Neurophysiological basis of personality ( Eysenck ) Flashcards
Aleksandrov and Schukina
According to Aleksandrov and Shchukina (1992), the neurophysiological indices of neurotic patients with different types of individual character and their dynamics are important factors of personality.
They took 107 patients with different patterns
of neuroses, who underwent group psychotherapy (a personality-oriented (reconstructive) variety).
Analysis of the dynamics of the neurophysiological characteristics, made during group psychotherapy, supported the clinical data on varying curability of neurotic patients with different types of character accentuations.
For instance, Patients with the hysteroid type character accentuation appeared more resistant to
psychotherapy.
Corticol Arousal
Neurophysiological basis of Extraversion-Introversion
Eysenck also made an attempt to specify a neurophysiological basis for each of his three personality super traits or types.
According to him, the super trait Introversion-extraversion is closely related to levels of cortical arousal as indicated by electroencephalographic recordings.
Eysenck(1982) used the term arousal to denote a continuum of excitation, ranging from a lower extreme (e.g.,sleep) to an upper extreme (e.g., state of panic).
He was of the view that introverts are over aroused and thus are highly sensitive to incoming stimulation. For this reason, they avoided situations that are apt to overwhelm them.
Extraverts are under aroused and thus are highly insensitive to incoming stimulation and thus they constantly seek out situations that are apt to excite
them.
ANS reaction to stimuli
Neurophysiological basis of Stable vs neurotic
Eysenck hypothesized that individual differences in stability vs neuroticism reflected the degree to which the autonomic nervous system reacts to stimuli.
He linked this dimension with the limbic system, the brain’s visceral or feeling system, which influences motivation and emotional behaviour.
He pointed out that persons high on neuroticism tend to react more quickly to painful, novel, disturbing, or other stimuli than do more stable persons.
Such persons also exhibit a more persistent reaction (even after the stimulus has disappeared) than do highly stable persons.
Psychopathology:
Neurophysiological basis
Eysenck’s neurophysiological interpretation of the dimensions of personality is closely related to his theory of psychopathology.
He was of the view that the symptoms or disorders that befall a person are related to the combined impact of personality traits and nervous system functioning.
For instance, the person who is high on the dimensions of introversion and neuroticism is more prone to develop anxiety disorders such as phobias, obsessions, and, compulsions.
On the other hand, the person who is high on the extraversion and neuroticism dimensions is at a risk for psychopathic (antisocial) disorders.
Eysenck stated that psychological disorders do not automatically occur as a result of genetic predisposition. These genetic predispositions when interact with the environment or a certain situation produce psychological disorders.
Extraversion and Corticol Arousal
According to the arousal theory, Eysenck (1990) provides a biological explanation of extraversion in terms of cortical arousal via the ascending reticular activating system (ARAS).
Activity in the ARAS stimulates the cerebral cortex, which, in turn, leads to higher cortical arousal.
Cortical arousal can be measured by skin conductance, brain waves, or sweating (Eysenck, 1990).
Because of the different levels of ARAS activity, “introverts are characterised by higher levels of activity than extraverts and so are chronically more cortically aroused than extraverts” (Eysenck & Eysenck, 1985, p. 197, emphasis added).
Based on the Yerkes-Dodson law, which suggests that arousal and performance have an inverted-U relationship, the arousal theory of the PEN model assumes that “some intermediate level of arousal is optimal for performance” (Eysenck
& Eysenck, 1985, p. 199).
Neuroticism and Visceral Brain Activation
Eysenck (1990) also explains neuroticism in terms of activation thresholds in the sympathetic nervous system or visceral brain.
The visceral brain is also referred to as the limbic system, which consists of the hippocampus, amygdala, septum, and hypothalamus, and regulates such emotional states as sex, fear, and aggression.
It is responsible for the fight-or-flight response in the face of danger.
Heart rate, blood pressure, skin conductance, sweating, breathing rate, and muscular tension
in the forehead can measure activation levels of the visceral brain.
Neurotic individuals have greater activation levels and lower thresholds within the visceral brain. They are easily upset in the face of very minor stresses.
However, emotionally stable people are calm under such stresses because they have lesser activation levels and higher thresholds (Eysenck, 1990).
Psychoticism and Gonadal Hormones
Eysenck (1990) also provides a biological explanation of psychoticism in terms of gonadal hormones such as testosterone and enzymes such as monoamine oxidase (MAO).
Eysenck (1992a) reports that “low platelet monoamine oxydase (MAO) has been found in psychotic patients, and also in their relatives and inpatients who have recovered, suggesting that low MAO activity may be a marker for ‘vulnerability’”
(p. 774).
All things considered, the PEN model has contributed to the study of personality in three distinctive ways.
1) It combines both descriptive and causal aspects of personality in one theory (Eysenck, 1997; Stelmack, 1997). This characteristic clearly distinguishes the PEN model from most other trait theories such as the five-factor model (Costa & McCrae, 1992a, 1992b; Eysenck, 1991, 1992b, 1992c).
2) It provides causal explanations in addition to the description of personality.
3) The PEN model is supported by more credible evidence than purely descriptive models.
4) The PEN model is comprehensive in description by proposing a hierarchy of four levels and by making a clear distinction among those levels.
5) Finally, the PEN model becomes most compelling because of its experimental approach to the study of personality, which makes the model more testable.
Consequently, the PEN model is likely to generate more specific predictions about personality.
Essence of the theory:
Thus the essence of Eysenck’s Trait-Type theory is that
1) Elements of personality can be arranged hierarchically.
2) Certain supertraits or types, such as extraversion, exert a powerful influence over behaviour.
3) These supertraits comprised of several component traits, and these component
traits either are more superficial reflections of the underlying type dimension, or are specific qualities that contribute to that dimension.
According to Eysenck, traits are composed of numerous habitual responses, which, in turn, are derived from a multitude of specific responses.
The trait of sociability correlates with such response dispositions as activity, liveliness, assertiveness etc. Taken together, these traits define a super trait or
type Eysenck calls extraversion.
Continuum in type concept
In considering Eysenck’s hiearchichal model of personality structure, it should be noted that the word “type” refers to dimensions of personality that he regards as normally distributed along a continuum. This is almost equivalent to traits.
Thus, for example, the type concept of extraversion is a dimension with a low end and a high end along which people may fall at various points between the
two extremes. It is not a dimension on which people can be classified as either low or high.
Eysenck does not imply discontinuity when he uses the word “type”.
Self Assessment Questions
1) Describe the neurophysiological basis of trait and types.
2) How does Eysenck explain extraversion in terms of neurophysiological explanation
3) How is Neuroticism explained in terms neurophysiological mechanism?
4) How does Eysenck connect psychoticism to Gomadal hormones. Explain?
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