A special issue of the journal Personality and Individual Differences marking the centenary of Hans Eysenck’s birth is now available online. Among the many varied contributions to the forthcoming issue are a number of personal reminiscences of Eysenck and his influence, including ones from his wife Sybil Eysenck and son Michael Eysenck, both psychologists in their own right.

Particularly interesting contributions to the special issue include an article and commentary addressing Eysenck and the question of his Jewish ancestry. Articles that focus on the history of Eysenck and his work are highlighted below.

“Hans J. Eysenck: Introduction to centennial special issue,” by Philip J. Corr.

“Hans Eysenck and the Jewish question: Genealogical investigations,” by Andrew M. Colman and Caren A. Frosch. The abstract reads,

We present evidence establishing that Hans Eysenck was half Jewish. He went out of his way to conceal this fact and to disavow his Jewish ancestry until the publication of his full-length autobiography in 1990, long after he retired, when he revealed that one of his grandparents was Jewish. Using specialized genealogical techniques and resources, we trace his Jewish maternal grandmother, who died in Theresienstadt concentration camp in 1944, and his Jewish maternal grandfather, who practised medicine in Königshütte and later in Berlin. We discuss Eysenck’s possible motives for disavowing his Jewish heritage for most of his life.

“Commentary on “Hans Eysenck and the Jewish Question: Genealogical Investigations” — by Andrew M. Colman and Caren A. Frosch,” by Roderick D. Buchanan. The abstract reads,

Several intriguing questions pertaining to Hans Eysenck’s family background were raised but only partially resolved by Buchanan (2010). Here I comment on the implications of the new genealogical evidence unearthed by Coleman and Frosch (2016; this Special Issue) in light of Eysenck’s life and career.

“H. J. Eysenck: Scientist, psychologist and family man,” by Sybil B. Eysenck. The abstract reads,

I am absolutely delighted that Elsevier and the journal Personality and Individual Differences have produced a Special Issue devoted to my late husband, Professor H. J. Eysenck! As founding Editors, we have a special interest and allegiance to this journal and I am sure Hans would have been pleased at the prospect of this issue conceived, suggested and edited by Philip Corr.

“Hans Eysenck: The ‘Great Scientist’,” by Jan Strelau. The abstract reads,

Professor Hans Eysenck’s supportive style is presented to demonstrate his unique contribution to Jan. Strelau’s academic achievements starting from the year 1966. It was the period of the, so-called, “iron curtin” that lasted in Poland, as well as in other East-European countries, under the Soviet regime from 1948 until the end of 1980s. His contribution and support have been manifested in such forms as sending scientific papers and books, which from many years were not available in Poland, as well as by private and official meetings, and a long-lasting correspondence with his full sympathy and friendship. He was an essential promoter of my achievements in the study of temperament, as well as very supportive in my activities in the development of psychology of individual differences and in building bridges between psychologists from the West and East. Hans Eysenck influenced my academic career in very positive ways for which I am extremely grateful to him. In my memory, he is a Great Scientist.

“Reflections on Hans Eysenck: First encounter and the founding of ISSID,” by Robert M. Stelmack. The abstract reads,

This short memoir is a reflection on my first encounter with Hans Eysenck in 1976, and subsequently on the founding of the International Society for the Study of Individual Differences (ISSID). I summarize the first scientific meeting and how Personality and Individual Differences (PAID) become the journal of the new Society. I also recount the people involved at the very beginning and how the Society developed during these early days. ISSID is now a vibrant Society of international scholars and this is due to the work of the founding members and the intellectual leadership provided by Hans Eysenck.

“Clever Hans Eysenck and the Light Blue Fringe,” by Patrick Rabbitt. The abstract reads,

Eysenck believed that he was undervalued by a ‘Light Blue Fringe’ of the British Psychological Establishment. His biographers choose not to question this view and imply that deliberate neglect caused him personal pain, muffled the impact of his work and so obstructed the development of scientific psychology in Britain during the 20th century. An alternative view is that in so far as Eysenck was neglected this was because his scientific insights were weakened by his failure to recognise and assimilate the fundamental changes in psychology that occurred during his working lifetime.

“A unique British psychologist: Why there can never be another Hans Eysenck,” Roderick D. Buchanan. The abstract reads,

Hans Eysenck was a compelling figure in British psychology. In many respects, his impact can never be duplicated. His astonishing output and way of doing science capitalized on his strengths, and was geared to maximal effectiveness. He became postwar British psychology’s most visible researcher and most influential disciplinary voice. Eysenck’s extraordinary personal qualities certainly amplified his impact. But the singular nature of this impact was made possible by the special contingencies of time and place. Eysenck arrived on the scene fully formed just prior to a period of great expansion in British psychology. He took full advantage of the circumstances he found himself in and the unprecedented opportunities with which he was presented. His exceptional impact can readily be gauged by contemplating the counterfactual effects of his absence. Hans Eysenck was a compelling figure, probably the most significant player in the history of British psychology. He is also likely to remain so for the foreseeable future precisely because he had a role and an impact that can never be duplicated. Eysenck was unusual: he had a rare combination of talent and ambition that both enabled and augmented his influence. But these personal qualities were not in themselves sufficient to make him the unique figure he was. Fate was the key. The circumstances and opportunities that marked his early career are unlikely, or simply cannot, take place again. In this sense history, and Eysenck’s role in it, can never quite be repeated.

“Hans Eysenck: Personality theorist,” William Revelle. The abstract reads,

Hans Eysenck was the leading personality and individual differences theorist of the 20th century. His goal was to combine the best theories and practices of experimental psychology with the best measurement techniques of individual differences. From his earliest analyses of the dimensions of individual differences, through multiple iterations at theory building to his lasting achievements in building a paradigm for personality research he left a legacy of broad and rigorous research. He strove to integrate behaviour genetics, psychophysiology, cognitive psychology, aesthetics, and psychometrics into a unified theory of personality and individual differences. Although best known for his biological theory of extraversion, his impact upon the field was much more than that and cannot be summarized in a brief article. I review his major theoretical contributions and relate them to modern personality theory and show how his many contributions continue to shape current personality research.

“Hans J. Eysenck and Raymond B. Cattell on intelligence and personality,” by Gregory J. Boyle, Lazar Stankov, Nicholas G. Martin, K.V. Petrides, Michael W. Eysenck, Generos Ortet

The two most prominent individual differences researchers of the twentieth century were Hans J. Eysenck and Raymond B. Cattell. Both were giants of scientific psychology, each publishing scores of books and hundreds of empirical peer-reviewed journal articles. Influenced by Hebb’s distinction between physiological (Intelligence A) and experiential (Intelligence B), Eysenck focused on discovering the underlying biological substrata of intelligence. Analogously, Cattell proposed the Gf–Gc theory which distinguishes between fluid and crystallised intelligence. Cattell’s Culture Fair Intelligence Test (CFIT), a measure primarily of fluid intelligence, was constructed specifically to minimise differences in test bias in IQ scores between different ethnic/racial groups. Within the personality realm, Eysenck adopted a pragmatic three-factor model as measured via the Eysenck Personality Questionnaire (EPQ-R) and its variants. In contrast, Cattell employed a lexical approach that resulted in a large number of primary and secondary normal and abnormal personality trait dimensions, measured via theSixteen Personality Factor Questionnaire (16PF), and the corresponding Clinical Analysis Questionnaire (CAQ), respectively. Recent molecular genetics findings provide empirical confirmation of Eysenck and Cattell’s positions on the biological underpinnings of personality and ability traits, allowing an improved understanding of the causes of individual differences.

 

“Hans Eysenck in Latin America: His influence in the psychology, the study of personality and individual differences,” by Carmen Flores-Mendoza, Ruben Ardila, Miguel Gallegos, Luciana Sampaio Braga, Bruna Miranda Carvalhais Santiago, and Daniel Marcos Andrade. The abstract reads,

Hans Eysenck’s works have had a substantial influence on the study of psychology in Latin America. His personality characteristics (sometimes dogmatic and incisive) and high intelligence (shrewd critic, a rigorous methodologist) were noted in the few visits that he made to the Latin America region (one of those visits called as “The Eysenck Affairs”). Considered as one of the most important scientists of psychology, Eysenck arrived into Latin American academic establishment in an epoch dominated by psychoanalysis, and showed us one of the strongest personality paradigms that the psychology has given to our times. The Latin-America psychology is returning to the investigation of personality traits from a psychometric approach. Certainly, underlying this returning, the Eysenck’s PEN model is the principal driver. This tribute shows how the Eysenck’s ideas arrived in the Latin American region and the potential of his influence in the future.

“Classical eyelid conditioning, psychopathy, and Hans Eysenck’s grand theory,” by Ian M. Evans, Nick Wilson. The abstract reads,

The concept of conditionability, usually assessed in classical preparations such as the eyelid conditioning paradigm, was one of the original cornerstones of Eysenck’s goal for a grand theory moving seamlessly from biology (inherited and acquired CNS differences), through basic learning, to personality, and to clinical syndromes, including psychopathy and criminal conduct. From a somewhat personal perspective we trace the beginning of classical conditioning research in Eysenck’s research programme at the Institute of Psychiatry (Maudsley Hospital), through various technical developments, which eventually led to questions regarding the adequacy of the construct of conditionability itself. Nevertheless, contemporary research on psychopathy, drawing on new approaches to personality theory and sub-types of psychopathic individuals, is still influenced by Eysenck’s interest in crime and personality. While most of the details of the original model have been challenged, there is still a surprising consonance between Eysenck’s theory and modern approaches to research on the nature of psychopathy. Conditioning studies of psychopathic individuals could still benefit further from insights developed in Eysenck’s laboratories.

“Hans Eysenck’s contributions to clinical psychology and behavior therapy,” by
S.J. Rachman. The abstract reads,

Hans Eysenck’s contributions to the growth of clinical psychology in the UK, and to the development of Behavior Therapy are described and evaluated. He construed clinical psychology as an applied science and accordingly the graduate training provided in his Department was based on this view. He was critical of psychodiagnostic tests such as the Rorschach, and criticized the poor quality of research on the effects of psychotherapy. Eysenck was a prolific and accomplished writer and a forceful advocate of Behavior Therapy.

“Hans Eysenck’s contribution to our understanding of personality and psychological disorders: A personal view,” by Gordon Claridge. The abstract reads,

In this autobiographically themed paper an account is first given of an early testing, in psychiatric patients, of the causal part of Eysenck’s introversion–extraversion (I–E) theory. On a range of laboratory measures dysthymic and hysterico-psychopaths were found to differ, exactly as predicted; especially on a key index of depressant drug response, the sedation threshold. However, closer scrutiny revealed that observed effects in the data were due not solely to I–E, but to an interaction between I–E and neuroticism (N), true in both normal and clinical populations. Eysenck’s recognition of the importance of N in personality differences is discussed, together with his shift from a Pavlovian to a more Western-style model of the nervous system. It is noted that the significance of this new formulation was overtaken by the revision to the theory developed by Gray and his followers. Considering the latter prompted a discussion about whether theories in this genre are really theories of temperament, and not personality in the full sense. Eysenck’s later revision of his psychoticism dimension is then evaluated and found to be fatally flawed due to its failure to incorporate key defining features of psychosis. The overall conclusion reached is that, despite serious deficiencies in the details of his theorising, Eysenck made important contributions to the field reviewed: a) emphasising a dimensional view of psychological disorders; b) opening the discussion, at a time of much opposition, about unitary psychosis; c) promoting a biological approach to the study and explanation of personality (or temperament!).

“A criminologist’s tribute to Hans Eysenck: The r/K story,” by Lee Ellis. The abstract reads,

Hans Eysenck influenced my professional life in important ways. Here, I will describe how those influences became interwoven with a personal friendship that we developed. This brief essay will also sketch out how I think his editorship of Personality and Individual Differences has substantially influenced the understanding of behaviour from a biological perspective, including in my own field of criminology.

Hans Eysenck’s theory of intelligence, and what it reveals about him
Linda S. Gottfredson. The abstract reads,

Hans Eysenck was a highly analytical, objective, independent-minded experimentalist. He personified the biological perspective of the Galton–Spearman ‘London School of Psychology’, which he led for many decades. His first (1939) and last publications (1998) were on intelligence. Returning to the topic in the 1960s, he formulated, tested, and promulgated the theory that general intelligence (g) is a biological phenomenon with broad social consequences. I examine the status of Eysenck’s theory, advances in the field, and social reactions to them during the 1960s–1970s, 1980s–1990s, and since 2000. My perspective is that of a sociologist who, in testing alternative theories of social inequality, was drawn inexorably into the intelligence literature, policy debates over fairness in employee selection, and first-hand observation of the sort of controversies he experienced. Eysenck’s 1979 and 1998 textbooks on intelligence mark developments in his theory and supporting evidence during the first two periods. They exhibit considerable knowledge about the philosophy and history of science, and the nature of scientific controversy. Advances in intelligence since 2000, in particular, from neuroimaging and molecular genetics, vindicate his biological perspective. It was controversial during his lifetime because he was so far ahead of his time.

“Electrophysiology, chronometrics, and cross-cultural psychometrics at the Biosignal Lab: Why it began, what we learned, and why it ended,” by Paul Barrett. The abstract reads,

This article is about why and how Hans Eysenck began investigating the brain evoked potential and sensory nerve conduction correlates of psychometric IQ, his investigations into the timed/speeded performance (chronometrics) results being published by Art Jensen, and the initial results being reported by Doug Vickers and Ted Nettelbeck on the relation of Inspection Time to psychometric IQ. In the midst of this experimental work, Hans and Sybil Eysenck were also engaged in the final stages of their multi-country investigation into the universals of human personality and temperament, using the Eysenck Personality Questionnaire (EPQ). Although many regarded both the experimental and cross-cultural work as ‘mildly amusing but not his best work’, we did actually learn a great deal from these efforts. (1) None of the previously reported evoked potential parameter correlations with psychometric IQ replicated with any substantive consistency. Neither did the sensory nerve conduction parameters. (2) The expected relationship between Reaction Time parameters and psychometric IQ was replicable, but theoretically and scientifically deficient. Why? Because we observed many individuals with low IQ possessing reaction times faster than high IQ individuals, even when retested on a second occasion. (3) The expected relationship between Inspection Time parameters and psychometric IQ was replicable, but again, theoretically and scientifically deficient. Too many cases were observed showing the opposite of the expected effect (i.e. low IQ individuals possessed much shorter Inspection Times than high IQ individuals). (4) The four personality constructs assessed with the EPQ showed ‘good enough’ replicability within datasets acquired across 35 different countries, although the Psychoticism scale was the weakest in terms of factor recovery.

“Hans Eysenck and the First Wave of Socio-Political Genetics,” by Gary J. Lewis. The abstract reads,

Hans Eysenck was a pioneer in many fields of psychological science and is widely recognised for his many outstanding achievements. One field, however, in which Eysenck contributed the important initial flagstones, although remains largely forgotten, is that of socio-political genetics. In this essay I outline Eysenck’s early work (c. 1950s) on the structure of political attitudes, details how Eysenck used the classical twin design in order to examine whether genetic factors contributed to individual differences in social and political attitudes, as well as discuss the challenges of publishing such provocative findings amidst a 1970s scientific culture that tended to favour purely environmental explanations of human behaviour. Finally, I provide an overview of the development of the field of socio-political genetics over the last 40 years and briefly note some of the challenges that lie ahead for the field.

Hans Eysenck: Sex and violence on television, the paranormal, graphology, and astrology
David K.B. Nias. The abstract reads,

The views of Hans Eysenck and how they have fared in the light of subsequent research are presented for four controversial topics: (1) In the case of pornographic films, and violence as shown on television (and in the media generally), he interpreted the early evidence as indicating social effects that were predominantly harmful and anti-social, especially for predisposed and vulnerable individuals—as predicted by learning and personality theories. Further research has reinforced these views, unpopular at the time, and so they appear to have definitely stood the test of time. (2) In the case of the paranormal, he continued to see the experimental evidence as promising. However, rigorous testing has found that the demand for replicability is simply not met, at least not replicability commensurate with the claims. (3) For graphology, he found there was no evidence of a useful correlation between handwriting and personality, a conclusion that has since been confirmed. (4) For astrology, he found that there was only one replicable finding (the Mars effect), which urgently required an explanation (none were in sight at the time). After much thought and detective work a likely explanation has been forthcoming in terms of social effects that can bias birth times as reported to registry offices—the raw data. In the context of Eysenck’s broad interests and his influential role as a teacher and writer, the progress of research into these topics helps to throw light on his approach to controversial issues.

“Eysenck at work: The application of his theories to work psychology,” by Adrian Furnham. The abstract reads,

This rather personal paper looks at the extent to which Hans Eysenck’s research influenced work psychology presently and in his lifetime. Whilst he was interested in, and eager to apply his theory very widely from criminology to politics, he seemed less interested in the world of work. Yet his influence can be seen in correlational work psychology, which looks at personality and intelligence correlates of work beliefs and behaviours as well as experimental work psychology, which uses classic experimental psychology to test hypotheses. He “gave away” intellectually his measures and ideas to entrepreneurs preferring to test his ideas in the laboratory, classroom or clinic.

“Hans Eysenck as a health psychologist,” by Shulamith Kreitler. The abstract reads,

Health psychology held a special place in Hans Eysenck’s broad range of contributions to psychology. The paper outlines briefly the developmental course of Eysenck’s interest in medicine and health from the early groping attempts focused on studying, on the one hand, psychological correlates of physical disorders and, on the other hand, the personality correlates of psychological ones. From the eighties onward he focused increasingly on the personality contributions to predicting the occurrence and course of disease, mainly cancer and coronary heart disease. A great number of publications on this theme were done with associates, mainly Grossarth-Maticek, and have become the focus of controversies. However, this should not obscure the contributions of Eysenck to health psychology which are mainly highlighting the role of personality in regard to physical disorders, and suggesting several major conceptual and methodological paradigms for the study of the impact of psychological, genetic, and life-style factors on physical health.

“Order in complexity: How Hans Eysenck brought differential psychology and aesthetics together,” by Nils Myszkowski, Martin Storme, and Franck Zenasni. The abstract reads,

Although Hans Eysenck’s reputation is for the most part related to other works, empirical aesthetics was the topic of his PhD, a field in which he remained interested for a very long time, steering the domain’s wheel towards the study of individual differences. In this article, we review his work and impact in the field. We first argue that his works on aesthetics demonstrate his interest for natural sciences and arts, his gestaltist views on art and psychology, as well as the influence of Burt and of his first wife, Margaret Davies, on his work. We then analyze his first factor analytic works on aesthetic preferences, leading to the discovery of the two factors of aesthetic judgment – ‘T’ (for taste) and ‘K’ (for appreciation of complexity) – and show how, in spite of his impact in other fields, he kept demonstrating concern for the measure and determinants of these two factors. Finally, we discuss the extensions and limitations of Eysenck’s contribution to the field of empirical aesthetics, proposing that the ‘T–K’ duality sowed important seeds for a unified concept of ‘Aesthetic Quotient’.

“What does Hans Eysenck mean for young researchers?,” by Benjamin R. Walker. The abstract reads,

In some people’s eyes, Hans Eysenck holds a mixed legacy with remarkable achievements alongside engagement with some, apparently, futile research areas. I suggest that rather than perceiving his career as having successes and failures, an alternative way to understand Eysenck is to appreciate that he had an underlying willingness to push the boundaries and explore new frontiers, and the outcome of this is unsurprisingly some less productive areas as well as achievements. He was willing to seek the truth despite the perceptions of his peers. A lesson for young researchers from Eysenck’s biography is a choice of whether to play it safe and engage in relatively incremental research or aim for big picture research, which may change a whole field but may — to use a football analogy, which because of his interest in the sport, Eysenck may have approved — put people offside.

“Race differences in IQ: Hans Eysenck’s contribution to the debate in the light of subsequent research,” by Andrew M. Colman. The abstract reads,

Hans Eysenck was one of the earliest protagonists in the controversy over race and intelligence. He believed that the observed variability in IQ scores is genetically determined to a high degree (80% heritability) and that, in consequence, the Black–White IQ gap in the US is due predominantly to genetic factors. Subsequent investigations have confirmed that IQ is indeed heritable, though at a level substantially below 80%, and a deeper understanding of population genetics has shown that race differences in IQ could be determined entirely by environmental factors even if its heritability were as high as Eysenck believed it to be. Several lines of research, notably racial admixture studies, racial crossing studies involving interracial parenting or adoption, and especially investigations using more recent techniques of molecular genetics, have provided evidence suggesting that the Black–White IQ gap is not determined significantly by genetic factors.

 

“Hans Eysenck: A research evaluation,” by Michael W. Eysenck. The abstract reads,

Hans Eysenck made outstanding contributions to the description of human personality with his identification of three orthogonal personality dimensions although his approach was less exhaustive than that of subsequent researchers. He also proposed an ambitious agenda for developing comprehensive theoretical explanations based on the experimental approach and the biological underpinnings of major personality dimensions. Subsequent theories have followed his blueprint. Hans Eysenck’s higher-level theoretical assumptions have stood the test of time better than his lower-level ones. However, a general limitation was his de-emphasis of cognitive processes and structures. He was less successful at implementation and interpretation than theory generation. This occurred in part because of his preference for a lawyer-like approach to research rather than a more scientific and objective one.