Absolute and relative sensitivity thresholds. Basic psychophysical law.

In order for a sensation to arise as a result of the action of a stimulus on the sense organs, it is necessary that the stimulus causing it reaches a certain value or threshold of sensitivity. There are two types of sensitivity thresholds: absolute and differential (or discrimination sensitivity threshold).

The lowest strength of the stimulus at which a barely noticeable sensation occurs is called the lower absolute threshold of sensation .

The lower threshold of sensations is opposed by the upper threshold. The greatest strength of the stimulus, at which a sensation of this type still occurs, is called the upper absolute threshold of sensation . The upper threshold limits sensitivity on the greater side, and up to a certain limit, above which pain occurs or there is no change in the intensity of sensations.

Thresholds of sensations are individual for each person and change throughout his life. Sensations, in addition to the magnitude of the absolute threshold, are also characterized by a threshold for discrimination, which is called the differential threshold.

Differential threshold is the smallest value of differences between stimuli when the difference between them is still perceived. The differential threshold of sensations for different sense organs is different, but for the same analyzer it is a constant value.

The Bouguer-Weber law states: the differential threshold of sensation is different for different sense organs, but for the same analyzer it is a constant value. The constant itself is called the Weber constant.

The values ​​of the Weber constant for various senses are given in the table:

Lower and upper absolute thresholds of sensation (absolute sensitivity) and differential thresholds of discrimination (relative sensitivity) characterize the limits of human sensitivity .

Along with this, operational thresholds of sensations - the magnitude of the signal at which the accuracy and speed of its discrimination reaches a maximum. This value is an order of magnitude larger than the discrimination threshold and is used in various practical calculations.

Pathological changes in sensitivity thresholds include a decrease in sensitivity thresholds - hyperesthesia, an increase - hypoesthesia, complete loss - anesthesia and perversion - senesthopathy, psychotic states (acute hallucinosis, paranoid, etc.), initial manifestations of non-paroxysmal clouding of consciousness (delirium, oneiroid, amentia).

Hyposthesia is a decrease in susceptibility to external stimuli, when the surrounding world, individual objects and properties lose their brightness, colorfulness, richness, and distinct individuality. Occurs in cases of stupor, depressive states, hysterical syndromes, alcohol and drug intoxication.

Hyperalgesia is an increase in pain sensitivity, observed in various pathological conditions, in particular with depression, especially masked depression (“algic melancholia” (Petrilovich, 1970)).

Anesthesia is manifested by anatomical and functional damage to the analyzer, starting from the receptor section and ending with the cortical representation, which is clinically accompanied by loss of skin sensitivity, loss of taste, smell, blindness, and deafness.

In neurology, visual agnosia (failure to recognize visual images, letters, words), auditory (failure to recognize objects when palpating), autotopoagnosia (failure to recognize parts of one’s body), anosognosia (failure to recognize illness, injury), and facial agnosia are distinguished. In hysterical neurotic syndromes, mental amblyopia (blindness), mental anosmia (insensitivity to smells), mental ageusia (loss of the sense of taste), mental deafness, mental tactile and pain anesthesia (analgesia) are observed.

Attention. Pathology of attention

Attention is the direction and concentration of consciousness.

Properties of attention:

1. Stability – the duration of maintaining intense attention.

2. Switching attention is a deliberate transition from one object to another.

3. Distribution of attention - simultaneously successfully performing two or more types of activities.

4. Volume of attention – the number of objects of attention simultaneously held in consciousness.

Types of attention:

- voluntary (the highest type of attention is active attention)

- involuntary (determined by the psychophysiological characteristics of a person and the qualitative characteristics of the stimulus).

Theories of attention:

— Motor theory ( R. Descartes ). Since the state of attention can be caused by volitional effort, Descartes suggested that such effort must be exclusively muscular

— Attention as a result of limited consciousness. ( Herbert and Hamilton ). They noticed that if one of the ideas is most intense, then all others are repressed from consciousness. A person focused on a certain thought or perception does not hear or notice anything extraneous in relation to the object of attention and turns out to be, as it were, “blind” and “deaf” to the entire world around him.

— Activation theory ( Lindsley ). Human behavior is determined by fluctuations in arousal. The lower limit is sleep, the upper limit is hyperexcitation. Between sleep and states of extreme arousal, there are a number of levels that make up the range of intensity of behavior. A certain segment of this range corresponds to the highest performance, which represents attention.

— The principle of dominance ( A.A. Ukhtomsky ). The excitatory process can create a temporary focus of excitation that summarizes and accumulates impulses flowing into the central nervous system, while simultaneously suppressing the activity of other centers.

Attention is the ability to concentrate on any external or internal events, objects or activities. Attention contributes to a sustainable increase in the level of sensory, intellectual and motor activity, ensuring the productivity of mental activity. Attention does not have its own, separate and specific product. Its result is the improvement of any mental activity to which it is connected.

There are active (voluntary) and passive (involuntary), post-voluntary attention. Among the properties of attention are stability, volume, switchability, and direction.

Attention disorders include:

• absentmindedness - impaired ability to maintain focus for a long time;
• exhaustion - weakening of the intensity of attention, rapid transition of active attention to passive;
• distractibility - increased mobility, rapid changes in direction, concentration, intensity of attention;
• stiffness - inertia, fixed attention, with difficulty switching from one object to another;
• narrowing of the scope of attention is a pathological concentration caused by the weakness of its distribution between objects.

Attention disorders are part of all positive and negative syndromes.

Study methods

Research methods:

1. Boundary method. The researcher influences the experimental subjects with different stimuli, gradually reducing the intensity. The subject must respond when he no longer feels the influence from the outside. This is how the boundaries of perception are determined.
2. Method of constant stimuli. The experimental subject is exposed to various stimuli over a wide range. The subject must answer what he feels and at what moments.
3. Average error method. This is a procedure for equalizing incentives. The intensity of the effect on the body is slowly raised to a noticeable level.

Methods are often used in a comprehensive manner to obtain more accurate information.

Imagination and representation.

Imagination and representation are tools for reflecting and designing the world around us.

Imagination is a mental cognitive process of creating new ideas based on existing experience, that is, a process of transformative projection of reality.

Imagination is a reflection of external space in new unusual combinations and connections. It occupies an intermediate position between perception and thinking, thinking and memory. This is one of the most mysterious psychic phenomena. We know almost nothing about the mechanism of imagination, its anatomical and physiological basis.

Imagination is unique to humans. It allows him to go beyond the real world in time and space, giving him the opportunity to imagine the finished result of his work even before starting work. Almost all human material and spiritual culture is a product of people's imagination and creativity.

Involuntary imagination is also called passive or unintentional imagination - this is the creation of new images without any external stimuli. It consists in the emergence and combination of ideas and their elements into new ideas without a specific intention on the part of a person, with a weakening of conscious control on his part over the course of his ideas.

It appears most clearly in dreams or in a half-asleep, drowsy state, when ideas arise spontaneously, replace, combine and change on their own, sometimes taking on the most fantastic forms.

Voluntary imagination , or, as it is also called, active or deliberate imagination, is the creation of new images through volitional efforts. It represents the deliberate construction of images in connection with a consciously set task in one or another type of activity.

Representation is the process of mentally recreating images of objects and phenomena that currently do not affect the human senses.

In accordance with the division of views by types of the leading analyzer, the following types of views are distinguished:

— visual (image of a person, place, landscape);

- auditory (reproduction of a musical melody);

- olfactory (ideation of some characteristic smell - for example, cucumber or perfume);

- gustatory (ideas about the taste of food - sweet, bitter, etc.)

- tactile (idea of ​​the smoothness, roughness, softness, hardness of an object);

- temperature (idea of ​​cold and heat);

However, often several analyzers are involved in the formation of representations. Thus, imagining a cucumber in one’s mind, a person simultaneously imagines its green color and pimply surface, its hardness, characteristic taste and smell.

Ideas are formed in the process of human activity, therefore, depending on the profession, predominantly one type of ideas develops: for an artist - visual, for a composer - auditory, for an athlete and ballerina - motor, for a chemist - olfactory, etc.

Ideas also differ in the degree of manifestation of volitional efforts. In this case, they are divided into involuntary and voluntary. Involuntary ideas are ideas that arise spontaneously, without activating the will and memory of a person, for example, dreams.

Arbitrary ideas are ideas that arise in a person under the influence of the will, in the interests of the goal he has set. These ideas are controlled by a person’s consciousness and play a large role in his professional activity.

Duration and spatial localization

The duration of sensations indicates how long they last. This characteristic is related to the intensity of the stimulus and the time of its exposure. The initial period of occurrence of the action of the stimulus is hidden: the stimulus has already begun to act, but the person has not yet felt it. In addition, after the cessation of the stimulus, the sensation persists for some time. This phenomenon in psychology is called the aftereffect.

Additional Information. The duration of the latent period varies among different types of receptors. For taste sensations it lasts 50 ms, for tactile sensations – 130 ms, for pain – 370 ms.

The spatial localization of sensations contains information about in which part of the body they occur. A person can easily determine the source of sound or light, and upon contact with a hot or cold object, he realizes the exact localization of the resulting cold or heat in the body.

Cold

Thus, the ability to sense provides a person with the opportunity to form a complete picture of the world around him. The ability to distinguish the smells and tastes of food makes it possible to eat healthy and enjoy eating; auditory and visual sensations are necessary for the acquisition of knowledge. In addition, receptor sensitivity contributes to the full functioning of the self-preservation instinct, sending information to the brain about approaching danger.

Thinking. Intelligence. Pathology of thinking

Thinking is a person’s ability to acquire new knowledge bypassing the senses.

2 sides of thinking (phenomenon of the human psyche):

1) A property extracted from a specific fact is recognized as equivalent to the fact.

2) The selected property leads to a certain conclusion that cannot be obtained directly from the fact.

Thinking obeys the laws of logic. The main logical forms are:

— Concept (a thought that includes essential features of an object)

— Judgment (reflection of the connection between concepts)

— Inference (judgment based on other judgments)

The thinking process includes:

— Synthesis (combining information into a whole)

— Comparison (establishing similarities)

— Generalization (highlighting the general, specifying)

Thinking is not needed if there is no goal. The need to think arises when a problem appears. The problem is transformed into a task, i.e. into a specific task.

Types of thinking:

— Visually effective (pragmatists)

— Figurative (poets)

— Abstract (philosophers)

Thinking is the main component of intelligence (mind, thinking abilities). The individual characteristic of thinking, that is, thinking in action, the quality of the mind (intelligence), includes breadth, depth, independence, criticality and flexibility, consistency and speed of mental operations. Intelligence itself, the ability to form new conclusions and grasp different points of view, includes the prerequisites of intelligence (memory, attention, speech, etc.), spiritual inventory (stock of knowledge and skills).

a) Acceleration of thinking is observed in manic states and is characterized by verbosity, distractibility, and the superficial nature of associations. Judgments arise easily, are frivolous, superficial, and the depth of thought suffers. Acceleration of thinking to a pronounced degree reaches a “jump of ideas”, speech does not keep up with thoughts and can be outwardly incoherent (“manic confusion”)

b) inhibited (slow) thinking is observed in depression, states of deafness, epilepsy, organic brain damage, and is characterized by a poverty of associations, judgments are formed with difficulty, speech is laconic, monosyllabic.

“Schizophasia” is a form of speech disorders against the background of clear consciousness (as opposed to amentive, incoherent thinking) that appears in the meaningless “stringing” of individual words, names, terms that do not have “grammatical coherence and logical sequence.

Body sensors