Eysenck\'s three dimension of personality PDF

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Behavioral Genetics We have mentioned the growing evidence to support the idea that some traits are influenced by hereditary factors. The area of study focusing on the connection between genetics and personality is often called behavioral genetics. Regardless of the method used to evaluate or investigate personality, a significant genetic component must be considered. Allport and Cattell were among the first to suggest that inherited factors shape personality and that they rank in importance with environmental factors. Let us now consider other researchers who have pursued this causal connection between genetic inheritance and personality. Eysenck’s Personality Theory Eysenck proposed a theory of personality based on biological factors, arguing that individuals inherit a type of nervous system that affects their ability to learn and adapt to the environment. Eysenck's theory of personality focused on temperaments, which he believed were largely controlled by genetic influences. He utilized a statistical technique known as factor analysis to identify what he believed were the two primary dimensions of personality: extraversion and neuroticism. He later added a third dimension known as psychoticism. The Primary Role of Heredity To Eysenck, traits and dimensions are determined primarily by heredity, although the research evidence shows a stronger genetic component for extraversion and neuroticism than for psychoticism. Eysenck did not rule out environmental and situational influences on personality, such as family interactions in childhood, but he believed their effects on personality were limited. His research design involved comparisons of identical (monozygotic) and fraternal (dizygotic) twins. The studies showed that identical twins are more alike in their personalities than are fraternal twins, even when the identical twins were reared by different parents in different environments during childhood. Studies of adopted children demonstrate that their personalities bear a greater similarity to the personalities of their biological parents than of their adoptive parents, even when the children had no contact with their biological parents. This is additional support for Eysenck’s idea that personality owes more to our genetic inheritance than to our environment. Cross-cultural research demonstrates that Eysenck’s three personality dimensions have been found consistently in more than 35 nations including the United States, England, Australia, Japan, China, Nigeria, and Sweden (see, for example, Bouchard, 1985; Eaves, Eysenck, & Martin, 1989; Floderus-Myrhed, Pedersen, & Rasmuson, 1980; Hur, 2009; Martin & Jardine, 1986; Tellegen, Lykken, Bouchard, Wilcox, Segal, & Rich, 1988). The confirmation of the same three personality dimensions in diverse cultures is further evidence for the primacy of inherited factors in the shaping of personality. Three Dimensions of Personality The result of their efforts is a personality theory based on three dimensions, defined as combinations of traits or factors. We might think of the dimensions as superfactors. The three personality dimensions are: E—Extraversion versus introversion

N—Neuroticism versus emotional stability P—Psychoticism versus impulse control (or superego functioning) Eysenck noted that the dimensions of extraversion and neuroticism have been recognized as basic elements of personality since the time of the ancient Greek philosophers. Eysenck also suggested that formulations of the same dimensions could be found on nearly every personality assessment device ever developed. The Eysenck Personality Inventory has since been used with great success in translated forms in nearly 40 countries, including those as diverse as Italy and Kuwait . Consider the list of personality traits associated with Eysenck’s three personality dimensions. You can see clearly, for example, that people who score high on the traits of the E dimension would be classified as extraverts, whereas people who score low would be classified as introverts.

Extraverts are sociable and crave excitement and change, and thus can become bored easily. They tend to be carefree, optimistic, assertive, and impulsive. They are more likely to take risks and be thrill seekers. Eysenck argues that this is because they inherit an under aroused nervous system and so seek stimulation to restore the level of optimum stimulation. In addition, people who score high in extraversion on the Eysenck Personality Inventory have been found to experience more pleasant emotions and to be happier than those who score low in extraversion. Extraverted businessmen have been shown to be much better at performing difficult tasks than introverted businessmen. Introverts on the other hand lie at the other end of this scale, being quiet and reserved. They are already over-aroused and shun sensation and stimulation. Introverts are reserved, plan their actions and control their emotions. They tend to be serious, reliable and pessimistic. Eysenck found that extraverts have a lower base level of cortical arousal than introverts do. Because the cortical arousal levels for extraverts are low, they need, and actively seek, excitement and stimulation. In contrast, introverts shy away from excitement and stimulation because their cortical arousal levels are already high. As a result, introverts react more strongly than extraverts to sensory stimulation. Studies have shown that introverts exhibit greater sensitivity to low-level stimuli and have lower pain thresholds than extraverts. Other research supports differential responses to sensory stimulation but reports less convincing evidence that such differences can be attributed to variations in cortical arousal levels. Nevertheless, as Eysenck predicted, these differences are genetically based. Activation of the reticular formation of the brain. Cortical arousal increases wakefulness, vigilance, muscle tone, heart rate, and minute ventilation.

Neuroticism/stability A person’s level of neuroticism is determined by the reactivity of their sympathetic nervous system. A stable person’s nervous system will generally be less reactive to stressful situations, remaining calm and level headed. While someone high in neuroticism on the other hand will be much more unstable, and prone to overreacting to stimuli and may be quick to worry, anger or fear. They are overly emotional and find it difficult to calm down once upset. Neurotic individuals have an ANS that responds quickly to stress (They perform better when they are stressed). Eysenck suggested that neuroticism is largely inherited, a product of genetics rather than learning or experience. People high in neuroticism have greater activity in the brain areas that control the sympathetic branch of the autonomic nervous system. This is the body’s alarm system, which responds to stressful or dangerous events by increasing breathing rate, heart rate, blood flow to the muscles, and release of adrenaline. Eysenck argued that in neurotics, the sympathetic nervous system overreacts even to mild stressors, resulting in chronic hypersensitivity. This condition leads to heightened emotionality in response to almost any difficult situation. Indeed, neurotics react emotionally to events other people consider insignificant. According to Eysenck, these differences in biological reactivity on the neuroticism dimension are innate. People are genetically predisposed either toward neuroticism or toward emotional stability. Psychoticism/ impulse control (or superego functioning) Eysenck (1966) later added a third trait / dimension - Psychoticism – e.g., lacking in empathy, cruel, a loner, aggressive and troublesome. This has been related to high levels of testosterone. The higher the testosterone, the higher the level of psychoticism, with low levels related to more normal balanced behavior. Men generally tend to score higher on psychoticism than women, which led Eysenck to suggest that psychoticism may be related to male hormones. He also speculated that people who score high on all three dimensions may be apt to display criminal behavior but cited only modest empirical support for this idea. Research conducted in China has demonstrated a significant positive correlation between criminal behavior and high scores on both the psychoticism and neuroticism dimensions. People who score high in psychoticism are aggressive, antisocial, tough-minded, cold, and egocentric. Also, they have been found to be cruel, hostile, and insensitive to the needs and feelings of others. In addition, they score low on emotional well-being and have greater problems with alcohol, drug abuse, and violent criminal behavior than people who score low in psychoticism. Paradoxically, people who score high in psychoticism can also be highly creative. The research evidence tends to suggest a large genetic component. However, it has also been found that those who scored high in psychoticism had more authoritarian and controlling parents than those who scored low, thus supporting the potentially harmful influence of the childhood environment. Eysenck believed that society needs the diversity provided by people characterized by all aspects of these three personality dimensions. An ideal society affords people the opportunity to make the best use of their traits and abilities. However, some people will adapt to the social environment better than others will. The person high in psychoticism, for example, typified by hostile and aggressive behaviors, may become emotionally disturbed, or exhibit criminal tendencies, or channel the aggressive traits into a socially acceptable enterprise such as coaching college football.

He was especially interested in the characteristics of people whom he considered to have achieved their potential as individuals. According to Eysenck, the two dimensions of neuroticism (stable vs. unstable) and introversionextroversion combine to form a variety of personality characteristics.

Stability over Time The traits and dimensions Eysenck proposed tend to remain stable throughout the life span despite our different social and environmental experiences. Our situations may change but the dimensions remain consistent. For instance, the introverted child tends to remain introverted through adolescence and into adulthood. Other studies in England and the Scandinavian countries confirm the stability over time of Eysenck’s dimensions, particularly extraversion and neuroticism. The Role of Intelligence Eysenck also conducted considerable research on intelligence. Although he did not list intelligence as a personality dimension, he considered it an important influence on personality. He noted that a person with an IQ of 120, which is high, is likely to have a more complex and multidimensional personality than a person with an IQ of 80. His research also suggested that some 80 percent of our intelligence is inherited, leaving only 20 percent as the product of social and environmental forces. One good element of Eysenck’s theory is that it takes into account both nature and nurture. Eysenck’s theory argues strongly that biological predispositions towards certain personality traits combined with conditioning and socialization during childhood in order to create our personality....