Critical Evaluation of Eysenck's Theory

Critical Evaluation of Eysenckâs Theory Of Personality

Introduction

This essay attempts to highlight what I consider to be some of Eysenck’s main contributions to the study of personality, and his impact on psychology in general. The first part of the paper outlines his theory and elaborates on some key themes, including the dimensions of personality, and the construct of traits and its importance for individual difference psychology. After considering some aspects of research on personality, I then turn to take a brief look at some of the main criticism of his work, both from within his own theoretical frame of reference, as well as from those who operate from outside of it.

Eysenck’s Theory of Personality

Personality and Psychology

To Eysenck, the scientific study of “˜personality’ is of utmost importance to general scientific psychology (Corr, 2007; Costa & McCrae, 1986). Personality, a hypothetical construct, is here defined as a “pattern of deeply embedded psychological characteristics” that are, for the most part, “non-conscious”, not easily subjected to alteration, and “expressing themselves automatically in almost every facet of functioning” (Millon & Davis, 1996, cited in Haslam, Bastian & Bissett, 2004, p. 1662).

Unlike some of his colleagues in the Behaviorist tradition, he sees personality as encompassing more than just observable behavior; the latter, of course, could be relatively easily manipulated and changed (Eysenck, 1985, cited in Eysenck, 1991). Instead, the individual’s personality harbours and “reflects fundamental brain-behavioral systems” which have permeating effects on the person, and proves to be (relatively) unchanging over time (Corr, 2007, p. 667). These very same processes, the latter author continues, are seen by Eysenck as being at the core of the personality, and are responsible for individual differences (ibid.).

Although the environment and social processes are theorized as taking place outside the individual person, Eysenck does not regard these as unimportant in shaping and influencing his/her personality functioning (Boeree, 2006). However, Eysenck sees these as operating at a distance from the centre of personality. As such they are not crucially important to the study and functioning of individual difference psychology. Instead, Eysenck believes individual differences to be driven primarily by inherent biological processes (Claridge, 1986). Even though Eysenck advocates that personality be investigated at as many levels as possible “” “from DNA to social interaction”, (Corr, 2007, p.666), he regards the study of biological processes as far more useful to, and informative of, personality functioning (Bouchard & McGue, 2003).

Personality Dimensions

How does Eysenck describe personality? He argues that personality can best be seen as consisting of three grand, overarching and inclusive dimensions: namely Neuroticism (N), Extraversion (E), and Psychoticism (P) (Eysenck, 1991; Boeree, 2006; Costa & McCrae, 1986; Corr, 2007). On the Neuroticism dimension, personalities range from being “normal, fairly calm and collected”, to being “nervous” and easily excited (Boeree, 2006). On the Extraversion-Introversion plane, they tend to be outgoing and sociable, or be more reserved, shy and withdrawn. And although they may not show the qualities of the raving psychotic on the Psychoticism dimension, given the right time and stimulus, they could exhibit unwarranted emotional expression, for example (Boeree, 2006).

Clardige (1986) notes that what has also contributed to the development of his work and the strength of his theory, is the links Eysenck draws between his dimensional theory of personality and abnormal psychology. This allows him to make hypotheses about the interaction of the three dimensions. For example, highly neurotic people who are also introverted would tend to respond with exaggeration to mildly fear-inducing situations, and also learn to avoid new situations rather quickly (Boeree, 2006). Furthermore, Eysenk could then also collect data about these dimensions and learn about their abnormal extremes; as such personality characteristics also serves as “predispositions” to personality pathology (Claridge, 1986, p. 75).

Personality Dimensions and Traits

In order to assign differences to individuals, scientific psychology needs to come up with “some core consistency of a behavior pattern” that would make the differences stand out (Budaev, 2002, p. 2). This is precisely where the concept of traits play an important role. Costa and McCrae (1986) are of the view that by identifying the basic dimensions of personality, Eysenck has inaugurated the basis of trait psychology. Since 1968, according to Roberts and Pomerantz (2004), there is accumulated evidence which strongly supports the usefulness of the notion of traits in personality psychology.

In a nutshell, a trait (which is a hypothetical construct) refers to that aspect of personality which makes the individual relatively consistent and predictable in his/her thoughts, feelings and actions over time and across situations (McCrae, 2001). We could say that traits encapsulate and express the individual’s habitual modes of behaving, irrespective of place and time. Traits, in turn, form a part of and are subsumed by the larger dimensions of personality (Heffner, 2002).

Personality and Individual Difference

Given that Eysenck is not comfortable with the idea of the “˜typical individual’, he is interested in knowing what makes people as individuals different from one another (Martin & Jardine, 1986). This leads him to invest in genetic studies (Martin & Jardine, 1986), and to develop and elaborate his theory of personality along physiological and genetic lines (Boeree, 2006). Personality differences, he believes, are by and large the outcome of what a person inherits genetically (ibid.).

Even though Eysenck conceives of traits as “intrinsically biologically based properties of the individual,” (McCrae, 2001, p.839), he also states that this doesn’t necessarily mean that individual traits are “fixed for all eternity” (Eysenck & Gudjonsson, 1989, p.94). Notwithstanding the power of the individual’s genetic inheritance over his/her personality, Eysenck still holds that genetic motivations do not have total sway of over the individual’s actions (ibid.).

Support for his view comes from Costa & McCrae’s (1986) longitudinal studies which shows that even though personality is a relatively stable phenomenon, some research also shows that for some individuals, under some conditions, traits do change (McCrae, 2001). This could be the result of, say, age, brain-damage, or psychopathology. Nevertheless, Costa and McCrae (1986) concurs with Eysenck that overall, personality traits change very little, as their biological foundations remain largely intact throughout an individual’s life.

Personality, Biology and Behavior

Eysenck’s original idea that the major personality dimensions rest upon a biological substrate (Claridge, 1986), is in line with his thinking that human beings are in essence “biosocial animals” (Eysenck, 1980b, cited in Eysenck, 1991, p.87). Heffner (2002) reports on research which confirms that aspects of our general psychology “” like intelligence or the three major dimensions identified by Eysenck “” are to some degree largely inherited. Corr (2007) cites research inspired by Eysenck’s theories which confirms that personality is not an entity separate from brain-behavioral processes, but is in fact defined by it.

Personality Research, Measurement and Experimentation

Like other behavioral psychologists who share with him the scientific, positivist paradigm of the natural sciences as a framework within which to work, Eysenck believes in the scientific method as the only way to gain adequate knowledge/facts about his subject matter (Boeree, 2006). As a consequence, he thinks that personality could best be investigated and explained in physiological terms: thus he concludes, for instance, that aspects of temperament (emotionally-laden traits) are significantly inherited (Eysenck, 1991). Using research instruments developed by Eysenck – such as the EPI (Eysenck Personality Inventory) and/or EPQ (Eysenck Personality Questionnaire) – many investigators, applauding their psychometric sophistication, concurs with Eysenck that inherited “individual differences” are of utter importance in shaping human behavior (Eysenck & Eysenck, 1980, cited in Costa & McCrae, 1986).

The following part of the essay offers some critical views on Eysenck’s theory of personality and related issues. In my view, the criticism can be categorized as falling into two broad classes: those leveled at Eysenck’ theory from within the same scientific, positivist frame of thinking, and those from outside this frame of reference.

(Some) Criticism of Eysenck’s Theory of Personality

Problems with Measurement and Experimentation

To begin with, there are areas of weakness pertaining to the research and measurement of his theory. Even though Eysenck himself is aware of these, they nevertheless remain troublesome. For example, in investigating the links between individual responses and cortical arousal (Eysenck, 1991), he points out that “different systems of cortical arousal are activated in different people” (p. 90). Some individuals may respond with excessive sweating, while others respond with increased breathing. In other words, how could one be sure which arousal system is activated in a particular individual at a specific time? To put it simply, a particular theory may not be supported because the wrong measuring instrument was used (Eysenck, 1991, p. 90)

Along the same lines is the phenomenon of “response specificity” (Eysenck, 1991, p. 90). As an example, since “[g]enetic factors predispose individuals” to become anxious in the face of specific stimuli, how does the researcher know which stimulus is the correct one, and for which particular individual, to induce and measure anxiety, at a particular point in time? (Salz, 1970, cited in Eysenck, 1991, p. 90).

Another area of uncertainty concerns the attribution of causality when trying to understand the motives for a particular person’s responses under given conditions. Again, Eysenck himself remarks that “the arrow of causality” does not always or necessarily go in one direction, from the biological/genetic processes to the behavioral side (Eysenck, 1991, p. 99). Referring to studies which examine the influence of testosterone levels on behavior, he states that aggressive and sexual behavior may change the levels of testosterone released in the body, while at the same time being influenced by this level (ibid.). In the same vein, Quinsey et al. (2001) “” working in the field of individual differences and criminal behavior – refer to the difficulty in making fruitful causal connections given the large amount of correlational data and their complex relationships.

Challenges from within Scientific, Positivist Psychology

First off is the ever-present and long-standing debate in psychology of whether the (external) environment or inner attributes (such as personality) play a more important role in determining and shaping individual behavior (Haynes and Uchigakiuchi, 1993). B.F. Skinner, an arch-behaviorist, believes that conditioning (environmental) processes to be far more fundamental in this regard than say, physiological ones (Boeree, 2006). Even though many personality psychologists take the middle road and offer interactional models which try to give equal prominence to both personality and environmental processes, adherents of both models are “reluctant to advocate variance in behavior to sources outside their adopted paradigm” (Haynes and Uchigakiuchi, 1993, p. 73).

This relates to the crucial issue of personality (and by implication, social) change. In Skinner’s thinking, for instance, individuals learn most of their behavior and, in principle, can therefore unlearn negative behaviors and learn new and uplifting ones. This is not so for trait psychologists like Eysenck. If traits are essentially biologically based and genetically inherited, and therefore sources of consistency across space and time, how can individuals change? In other words, trait theory does not inherently provide a medium of personality change (Heffner, 2002, p.6). Consequently, trait psychology is discredit by some for its anti-human stance, as it were: it leaves very little room for the exercise of free will and choice (Smith, 1978; Hardin, 1956).

On another level, many of Eysenck’s colleagues in the behaviorist camp have a distaste for concepts which, to them, smack of unscientific, subjective psychology. Personality itself is something not directly observable, they argue, and therefore not subject to experimentation, direct manipulation, measurement, and control (Smith, 1978). Constructs which refer to an “internal entity” (Haynes and Uchigakiuchi, 1993, p. 76), are questionable for purposes of gaining hardcore facts in science because they are open to “ambiguous definitions” and other “semantic” uncertainties (ibid.).

Challenges from Outside Positivist Psychology

The Positivist or Essentialist meta-theoretical paradigm informing much contemporary psychology are largely guilty of disregarding the social context of human life (Smith, 1978, Tolman, 2009, Igarashi, 2006). In this vein Eysenck’s psychology is also guilty as personality/mental processes are studied as fundamentally isolated from its social context (Igarashi, 2006). Larger social processes which shape and motivate the individual’s behavior, such as gender, class and/or race dynamics become obscured or relegated as irrelevant background noise. So, for example, if and when women cross-culturally appear to be socially shy, demure or withdrawn, it has little to do with so-called inherent introverted traits, but largely to do with universal gender beliefs and social constructions of men and women.

Igarashi (2006) among others, comments on the negative effects of much of trait psychology as it is partly responsible for generating labels about individuals which tend to have devastating personal and social effects. He points out that many psychotherapy clients and others, for instance, tend to be assigned diagnostic labels “” such as “˜abnormal’, “˜inferior’, or “˜pathologically introverted’ that often result in suffering and loss of life opportunities (Igarashi, 2006,). In this way much of contemporary psychology, including trait psychology, lacks respect for the subjectivity of its subject: the human being (Tolman, 2009). Lamiell (2007) suggests that contemporary mainstream personality psychologists, including those under Eysencks’ influence, should seriously and critically examine “the paradigmatic commitments that have shaped, and continue to dominate, mainstream thinking about what a scientific psychology of personality should be” (p.170).

Conclusion

In this paper I started off by highlighting aspects of Eysenck’s theory, especially his insistence on the importance of the concept of personality for psychology. The discussion then briefly elaborated on related themes such as the major personality dimensions, the concept of traits and the general importance of brain-behavioral processes and its importance to individual differences. After highlighting some aspects of research on personality, I then turn to some critical comments about Eysenck’s theory. I think it is fair to say that even though his theory, like most other theories, can be slighted for its shortcomings, Eysenck certainly left a significant mark in his contributions on personality psychology in particular, and on psychology in general.

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