Eysenck combines the correlational tradition (descriptive or taxonomic model) with the experimental one (causal or explanatory model). The descriptive model speaks of three independent dimensions to describe personality: Psychoticism (P), Extraversion (E) and Neuroticism (N). The causal model links the dimensions with psychophysiological processes that explain the differences behavioral individuals. For him. These differences are due to differences in the functioning of the SN.
Background and influences of Eysenck’s theory
Typological approach:
- Galen He is credited with formulating the theory of the four temperaments (melancholic, choleric, phlegmatic and sanguine).
- Another contribution is due to Kant, who updated, popularized and made Galen’s doctrine credible.
Wundt’s contributions: He made the leap to considering separate categories (types) as continuous dimensions.
Psychiatric tradition:
- Gross He was the first to relate the extraversion dimension to a functional brain property.
- Heymans and Wiersma He was the first to realize the importance of quantifying the relationships between variables, proposing the use of correlational methods. He was also a pioneer in conducting experimental personality studies.
- Jung popularized the terms Extraversion-Introversion.
- Kretschmer He attributed great importance to the morphological constitution as an etiological element of mental illness.
Psychometric contributions:
- Spearman He introduced FA in psychology, which allowed speculation to be replaced by objective and quantitative data, and he was the first to demonstrate the existence of strictly defined and measured factors (extraversion and emotionality or Neuroticism).
- He is also indebted to Guilfordsince the first questionnaire developed by Eysenck to measure the dimensions of Extraversion and Neuroticism consisted of items that came from scales created by this author.
Experimental contributions:
- Collect the influence of russian school which develops a large number of experimental studies on individual differences of a psychophysiological type.
- Also the concepts of reactive and conditioned inhibition of Hull They influenced Eysenck.
- The work of Duffy on arousal as a non-specific activation of the CNS in response to stimulation also influences his theory significantly.
The structure of personality: descriptive or taxonomic model.
Eysenck proposes a hierarchical model of personality with different levels of increasing generality:
- First level: Specific answers that can be observed once and that may or may not be characteristics of the individual.
- Second level: Common responses which would be specific responses that are repeated when the circumstances are similar.
- Third level: Traits which are theoretical constructs based on the intercorrelations between habitual responses that are observable. They would be first order factors, because they come from the first AF.
- Fourth level: Guys that arise from the intercorrelations between the different traits, and would be second-order factors. They are considered continuous dimensions, along which the individual can be positioned, and not separate and pure categories.
The three types or superfactors (Extraversion, Neuroticism and Psychoticism) are sufficient to adequately describe the personality. The reasons for using types and not traits are:
- Different analyzes lead to the appearance of these three factors, and if more are obtained, they are usually not important.
- First-order factors are more unstable from one investigation to another.
- From these three types, satisfactory predictions can be made at different levels:
Physiological (individual differences in cortical activation, etc.), psychological (individual differences in performance, etc.) and social (differences in criminal behavior, etc.).
Extraversion in Eysenck’s theory
Extraverted individuals are sociable, communicative, uninhibited, active, talkative and dominant. They also seek excitement and stimulation. Eysenck has proposed two theories to explain the differentiated behavior of introverts and extraverts:
The excitation-inhibition model: Uses physiological processes without specifically locating them. He proposed that people who are predisposed to develop patterns of extraverted behavior are those who have: weak excitatory potentials and strong reactive inhibition. People who develop introverted behavior patterns are those who have: strong excitatory potentials and weak reactive inhibition. Therefore, physiological inhibition It is inversely proportional to behavioral inhibition.
The cortical activation theory: It appears because the previous proposal did not allow empirically testable predictions to be made. According to this theory, people who have, under resting conditions, a chronically high level of arousal, behave in an introverted manner. Thus, the greater the cortical activation, the less behavioral activation and vice versa. It proposes the SARA (Ascending Reticular Activation System) as the neurological basis responsible for the level of activation. chronically low tend to behave following the extraverted pattern. The ones that have
Some studies have shown that extraverts orient themselves towards sources of stimulation in the environment that provide them with a higher level of stimulation. These studies only show that extraverts prefer these situations, but not that they have greater chronic cortical arousal. Proving this is not easy for several reasons:
- Due to the lack of a single and direct measurement of arousal, since there is individual specificity of response (one person reacts to stimuli by increasing their heart rate and another by increasing their breathing).
- Because there is specificity of the response to the stimulus (different stimuli produce different activation patterns).
- The relationships between stimuli and responses are inverted U (Yerker-Dodson Law). Optimal performance would be obtained with medium levels of activation.
The results show that introverts present greater reactivity to sensory stimulation, and that introverts and extroverts do not differ in arousa in neutral or chronic conditions. Therefore, although the theory is not completely accurate, it is correct about introverts’ sensitivity to stimulation.
In performance studies, introverts perform better in situations with moderate levels of stimulation, and extraverts with high levels. Which indicates that they differ in the level of stimulation to perform better.
Neuroticism (Emotional Stability-Instability)
People with high scores in this dimension have frequent mood swings, are usually worried, anxious, depressed and feel guilty. They react strongly to stimuli.
The neurological bases are found in the limbic system or visceral brain, which is related to neurovegetative activation (sweating, heart rate, muscle tension, etc.). For Eysenck, the most unstable subjects present greater neurovegetative activation. This system and the SARA are only partially independent, because cortical arousal can be produced through visceral activation.
The empirical evidence on this is unsatisfactory. There is no evidence that subjects high in neuroticism are more physiologically reactive. This inconsistency may be due to several reasons:
- 1. The automatic activation measures are not correlated with each other (increased heartbeats do not lead to a greater electrodermal response).
- 2. There is the problem of individual response specificity.
- 3. Different stressors produce different patterns of physiological activation.
- 4. Inducing emotional states is unethical.
- 5. The dimension is heterogeneous, and since anxiety is not its only component, not all those who score high in this dimension have high anxiety.
- 6. People who score high are characterized by chronic worry, dissatisfaction, pessimism, and not by acute reactions.
Psychoticism and genetic bases
People with high scores on this dimension are cold, self-centered, impulsive and aggressive. They do not care about others and are indifferent to danger. Despite the many socially negative characteristics, Eysenck relates this dimension to creativity and divergent thinking (since it inclines people to all kinds of strange or abnormal behaviors).
Impulsivity itself would also be one of its components, although some aspects of this characteristic (daring and sensation seeking) are included in Extraversion.
Eysenck has proposed that Psychoticism is related to an excess of dopamine and a decrease in serotonin. Dopamine reduces cognitive inhibition, and serotonin increases it. Several studies support this idea, since Psychoticism is linked to lower levels of serotonin. The relationship of the dimension with creativity is also confirmed.
Although the theory proposes that the differences in the functioning of the different neurophysiological systems (responsible for the proposed dimensions) are of genetic origin, Eysenck does not believe that behavior is in the genes. Genes do not cause behavior directly, but DNA affects a whole series of intermediary biological mechanisms (physiological, hormonal and neurological) that, in interaction with social factors, produce behavior.
It proposes, therefore, that the individual inherits certain physiological and neurological characteristics such as SARA, which influences the level of cortical arousal, which determines the conditioning possibilities, sensory thresholds and other basic processes. Thus, introverts are better conditioned and have lower sensory thresholds. The different interaction of individuals with their environment produces the behavioral traits that characterize introverts and extraverts.
Many findings suggest that biological factors are important in the genesis of individual differences:
- Temporal stability or consistency: individuals tend to maintain their position on each dimension over long periods of time. It seems that daily events have little influence on the dimensions.
- The dimensions have been found in cross-cultural studies, so biological factors must be important.
- Studies with mono- and dizygotic twins reveal that genetic factors explain some of the variance in individual differences.
Eysenck personality questionnaires.
- MMQ: It only evaluated Neuroticism.
- MPI: Evaluated Extraversion and Neuroticism.
- PPE: As the MPI that weighted both Neuroticism and Introversion and received criticism for the supposed dependence on both dimensions, it purged the problematic elements in this inventory.
- EPQ: Evaluate the three superfactors.
- EPQ: Evaluate the three superfactors.
Dimensions of personality and well-being.
In recent years, many studies have been carried out on the association between Extraversion and Neuroticism with different measures related to aspects…