Russian physiologist Ivan Petrovich Pavlov (1849-1936) He is best known for being the initiator of the classical conditioning paradigm, also called “Pavlovian”. However, Pavlov and his followers made other significant contributions to psychology, such as their personality typology based on the study of the nervous system.
In this article we will describe the 4 personality types that exist according to Pavlov’s theory as well as the main concepts of this model, the most important of which are related to the basic nervous processes (excitation and inhibition) and their properties, which determine behavioral differences between human beings.
Pavlov developed his theory of personality through experiments he carried out in his laboratory. Specifically, this author investigated the learning of reflex responses by conditioning using dogs as experimental subjects; In relation to these animals, Pavlov’s studies on salivation are particularly well known.
Unlike other personality models in force at the time, among which Sigmund Freud’s psychoanalytic theory stands out, Pavlov’s does not focus only on the description of psychological differences between individuals, but also seeks to explain them through the study of the activity of the nervous system, which gives rise to temperament the basis of personality.
This is why Pavlov’s proposal on personality is framed within biological theories, which uses constructs related to biology to explain individual differences. The somatic typologies of Kretschmer and Sheldon, Gall’s phrenology or more current models such as those of Eysenck, Gray or Zuckerman are part of the same category.
Pavlov’s personality typology is derived from his hypotheses about the basic properties of the nervous system. In this sense it is important to consider two physiological processes, excitation and inhibition as well as its three main properties: strength, balance and mobility.
Excitatory and inhibitory nervous processes occur independently, although they interact, giving rise to different states of cortical activity depending on the degree of predominance of each of them. The definition of these concepts is similar to the one we currently use when talking about the sympathetic and parasympathetic nervous systems.
Pavlov stated that Interindividual differences in behavior are explained by the properties of the processes excitatory and inhibitory of each person (or animal). He spoke of “strength” to refer to the general work capacity of neurons, of the “balance” between excitation and inhibition and of the “mobility” or speed of these processes.
Strength, balance and mobility would be the most relevant properties, but Pavlov also described the irradiation, or diffusion of the process to other areas of the nervous system, and its concentration in a certain region. Later, his disciple Vladimir Nebylitsyn added a fourth property: dynamism or speed of reflex formation.
The 4 types of nervous system
According to Pavlov, the characteristics of the fundamental nervous processes in a specific person determine the type of activity of his nervous system, and therefore his temperament. These biological traits would constitute the basis of personality ; When interacting with environmental factors they would produce differences in behavior between individuals.
The criteria that Pavlov used to make his classification were quite arbitrary. He first divided the dogs into two groups based on whether their nervous system was strong or weak. Then he separated the strong ones based on whether they were balanced or not; Finally, he created the categories “strong-balanced-slow” and “strong-balanced-impulsive.”
This type of temperament is characterized by lack of balance between excitation and inhibition processes ; There is, therefore, a tendency towards the appearance of physiological states in which one of the two predominates in a very marked way.
We can relate the strong and unbalanced (or impetuous) personality with the choleric temperament of the typology of the humors of Galen, a Greek doctor who lived in the 2nd century AD and from whom Pavlov was inspired. In Eysenck’s PEN model it would be comparable with high levels of extraversion and low levels of emotional stability.
2. Strong, balanced and slow
In this case, the neurons have a good work capacity and the balance between excitation and inhibition is adequate, but the speed of initiation and termination of these processes is low. The strong-balanced-slow type corresponds to introversion and emotional stability in Eysenck’s model and with the phlegmatic type of Galen.
3. Strong, balanced and impulsive
Unlike the previous type, in the strong-balanced-impulsive type the speed of the excitation and inhibition processes is high. Following Galen’s classification we would talk about the sanguine temperament and in Eysenck’s theory these people would have a high degree of extraversion and emotional stability.
4. Weak
The fourth type is equivalent to Galen’s phlegmatic temperament and would present introversion and emotional instability in Eysenck’s model. Pavlov defines it simply as a low working capacity of the cells of the nervous system
