diagram:
Irritation -> Excitement -> Feeling -> Judgment (physics) (physiology) (psychology) (logic)
The most important thing in Fechner's idea was that he was the first to include elementary sensations in the range of interests of psychology. Before Fechner, it was believed that the study of sensations, if anyone was interested in it, should be carried out by physiologists, doctors, even physicists, but not psychologists. This is too primitive for psychologists.
According to Fechner, the desired boundary passes where sensation begins, that is, the first mental process arises. Fechner called the magnitude of the stimulus at which sensation begins the 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.
1. The human sensory system is a measuring device that responds appropriately to physical stimuli.
2. Psychophysical characteristics in people are distributed according to a normal law, that is, they randomly differ from some average value, similar to anthropometric characteristics.
Today there is no doubt that both of these paradigms are already outdated and, to a certain extent, contradict modern principles of psychic research. In particular, we can note the contradiction to the principle of activity and integrity of the psyche, since today we understand that it is impossible to isolate and experimentally study one, even the most primitive, mental system from the entire structure of the human psyche. In turn, 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 individual approach to each subject.
Nevertheless, Fechner's research was innovative in its essence. He believed that a person cannot directly evaluate his sensations quantitatively, so he developed “indirect” methods with which one can
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quantitatively represent the relationship between the magnitude of the stimulus (stimulus) and the intensity of the sensation caused by it. Suppose we are interested in at what minimum value of the sound signal the subject can hear this signal, i.e. we must determine lower absolute threshold volume. Measurement minimal change method is carried out as follows. The subject is given instructions to say “yes” if he hears the signal, and “no” if he does not hear it. First, the subject is presented with a stimulus that he can clearly hear. Then, with each presentation, the stimulus magnitude decreases. This procedure is carried out until the subject’s answers change. For example, instead of “yes,” he may say “no” or “apparently not,” etc.
The magnitude of the stimulus at which the subject's responses change corresponds to the threshold for the disappearance of sensation (P 1). At the second stage of measurement, in the first presentation the subject is presented with a stimulus that he cannot hear in any way. Then, at each step, the stimulus magnitude increases until the subject's responses move from “no” to “yes” or “maybe yes.” This stimulus value corresponds threshold of appearance sensations (P 2). But the threshold for the disappearance of a sensation is rarely equal to the threshold for its appearance. Moreover, two cases are possible:
P 1 >P 2 or P 1< Р 2 .
Accordingly, the absolute threshold (Stp) will be equal to the arithmetic mean of the appearance and disappearance thresholds:
Stp = (P 1 + P 2)/ 2
In a similar way, it is determined upper absolute threshold - the value of the stimulus at which it ceases to be perceived adequately. The upper absolute threshold is sometimes called pain threshold, because with corresponding magnitudes of stimuli we experience pain - pain in the eyes when the light is too bright, pain in the ears when the sound is too loud.
Absolute thresholds - upper and lower - determine the boundaries of the surrounding world accessible to our perception. By analogy with a measuring device, absolute thresholds determine the range over which the sensory system can measure stimuli, but beyond this range, the performance of the device is characterized by its accuracy, or sensitivity. The absolute threshold value characterizes absolute sensitivity. For example, the sensitivity of two people will be higher in the one who experiences sensations when exposed to a weak stimulus, when the other person has not yet experienced sensations (i.e., who has a lower absolute threshold value). Consequently, the weaker the stimulus that causes the sensation, the higher the sensitivity.
Thus, absolute sensitivity is numerically equal to a value inversely proportional to the absolute threshold of sensations. If absolute sensitivity is denoted by the letter E, and the value of the absolute threshold R, then the relationship between absolute sensitivity and absolute threshold can be expressed by the formula:
E = 1/P
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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 the sensation of taste than to produce the sensation of smell.
The absolute sensitivity of the analyzer depends equally on both the lower and the upper threshold of sensation. The value of absolute thresholds, both lower and upper, varies depending on various conditions: the nature of the person’s activity and age, the functional state of the receptor, the strength and duration of the stimulus, etc.
Another characteristic of sensitivity is sensitivity to difference. She is also called relative, or difference, since it is sensitivity to changes in stimulus. If we put a load weighing 100 grams on our hand, and then add another gram to this weight, then not a single person will be able to feel this increase. In order to feel an increase in weight, you need to add three to five grams. Thus, in order to feel a minimal difference in the characteristics of the influencing stimulus, it is necessary to change the strength of its influence by a certain amount, and that minimum difference between stimuli that gives a barely noticeable difference in sensations is called the discrimination threshold.
Back in 1760 French physicist P. Bouguer, using the material of light sensations, established a very important fact regarding the magnitude of discrimination thresholds: in order to feel a change in illumination, it is necessary to change the flow of light by a certain amount. We will not be able to notice changes in the characteristics of the light flux by a smaller amount with the help of our senses. Later, in the first half of the 19th century. The German scientist M. Weber, studying the feeling 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 differences to the size of the compared objects. So, if you need to add three grams to a load of 100 grams in order to feel the difference, then you need to add six grams to a load of 200 grams in order to feel the differences. In other words: in order to notice an increase in weight, you need to add approximately ^d of its mass to the original load. Further research showed that a similar pattern exists for other types of sensations. For example, if the initial illumination of a room is 100 lux, then the increase in illumination that we first notice should be at least one lux. If the illumination is 1000 lux, then the increase should be at least 10 lux. The same applies to auditory, motor, and other sensations. So, the threshold for differences in sensations is determined by the relation
DI/I
Where DI- the amount by which the original stimulus that has already generated the sensation must be changed in order for a person to notice that it has really changed; I- the magnitude of the current stimulus. Moreover, studies have shown that the relative
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the value characterizing the discrimination threshold is constant for a particular analyzer. For a visual analyzer this ratio is approximately 1/1000, for an auditory analyzer - 1/10, for a tactile analyzer - 1/30. Thus, the discrimination threshold has a constant relative value, that is, it is always expressed as a ratio showing what part of the original value of the stimulus must be added to this stimulus in order to obtain a barely noticeable difference in sensations. This position was called Bouguer-Weber law. In mathematical form, this law can be written as follows:
DI/I= const,
Where const(constant) - a constant value characterizing the threshold of difference in sensation, called Weber's constant. The parameters of the Weber constant are given in table. 7.1.
Table 7.1 The value of Weber's constant for various senses
Based on Weber's experimental data, another German scientist, G. Fechner, formulated the following law, usually called Fechner's law: if the intensity of stimulation increases in geometric progression, then sensations will increase in arithmetic progression. In another formulation, this law sounds like this: the intensity of sensations increases in proportion to the logarithm of the intensity of the stimulus. Therefore, if the stimulus forms the following series: 10; 100; 1000; 10,000, then the intensity of the sensation will be proportional to the numbers 1; 2; 3; 4. The main meaning of this pattern is that the intensity of sensations does not increase in proportion to the change in stimuli, but much more slowly. In mathematical form, the dependence of the intensity of sensations on the strength of the stimulus is expressed by the formula:
S = K * LgI +C,
(Where S- intensity of sensation; I - stimulus strength; K and C- constants). This formula reflects the situation, which is called basic psychophysical law, or the Weber-Fechner law.
Half a century after the discovery of the basic psychophysical law, it again attracted attention and generated much controversy over its accuracy. The American scientist S. Stevens came to the conclusion that the main psychophysical
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The physical law is expressed not by a logarithmic curve, but by a power curve. He proceeded from the assumption that sensations, or sensory space, are characterized by the same relationship as stimulus space. This pattern can be represented by the following mathematical expression:
D E / E = K
Where E - primary sensations D E - the minimal change in sensation that occurs when the acting stimulus changes by the minimum amount noticeable to a person. Thus, from this mathematical expression it follows that the relationship between the minimum possible change in our sensations and the primary sensation is a constant value - TO. And if this is so, then the relationship between stimulus space and sensory space (our sensations) can be represented by the following equation:
DE/E = K xDI / I
This equation is called Stevens law. The solution to this equation is expressed by the following formula:
S = K x Rn,
where S - strength of sensations, TO - constant determined by the chosen unit of measurement, P - an indicator depending on the modality of sensations and varying from 0.3 for the sensation of loudness to 3.5 for the sensation obtained from an electric shock, R - the value of the influencing stimulus.
American scientists R. and B. Tetsunyan tried to mathematically explain the meaning of the degree P. As a result, they came to the conclusion that the value of the degree P for each modality (i.e., for each sense organ) determines the relationship between the range of sensations and the range of perceived stimuli.
The debate about which law is more accurate has never been resolved. Science knows of numerous attempts to answer this question. One of these attempts belongs to Yu. M. Zabrodin, who proposed his own explanation of the psychophysical relationship. The world of stimuli is again represented by the Bouguer-Weber law, and Zabrodin proposed the structure of sensory space in the following form:
DHERz
DHERz= K xDI / I
Obviously, at z = 0 the formula of the generalized law transforms into Fechner’s logarithmic law, and at z = 1 - to Stevens' power law.
Why did Yu. M. Zabrodin introduce the constant 2 and what is its meaning? The fact is that the value of this constant determines the degree of awareness of the subject about the goals, objectives and progress of the experiment. In G. Fechner's experiments they took
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participation of “naive” subjects who found themselves in a completely unfamiliar experimental situation and knew nothing except the instructions about the upcoming experiment. Thus, in Fechner’s law z = 0, which means complete ignorance of the subjects. Stevens solved more pragmatic problems. He was rather interested in how a person perceives a sensory signal in real life, not abstract work problems sensory system. He proved the possibility of direct estimates of the magnitude of sensations, the accuracy of which increases with proper training of the subjects. His experiments involved subjects who had undergone preliminary training and were trained to act in a situation of a psychophysical experiment. Therefore, in Stevens' law z = 1, which shows the complete awareness of the subject.
Thus, the law proposed by Yu. M. Zabrodin removes the contradiction between Stevens' and Fechner's laws. Therefore, it is no coincidence that it received the name generalized psychophysical law.
However, no matter how the contradiction between Fechner’s and Stevens’ laws is resolved, both options quite accurately reflect the essence of the change in sensations when the magnitude of stimulation changes. First, sensations change disproportionately to the strength of the physical stimuli acting on the senses. Secondly, the strength of sensation grows much more slowly than the magnitude of physical stimuli. This is precisely the meaning of psychophysical laws.
7.4. Sensory adaptation and interaction of sensations
Speaking about the properties of sensations, we cannot help but dwell on a number of phenomena associated with sensations. It would be wrong to assume that absolute and relative sensitivity remain unchanged and that their thresholds are expressed in constant numbers. Research shows that sensitivity can vary within very wide limits. For example, in the dark our vision becomes sharper, and in strong light its sensitivity decreases. This can be observed when you move from a dark room to light or from a brightly lit room to darkness. In both cases, the person becomes temporarily “blind”; it takes some time for the eyes to adjust to bright light or darkness. This suggests that depending on the surrounding environment (lighting), a person’s visual sensitivity changes dramatically. Studies have shown that this change is very large and the sensitivity of the eye in the dark increases 200,000 times.
The described changes in sensitivity, depending on environmental conditions, are associated with the phenomenon of sensory adaptation. Sensory adaptation is a change in sensitivity that occurs as a result of the adaptation of a sensory organ to the stimuli acting on it. As a rule, adaptation is expressed in the fact that when the sense organs are exposed to sufficiently strong stimuli, sensitivity decreases, and when exposed to weak stimuli or in the absence of a stimulus, sensitivity increases.
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This change in sensitivity does not occur immediately, but requires a certain amount of time. Moreover, the time characteristics of this process are not the same for different sense organs. So, in order for vision in a dark room to acquire the necessary sensitivity, about 30 minutes should pass. Only after this does a person acquire the ability to navigate well in the dark. Adaptation of the auditory organs occurs much faster. Human hearing adapts to the surrounding background within 15 s. The sensitivity of touch also changes quickly (a slight touch to the skin is no longer perceived after just a few seconds).
The phenomena of thermal adaptation (getting used to changes in ambient temperature) are quite well known. However, these phenomena are clearly expressed only in the average range, and habituation to extreme cold or extreme heat, as well as to painful stimuli, almost never occurs. The phenomena of adaptation to odors are also known.
The adaptation of our sensations mainly depends on the processes occurring in the receptor itself. For example, under the influence of light, visual purple, located in the rods of the retina, decomposes (fades). In the dark, on the contrary, visual purple is restored, which leads to increased sensitivity. However, the phenomenon of adaptation is also associated with processes occurring in the central sections of the analyzers, in particular with changes in the excitability of nerve centers. With prolonged stimulation, the cerebral cortex responds with internal protective inhibition, reducing sensitivity. The development of inhibition causes increased excitation of other foci, contributing to increased sensitivity in new conditions. In general, adaptation is an important process, indicating the greater plasticity of the organism in its adaptation to environmental conditions.
There is one more phenomenon that we must consider. All types of sensations are not isolated from each other, therefore 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 acting in this moment to other senses. A change in the sensitivity of the analyzer under the influence of irritation of other sense organs is called interaction of sensations.
It is necessary to distinguish between two types of interaction of sensations: 1) interaction between sensations of the same type and 2) interaction between sensations of different types.
The interactions between sensations of different types can be illustrated by the research of academician P. P. Lazarev, who found that illumination of the eyes makes audible sounds louder. Similar results were obtained by Professor S.V. Kravkov. He established that not a single sense organ can work without influencing the functioning of other organs. Thus, it turned out that sound stimulation (for example, a whistle) can sharpen the functioning of the visual sense, increasing its sensitivity to light stimuli. Some odors have a similar effect, increasing or decreasing light and auditory sensitivity. All our analyzing systems are capable of influencing each other to a greater or lesser extent. At the same time, the interaction of sensations, like adaptation, manifests itself in two opposite processes -
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Luria Alexander Romanovich(1902-1977) - Russian psychologist who dealt with many problems in various areas of psychology. He is rightfully considered the founder of Russian neuropsychology. Full member of the Academy of Pedagogical Sciences of the USSR, Doctor of Psychological and Medical Sciences, professor, author of more than 500 scientific papers. He worked with L. S. Vygotsky to create a cultural-historical concept of the development of higher mental functions, as a result of which in 1930, together with Vygotsky, he wrote the work “Etudes on the History of Behavior.” Exploring in the 1920s. affective states of a person, created an original psychophysiological method of conjugate motor reactions intended for the analysis of affective complexes. He repeatedly organized expeditions to Central Asia and personally took part in them. Based on the material collected on these expeditions, he made a number of interesting generalizations regarding cross-cultural differences in the human psyche.
The main contribution of A. R. Luria to the development of psychological science is the development of the theoretical foundations of neuropsychology, which was expressed in his theory of systemic dynamic localization of higher mental functions and their disorders during brain damage. He conducted research on the neuropsychology of speech, perception, attention, memory, thinking, voluntary movements and actions.
increase and decrease in sensitivity. The general pattern is that weak stimuli increase, and strong ones decrease, the sensitivity of analyzers during their interaction.
A similar picture can be observed during the interaction of sensations of the same type. For example, a point in the dark is easier to see against a light background. An example of the interaction of visual sensations is the phenomenon of contrast, which is expressed in the fact that a color changes in the opposite direction in relation to the colors surrounding it. For example, gray against a white background will appear darker, but when surrounded by black it will appear lighter.
As the examples above suggest, there are ways to increase the sensitivity of the senses. Increased sensitivity as a result of the interaction of analyzers or exercise is called sensitization. A. R. Luria distinguishes two aspects of increased sensitivity according to the type of sensitization. The first is long-term, permanent and depends mainly on lasting changes occurring in the body, so the age of the subject is clearly related to changes in sensitivity. Research has shown, What The sensitivity of the sensory organs increases with age, reaching a maximum by 20-30 years, in order to gradually decrease thereafter. The second side of increased sensitivity according to the type of sensitization is temporary and depends on both physiological and psychological emergency effects on the subject’s condition.
The interaction of sensations is also found in a phenomenon called synesthesia - the occurrence, under the influence of irritation of one analyzer, of a sensation characteristic of other analyzers. In psychology, the facts of “colored hearing” are well known, which occurs in many people, and especially
Chapter 7. Sensation 183
many musicians (for example, Scriabin). Thus, it is widely known that we evaluate high sounds as “light” and low sounds as “dark”.
In some people, synesthesia manifests itself with exceptional clarity. One of the subjects with exceptionally pronounced synesthesia - the famous mnemonist Sh. - was studied in detail by A. R. Luria. This person perceived all voices as colored and often said that the voice of the person addressing him, for example, was “yellow and crumbly.” The tones he heard gave him visual sensations of various shades (from bright yellow to purple). The perceived colors were felt by him as “ringing” or “dull”, as “salty” or “crispy”. Similar phenomena in more erased forms occur quite often in the form of an immediate tendency to “color” numbers, days of the week, names of months in different colors. The phenomena of synesthesia are another evidence of the constant interconnection of the analytical systems of the human body, the integrity of the sensory reflection of the objective world.
7.5. Development of sensations
The sensation begins to develop immediately after the birth of the child. Shortly after birth, the baby begins to respond to stimuli of all kinds. However, there are differences in the degree of maturity of individual feelings and in the stages of their development.
Immediately after birth, the baby's skin sensitivity is more developed. When born, the baby trembles due to the difference in the mother’s body temperature and the air temperature. A newborn baby also reacts to touch, with the lips and the entire mouth area being the most sensitive. It is likely that a newborn can feel not only warmth and touch, but also pain.
Already by the time of birth, the child’s taste sensitivity is quite highly developed. Newborn babies react differently to the introduction of a solution of quinine or sugar into their mouth. A few days after birth, the child distinguishes mother's milk from sweetened water, and the latter from plain water.
From the moment of birth, the child’s olfactory sensitivity is already quite developed. A newborn baby determines by the smell of mother's milk whether the mother is in the room or not. If a child has been fed mother's milk for the first week, he will turn away from cow's milk only when he smells it. However, olfactory sensations not related to nutrition take quite a long time to develop. They are poorly developed in most children even at four to five years of age.
Vision and hearing go through a more complex path of development, which is explained by the complexity of the structure and organization of the functioning of these sense organs and their lower maturity at the time of birth. In the first days after birth, the baby does not respond to sounds, even very loud ones. This is explained by the fact that the newborn’s ear canal is filled with amniotic fluid, which resolves only after a few days. Usually the child begins to respond to sounds during the first week, sometimes this period lasts up to two to three weeks.
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The child's first reactions to sound are of the nature of general motor excitement: the child throws up his arms, moves his legs, and emits a loud cry. Sensitivity to sound is initially low, but increases in the first weeks of life. After two to three months, the child begins to perceive the direction of sound and turns his head towards the sound source. In the third or fourth month, some children begin to respond to singing and music.
As for the development of speech hearing, the child first of all begins to respond to the intonation of speech. This is observed in the second month of life, when a gentle tone has a calming effect on the child. Then the child begins to perceive the rhythmic side of speech and the general sound pattern of words. However, the distinction of speech sounds occurs by the end of the first year of life. From this moment the development of speech hearing itself begins. First, the child develops the ability to distinguish vowels, and at a subsequent stage he begins to distinguish consonants.
A child's vision develops most slowly. Absolute sensitivity to light in newborns is low, but increases markedly in the first days of life. From the moment visual sensations appear, the child reacts to light with various motor reactions. Color discrimination increases slowly. It has been established that the child begins to distinguish color in the fifth month, after which he begins to show interest in all kinds of bright objects.
A child, starting to sense light, at first cannot “see” objects. This is explained by the fact that the child’s eye movements are not coordinated: one eye may look in one direction, the other in another, or may even be closed. The child begins to control eye movements only at the end of the second month of life. He begins to distinguish objects and faces only in the third month. From this moment, the long-term development of the perception of space, the shape of an object, its size and distance begins.
In relation to all types of sensitivity, it should be noted that absolute sensitivity reaches a high level of development already in the first year of life. The ability to distinguish sensations develops somewhat more slowly. In a preschool child, this ability is developed incomparably less than in an adult. Rapid development of this ability is observed during school years.
It should also be noted that the level of development of sensations in different people not the same. This is largely due to human genetic characteristics. Nevertheless, sensations can be developed within certain limits. The development of sensation is carried out through constant training. It is thanks to the possibility of developing sensations that, for example, children learn music or drawing.
7.6. Characteristics of the main types of sensations
Skin sensations. We will begin our acquaintance with the main types of sensations with the sensations that we receive from the influence of various stimuli on the receptors located on the surface of human skin. All the sensations
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which a person receives from skin receptors can be combined under one name - skin sensations. However, the category of these sensations also includes those sensations that arise when exposed to irritants on the mucous membrane of the mouth and nose, and the cornea of the eyes.
Skin sensations belong to the contact type of sensations, i.e. they arise when the receptor comes into direct contact with an object in the real world. In this case, sensations of four main types may arise: sensations of touch, or tactile sensations; feeling cold; sensations of warmth; sensations of pain.
Each of the four types of skin sensations has specific receptors. Some points of the skin give only sensations of touch (tactile points), others - sensations of cold (cold points), others - sensations of warmth (heat points), and fourth - sensations of pain (pain points) (Fig. 7.2).
Rice. 7.2. Skin receptors and their functions
Normal irritants for tactile receptors are touches that cause deformation of the skin, for cold ones - exposure to objects at a lower temperature, for thermal ones - exposure to objects at a higher temperature. high temperature, for pain - any of the listed effects, provided the intensity is sufficiently high. The location of the corresponding receptor points and absolute sensitivity thresholds are determined using an aesthesiometer. The simplest device is a hair esthesiometer (Fig. 7.3), consisting of horse hair and a device that allows you to measure the pressure exerted by this hair on any point of the skin. When a hair gently touches the skin, sensations arise only when it directly hits a tactile point. The location of cold and heat points is determined in the same way, only instead of a hair, a thin metal tip is used, filled with water, the temperature of which can vary.
You can verify the existence of cold spots without a device. To do this, just run the tip of a pencil along the drooping eyelid. As a result, you will experience a feeling of cold from time to time.
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Repeated attempts have been made to determine the number of cutaneous receptors. Accurate results no, but it is approximately established that touch points are about one million, pain points are about four million, cold points are about 500 thousand, heat points are about 30 thousand.
The points of certain types of sensations on the surface of the body are located unevenly. For example, on the fingertips there are twice as many touch points as pain points, although the total number of the latter is much greater. On the cornea of the eye, on the contrary, there are no touch points at all, but only pain points, so any touch to the cornea causes a sensation of pain and a protective reflex of closing the eyes.
The uneven distribution of skin receptors over the surface of the body causes uneven sensitivity to touch, pain, etc. Thus, the tips of the fingers are most sensitive to touch and the back, stomach and outer side of the forearm are less sensitive. Sensitivity to pain is distributed quite differently. The back and cheeks are most sensitive to pain and the fingertips are the least sensitive. As for temperature conditions, the most sensitive are those parts of the body that are usually covered by clothing: the lower back, chest.
Tactile sensations carry information not only about the stimulus, but also about localization its impact. In different parts of the body, the accuracy of determining the localization of the effect is different. It is characterized by the size spatial threshold of tactile sensations. If we touch the skin of one
But at two points at the same time, then we will not always feel these touches as separate - if the distance between the points of contact is not large enough, both sensations will merge into one. Therefore, the minimum distance between the places of contact, which allows one to distinguish the touch of two spatially separate objects, is called spatial threshold of tactile sensations.
Usually, to determine the spatial threshold of tactile sensations, it is used circular aesthesiometer(Fig. 7.4), which is a compass with sliding legs. The lowest threshold of spatial differences in skin sensations is observed in areas that are more sensitive to touch
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Rice.
7.4. Circular esthesiometer
kah bodies. Thus, on the back the spatial threshold of tactile sensations is 67 mm, on the forearm - 45 mm, on the back of the hand - 30 mm, on the palm - 9 mm, at the fingertips 2.2 mm. The lowest spatial threshold is so-
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The typical sensation is located at the tip of the tongue -1.1 mm. This is where touch receptors are most densely located.
Taste and olfactory sensations. The taste receptors are taste buds, consisting of sensitive taste cells connected to nerve fibers (Fig. 7.5). In an adult, taste buds are located mainly at the tip, along the edges and on the back of the upper surface of the tongue. The middle of the upper surface and the entire lower surface of the tongue are not sensitive to taste. Taste buds are also found on the roof of the mouth, tonsils, and the back of the throat. In children, the distribution of taste buds is much wider than in adults. Dissolved taste substances serve as irritants for taste buds.
Receptors olfactory sensations are olfactory cells immersed in the mucous membrane of the so-called olfactory region (Fig. 7.6). Various odorous substances serve as irritants for the olfactory receptors,
Rice.
7.6. Olfactory receptors
188 Part II. Mental processes
penetrating the nose along with air. In an adult, the area of the olfactory region is approximately 480 mm2. In a newborn it is much larger. This is explained by the fact that in newborns the leading sensations are taste and smell. It is thanks to them that the child receives the maximum amount of information about the world around him, and they also provide the newborn with satisfaction of his basic needs. In the process of development, olfactory and taste sensations give way to other, more informative sensations, and primarily vision.
It should be noted that taste sensations in most cases mixed with olfactory. The variety of taste largely depends on the admixture of olfactory sensations. For example, with a runny nose, when the olfactory sensations are “turned off,” in some cases food seems tasteless. In addition, tactile and temperature sensations from receptors located in the area of the mucous membrane in the mouth are mixed with taste sensations. Thus, the originality of the “sharp” or “astringent” mint is mainly associated with tactile sensations, and the characteristic taste of mint largely depends on the irritation of cold receptors.
If we exclude all these admixtures of tactile, temperature and olfactory sensations, then the actual taste sensations will be reduced to four main types: sweet, sour, bitter, salty. The combination of these four components allows you to get a variety of flavor options.
Experimental studies of taste sensations were carried out in the laboratory of P. P. Lazarev. To obtain taste sensations, sugar, oxalic acid, table salt and quinine were used. It was found that with the help of these substances it is possible to imitate most taste sensations. For example, the taste of a ripe peach gives a combination of sweet, sour and bitter in certain proportions.
It has also been experimentally established that different parts of the tongue have different sensitivity to the four taste qualities. For example, sensitivity to sweet is maximum at the tip of the tongue and minimal at the back of it, and sensitivity to bitter, on the contrary, is maximum at the back and minimal at the tip of the tongue.
Unlike taste, olfactory sensations cannot be reduced to combinations of basic odors. Therefore, there is no strict classification of odors. All smells are tied to a specific object that possesses them. For example, a floral smell, the smell of a rose, the smell of jasmine, etc. As with taste sensations, admixtures of other sensations play a large role in the production of smell:
gustatory (especially from irritation of the taste buds located in the back of the throat), tactile and temperature. The pungent, pungent smells of mustard, horseradish, and ammonia contain an admixture of tactile and painful sensations, while the refreshing smell of menthol contains an admixture of cold sensations.
You should also pay attention to the fact that the sensitivity of the olfactory and taste receptors increases during a state of hunger. After several hours of fasting, absolute sensitivity to sweets increases significantly, and sensitivity to sour increases, but to a lesser extent. This suggests that olfactory and gustatory sensations are largely
Chapter 7. Sensation 189
to a certain extent related to the need to satisfy such biological needs as the need for food.
Individual differences in taste sensations among people are small, but there are exceptions. Thus, there are people who are able to distinguish components of smell or taste to a much greater extent than most people. The senses of taste and smell can be developed through constant training. This is taken into account when mastering the profession of taster.
Auditory sensations. The irritant for the organ of hearing is sound waves, i.e., longitudinal vibrations of air particles, spreading in all directions from the vibrating body, which serves as a source of sound.
All sounds that the human ear perceives can be divided into two groups: musical(sounds of singing, sounds musical instruments etc.) and noises(all kinds of creaks, rustles, knocks, etc.). There is no strict boundary between these groups of sounds, since musical sounds contain noise, and noise can contain elements of musical sounds. Human speech typically contains sounds from both groups simultaneously.
Sound waves are distinguished by frequency, amplitude and vibration shape. Accordingly, auditory sensations have the following three sides: pitch, which is a reflection of the vibration frequency; sound volume, which is determined by the amplitude of the oscillation waves; timbre, That is reflection of the waveform.
The pitch of sound is measured in hertz, i.e., in the number of vibrations of a sound wave per second. The sensitivity of the human ear has its limits. The upper limit of hearing in children is 22,000 hertz. By old age, this limit drops to 15,000 hertz and even lower. Therefore, older people often cannot hear high-pitched sounds, such as the chirping of grasshoppers. The lower limit of human hearing is 16-20 hertz.
Absolute sensitivity is highest for mid-frequency sounds, 1000–3000 hertz, and the ability to discriminate pitch varies greatly among individuals. The highest threshold of discrimination is observed among musicians and tuners of musical instruments. The experiments of B.N. Teplov indicate that in people of this profession the ability to distinguish the pitch of a sound is determined by a parameter of 1/20 or even 1/30 of a semitone. This means that between two adjacent piano keys the tuner can hear 20-30 intermediate pitch steps.
The loudness of a sound is the subjective intensity of an auditory sensation. Why subjective? We cannot talk about the objective characteristics of sound, because, as follows from the basic psychophysical law, our sensations are proportional not to the intensity of the stimulus, but to the logarithm of this intensity. Secondly, the human ear has different sensitivity to sounds of different pitches. Therefore, sounds that we cannot hear at all can exist and influence our body with the highest intensity. Thirdly, there are individual differences between people in terms of absolute sensitivity to auditory stimuli. However, practice determines the need to measure sound volume. The units of measurement are decibels. One unit of measurement is the intensity of the sound emanating from the ticking of a clock at a distance of 0.5 m from the human ear. Thus, the volume of ordinary human speech at a distance of 1 meter
Part II. Mental processes
Names
|
Helmholtz Hermann(1821-1894) - German physicist, physiologist and psychologist. Being a physicist by training, he sought to bring into the study of a living organism physical methods research. In his work “On the Conservation of Force,” Helmholtz mathematically substantiated the law of conservation of energy and the position that a living organism is a physicochemical environment in which this law is precisely fulfilled. He was the first to measure the speed of excitation along nerve fibers, which marked the beginning of the study of reaction time.
Helmholtz made significant contributions to the theory of perception. In particular, in the psychology of perception, he developed the concept of unconscious inferences, according to which actual perception is determined by the habitual ways a person already has, through which the constancy of the visible world is maintained and in which muscle sensations and movements play a significant role. Based on this concept, he made an attempt to explain the mechanisms of space perception. Following behind M. V. Lomonosov developed a three-component theory of color vision. Developed the resonance theory of hearing. In addition, Helmholtz made a significant contribution to the development of world psychological science. Yes, him
collaborators and students were V. Wundt, I. M. Sechenov and others.
will be 16-22 decibels, noise on the street (without a tram) - up to 30 decibels, noise in the boiler room - 87 decibels, etc.
Timbre is that specific quality that distinguishes sounds of the same pitch and intensity produced by different sources from each other. Timbre is often spoken of as the “color” of sound.
Differences in timbre between two sounds are determined by the variety of forms of sound vibration. In the very simple case the shape of the sound vibration will correspond to a sinusoid. Such sounds are called “simple”. They can only be obtained using special devices. Close to a simple sound is the sound of a tuning fork - a device used to tune musical instruments. In everyday life we do not encounter simple sounds. The sounds around us consist of various sound elements, so the shape of their sound, as a rule, does not correspond to a sine wave. But nevertheless, musical sounds arise from sound vibrations that have the form of a strict periodic sequence, and in noise it is the other way around. The form of sound vibration is characterized by the absence of strict periodization.
It should also be borne in mind that in everyday life we perceive many simple sounds, but we do not distinguish this variety, because all these sounds merge into one. For example, two sounds of different pitches are often, as a result of their merging, perceived by us as one sound with a certain timbre. Therefore, the combination of simple sounds in one complex one gives originality to the shape of the sound vibration and determines the timbre of the sound. The timbre of the sound depends on the degree of fusion of sounds. The simpler the form of sound vibration, the more pleasant the sound. Therefore, it is customary to highlight a pleasant sound - consonance and unpleasant sound - dissonance.
Chapter 7. Sensation 191
Rice. 7.7. The structure of auditory receptors
The best explanation of the nature of auditory sensations comes from Helmholtz's resonance theory of hearing. As is known, the terminal apparatus of the auditory nerve is the organ of Corti, resting on main membrane, running along the entire spiral bone canal called snail(Fig. 7.7). The main membrane consists of a large number (about 24,000) of transverse fibers, the length of which gradually decreases from the apex of the cochlea to its base. According to Helmholtz's resonance theory, each such fiber is tuned, like a string, to a certain vibration frequency. When sound vibrations of a certain frequency reach the cochlea, a certain group of fibers of the main membrane resonates and only those cells of the organ of Corti that rest on these fibers are excited. Shorter fibers lying at the base of the cochlea respond to higher sounds, longer fibers lying at its apex respond to low sounds.
It should be noted that the staff of I.P. Pavlov’s laboratory, who studied the physiology of hearing, came to the conclusion that Helmholtz’s theory quite accurately reveals the nature of auditory sensations.
Visual sensations. The irritant for the organ of vision is light, i.e. electromagnetic waves having a length of 390 to 800 millimicrons (a millimicron is a millionth of a millimeter). Waves of a certain length cause a person to feel a certain color. For example, the sensations of red light are caused by waves with a length of 630-800 millimicrons, yellow - by waves from 570 to 590 millimicrons, green - by waves from 500 to 570 millimicrons, blue - by waves from 430 to 480 millimicrons.
Everything we see has color, so visual sensations are sensations of color. All colors are divided into two large groups: colors achromatic and colors chromatic. Achromatic colors include white, black and gray. All other colors (red, blue, green, etc.) are chromatic.
192 Part II. Mental processes
From the history of psychology Hearing theories It should be noted that Helmholtz's resonance theory of hearing is not the only one. Thus, in 1886, the British physicist E. Rutherford put forward a theory with which he tried to explain the principles of coding the pitch and intensity of sound. His theory contained two statements. First, in his opinion, a sound wave causes the entire eardrum (membrane) to vibrate, and the frequency of vibration corresponds to the frequency of sound. Secondly, the frequency of vibration of the membrane sets the frequency of nerve impulses transmitted along the auditory nerve. Thus, a tone with a frequency of 1000 hertz causes the membrane to vibrate 1000 times per second, causing the auditory nerve fibers to discharge at a frequency of 1000 impulses per second, and the brain interprets this as a certain pitch. Since this theory assumed that pitch depends on changes in sound over time, it was called the time theory (in some literary sources it is also called frequency theory). It turned out that Rutherford's hypothesis is not able to explain all the phenomena of auditory sensations. For example, it was discovered that nerve fibers can transmit no more than 1000 impulses per second, and then it is unclear how a person perceives pitches with a frequency of more than 1000 hertz. In 1949, V. Weaver attempted to modify Rutherford's theory. He suggested that frequencies above 1000 hertz are encoded by different groups of nerve fibers, each of which fires at slightly different rates. If, for example, one group of neurons produces 1000 impulses per second, a. then 1 millisecond later another group of neurons starts firing 1000 pulses per second, then the combination of the pulses of these two groups will give 2000 pulses per second. However, after some time it was found that this hypothesis can explain the perception of sound vibrations, the frequency of which does not exceed 4000 hertz, and we can hear higher sounds. Since Helmholtz's theory can more accurately explain how the human ear perceives sounds of different pitches, it is now more accepted. To be fair, it should be answered that the main idea of this theory was expressed by the French anatomist Joseph Guichard Duvernier, who in 1683 suggested that frequency is encoded by the pitch of sound mechanically, by resonance. Exactly how the membrane oscillates was not known until 1940, when Georg von Bekesy was able to measure its movements. he found that the membrane behaved not like a piano with separate strings, but like a sheet that had been shaken at one end. When a sound wave enters the ear, the entire membrane begins to vibrate (vibrate), but at the same time, the location of the most intense movement depends on the pitch of the sound. High frequencies cause vibration at the near end of the membrane; As the frequency increases, the vibration shifts towards the oval window. For this and for a number of other studies of hearing, von Bekesy received the Nobel Prize in 1961. However, it should be noted that this theory of locality explains many, but not all, phenomena of pitch perception. In particular, the main difficulties are associated with low frequency tones. The fact is that at frequencies below 50 hertz, all parts of the basilar membrane vibrate approximately equally. This means that all receptors are activated equally, which means that we have no way of distinguishing between frequencies below 50 hertz. In fact, we can distinguish a frequency of only 20 hertz. Thus, at present, there is no complete explanation of the mechanisms of auditory sensations. |
Sunlight, like light from any artificial source, consists of waves of different lengths. At the same time, any object, or physical body, will be perceived in a strictly defined color (color combination). The color of a particular object depends on what waves and in what proportion are reflected by this object. If an object uniformly reflects all waves, i.e. it is characterized by a lack of selectivity of reflection, then its color will be achromatic. If it is characterized by selectivity of wave reflection, i.e. it reflects
Chapter 7. Sensation 193
predominantly waves of a certain length, and absorbs the rest, then the object will be painted in a certain chromatic color.
Achromatic colors differ from each other only in lightness. Lightness depends on the reflectance of the object, i.e., on what part of the incident light he reflects. The higher the reflectance, the lighter the color. For example, white writing paper, depending on its type, reflects from 65 to 85% of the light incident on it. The black paper in which photographic paper is wrapped has a reflectance of 0.04, i.e., it reflects only 4% of the incident light, and good black velvet reflects only 0.3% of the light incident on it - its reflectance is 0.003.
Chromatic colors are characterized by three properties: lightness, hue and saturation. The color tone depends on which wavelengths predominate in the light flux reflected by a given object. Saturation is the degree of expression of a given color tone, i.e. the degree of difference between a color and gray that is the same in lightness. Color saturation depends on how dominant the wavelengths in the light flux are that determine its color tone.
It should be noted that our eye has unequal sensitivity to light waves of different lengths. As a result, the colors of the spectrum, with objective equality of intensity, seem to us to be unequal in lightness. The lightest color seems to us to be yellow, and the darkest color to be blue, because the sensitivity of the eye to waves of this length is 40 times lower than the sensitivity of the eye to yellow color. It should be noted that the sensitivity of the human eye is very high. For example, between black and white, a person can distinguish about 200 transitional colors. However, it is necessary to separate the concepts of “eye sensitivity” and “visual acuity”.
Visual acuity is the ability to distinguish between small and distant objects. The smaller the objects that the eye is able to see under specific conditions, the higher its visual acuity. Visual acuity is characterized by a minimum gap between two points, which from a given distance are perceived separately from each other, and do not merge into one. This value can be called the spatial visual threshold.
In practice, all the colors we perceive, even those that appear monochromatic, are the result of a complex interaction of light waves of different lengths. Waves of different lengths simultaneously enter our eye, and the waves mix, resulting in us seeing one specific color. The laws of color mixing were established through the work of Newton and Helmholtz. Of these laws, two are of greatest interest to us. Firstly, for each chromatic color you can choose another chromatic color, which, when mixed with the first one, gives an achromatic color, i.e. white or grey. These two colors are usually called complementary. And secondly, by mixing two non-complementary colors, a third color is obtained - an intermediate color between the first two. One very important point follows from the above laws: all color tones can be obtained by mixing three appropriately selected chromatic colors. This point is extremely important for understanding the nature of color vision.
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In order to understand the nature of color vision, let's take a closer look at the theory of three-color vision, the idea of which was put forward by Lomonosov in 1756, expressed 50 years later by T. Jung, and another 50 years later developed in more detail by Helmholtz. According to Helmholtz's theory, the eye is assumed to have the following three physiological apparatuses: red-sensing, green-sensing and violet-sensing. Isolated excitation of the first gives the sensation of red color. The isolated sensation of the second apparatus gives the sensation of the color green, and the excitation of the third gives the color violet. However, as a rule, the light simultaneously affects all three devices or at least two of them. Moreover, the excitation of these physiological apparatuses with different intensities and in different proportions in relation to each other gives all known chromatic colors. The sensation of white color occurs when all three apparatuses are uniformly excited.
This theory explains well many phenomena, including the disease of partial color blindness, in which a person cannot distinguish individual colors or shades of color. Most often, there is an inability to distinguish shades of red or green. This disease was named after the English chemist Dalton, who suffered from it.
The ability to see is determined by the presence of a retina in the eye, which is a branch of the optic nerve that enters the eyeball from behind. There are two types of apparatus in the retina: cones and rods (so named because of their shape). Rods and cones are the terminal devices of the nerve fibers of the optic nerve. The retina of the human eye has about 130 million rods and 7 million cones, which are unevenly distributed across the retina. Cones fill the central fovea of the retina, that is, the place where the image of the object we are looking at falls. Toward the edges of the retina, the number of cones decreases. There are more rods at the edges of the retina; in the middle they are practically absent (Fig. 7.8).
Cones have low sensitivity. To provoke their reaction, you need a strong enough light. Therefore, with the help of cones we see in bright light. They are also called day vision devices. Rods are more sensitive, and with their help we see at night, which is why they are called night vision apparatus. However, it is only with the help of cones that we distinguish colors, since they determine the ability to cause chromatic sensations. In addition, cones provide the necessary visual acuity.
There are people whose cone apparatus does not function, and they see everything around them only in gray. This disease is called complete color blindness. Conversely, there are cases when the rod apparatus does not function. Such people cannot see in the dark. Their disease is called hemeralopia(or “night blindness”).
Concluding our consideration of the nature of visual sensations, we need to dwell on several more phenomena of vision. Thus, the visual sensation does not cease at the same instant as the action of the stimulus ceases. It continues for some time. This happens because visual stimulation has a certain inertia. This continuation of sensation for some time is called in a positive, consistent manner.
Chapter 7. Sensation 195
Rice. 7.8. Receptors of visual sensations
To observe this phenomenon in practice, sit near a lamp in the evening and close your eyes for two to three minutes. Then open your eyes and look at the lamp for two to three seconds, then close your eyes again and cover them with your hand (so that the light does not penetrate through the eyelids). You will see a light image of a lamp against a dark background. It should be noted that it is thanks to this phenomenon that we watch movies when we do not notice the movement of the film due to the positive sequential image that appears after the frame is exposed.
Another vision phenomenon is associated with a negative sequential image. The essence of this phenomenon is that after exposure to light, the sensation of an opposing stimulus in brightness persists for some time. For example, place two clean white sheets of paper in front of you. Place a square of red paper in the middle of one of them. Draw a small cross in the middle of the red square and look at it for 20-30 seconds without taking your eyes off. Then look at a blank white piece of paper. After a while you will see an image of a red square on it. Only its color will be different - bluish-green. After a few seconds it will begin to fade and will soon disappear. The image of the square is a negative sequential image. Why is the image of the square greenish-blue? The fact is that this color is complementary to the red color, i.e. their fusion gives an achromatic color.
The question may arise: why, under normal conditions, do we not notice the emergence of negative sequential images? Only because our eyes are constantly moving and certain parts of the retina do not have time to get tired.
196 Part II. Mental processes
From the history of psychology Theories of color vision Considering the problem of color vision, it should be noted that in world science the three-color theory of vision is not the only one. There are other points of view on the nature of color vision. Thus, in 1878, Ewald Hering noticed that all colors can be described as consisting of one or two of the following sensations: red, green, yellow and blue. Hering also noted that a person never perceives anything as reddish-green or yellowish-blue; a mixture of red and green will look more yellow, and a mixture of yellow and blue will look more white. From these observations it follows that red and green form an opponent pair - just like yellow and blue - and that the colors included in the opponent pair cannot be perceived simultaneously. The concept of "opponent pairs" was further developed in studies in which the subject first looked at a colored light and then at a neutral surface. As a result, when examining a neutral surface, the subject saw on it a color complementary to the original one. These phenomenological observations led Hering to propose another theory of color vision, called the opponent color theory. Hering believed that there are two types of color-sensitive elements in the visual system. One type responds to red or green, the other to blue or yellow. Each element reacts oppositely to its two opponent colors: for a red-green element, for example, the strength of the reaction increases when presented with red and decreases when presented with green. Since an element cannot respond in two directions at once, when two opponent colors are presented simultaneously, the color yellow is perceived. The theory of opponent colors can explain a number of facts with a certain degree of objectivity. In particular, according to a number of authors, it explains why we see exactly the colors that we see. For example, we perceive only one tone - red or green, yellow or blue - when the balance is shifted in only one type of opponent pair, and we perceive combinations of tones when the balance is shifted in both types of opponent pairs. Objects are never perceived as red-green or yellow-blue because the element cannot react in two directions at once. Additionally, this theory explains why subjects who first looked at a colored light and then at a neutral surface reported seeing additional colors; if, for example, the subject looks at red first, then the red component of the pair becomes tired, as a result of which the green component comes into play. . Thus, in the scientific literature one can find two theories of color vision - three-color (trichromatic) and the theory of opponent colors - and each of them can explain some facts, but not others. For many years, these two theories in the works of many authors were considered as alternative or competitive, until researchers proposed a compromise theory - a two-stage one. According to the two-stage theory, the three types of receptors that are considered in the tri-chromatic theory supply information to opponent pairs located at a higher level of the visual system. This hypothesis was expressed when color-opposite neurons were discovered in the thalamus - one of the intermediate links between the retina and the visual cortex. As studies have shown, these nerve cells have spontaneous activity that increases in response to one wavelength range and decreases in response to another. For example, some cells located at higher levels of the visual system fire faster when the retina is stimulated with blue light than when it is stimulated with yellow light; such cells form the biological basis of the blue-yellow opponent pair. Consequently, targeted studies have established the presence of three types of receptors, as well as color-opponent neurons located in the thalamus. This example convincingly demonstrates how complex a person is. It is likely that many judgments about mental phenomena that seem true to us may after some time be questioned, and these phenomena will have a completely different explanation. |
Chapter 7. Sensation 197
Rice. 7.9. Receptors for the sense of balance
Proprioceptive sensations. As you remember, proprioceptive sensations include sensations of movement and balance. Receptors for sensations of balance are located in the inner ear (Fig. 7.9). The latter consists of three parts:
vestibule, semicircular canals and cochlea. Balance receptors are located in the vestibule.
The movement of fluid irritates the nerve endings located on the inner walls of the semicircular tubes of the inner ear, which is the source of the sense of balance. It should be noted that under normal conditions we receive a sense of balance not only from the named receptors. For example, when our eyes are open, the position of the body in space is determined with the help of visual information, as well as motor and skin sensations, through the information they transmit about movement or information about vibration. But in some special conditions, for example when diving into water, we can only obtain information about the position of the body through a sense of balance.
It should be noted that signals coming from balance receptors do not always reach our consciousness. In most cases, our body reacts to changes in body position automatically, that is, at the level of unconscious regulation.
Receptors for kinesthetic (motor) sensations are located in muscles, tendons and joint surfaces. These sensations give us ideas about the magnitude and speed of our movement, as well as the position in which this or that part of our body is located. Motor sensations play a very important role in coordinating our movements. When performing a particular movement, we, or rather our brain, constantly receive signals from receptors located in the muscles and on the surface of the joints. If a person has impaired processes of forming sensations of movement, then, having closed his eyes, he cannot walk, since he cannot maintain balance in movement. This condition is called ataxia, or movement disorder.
198 Part II. Mental processes
Touch. It should also be noted that the interaction of motor and skin sensations makes it possible to study the subject in more detail. This process - the process of combining skin and motor sensations - is called touch. A detailed study of the interaction of these types of sensations yielded interesting experimental data. Thus, various figures were applied to the skin of the forearm of subjects sitting with their eyes closed: circles, triangles, rhombuses, stars, figures of people, animals, etc. However, they were all perceived as circles. The results were only slightly better when these figures were applied to a stationary palm. But as soon as the subjects were allowed to touch the figures, they immediately and accurately determined their shape.
To the sense of touch, that is, the combination of skin and motor sensations, we owe the ability to evaluate such properties of objects as hardness, softness, smoothness, roughness. For example, the feeling of hardness mainly depends on how much resistance the body provides when pressure is applied to it, and we judge this by the degree of muscle tension. Therefore, it is impossible to determine the hardness or softness of an object without the participation of motion sensations.
In conclusion, we should draw your attention to the fact that almost all types of sensations are interrelated with each other. Thanks to this interaction, we receive the most complete information about the world around us. However, this information is limited only to information about the properties of objects. We obtain a holistic image of the object as a whole through perception.
Control questions
1. What is “sensation”? What are the main characteristics of this mental process?
2. What is the physiological mechanism of sensations? What is an "analyzer"?
3. What is the reflex nature of sensations?
4. What concepts and theories of sensations do you know?
5. What classifications of sensations do you know?
6. What is “modality of sensations”?
7. Describe the main types of sensations.
8. Tell us about the basic properties of sensations.
9. What do you know about absolute and relative sensation thresholds?
10. Tell us about the basic psychophysical law. What do you know about Weber's constant?
11. Talk about sensory adaptation.
12. What is sensitization?
13. What do you know about skin sensations?
14. Tell us about physiological mechanisms visual sensations. What theories of color vision do you know?
15. Tell us about auditory sensations. What do you know about the resonance theory of hearing?
1. Ananyev B. G. On the problems of modern human knowledge / USSR Academy of Sciences, Institute of Psychology. - M.: Nauka, 1977.
2. Vecker L. M. Mental processes: In 3 volumes. T. 1. - L.: Leningrad State University Publishing House, 1974.
3. Vygotsky L. S. Collected works: In 6 volumes. T. 2.: Problems general psychology/ Ch. ed. A.V. Zaporozhets. - M.: Pedagogy, 1982.
4. Gelfand S. A. Hearing. Introduction to psychological and physiological acoustics. - M., 1984.
5. Zabrodin Yu. M., Lebedev A. N. Psychophysiology and psychophysics. - M.: Nauka, 1977.
6. Zaporozhets A.V. Selected psychological works: In 2 volumes. T. 1: Mental development of the child / Ed. V. V. Davydova, V. P. Zinchenko. - M.: Pedagogy, 1986.
7. Krylova A. L. Functional organization auditory system: Textbook. - M.: Moscow State University Publishing House, 1985.
8. Lindsay P., Norman D. Processing information in humans: Introduction to psychology / Trans. from English edited by A. R. Luria. - M.: Mir, 1974.
9. Luria A. R. Sensations and perception. - M.: Moscow State University Publishing House, 1975.
10. LeontyevA. N. Activity. Consciousness. Personality. -2nd ed. - M.: Politizdat, 1977.
11. Neisser W. Cognition and reality: The meaning and principles of cognitive psychology / Transl. from English under general ed. B. M. Velichkovsky. - M.: Progress, 1981.
12. Mute R.S. Psychology: Textbook for students. higher ped. textbook institutions: In 3 books. Book 1:
General fundamentals of psychology. - 2nd ed. - M.: Vlados 1998.
13. General psychology: Course of lectures / Comp. E. I. Rogov. - M.: Vlados, 1995.
14. Rubinshtein S. L. Fundamentals of general psychology. - St. Petersburg: Peter, 1999.
15. Fresse P., Piaget J. Experimental psychology / Sat. articles. Per. from French:
Vol. 6. - M.: Progress, 1978.
1. The cognitive sphere of personality includes...
Possible answers:
a) imagination;
b) temperament;
d) character.
2. Specific feature of a given sensation, distinguishing it from all other types of sensations and varying within a specific modality, is the _____________ sensation.
Possible answers:
a) duration;
b) intensity;
c) spatial localization;
d) quality.
3. Proprioceptive sensations include...
Possible answers:
a) bitter taste;
b) bright light;
c) muscle relaxation and contraction;
d) loud sound.
4. The characteristic of visual sensation corresponding to the intensity of the stimulus is called...
Possible answers:
a) saturation;
b) brightness;
c) duration;
5. An increase in the sensitivity of nerve centers under the influence of a stimulus is called...
Possible answers:
a) adaptation;
b) apperception;
c) synesthesia;
d) sensitization.
6.According to systematic classification types of sensations interoceptive sensations include sensation...
Possible answers:
b) balance;
c) movements;
7. Sensations of movement, heat, cold and pain are types of _____ sensitivity.
Possible answers:
a) visual;
b) skin;
c) taste;
d) auditory.
8. The reflexive nature of perception was revealed in the works of...
Possible answers:
a) L. M. Vecker;
b) I. P. Pavlova;
c) N. N. Lange;
d) V. M. Bekhtereva.
9. The idea about the _________ nature of perception belongs to the famous physiologist I. Muller.
Possible answers:
a) reflex;
b) color;
c) receptor;
d) symbolic.
10. Accommodation and convergence of the eyes are involved in perception...
Possible answers:
b) movements;
c) depth;
d) quantities.
11. The property of perception is...
Possible answers:
a) criticality;
b) duration;
c) intensity;
d) constancy.
12. The phenomenon of false or distorted perception is called...
Possible answers:
a) perception;
b) illusion;
c) an error;
d) apperception.
13. A distorted perception of actually existing reality is called...
Possible answers:
a) hallucination;
b) a dream;
c) illusion;
d) dreams.
14. Apperception is called...
Possible answers:
a) subconscious generalizations based on an ideal image;
b) reflection of the subject as a stable systemic integrity;
c) preferential selection of an object from the background;
d) dependence of perception on experience, knowledge, interests, and personal attitudes.
15. The property of perception, characterized by the dependence of perception on a person’s previous experience, is called...
Possible answers:
a) constancy;
b) integrity;
c) apperception;
d) meaningfulness.
16. The numerical characteristic of the average attention span of people is equal to __________ units of information.
Possible answers:
17. The theory of memory, which is based on the concept of connections between individual mental phenomena, is a ___________ theory.
Possible answers:
a) associative;
b) informational;
c) semantic;
d) active.
18. The device with which V. Wundt measured the amount of attention is called ...
Possible answers:
a) tachistoscope;
b) esthesiometer;
c) strobe light;
d) anomaloscope.
19. The criterion of attention associated with the organization of activities and control over its implementation is ...
Possible answers:
a) concentration;
b) clarity;
c) clarity;
d) selectivity.
20. The idea that attention is represented by the control part of human actions belongs to
Possible answers:
a) L. S. Vygotsky;
b) D. N. Uznadze;
c) P.K. Anokhin;
d) P. Ya. Galperin.
21. Maintaining attention on one object or one activity while distracting from everything else is called _________attention.
Possible answers:
a) volume;
b) concentration;
c) switchability;
d) distribution.
22. The properties and characteristics of stimuli are factors that determine _______ attention.
Possible answers:
a) post-voluntary;
b) involuntary;
c) arbitrary;
d) internal.
23. Estimates of the frequency of vibrations and shifts characterize ________ attention to a given object.
Possible answers:
a) distribution;
b) stability;
d) concentration.
24. The length of time during which attention is focused on an object characterizes _______ attention.
Possible answers:
b) distribution;
c) switchability;
d) stability.
25. Normally, an adult’s attention span is limited to _____ objects.
Possible answers:
26. Conscious and meaningful movement of attention from one object to another is a property...
Possible answers:
a) distractibility;
b) concentrations;
c) switchability;
d) distribution.
27. A corrective test that allows you to study the stability of attention was proposed by a French psychologist...
Possible answers:
a) J. Piaget;
b) A. Binet;
c) P. Janet;
d) B. Burdon.
28. Memory processes include...
Possible answers:
a) forgetting;
b) concentration;
c) distribution;
d) abstraction.
29. The volume of mechanical memory (in units) characteristic of the average person is ...
Possible answers:
30. The phenomenon characterizing the influence of breaks in activity on memory processes was described by B.V. Zeigarnik as an effect ...
Possible answers:
a) novelty;
c) unfinished action;
d) savings.
31. The condition for successful involuntary memorization is (are) ...
Possible answers:
a) the art of memorization;
b) awareness of the significance of the material;
c) setting the need for reproduction;
d) strong and significant physical stimuli.
32. The inability to remember events for the future is called _____________ amnesia.
Possible answers:
a) progressive;
b) anterograde;
c) retrograde;
d) retarded.
33. The concept of “mnemonics” refers to mental process…
Possible answers:
a) thinking;
b) memory;
c) perception;
d) imagination.
34. The qualities of memory include...
Possible answers:
a) efficiency, arbitrariness, individuality, dynamism;
b) individuality, imagery, stability, dynamism;
c) stability, duration, imagery, readiness;
d) volume, speed, strength, readiness.
35. In ontogenesis, the beginning of ___________ memory is associated with the second year of a child’s life.
Possible answers:
a) logical;
b) affective;
c) motor;
d) figurative.
36. The characteristics of memory, based on the duration of storage of the material, are reflected in the division of memory into ...
Possible answers:
a) voluntary and involuntary;
b) implicit and explicit;
c) visual and auditory;
d) short-term and long-term.
37. Memory capacity from 5 to 9 units of information is typical for ___________ memory.
Possible answers:
a) short-term;
b) operational;
c) long-term;
d) instant.
38. In the classification of types of memory, based on differences in the nature of the material being remembered, _______ memory is distinguished.
Possible answers:
a) involuntary and voluntary;
b) direct, indirect;
c) sensory, short-term, long-term;
d) figurative, verbal, motor and emotional.
39. The type of memory associated with the ability to remember and reproduce feelings is called _________ memory.
Possible answers:
a) episodic;
b) emotional;
c) semantic;
d) figurative.
40. Imagination, in which reality is consciously constructed by a person, and not simply mechanically copied or recreated, is called ...
Possible answers:
a) fantastic;
b) passive;
c) productive;
d) reproductive.
41. Fantastic visions that have almost no connection with the reality surrounding a person are called...
Possible answers:
a) dreams;
b) dreams;
c) hallucinations;
d) dreams.
42. The mechanism for creating images, which is based on a kind of “gluing”, is...
Possible answers:
a) hyperbolization;
c) schematization;
d) agglutination.
43. Methods of creating imaginative images include...
Possible answers:
a) agglutination;
b) classification;
For comparison;
d) apperception.
44. The inverse operation of generalization is...
Possible answers:
a) abstraction;
b) synthesis;
c) specification;
d) analysis.
45. The type of thinking usually used to solve problems and tasks and consists in finding multiple solutions to the same problem -
Possible answers:
a) panoramic;
b) sanogenic;
c) divergent;
d) reproductive.
46. The main forms of verbal-logical thinking are: concept, judgment and ...
Possible answers: