Hans J. Eysenck

William Revelle Northwestern University

Hans Juergen Eysenck (1916-1997) was one of the most influential personality psychologists of the 20th century. He was a champion of the scientific approach to psychology in general and to personality in particular. His approach emphasized the integration of basic psychological theory with an experimental approach to the study of individual differences. During his life, his work on behavior genetics, ability, dimensions of personality, and a biological basis to personality went from being disbelieved and controversial to accepted wisdom for the field.

Hans Juergen Eysenck (born March 4, 1916, uate degree and subsequent Ph.D. in psychology. Berlin; died 4 September, 1997, London) was one of In contrast to the emphasis on experimental the most influential personality psychologists of the psychology at Cambridge, the so called “London 20th century. He was a champion of the scientific school” of psychology emphasized individual dif- approach to psychology in general and to personal- ferences. UCL had been the home of Charles Spear- ity in particular. His approach emphasized the in- man and subsequently, Cyril Burt. Both were tal- tegration of basic psychological theory with an ex- ented psychometricians heavily influenced by Fran- perimental approach to the study of individual dif- cis Galton’s emphasis on the study of individual ferences. During his lifetime his work on behavior differences and the inheritance of personality and genetics, ability, dimensions of personality, and a ability. Despite some initial language difficulties, biological basis to personality went from being dis- Eysenck fit in very well at UCL and took a first believed and controversial to accepted wisdom for class undergraduate degree working with Burt be- the field. fore continuing on for his Ph.D. also under Burt’s Eysenck was born in Germany to parents both of supervision. whom were renowned actors. Because they were His first appointment after his Ph.D. was as a re- frequently on tour, the young Eysenck was raised search psychologist at the Mill Hill hospital, the war mainly by his maternal grandmother. After fin- time home of the Maudsley Hospital which even- ishing secondary school in 1934, he realized that tually became the Institute of Psychiatry (IoP). His an academic career would require joining the Nazi subjects were primarily soldiers diagnosed with var- party, which he despised. Thus, at age 18, he em- ious psychiatric disorders. Working at the IoP pro- igrated to the UK where he did his undergraduate vided him with a golden chance to analyze the data and graduate work at the University College of Lon- already collected on the numerous patients. In con- don. Although most interested in physics, he did trast to other practioners of factor analysis of per- not have the necessary course work for the entrance sonality ratings or self reports, Eysenck used be- exam for physics and instead pursued an undergrad- havioral ratings, psychiatric diagnoses, and exper- imental measures such as those of hypnotic sug- gestibility. His goal was to marry the best of exper- imental psychology with the best of psychometrics. His first book, Dimensions of Personality (1947) did contact: William Revelle [email protected] just that. Based upon the factor analytic results, Version of March 1, 2014 Eysenck proposed support for a general factor of To appear in Cautin, R. and Lilienfeld, S (Eds) The Ency- neurosis with a second, bipolar factor that he con- clopedia of Clinical Psychology. Wiley-Blackwell sidered introversion-extraversion. This is the submitted LATEXversion and might differ from Eysenck continued to integrate what he per- the final published version. ceived to be the best theories from experimental 2 HANS EYSENCK psychology with his factor analytic results. A sub- vor and opposed to his theories and suggested that sequent book proposing a biological basis of per- personality was indeed moving towards becoming a sonality based upon classic learning principles, The paradigmatic science. dynamics of anxiety and hysteria (1957), met with In cooperation with a number of other individ- serious criticism, however a later model based upon ual differences psychologists interested in the study individual differences in arousal, The biological ba- of intelligence, the biological basis of personality, sis of personality (1967) was much better received and behavior genetics, Eysenck founded the Inter- and continues to be well cited. It was an ambi- national Society for the Study of Individual Differ- tious attempt to relate introversion-extraversion to ences and was its first president. In addition, he was the arousal dimension being studied by experimen- the founding editor of the journal Personality and tal psychologists such as Donald Broadbent. Re- Individual Differences. As evidence for his trust flecting the current physiological thinking, the pro- in the scientific process, at the first ISSID meeting posed biological mechanisms were the ascending after he critically reviewed the differences between reticular activating system and other parts of the his and Gray’s models of personality he cheerfully limbic system. Introverts were thought be have announced that Gray would be his successor at the higher resting levels of cortical arousal than did ex- Maudsley. traverts. With the assumption of an optimal level of In addition to his theoretical contributions to the arousal, the sensation seeking behavior of extraverts study of personality, Eysenck was also notorious for was explained as an attempt to compensate for their his strong critique of conventional psychoanalytic lower resting levels. therapy and his advocacy for what is now known This and his later theories influenced and were as behavioral therapy. Although mild mannered in- influenced by Jeffrey Gray whose theories of anxi- terpersonally, his writings could be bitter critiques ety and impulsivity reflected individual differences of the works of others. He wrote not just for the in sensitivities to cues for reward and punishment. scientific community but also wrote several very in- As is true of any developing scientific theory, many fluential critiques for the general public. He did not of Eysenck’s ideas have been shown during the sub- avoid controversy. From his political analysis of the sequent 40 years to be wrong or to be oversimpli- similarities of the far right and the far left, to his fications, but his general emphasis upon integrating critiques of psychotherapy, to discussions of racial genetic and biological principles within the study differences in intelligence, he was always willing to of individual differences has become the standard take unpopular views. model of personality. Eysenck has had a lasting impact upon the field Eysenck and Gray took a very different approach of personality not just because of the number of stu- to the study of personality than was common in dents trained at the IoP, nor because of his particu- the United States. They both emphasized a “bot- lar theoretical models, but due to his emphasis upon tom up” approach, going from basic physiological personality as a paradigm driven scientific endeavor principles and looking for behavioral correlates and that needs to integrate biological and social mecha- consequences. This was in contrast to the lexical nisms to understanding individual differences. approach favored by many in the U.S. In addition, both Eysenck and Gray emphasized that personality See also had to have a biological basis which then interacted Correlational Designs; Eugenics; Raymond Cat- with social experience to lead to the surface traits tell; Francis Galton; Intelligence Testing; Charles observed by others. Eysenck’s continued empha- Spearman sis upon biological and genetic mechanisms were in start contrast to the general attack on trait theory References that swept the US in the 1970s. Eysenck believed that science was a self cor- Further Reading recting process and that good ideas would supplant weak ones. His 1985 book Personality and individ- References ual differences: a natural science approach (writ- Buchanan, R. D. (2010). Playing with fire: the contro- ten with his son, Michael) reviewed evidence in fa- versial career of Hans J. Eysenck. Oxford England: HANS EYSENCK 3

Oxford Univeristy Press. Eysenck, H. J., & Eysenck, M. W. (1985). Personal- ity and individual differences: a natural science ap- Eysenck, H. J. (1957). The dynamics of anxiety and hys- proach. New York: Plenum Press. teria; an experimental application of modern learning theory to psychiatry. Oxford, England: Frederick A Eysenck, H. J., & Himmelweit, H. T. (1947). Dimen- Praeger. sions of personality; a record of research carried out in collaboration with H.T. Himmelweit [and others] Eysenck, H. J. (1967). The biological basis of personal- . ity. Springfield: Thomas. London: Routledge & Kegan Paul. Eysenck, H. J. (1976). The measurement of personality. Nyborg, H. (Ed.). (1997). The scientific study of human Lancaster: MTP. nature: Tribute to Hans J. Eysenck at eighty. Amster- dam, Netherlands: Pergamon/Elsevier Science Inc. Eysenck, H. J. (1997). Rebel with a cause: the autobiog- raphy of Hans Eysenck (Rev. and expanded ed.). New Brunswick, N.J.: Transaction Publishers.