The contribution to the science of the Russian and Soviet scientist Ivan Petrovich Pavlov cannot be overestimated. Physiologist, vivisector, Nobel laureate, researcher - you can talk a lot about him for a long time. But now we will talk about the famous Pavlov's theory - about its main provisions, key principles, features and significance.
About the study
The object of attention of the Soviet vivisector was the "real physiology" of the brain of dogs. Studying it, Pavlov was able to accurately determine the concept of higher nervous activity (GNI).
What conclusions did the scientist draw? He assured that the activity of the cerebral hemispheres with the subcortex, which ensures the complex interaction of the organism with the outside world, should be called the highest. And it is fair to contrast her with the activities carried out by further sections of the spinal cord and brain. Since they "manage" only the integration and the ratio of the parts of the body. This, in turn, is called lower nervous activity.
Considering the theory of Pavlov, it is necessary to make a reservation that it concerns the physiology of higher nervous activity, and not mental functions. It is wrong to identify these concepts, as did the mechanistic materialists (because of which, by the way, psychology is no longer considered an independent science).
I.P. Pavlov investigated the GNI of dogs, and not people, and he himself focused on the fact that it is unacceptable to identify the activity of the animal’s nervous system with the human psyche.
Key Points
Taking into account all of the above, we can proceed to the main topic. Here are some concepts identified in Pavlov's theory:
- Higher nervous activity. That which provides the animal with behavior in the external world that corresponds to the conditions of life.
- Lower nervous activity. Responsible for reflex independent regulation of work carried out by internal organs.
Based on these simple definitions, we can understand that Pavlov contrasted these two types of activity. But even despite this, the tendency has spread, on the contrary, to identify them.
Be that as it may, in the unity of both nervous activities, which can be seen in the union of autonomic reflexes with motor reflexes, the latter plays the leading role. Why? Because it is motor reflexes that determine the self-regulation of the digestive, cardiovascular, as well as other systems of internal organs.
It is important to explain something here. The fact is that the “inclusion” of some reflexes is determined by others. Which ones? Motor are controlled by motor-visceral and cerebral reflexes.
What conclusion can be made? The author of the theory, Pavlov, formulated it this way: “The GNI of a living organism is formed by conditioned and unconditioned reflexes. And the formation of some without the other is impossible. ”
The significance of the cerebral cortex
Continuing to study the features of the theory of I.P. Pavlov, the following nuance should be noted: the general behavior of people and higher animals is controlled by the higher department of the central nervous system. That is, the cerebral hemispheres with the nearest subcortex. What, on the basis of this statement, constitutes higher nervous activity? It can be argued that this is a combined function of the subcortical centers and cerebral hemispheres.
Also, Pavlov’s theory does not exclude the possibility that, under certain circumstances, conditioned reflexes can also form in other parts of the brain, outside the cerebral hemispheres.
If we talk about dogs, then we need to highlight one interesting point. The fact is that adult dogs without the cerebral cortex completely lose all conditioned reflexes acquired by them throughout their lives. They cease to respond to the owner, to the nickname, etc. And this entails a violation of communication with the outside world. However, after removal of the cerebral cortex, conditioned motor reflexes may form in dogs.
Incidentally, S. S. Poltyrev, G. P. Zeleny, and also N. N. Dzidzishvili devoted their work to this topic. In general, many scientists have been able to establish that in dogs, cats and rabbits, the removal of the cerebral cortex entails the formation of conditioned vegetative reflexes. This is a proven fact.
The effect of removing parts of the cerebral cortex on reflexes
This is a very important topic, and it is necessary to pay attention to it, talking about the principles of Pavlov's reflex theory. Removal of certain parts of the cerebral cortex is reflected in reflexes. And here's how:
- Neocortex removal. Dogs and cats then develop conditioned defense and food reflexes. But if the archio- and paleocortex are additionally removed, then the probability of their formation is reduced to a minimum. Reflexes are formed, but rarely, and are very different from the true ones.
- Removal of the new cerebral cortex. After that, in cats there is a closure of conditioned reflexes, localized in the hippocampus and cingulate gyrus. For them to form, you need an old and ancient bark - they form an emotional background. And he is a prerequisite for the development of reflexes.
- Removal of the hypocampus. This operation does not affect the speed of formation of food reflexes, but complicates their hardening. This happens due to a sharp increase in the orientational reaction, the cause of which is the prolapse of the hippocampus, which inhibits the reticular formation. In general, due to its removal, the internal inhibition of reflexes is disrupted. The formation of short-term memory is still more complicated. Also, after elimination of the hippocampus, defensive reflexes do not form.
- Removal of the amygdala. As a result of this operation, the animal disrupts normal behavior that corresponds to a particular situation. This operation does not affect food reflexes in any way, but the defensive ones disappear, after which they are restored with great difficulty.
- Removing from the cingulate anterior gyrus of the knee. It is proved that as a result of this, disinhibition of food inhibitory motor reflexes occurs. But the removal of the posterior region does not affect this process. Accordingly, the front part is one of the most important areas of inhibition of certain affective reactions.
- Bilateral removal of premotor zones. Intervention of this kind entails the formation of motor conditioned reflexes.
- Damage to the reticular formation located in the midbrain. This operation is fraught with the disappearance of the salivary reflex.
- Removal of the frontal lobes (more precisely, their anterior parts). This entails impaired inhibition of motor and salivary reflexes.
Considering the features, provisions and principles of Pavlov's theory, it is worth noting that the following was also proved: the formation of the notorious reflexes is simplified under the condition of excitation of sympathetic nuclei located in the sub-tubercle region. But they will disappear if they are damaged.
However, these, of course, are just some of the features that can be distinguished from Pavlov’s theory of higher nervous activity. In our time, such experiments continue, and now they use special microelectrodes that irritate some brain areas, which helps to track the process of formation / disappearance of reflexes.
Conclusions and evidence
The key principles of Pavlov’s reflex theory were considered above. If we study all its provisions, we can make a logical, justified conclusion: the removal of the new cortex of the cerebral hemispheres entails the formation of conditioned reflexes in the old and ancient cortex (i.e., in the subcortical centers).
Based on this, another statement follows. It reads: the opinion that the notorious conditioned reflexes are formed in animals exclusively in the cerebral cortex is incorrect. Why? Because it contradicts reality - after all, conditioned reflexes are also formed in those creatures in which the cerebral cortex is absent. A striking example are fish and insects.
It was on the basis of these facts that a famous scientist argued that GNI is inherent in all animals without exception, with a nervous system. And it is carried out by the higher department of the nervous system.
The meaning of the theory
It is also necessary to talk about him. Thanks to Pavlov’s reflex theory, it became possible to study the brain activity not only of animals, but also of humans (of course, in natural conditions). The main laws of the GNI were able to be revealed largely due to the work done by scientists. Here is what contributed to this:
- Knowledge of the basic laws of the central nervous system.
- Accurate consideration of the quality of stimuli, as well as how long they have an effect on receptors, and what is their intensity.
- Knowledge of the time of formation of the reflex, as well as its size and character.
Pavlov's theory of conditioned reflexes is the basis for the prehistory of consciousness as the highest form of the psyche that is inherent in man.
It must be said that the scientist’s method, as well as his works, provide an opportunity to study the qualitative features of the activity that occurs in the human brain. It is the theory of activity formed by Pavlov that forms the natural-scientific basis for the dialectical-materialistic worldview. Why? Because it is precisely on the works of the scientist that the philosophy of dialectical materialism is based in the struggle against ideas of an idealistic and metaphysical nature.
It should also be noted that after the spread of Pavlov's theory in society, a negative attitude towards psychology has strengthened. Because some researchers tried to “dissolve” its subject in the physiology of GNI in order to present it as the only opportunity for studying the psyche. The identification of this concept with higher nervous activity turned out to be fraught not only with the biologization of people. It also led to the fact that people began to deny the socio-historical essence of the human psyche.
Theory of Sechenov and Pavlov
It is thanks to the tandem of these two greatest scientists in the history of the study of the physiology of the brain that a new stage has taken shape. And by the way, it’s Ivan Mikhailovich Sechenov who is the first to formulate reflex theory.
I.P. Pavlov and his colleague formed a very fruitful tandem. Their common work is a kind of materialistic determinism in the study of the functions of the central nervous system. The theory they created became the basis for the subsequent development of the psychology and physiology of GNI.
It should be given a little attention to its study. The key points of the reflex theory of I.P. Pavlov and I.M.Sechenov can be distinguished in such a small list:
- Determinism. In other words, causality. This principle is manifested in the following: each reflex reaction is conditioned. There can be no action without reason. Any act of nervous activity is a reaction to an impact coming from an internal or external environment.
- Structurality. This principle says: all reflex reactions occur with the help of certain brain structures. There are no processes without a material basis. Any act of nervous activity is necessarily confined to a specific structure.
- Analysis and synthesis. These concepts also take place in Pavlov's theory. In short, the nervous system always analyzes stimuli that affect the body. And then synthesizes the response. These two processes are ongoing. Their result is the extraction by the body of the information that it needs from the environment, and its further processing with subsequent fixation in memory. The last stage is the formation of a response that always meets the needs and circumstances.
Studying the reflex theory of Pavlov and Sechenov, I would also like to pay attention to the concept of nervousness. This is the name of the concept that recognizes the following fact: the nervous system plays a leading role in regulating the functions of all tissues and organs.
Mental aspect
It also takes place. The value of the mental aspect has always been emphasized by I.M.Sechenov. He characterized the first part of the reflex act as a signal one.
What does it mean? Sensual signals seem to “warn” the nervous system of what is happening in the external environment. And Pavlov, adhering to the physiological aspect, recognized the need to supplement the theory with a provision on the signal system. It is advisable in relation to the person.
Pavlov also confirmed the need to begin to study the signal system associated with the role of speech in the human psyche. This is already directly related to the topic of consciousness - different, but nevertheless related to the theory under consideration. After all, it was the development of the human brain that became its first premise. And the main law of the biological improvement of organisms, which determines the formation of the psyche, lies in the provision that speaks of the unity of their structure and functions.
The fundamental properties of nervous processes
They need to be listed before moving on to Pavlov’s theory of temperament. The scientist devoted much time to the study of the development of conditioned reflexes, and he was able to establish that in this process there is a certain individuality. And its basis is certain properties, namely:
- The power of excitement. In other words, working capacity, endurance of a nerve cell. It manifests itself in maintaining the nervous system with strong excitement, which does not end with the transition to a state of inhibition. By the way, both of these processes are independent properties of NS.
- Braking power. It manifests the ability of the nervous system to fade and differentiate.
- Equilibrium. This property determines the balance of the processes of inhibition and excitation. A person, for example, can be called physiologically unbalanced if the strength of one of these two processes is greater than the other.
- Mobility. She determines how quickly one nervous process passes into another. Mobility is the ability to change behavior depending on external conditions. The opposite process is inertia. A person can be called inert if he needs a lot of time to go from a passive state to an active one.
Typology of temperaments
Having studied the theory of Pavlov reflexes, we can proceed to this topic. The properties of nervous processes, as the scientist has determined, form combinations that determine the type of GNI or the entire system itself. What does it consist of? From the aggregate of the key properties of the nervous system listed above.
What is Pavlov’s theory of temperament? The scientist has proven that there are four types of nervous system. And they are very similar to the types of temperament according to Hippocrates.
Differences in strength determine weak and powerful types. They, in turn, can be of two types:
- Balanced. Excitation and inhibition are in balance. Nevertheless, they are prone to inertia or mobility.
- Unbalanced. In this case, excitation strongly prevails over inhibition.
Types of the nervous system, according to Pavlov, also in terms of characteristics correspond to types of temperament (and not just in quantity). This can be traced:
- Movable type. Differs in balance and power - sanguine.
- Inert type, but different in strength and poise - phlegmatic.
- Strong and unbalanced, with a predominance of excitement - choleric.
- The weak type is melancholic.
The type of nervous system (just like temperament) is an innate property. Practically unchanged. Moreover, the type of nervous system is considered the physiological basis of temperament. And he, in turn, is a mental manifestation of the type of NS.
Further experiments
A large-scale study of adult behavior was organized in the 1950s. At first it was led by V. M. Teplov, but then it passed under the leadership of V. D. Nebylitsyn. As a result of this study, the main provisions of Pavlov's theory were supplemented by new ones.
Firstly, it was possible to develop methods for the study of properties inherent in the human nervous system. Secondly, it turned out to highlight and describe two more qualities. Among them:
- Lability. It manifests itself in the rate of occurrence, and then the termination of nervous processes.
- Dynamism. It affects the ease and speed of the formation of inhibitory and positive conditioned reflexes.
Today in science has accumulated many different facts regarding the properties of the nervous system. And the more they become (progress does not stand still) - the less importance is attached to the types of NS. More significant are the individual properties of the nervous system, which are truly fundamental. Many scientists take to the background the problem of the separation of NS into types.
However, since they are just formed from a combination of the listed properties, only a detailed study of them can provide the most complete understanding of the typology.