Humans are curious beings, it seems that it is part of our nature to question ourselves about many things, especially regarding our existence, at least, at some point in our life. Many philosophers and scientists throughout history have tried to solve many questions about man and his behavior or his way of proceeding, finding others in his wake. Why do we act in a certain way under certain circumstances? What makes us "similar" and at the same time different from others?
To develop his theories, he was based on the Hippocratic-Galenic typology, in the update carried out by Kant and by Wundt, which tries to explain the similarities and differences between people, through the description of the 4 types of human temperament, made up of by personality: sanguine, choleric, phlegmatic and melancholic. However, it also relied on the contributions of great theorists within psychiatry such as: Gross, Heymans and Wiersma, Kretchmer and the famous Carl Gustav Jung, to name just a few.
Hans Jürgen Eysenck was a great English scientist and psychologist of German origin. He believed that to a large extent the personality was also determined by physiological aspects of the individual such as genes, which can dispose a subject to behave in a particular way.
His hard work, led him to agree that each person has certain characteristics or traits, which are relatively stable despite time and circumstances, affirmed that individual differences in behavior are due to the nervous system thus participating in the establishment of the bases for further studies in this regard and contributing to the development of psychometrics.
Through his research, he was able to observe that these differences and similarities between individuals are also influenced by situational and environmental factors, that is, personality traits are also made up of sociocultural elements. Around this, he stated that:
"It is the more or less stable and lasting organization of a person's character, temperament, intellect and physique, which determines his unique adaptation to the environment".
The search for the answer to his questions, prompted him to be a great researcher, he used the correlational tradition, with its taxonomic or descriptive model and the experimental one, the latter was influenced by the Russian school, because in those times many experimental studies were developed about the differences of each individual in psychophysical aspects, this last tradition, followed it through the causal or explanatory model.
He tried to find the basic dimensions of personality like Cattell, although the latter was based on the terms that describe personality within language; On the other hand, Eysenck spoke of three heritable primary dimensions and with a physiological basis, this was measured by the reactivity of the autonomic nervous system. Through the taxonomic or descriptive model, it proposes a personality model based on the traits that make it up, it does so through factor analysis to describe the personality, then the three dimensions with their types of structure and some corresponding traits:
Psychoticism: It has to do with the traits of aggressiveness, impulsiveness (or under impulse control), creativity, coldness, cruelty, self-centeredness and harshness (unshakable), they do not usually empathize, it may be difficult or impossible for them to confront reality.
Extraversion-Introversion: The traits of vitality, brilliance, sensation seeker, sociability, impulsivity and activity belong to this category, they can be dogmatic and dominant.
Neuroticism-Emotionality: This dimension includes the traits of variability, emotionality, irrationality, shyness, taciturnity, low self-esteem, guilt, anxiety and restlessness. The associated brain structure would be specifically the limbic system, which is involved in emotional regulation. Individuals with a high degree of neuroticism are people whose autonomic nervous system can be activated very easily.
|Examples of elements of the Eysenck Personality Questionnaire (EPQ-R) (Eynsenck & Eynsenck, 1985) (Adapted from the Spanish version by Ortet, Ibañez, Moro & Silva, 1997)|
|1. Do you prefer to act independently rather than according to established norms?|
2. Do you like the hustle and bustle around you?
3. Does your mood fluctuate frequently?
4. Would you have a very bad time if you see a child or an animal suffer?
5. Do you do a lot of activities in your free time?
6. Do you tend to stay away from social situations?
7. Do you often have feelings of guilt?
8. Would you say of yourself that you are a nervous person?
9. Are you worried about having debt?
|Note: These items would be scored as follows: Extraversion: 2 yes, 4 yes and 6 no; Neuroticism: 3 yes, 7 yes and 8 yes; Psychoticism: 1 yes, 4 no and 9 no.|
It correlates it with the explanatory or causal model of personality by anchoring biological structures to the base of those dimensions and confirming them experimentally..
He said that the hierarchical structure of the personality has:
The extraversion-introversion dimension is determined by the differences between the cortical excitation and inhibition processes. Eysenck used physiological processes without locating them in any specific part of the cortical system, based mainly on Pavlov's and Hull's concepts. He said that people who develop introverted behavior patterns and who tend to have dysthymic problems, if psychopathology is generated, are characterized by strong excitation plus slow and weak cortical inhibition, which causes a behavior to be inhibited.
While in the dimensions of the extraverts, it is the opposite, he proposed that people who are predisposed to develop extraverted behavior patterns and to have hysterical-psychopathic alterations, also in the case that they have some psychopathology a weak excitement can be observed and an intense but rapid cortical inhibition, which produces uninhibited behavior. Here, the concept of physiological inhibition is inversely proportional to behavioral inhibition, that is:
The higher the cortical inhibition, the lower the behavioral inhibition, as shown in the behavior of extraverts and vice versa..
The concept of cortical or arousal activation can be understood as a continuum of excitement that goes from the lowest level, typical of sleep states, to the highest alert state, which is when panic states occur..
It tries to explain the differences related to extraversion-introversion and is determined through the level of cortical arousal (arousal-), which is controlled by a type of “door with access to stimulation”: Ascending Reticular Activation System (SARA) , serves as the neurological basis responsible for the level of care.
In natural circumstances of rest, introverts seem overstimulated, since they show a high arousal level, while extraverts are hypo-stimulated, so they will tend to seek stimulation, the latter have a low arousal level.
SARA activates and deactivates the upper parts of the brain (cerebral cortex), participates in the maintenance of alertness and concentration, as well as in the control of the sleep-wake cycle. One of the most direct strategies to test the highest level of cortical activation has been to work with the evoked potentials; their hypotheses have been indirectly verified through performance studies..
For a better understanding of the issues, here is a table that includes some important aspects that were taken into account within Eysenck's biofactorial theory.
|Similarity to the effect of depressant drugs||+||-|
|Speed of execution||+||-|
|Tolerance to stimulation||+||-|
|Involuntary rest patterns||+||-|
|Sensitivity to reinforcement||+||-|
|Sensitivity to punishment||-||+|
|Similarity to the effect of stimulant drugs||-||+|
|MAO enzyme levels||-||+|
|Search for sensations||+||-|
|Procrastination in the return to parasympathetic balance||+||-|
|Relationship with neurotic disorders||+||-|
|Relationship with psychosomatic disorders||+||-|
|Potentialization of socialized habits in introverts||+||-|
|Potentialization of antisocial habits in extraverts||+||-|
|Similarity to the effect of hallucinogenic drugs (LSD)||+||-|
|MAO enzyme levels||-||+|
|Association with crime||+||-|
|Association with psychotic disorders||+||-|
|Association with antisocial disorders||+||-|
|Association with aggressive symptoms||+||-|
Hans Eysenck was a great researcher who dedicated his life to the study of human behavior, thanks to his work we have been able to make progress in such important areas as psychometry and the measurement of personality traits, as his work established an important antecedent in this item; One of his main objectives was to analyze the neurophysiological bases of human behavior, he carried out theories, models and tests for the measurement of certain traits that he typified, which represented a great advance in the study of behavior.
Likewise, it established the empirical bases of therapies with a cognitive and behavioral approach. The theories presented by him have their framework within the psychobiological models of personality, sustenance and the fruit of them resided under the scrutiny of experimental methodology..