EYSENCK, HANS JüRGEN(b. Berlin, Germany, 4 March 1916;d. London, United Kingdom, 4 September 1997), psychology, personality and intellectual differences, popular science.Eysenck was a prominent and polarizing figure in postwar British psychology, noted for the expansive scope of his research and the forthright, often controversial, views he expressed. He developed a distinctive dimensional model of personality based on factor-analytic summaries and biogenetic processes. Eysenck married descriptive statistics with physiological experimentation, collapsing the distinction between pure and applied science. He was an outspoken advocate of the biogenetic basis of individual differences in intelligence and personality, as well as a trenchant critic of psychoanalytic psychotherapy. The author of eighty-five books and more than one thousand scientific papers, Eysenck was a renowned popularizer of psychological science.

Life and Career . Eysenck was born an only child in Berlin in 1916. His mother, Ruth Werner, was a notable silent film actress (with the stage name Helga Molander) in the early years of the German film industry, and his Catholic father, Eduard Eysenck, was a stage performer. Soon after he was born his parents separated, and he was raised by his Jewish maternal grandmother. Eysenck completed his secondary schooling at Prinz-Heinrichs-Gymnasium in Berlin in 1934. However, his ambiguous ethnic background left him with a difficult choice: He could either toe the National Socialist line or leave. His mother and her de facto partner, Jewish film producer Max Glass, had already fled to France. Eysenck chose to join them, spending a few months in Dijon in the summer of 1934 before moving on to London in August. His father Eduard stayed on, joining the Nazi Party in May 1937, much to Hans’s disgust.Eysenck did bridging courses at Pitman’s College in London in the winter of 1934–1935 and then applied to study physics at University College London, in October 1935. He found he lacked the necessary prerequisites, however, and instead enrolled in psychology. After taking his degree in 1938, Eysenck remained at University College, rapidly completing a PhD on the experimental analysis of aesthetic preferences, supervised by Cyril Burt. The war escalated just as Eysenck completed his doctorate in June 1940. Still a German national, he narrowly avoided being interned. Unable to enlist or get a job, he had a spell as a firewatcher. As restrictions eased, Eysenck landed a job at the Mill Hill Hospital in Northern London in June 1942. Headed by the imposing psychiatrist Aubrey Lewis, Mill Hill functioned as the relocated Maudsley psychiatric hospital. After the war, the Maudsley hospital was reestablished in South London and merged with Bethlem Hospital. A new Institute of Psychiatry (IoP) in London was added as a postgraduate training and research facility. Eysenck turned down offers at several other universities to head the IoP psychology department. It was his first and only job, providing a stable institutional environment until his retirement in 1983. He was given an unusual degree of bureaucratic freedom to organize the department around his research priorities. In 1938 Eysenck married Canadian graduate student Margaret Davies and they had one child, Michael Eysenck, born in 1944 and a notable psychologist in the early twenty-first century. The marriage, however, foundered soon after the war. In 1955 Hans Eysenck became a full professor at the IoP and a British citizen.

The Dimensional Approach to Personality . . Eysenck began at Mill Hill with little in the way of equipment or money, but he was drawn to psychometric descriptions of personality. He factor-analyzed the data sheets Lewis kept on new hospital arrivals, correlating the results with

questionnaire and experimental data. The various results were summarized in 1947 in Dimensions of Personality, Eysenck’s first and most important book. Dimensions of Personality outlined two personality factors of neuroticism (N) and introversion-extraversion (I-E), creating an inverted “T” grid with an I-E base and an N vertex. Eysenck was guided by the idea that two common psychiatric diagnoses, dysthymia and hysteria, were the introverted and extraverted manifestations of a highly neurotic personality. Eysenck deliberately contrasted these continuums with the discrete typologies of psychiatry and attempted to clear up the confusing and speculative trait lists of personality psychology. It was a work unprecedented in Britain, but Eysenck drew inspiration from the trait approach of Gordon Allport and James Cattell in the United States and the typological theories of Carl Jung and Ernst Kretschmer on the Continent. In 1952 The Scientific Study of Personality introduced a third factor, psychoticism (P), again constructed around the idea that psychotic disorders differed in terms of introversionextraversion.Eysenck looked to go beyond descriptive level theory, however, well aware that factor-analytic models were inherently arbitrary. Mind and body were a continuum, Eysenck wrote in his memoirs, Rebel with a Cause(1997), an assumption he always thought “too obvious to require supporting argument” (p. 64). Thus, he investigated the relationship of his dimensions to both specific behavior and brain processes. In his landmark 1957 book, The Dynamics of Anxiety and Hysteria, Eysenck argued that I-E was related to a simplified version of Ivan Pavlov’s notion of excitation and inhibition, while N was vaguely linked with anxiety drive strength. This allowed Eysenck to connect personality differences with conditioned learning; in particular, he suggested that introverts were far more responsive than extroverts, learning quicker, better, and for longer periods. As a consequence, introverts also tended to have a more developed sense of morality and a greater capacity for academic achievement. While critics such as Lowell Storms and John Sigal demurred, it remained the most sustained and ambitious attempt to combine trait description with neurological subsystems defined in terms of their behavior control function.By the mid-1960s, classical behaviorism had fallen out of favor, especially the formalism of Clark Hull that framed Eysenck’s first biological model of personality. Ambiguous results from a range of researchers suggested that modifications were necessary. Armed with a more sophisticated appreciation of Russian work courtesy of young student Jeffrey Gray, Eysenck outlined a revised model in his 1967 book, The Biological Basis of Personality. I-E was linked to cortical arousal levels in the brain stem’s activation systems. Learning was now seen as an interaction between external stimulation and internal activation levels, with introverts and extroverts having characteristically different optimal bandwidths. Conversely, N was more straightforwardly related to limbic system activation. It was a feed-forward model, wherein basic differences in neurobiology influenced more complex cerebral capacities that determined the rate and pattern of learning in any particular situation. Eysenck was an interactionist rather than a reductionist, arguing that behavior was the sum effect of genetic endowment and environment. From the early 1950s he collaborated on pioneering kinship studies concerning the inheritance of personality dimensions. Early work suggested extremely high hereditability estimates, for N especially. More extensive sampling and sophisticated models produced lower estimates but still indicated substantial heritabilities for all three dimensions, as well as mostly unique, nonfamily environmental influences.Many additional implications could be drawn from Eysenck’s personality theories, including the prediction of various forms of social distress from extreme positions on at least one of these dimensions. In the mid-1960s Eysenck raised eyebrows by likening conscience to a conditioned

reflex. He suggested that personalities with a lower capacity for conditioned learning (i.e., extroverts) were slower to develop socially acceptable behavior. Moreover, emotionally labile persons (i.e., high N) with antisocial tendencies were more likely to act out than emotionally stable people with similar tendencies. These suggestions did not fare particularly well, however, and provided additional impetus for an overhaul of his three-dimensional factor structure. High N was finally made up of traits such as anxiety, guilt, and tension and suggested a propensity for neurotic breakdown. Less theoretically driven, P was reworked to be more indicative of the sociopathy of current psychiatric nomenclature. P never received a clearly articulated biological basis either, with high P associated with impulsivity and creativity, as well as the persistence and severity of criminality. Neither extreme on the I-E dimension per se carried quite the same implications. High E was characterized by sociability, assertiveness, and sensation seeking, the introverted end by low levels of these traits.

In a bid to provide standardized measures for his dimensions, Eysenck developed a series of relatively short, accessible questionnaires. The first appeared in 1959 as the Maudsley Personality Inventory (measuring I-E and N) and was soon revised as the Eysenck Personality Inventory. With considerable input from his second wife, Sybil (née Rostal), the 1975 version was renamed the Eysenck Personality Questionnaire and included a measure of P as well. These inventories became some of the most widely used of their type in the world and served as valuable research tools for those researching Eysenck-related topics.

Clinical Psychology and Behavior Therapy . Eysenck also played a founding role in clinical psychology in Britain and was a key promoter of behavior therapy. When Eysenck was placed in charge of psychology at the IoP after the war, there were no formally recognized training courses, although other programs would soon commence at the Tavistock Clinic in London and the Crichton Royal Hospital in Dumfries, Scotland. Eysenck hired Monte Shapiro to head the clinical section, overseeing the new graduate training course for clinical psychologists to the hospital. However, Eysenck dominated as the professional spokesperson, even though he had little to do with clinical teaching and never treated patients.In the early 1950s, Eysenck argued for a research-based clinical discipline that put science ahead of social need. He saw the rapid development of clinical psychology in America as a mistake, a craven subservience to medical imperatives accompanied by a misplaced enthusiasm for psychotherapy. These pronouncements were accompanied by a research program highlighting the inadequacies of psychiatry. Eysenck and his clinical colleagues attacked the reliability of psychiatric diagnosis and the validity of projective tests like the Rorschach. His widely cited 1952 article, “The Effects of Psychotherapy: An Evaluation,” also famously questioned the efficacy of talk psychotherapy. Over the years, Eysenck’s antipathy to psychoanalysis became legendary. Psychoanalysis was, he wrote, insular and imprecise and seldom supported by the limited empirical testing it allowed. While hardly a lone anti-Freudian in Britain, Eysenck was probably the most vociferous, clearing the way for his preferred therapeutic alternative.

In the mid-1950s, Maudsley psychologists had begun treating patients with a new form of behavioral treatment, disguising it as case-based research. They borrowed from work done in the United States and South Africa, especially the work of Joseph Wolpe, mindful to put it in a Pavlovian learning framework. Reputedly demanding no empathy from the therapist, “behavior therapy” was perfectly in tune with Eysenck’s perspective of the detached clinical scientist. Behavior therapy was less talk and more a targeted course of remedial training summed up by Eysenck’s pithy 1959 slogan: “Get rid of the symptom and you have eliminated the neurosis.”

By late 1958 Eysenck began to advocate openly that psychologists practice behavioral treatment. This provoked a furious medical backlash, not least from Eysenck’s superior, Aubrey Lewis, who was scandalized by the idea of nonmedical practitioners treating patients rather than behavior therapy per se. Despite the bad interdisciplinary blood, the 1960s became the era of behavior therapy in British clinical psychology. Eysenck edited several books on the subject, linking up diverse practices into a seemingly coherent international movement. He also started the journal Behaviour Research and Therapy (BRAT) in 1963. The Maudsley program dominated in this period, supplying the rationale and most of the trained personnel for a small but growing profession. Maudsley graduates came to head many of the clinical courses started in the late 1950s and 1960s across the United Kingdom.Nonetheless, Eysenck’s vision of the clinical psychologist as a research-oriented scientist did not map easily onto the structure and demands of the public-sector National Health Service, which employed the majority of clincial psychologists in Britain. As the most visible and dominant psychological treatment, behavior therapy also proved vulnerable to the radical social critiques of the period. Advocates of behavioral interventions were obliged to soften their style, so diagnosis and directed therapy gave way to helping the patients help themselves.

While psychoanalysts learned to ignore his attacks, Eysenck helped ensure that clinical psychology became a more accountable, empirically based practice. However, his vision of clinical psychology as the research-based application of learning principles has been swamped by a more diverse, service-oriented profession wielding a hybrid variety of humanistic and cognitive-behavioral techniques. Eysenck would concede that cognitive factors were important, but he redescribed them in a manner which suggested that behavior therapy always allowed for them.

Personality and Politics . Eysenck extended his early success in getting a grip on personality via factor-analysis into the political realm. Although he published several more papers afterward, his 1954 book, The Psychology of Politics, remained his major statement in the area. Eysenck summarized social and political attitudes with two bipolar dimensions. One dimension made the usual distinction between radicalism and conservativism, the other contrasted tough- and tender-mindedness, following the thinking of William James. This produced a four-quadrant space, the most provocative implication being that the extremes of Fascism and Communism were separated by ideology but were similar in terms of personal style. For Eysenck, this balanced out the political picture, explaining the “same but different” paradox he had witnessed in pre-war Germany. His work clashed directly with postwar research on the authoritarian personality, with Eysenck controversially arguing that Theodor Adorno and his coauthors’ measure of Fascist potential in The Authoritarian Personality(1950) was practically synonymous with tough-mindedness. It led to an acrimonious, highly technical debate with Milton Rokeach and Richard Christie over the reality of left-wing authoritarianism in Western democratic societies. Although Eysenck largely left political attitudes research alone after this mid-1950s skirmish, the political fallout would carry over into the nature-nurture wars a decade and a half later.Intellectual Differences . Eysenck’s latter-day public reputation came to be overshadowed by his popular writings on intelligence——even though he came to it late as a research topic——because these musings touched on some sensitive areas of public concern. In the late 1960s, just as his four children from his second marriage were beginning their secondary education, the British government fore-shadowed sweeping reforms aimed at leveling the tripartite structure of the secondary school system. Eysenck quickly identified himself as an enemy of these reforms,

and further argued that compensatory measures such as more money for facilities and teacher salaries in the poorer regions of the country would be ineffective or even counterproductive for those they targeted. He raised his profile still further with his breezy 1971 book supporting Arthur Jensen’s contention that black-white differences in IQ scores were in part hereditary. WhileRace, Intelligence, and Education was poorly received by many of his peers, violent protests from leftist groups saw Eysenck transformed into an icon for freedom of scientific expression.Nevertheless, the public hounding he endured was enough to ensure he largely avoided debating the race issue.

The Cyril Burt scandal in the mid-1970s, in which Burt was accused of manufacturing data to show that intelligence is inherited, brought Eysenck back into the nature-nurture debate. He eventually and reluctantly distanced himself from his old mentor’s questionable practices but not his general ideas. Eysenck would repeat to the grave his contention that intellectual differences were 80 percent heritable—a high-end estimate in this field— most notably defending this position in a 1981 confrontation with Leon Kamin, the coauthored book The Intelligence Controversy. In the latter part of his postretirement career, Eysenck also played a key role in attempts to increase intelligence with vitamins. In an about-face of sorts, he even suggested that nutritional factors may account for race differences.Eysenck’s research on intelligence did not take off until the late 1970s, with Eysenck also playing a senior role in defining concepts and arbitrating debates. Throughout his career, he remained committed to the concept of general intelligence, or g, originated by his intellectual forefather Charles Spearman. True to his London School perspective, Eysenck focused on individual differences rather than component mechanisms of intelligence. He attempted to avoid the circularities of psycho-metric definitions of intelligence by looking beyond IQ tests to investigate the relationship between intellectual differences and central nervous system functioning.In the early 1980s, Eysenck urged psychologists to have another look at the contention of Francis Galton (1822–1911) that processing speed was an important factor in intellectual differences. Eysenck touted reaction time and electroencephalogram (EEG) measures of brain activity as holding great promise. However, Eysenck’s own postretirement EEG research of the early 1990s proved frustratingly inconsistent, and the biological basis of intelligence remained a work in progress. Speed was an important but not overriding factor, with Eysenck speculating that it was a by-product of more efficient, errorless neural transmission.

Personality, Smoking, and Physical Disease . Eysenck’s other major postretirement initiative examined the link between temperament with physical health. An early 1960s collaboration with oncologist David Kissen suggested an association between cancer and personality. Eysenck soon attracted more attention by claiming the causal role of cigarettes in cancer had not been convincingly proven. Certain types of people smoked, he argued, some of whom were also susceptible to cancer. Eysenck took a welter of criticism from public health advocates as the antismoking message became more visible and forceful in the late 1960s.Eysenck revisited the issue in the early 1980s and presented new genetic evidence linking personality, smoking, and disease. Although mostly declared, the financial support he received from the tobacco industry left him open to charge of a conflict of interest. In a series of papers in the late 1980s and early 1990s, Eysenck and the little-known Yugoslav researcher Ronald Grossarth-Maticek reported on a series of longitudinal studies apparently demonstrating a

striking association between personality types and cancer and coronary heart disease. While Eysenck did not set up these studies, his input helped fine-tune the presentation and analyses. A number of interventions were carried out suggesting that psychotherapy could have remarkably beneficial effects for cancer sufferers and those with unhealthy lifestyles. While the scope and ambition of these investigations were applauded, critics complained of a lack methodological controls and descriptive detail. Some, such as Anthony Pelosi and Louis Appleby, even suggested that the results were “too good to be true.”

Popular Writings . Over the years Eysenck authored a number of extremely popular paperbacks and made numerous media appearances. He was the people’s psychologist in Britain; his best-selling Pelican paperbacks of the 1950s and 1960s helped introduce the discipline to many would-be students. Eysenck’s rigorous empiricism was matched by a skeptical attitude that entertained nearly all except those he targeted. Eysenck’s race and IQ book was an extension of this popular role, a calculated provocation of his liberal critics. Yet it polarized his reputation to such an extent that it stalled his career as a mainstream spokesman. Afterward, Eysenck tended to turn to more offbeat topics both for serious research and popular presentations—including gender, sex and marriage, parapsychology, and astrology. One last set of writings looked at genius, creativity, and madness, exploring links with the P dimension in particular.Legacy and Wider Influence . Eysenck’s three-dimensional view of personality was always countered by more complex descriptive systems in the United States, particularly the sixteen personality factors of Raymond Cattell. However, Eysenck never compromised on his view that three dimensions were sufficient to describe the underlying, culturally universal structure of personality. In the early twenty-first century, five factors are seen as the most defensible, two of which are similar to Eysenck’s I-E and N. Eysenck dominated the study of the biological basis for personality and introduced testable theoretical accounts into an area that had appeared to avoid them. In hindsight, though, Eysenck was only partially successful in bridging Lee Cronbach’s two disciplines of psychology. The physiological aspects of his work alienated social psychologists, whereas experimentalists did not appreciate his insistence on accounting for individual variation in their search for basic mechanisms. Only a handful of researchers have shared his integrative approach. Within this tradition have come several major challenges, notably from his successor at the IoP, Jeffrey Gray.Without qualification, Eysenck was the most influential psychologist in postwar Britain. Yet he received only belated acknowledgment in the United States and was never truly honored in his adopted homeland. He was, his supporters recalled, a foreigner in many senses—too ambitious, too much the nonconformist. A pronounced introvert, Eysenck was uninterested in the more usual forms of social networking. He gave up on dominating or remodeling existing disciplinary bodies and instead created his own. People joined him rather than the other way around. However, to call him an outsider would be partly to buy into the rebel image he constructed for himself in wake of latter-day controversies.

Eysenck trained hundreds of research students. They were a key to his immense output, co-opted into an all-embracing, programmatic setup. Many subsequently took up key positions in universities in the United Kingdom and abroad. Although he was reluctant to push the idea of a dogmatic “Eysenckian school,” his ideas and approach continue to evolve in the hands of an international network centered on journals such asPersonality and Individual Differences and BRAT and the International Society for the Study of Individual Differences—all of which Eysenck was pivotal in founding.

Eysenck’s detached, hands-off approach to his work was both a strength and a weakness. Always with an eye on the big picture, Eysenck was able to see connections and consistencies others did not. But he came across as insensitive to the nuances and complexity at the heart of the many disputations he engaged in. Eysenck’s reputation as a controversial figure derived in part from his involvement in issues that were already controversial. However, his propensity to step over intellectual boundaries divided his peers. His brilliant and intimidating debating skills rallied the troops but left a pack of defeated opponents nursing a grudge. To his coterie he was stimulating and supportive, inclusive and trusting. To outsiders his style was confrontational, resembling that of a prosecuting lawyer selectively marshaling data and arguments. Eysenck claimed he never deliberately provoked debate, and certainly he could not have enjoyed the more vituperative attacks he and his family endured. However, he clearly wished to have his ideas actively discussed and saw something sinister in any kind of enforced consensus.

Eysenck’s Personality Theory

Eysenck (1952, 1967, 1982) developed a very influential model of personality. Based on the results of factor analyses of responses on personality questionnaires he identified three dimensions of personality: extraversion, neuroticism and psychoticism.

During 1940s Eysenck was working at the Maudsley psychiatric hospital in London. His job was to make an initial assessment of each patient before their mental disorder was diagnosed by a psychiatrist. Through this position he compiled a battery of questions about behavior, which he latter applied to 700 soldiers who were being treated for neurotic disorders at the hospital (Eysenck (1947).

He found that the soldiers's answers seemed to link naturally with one another, suggesting that there were a number of different personality traits which were being revealed by the soldier's answers. He called these first order personality traits

He used a technique called factor analysis. This technique reduces behavior to a number of factors which can be grouped together under separate headings, called dimensions.

Eysenck (1947) found that their behavior could be represented by two dimensions: Introversion / Extroversion (E); Neuroticism / Stability (N). Eysenck called these second-order personality traits.

According to Eysenck, the two dimensions of neuroticism (stable vs. unstable) and introversion-extroversion combine to form a variety of personality characteristics.

Extraverts are sociable and crave excitement and change, and thus can become bored easily. They tend to be carefree, optimistic and impulsive.

Introverts are reserved, plan their actions and control their emotions. They tend to be serious, reliable and pessimistic.

Neurotics / unstables tend to be anxious, worrying and moody. They are overly emotional and find it difficult to calm down once upset.

Stables are emotionally calm, unreactive and unworried.

Eysenck (1966) later added a third trait / dimension - Psychoticism – e.g. lacking in empathy, cruel, a loner, aggressive and troublesome.

Eysenck related the personality of an individual to the functioning of the autonomic nervous system (ANS). Personality has dependent on the balance between excitation and inhibition process of the nervous system. Neurotic individuals have a ANS that responds quickly to stress.

Click here to measure your personality using the Eysenck Personality Inventory (EPI).

Eysenck's three traits

H.J Eysenck (1967, 1982) developed a very influential model of personality. Based on the results

of factor analyses of responses on personality questionnaires he identified three dimensions of

personality: extraversion, neuroticism and psychoticism. Two of these also form part of the "Big

Five" model of personality (McCrae & Costa, 1985). Eysenck considered that psychological

disorders were related to the extremes of personality.

Extraversion

Extraverts are sociable and active, they enjoy meeting people and going to parties. The original

conception of extraversion linked it to arousal (Eysenck, 1967). Eysenck described extraverts as

showing low levels of cortical arousal, while introverts were seen as over-aroused. Later

explanations focussed on proposed differences in conditioning. Because of their higher arousal

introverts were claimed to condition more readily and were therefore more socialised, more

sensitive to social constraints.

Gray (1981) reconceptualised the biological bases of extraversion and neuroticism as reflecting

differences in sensitivity to reward and punishment. He argued that extraverts were more

sensitive to reward, whereas introverts (especially neurotic introverts) are more sensitive to

punishment

Neuroticism

Eysenck described neuroticism as reflecting differences in the intensity of emotional experience.

As described above Gray (1981) argued that neuroticism was indicative of a higher sensitivity to

punishment. Neuroticism is close to a number of other traits such as trait anxiety or negative

emotionality. It might be expected that individuals high in neuroticism might be more likely to

use drugs in order to reduce or avoid negative emotional states.

Psychoticism

The third of Eysenck's dimensions is a more recent addition and is less well defined than

extraversion and neuroticism. Individuals high on psychoticism are tough-minded, non-

conformist, willing to take risks and may engage in antisocial behaviour. The name of the scale

reflects Eysenck's original suggestion that the trait tapped personality traits related to psychosis,

just as neuroticism seems to measure traits related to anxiety and depression. Later revisions to

the scale have moved away from this view and recent explanations emphasise impulsive

nonconformity or tough-mindedness. The scale has obvious similarities to sensation seeking and

if the trait relates to a disorder it is psychopathy/antisocial personality disorder, rather than

psychosis. On the "Big Five" model high psychoticism overlaps with low scores on the traits of

agreeableness and conscientiousness.

Eysenck’s Personality Theory

Eysenck (1952, 1967, 1982) developed a very influential model of personality. Based on the results of factor analyses of responses on personality questionnaires he identified three dimensions of personality: extraversion, neuroticism and psychoticism.

During 1940s Eysenck was working at the Maudsley psychiatric hospital in London. His job was to make an initial assessment of each patient before their mental disorder was diagnosed by a psychiatrist. Through this position he compiled a battery of questions about behavior, which he latter applied to 700 soldiers who were being treated for neurotic disorders at the hospital (Eysenck (1947).

He found that the soldiers's answers seemed to link naturally with one another, suggesting that there were a number of different personality traits which were being revealed by the soldier's answers. He called these first order personality traits

He used a technique called factor analysis. This technique reduces behavior to a number of factors which can be grouped together under separate headings, called dimensions.

Eysenck (1947) found that their behavior could be represented by two dimensions: Introversion / Extroversion (E); Neuroticism / Stability (N). Eysenck called these second-order personality traits.

According to Eysenck, the two dimensions of neuroticism (stable vs. unstable) and introversion-extroversion combine to form a variety of personality characteristics.Extraverts are sociable and crave excitement and change, and thus can become bored easily. They tend to be carefree, optimistic and impulsive.

Introverts are reserved, plan their actions and control their emotions. They tend to be serious, reliable and pessimistic.

Neurotics / unstables tend to be anxious, worrying and moody. They are overly emotional and find it difficult to calm down once upset.

Stables are emotionally calm, unreactive and unworried.

Eysenck (1966) later added a third trait / dimension - Psychoticism – e.g. lacking in empathy, cruel, a loner, aggressive and troublesome.

Eysenck related the personality of an individual to the functioning of the autonomic nervous system (ANS). Personality has dependent on the balance between excitation and inhibition process of the nervous system. Neurotic individuals have a ANS that responds quickly to stress.

Measurement of intelligence

Eysenck was a proponent of the theory of human intelligence proposed by Donald Hebb and

elaborated by Philip Vernon. Hebb called the biological substrate of human cognitive ability

“Intelligence A.” When Intelligence A interacts with environmental influences, "Intelligence B"

is generated. Hebb regarded Intelligence B as essentially immeasurable due to the large number

of confounding variables, and Intelligence A not as a concrete “thing” that can be measured.

Eysenck believed that culturally-bounded tests and tests of educational attainment were likely to

capture the environmentally influenced Intelligence B, whereas physiological measures such as

positron emission tomography (PET) and electroencephalography (EEG) held more potential as

possible tools for capturing the genetically based Intelligence A (Jensen, 1994).

Philip Vernon had elaborated Hebb's view to include "Intelligence C," which is what manifests

on tests of cognitive ability. Vernon also believed that different tests, however, are imperfect and

vary to the degree that they reflect Intelligence A or B. Although he acknowledged the pivotal

role of environmental factors, Vernon’s research led him to conclude that approximately 60

percent of the variance in human intellectual ability is attributable to genetic contributions. He

extended this argument to implicate genes in the observed racial differences in intelligence test

scores. This controversial line of research was pursued by Eysenck and his student Arthur

Jensen, culminating in 1971, with the publication of Race, Intelligence, and Education, for which

Eysenck was physically assaulted by "progressive intellectuals" at a public talk.

Eysenck also carried support for the "general intelligence" factor ("g") proposed by Cyril Burt.

One of Eysenck's most influential papers, linking general intelligence to mental speed,

"Intellectual Assessment: A Theoretical and Experimental Approach," published in 1967,

described his efforts to develop accurate measurement of the elusive concept of human

intelligence. Always a proponent of advanced statistical methods to evaluate the complexities of

the data required to encapsulate the essence of the human mind, Eysenck concluded:

If we can derive a model of the intellect, therefore, from the existing literature, it may be suggested that a combination of Spearman’s g, Thurstone’s primary abilities (grouped under mental processes and test material), and the break-down of the IQ into speed, persistence and error-checking, may be the best available at the moment (Eysenck, 1979, p. 193).

Eysenck's model of personality (P-E-N)

Eysenck was one of the first psychologists to study personality using factor analysis, a statistical

technique introduced by Charles Spearman. Eysenck's results suggested two main personality

factors.

The first factor was the tendency to experience negative emotions, which Eysenck referred to

as Neuroticism. The Neuroticism (N) trait is measured on a bipolar scale anchored at the high

end by emotional instability and spontaneity, and by reflection and deliberateness at the low end.

Individuals high on the N trait are susceptible to anxiety-based problems. The second factor was

the tendency to enjoy positive events, especially social events, which Eysenck

named Extraversion. The Extraversion (also spelled Extroversion) (E) trait is measured on a

bipolar scale that is anchored at the high end by sociability and stimulation-seeking, and at the

low end by social reticence and stimulation avoidance. These two personality dimensions were

described in his 1947 book Dimensions of Personality. It is common practice in personality

psychology to refer to the dimensions by the first letters, E and N.

E and N provided a 2-dimensional space to describe individual differences in behavior. An

analogy can be made to how latitude and longitude describe a point on the face of the earth.

Eysenck noted how these two dimensions were similar to the four personality types first

proposed by the Greek physician Galen.

High N and High E = Choleric type

High N and Low E = Melancholic type

Low N and High E = Sanguine type

Low N and Low E = Phlegmatic type

The third dimension, Psychoticism, was added to the model in the late 1970s, based upon

collaborations between Eysenck and his wife, Sybil B.G. Eysenck (Eysenck & Eysenck, 1969;

1976). The Psychoticism (P) trait is a bipolar scale anchored at the high end by aggressiveness

and divergent thinking, and at the low end by empathy and caution. One common misconception

about the P scale is that it is diagnostic for psychosis. The EPQ is not a diagnostic instrument.

While appropriateness of the label “Psychoticism” for the trait has been debated, it has

nevertheless been retained. Eysenck's measurement instruments also contain a Lie (L) scale that

has been shown to function as an index of socialization or social conformity. The L scale is a

measure of the degree to which one is disposed to give socially expected responses to certain

types of questions.

Eysenck's studies of antisocial behavior (ASB) in children revealed that individuals at risk for

developing ASB had above average P scale scores. In addition, individuals who were also high

on the E and N scales and below average on the L scale were at the greatest risk. Eysenck

proponents have suggested implementing preventive programs targeting children at-risk for

developing ASB based on temperamental predispositions.

The major strength of Eysenck's model was to provide data supporting a clear theoretical

explanation of personality differences. For example, Eysenck proposed that extroversion was

caused by variability in cortical arousal; "introverts are characterized by higher levels of activity

than extraverts and so are chronically more cortically aroused than extraverts" (Eysenck &

Eysenck, 1985). While it seems counterintuitive to suppose that introverts are more aroused than

extroverts, the putative effect this has on behavior is such that the introvert seeks lower levels of

stimulation. Conversely, the extrovert seeks to heighten their arousal to a more optimal level (as

predicted by the Yerkes-Dodson Law) by increased activity, social engagement, and other

stimulation-seeking behaviors.

Comparison with other theories

The major alternative to Eysenck's three factor model of personality is a model that makes use of

five broad traits, often called the Big Five model. The traits in the Big Five are as follows:

1. Extraversion

2. Neuroticism

3. Conscientiousness

4. Agreeableness

5. Openness to experience

Extraversion and Neuroticism in the Big Five are similar to Eysenck's traits of the same name.

However, what Eysenck called the trait of Psychoticism corresponds to two traits in the Big Five

model: Conscientiousness and Agreeableness. Eysenck's personality system did not address

Openness to experience. He argued that his approach was a better description of personality

(Eysenck, 1992a; 1992b).

Aside from Jung's basic premise of an association between the dichotomy of introversion-

extroversion and the type of neurosis they were liable to develop, Eysenck accepted none of

Jung's formulation. In fact, Eysenck went to great lengths to point out that the concepts of

introversion-extroversion were not originated by Jung, but by many others, going back as far

as Galen and Hippocrates.

Eysenck's theory of personality is closely linked with the scales that he and his co-workers

developed. These include the Maudsley Medical Questionnaire, Eysenck Personality Inventory

(EPI), Eysenck Personality Questionnaire (EPQ), and Sensation Seeking Scale (developed in

conjunction with Marvin Zuckerman). The Eysenck Personality Profiler (EPP) breaks down

different facets of each trait considered in the model. There has been some debate about whether

these facets should include impulsivity as a facet of Extraversion, as Eysenck declared in his

early work, or Psychoticism. Eysenck declared for the latter, in later work

"EPQ" redirects here. For the qualification in the United Kingdom, see Extended Project

Qualification.

In psychology, Eysenck Personality Questionnaire (EPQ) is a questionnaire to assess

the personality traits of a person, with the result sometimes referred to as the Eysenck's

personality Inventory or (EPI).

It was devised by the psychologists Hans Jürgen Eysenck and Sybil B. G. Eysenck.[1]

Hans Eysenck's theory is based primarily on physiology and genetics. Although he was a

behaviorist who considered learned habits of great importance, he believed that personality

differences grow out of our genetic inheritance. He is, therefore, primarily interested in what is

usually called temperament.

Temperament is that aspect of our personalities that is genetically based, and present from birth

or even before. In devising a temperament-based theory Eysenck did not exclude the possibility

that some aspects of personality are learned, but left the consideration of these to other

researchers.

1 Dimensions 2 Versions 3 See also 4 References 5 External links

Dimensions[edit]

Eysenck initially conceptualized personality as two biologically-based independent dimensions

of temperament, E and N, measured on a continuum, but then extending this to include a third, P.

E - Extraversion/Introversion: Extraversion is characterized by being outgoing, talkative, high

on positive affect (feeling good), and in need of external stimulation. According to Eysenck's

arousal theory of extraversion, there is an optimal level of cortical arousal, and performance

deteriorates as one becomes more or less aroused than this optimal level. Arousal can be

measured by skin conductance, brain waves or sweating. At very low and very high levels of

arousal, performance is low, but at a better mid-level of arousal, performance is maximized.

Extraverts, according to Eysenck's theory, are chronically under-aroused and bored and are

therefore in need of external stimulation to bring them up to an optimal level of performance.

About 16 percent of the population tend to fall in this range. Introverts, on the other hand, (also

about 16 percent of the population) are chronically over-aroused and jittery and are therefore in

need of peace and quiet to bring them up to an optimal level of performance. Most people (about

68 percent of the population) fall in the midrange of the extraversion/introversion continuum, an

area referred to as ambiversion.[2]

N - Neuroticism/Stability: Neuroticism or emotionality is characterized by high levels of

negative affect such as depression and anxiety. Neuroticism, according to Eysenck's theory, is

based on activation thresholds in the sympathetic nervous system or visceral brain. This is the

part of the brain that is responsible for the fight-or-flight response in the face of danger.

Activation can be measured by heart rate, blood pressure, cold hands, sweating and muscular

tension (especially in the forehead). Neurotic people — who have low activation thresholds, and

unable to inhibit or control their emotional reactions, experience negative affect (fight-or-flight)

in the face of very minor stressors — are easily nervous or upset. Emotionally stable people —

who have high activation thresholds and good emotional control, experience negative affect only

in the face of very major stressors — are calm and collected under pressure.

The two dimensions or axes, extraversion-introversion and emotional stability-instability, define

four quadrants. These are made up of:

Stable extraverts (sanguine qualities such as outgoing, talkative, responsive, easygoing,

lively, carefree, leadership)

Unstable extraverts (choleric qualities such as touchy, restless, excitable, changeable,

impulsive, irresponsible)

Stable introverts (phlegmatic qualities such as calm, even-tempered, reliable, controlled,

peaceful, thoughtful, careful, passive)

Unstable introverts (melancholic qualities such as quiet, reserved, pessimistic, sober, rigid,

anxious, moody)

Further research demonstrated the need for a third category of temperament:[3]

P - Psychoticism/Socialisation: Psychoticism is associated not only with the liability to have a

psychotic episode (or break with reality), but also with aggression. Psychotic behavior is rooted

in the characteristics of toughmindedness, non-conformity, inconsideration, recklessness,

hostility, anger and impulsiveness. The physiological basis suggested by Eysenck for

psychoticism is testosterone, with higher levels of psychoticism associated with higher levels of

testosterone.

The following table describes the traits that are associated with the three dimensions in Eysenck's

model of personality:

Psychoticism Extraversion Neuroticism

Aggressive Sociable Anxious

Assertive Irresponsible Depressed

Egocentric Dominant Guilt Feelings

Unsympathetic Lack of reflection Low self-esteem

Manipulative Sensation-seeking Tense

Achievement-oriented

Impulsive Moody

Dogmatic Risk-taking Hypochondriac

Masculine Expressive Lack of autonomy

Tough-minded Active Obsessive

A fourth dimension, the L - Lie scale, was introduced later[4] in an attempt to measure to what

extent subjects were deliberately attempting to control their scores.

Versions

EPQ also exists in Finnish and Turkish versions.[5]

In 1985 a revised version of EPQ was described—the EPQ-R—with a publication in the

journal Personality and Individual Differences.[4] This version has 100 yes/no questions in its full

version and 48 yes/no questions in its short scale version. A different approach to personality

measurement developed by Eysenck, which distinguishes between different facets of these traits,

is the [Eysenck Personality Profiler].