Abstract
This text is a polemic commentary on McCrae’s article presenting the analogies of the main currents of psychology of personality to physics and chemistry. The article presents the problematicity of the comparison of the Big Five model to physics based on the comparison of psychology to Aristotelian and Galileian physics propounded by Lewin. According to the interpretation assumed hereunder, the Big Five model constitutes a peculiar physics of personality (in line with McCrae), but it is a physics performed in an Aristotelian manner (according to the differentiation of Lewin), which is connected with significant limitations. The integration of knowledge on personality posited by McCrae requires the change in paradigm of the physics of personality from the Aristotelian to the Galileian that Lewin postulated. The first step towards enacting such a change may be the introduction of Schwartz’s value model into the physics of personality in McCrae’s approach.
McCrae (2009) draws an inspiring metaphoric parallel between two basic natural sciences and two major branches of contemporary personality psychology. The purpose of the metaphor propounded by him is to facilitate the understanding of the current state of personality psychology and to undertake reflection on the possibility of integrating its various currents.
This commentary undertakes the metaphoric thinking of McCrae, as I consider it to be extremely valuable, while the goal that it should serve is of great significance. This metaphoric thinking will be undertaken by recalling another metaphoric parallel between psychology and the natural sciences. This was the proposal of Lewin (1935), who compared the psychology of his time (1930s) to Aristotelian and Galileian physics. Lewin’s goal was similar to that of McCrae—to reflect on the current state of psychology (of personality) and on the possibilities of its further development (integration).
This commentary has two purposes: (a) to reveal that McCrae, in his metaphor with physics, probably unintentionally, revealed the similarity of trait psychology to Aristotelian physics alone, therefore—as interpreted by Lewin—an archaic physics and (b) to point out a possible step that can be taken in the direction of modifying the paradigm of personality psychology and the Big Five model, which would correspond to Galileian physics, namely modern physics.
The physics and chemistry of personality according to McCrae
Physics and chemistry are, for McCrae (2009), the models of two currents in personality psychology. The equivalent of physics is trait psychology, particularly the Big Five Model, while the counterpart of chemistry is psychology of personality processes, thus, he stated elsewhere—social cognitive approaches. The author makes the analogies based on formal correspondence between physics and chemistry and the currents of personality psychology.
The similarity between physics and trait psychology is, according to McCrae, based on three pillars. First, both are focused on universals. The concept of traits, similarly to main concepts in physics, is abstract. Just as a physicist measures mass (regardless of whether they are measuring gold or lead, living or still matter), a psychologist measures, for instance, extraversion (regardless of the age, sex, and nationality of the persons measured). Traits in the Big Five Model are universal (as shown by cross-cultural research) and stable (as revealed by longitudinal studies).
Second, both physics as well as trait psychology apply mathematics to describe the studied phenomena. Among the advanced statistical methods used, McCrae particularly mentions factor analysis as a peculiar calculus of trait.
Third, both formulate general laws. Several basic physical laws are mentioned by McCrae (2009) in his article in the form of mathematical equations. The author concentrates mostly on the law of conservation of energy. He states that its equivalent is the thesis of personality psychology that various behaviours can be a manifestation of the same trait. In the way that measurable energy lies at the base of such diverse phenomena as sound, light, and movement, so the behaviours of a dutiful Muslim observing Ramadan and the behaviour of a dutiful Marxist campaigning for the elimination of religion, although so very different from each other, are a manifestation of the same trait—conscientiousness.
Chemistry also uses mathematics and formulates laws. Contrary to physics it does not construct concepts with which it would want to describe everything that exists, therefore, chemistry applies mathematics for other purposes and formulates different laws. While physics searches for fundamental and simple laws, chemistry concentrates on the infinite richness of possible bonds between a finite amount of elements. The main difference between physics and chemistry of personality consists of the fact that physics (trait theory) strives towards an abstract description of the entire universum, while chemistry (social cognitive approaches) heads towards a description of the richness of the concrete. In the further arguments, I concentrate on McCrae’s proposal of approaching physics as a metaphor for the Big Five.
Aristotelian physics, Galileian physics, and psychology according to Lewin
The overall intention of the metaphor propounded over 70 years before Lewin (1935) differs from the proposal of McCrae in two points. First, Lewin suggests that psychology be looked at as a whole, without dividing it into its currents. Second, it divides physics into two ways of applying it but they are not current and equal ways but ways that are ordered historically, therefore, one of them—the modern (Galileian)—is better than the other, outdated (Aristotelian). Lewin concentrates on the manner of constructing concepts and formulating laws as instruments of understanding the world in both modes of thoughts in physics and searches for its parallels in psychology.
Reiterating the heart of the matter—the difference between the two modes of thoughts in physics results from the fact that Aristotle classifies objects, whereas Galileo formulates laws (concerning all objects). In Aristotelian physics the correct classification is of vital importance because the behaviour of that object is designated by the given class to which it belongs. Light objects soar up, for instance, while heavy ones fall. Correct classification to a given class (heavy or light) enables its behaviour to be foreseen (falling or soaring up). The explanation of an object’s behaviour consists of assigning the object to a given class because the essence of the object defines its behaviour.
Explanation in the physics of Galileo looks completely different. It consists of indicating the law that connects various different sizes or objects together. An object falls not because it possesses the trait of falling (as Aristotle wanted) but because it results from the interaction of that object with the earth, described by the law of gravitation.
The interpretive thesis of Lewin was as follows: Contemporary psychology is applied in an Aristotelian manner. Its development is determined by the adaptation of the way of thinking proper to Galileian physics (namely, modern physics). Despite the fact that the diagnosis of Lewin is already almost 70 years old, today’s psychology is still most probably closer to Aristotle than to Galileo, to which the excellent article of McCrae (2009) testifies.
The Big Five: The physics of personality (but an Aristotelian physics)
This polemic commentary to McCrae’s (2009) article will be formulated in four steps. The first three have been inspired by the metaphor of Lewin and constitute a critique of McCrae’s proposal. The fourth step entails the proposal of extending Aristotelian physics towards Galileian physics (of personality).
Trait psychology is the physics of personality, as propounded by McCrae, but it is a physics that is applied in the Aristotelian spirit
The Big Five is an elegant, Aristotelian classification of traits. In fact, it can even be stated that it goes beyond the Aristotelian approach because it is rooted not only in the phenotype (which was specific to Aristotle), but also in the genotype. Although it concentrates on what can be observed, it can still penetrate the things that are directly imposed on observations in order to reach that which is fundamental and somewhat hidden (like the similarity between the religious behaviour of a Muslim and that of the atheist Marxist). The classification of personality traits assumes the form of dimensions with which the psychological universum can be described. A characteristic example is the already mentioned comparison of extraversion to mass—both sizes are dimensions describing the studied object. Classification is important because it designates the behaviour of an object in physics and a person in psychology. Thus, the behaviour of a Muslim and a Marxist results from the trait of conscientiousness that they both possess. The proper classification (measurement) of that trait allows us to explain their way of behaviour (conscientiousness), regardless of the content of that behaviour.
If, however, the example of the mass is comforting in terms of the condition of personality psychology (becoming similar in their descriptions to physics, the model of empirical science), the example of the Muslim and the Marxist gives rise to certain anxiety. The truly intriguing question is: why one of them is a conscientious follower of a religion and the other its conscientious enemy? If a physicist contended that both objects have the same mass but behave very differently—e.g., one is at rest and the other moves—they would be capable of explaining it using the laws concerning forces that are known to them. What laws has trait psychologist at its disposal? The similarity in the behaviour of the Muslim and the Marxist is explained by their personality traits, but what forces explain the differences in their behaviour?
Aristotelian physics of personality traits is connected with significant limitations
Aristotelian physics of traits is connected with two limitations that make it impossible for any of the two posed questions to receive satisfactory answers. The only laws that are formulated on the grounds of Aristotelian physics (and trait theory) are connected with belonging to a class that defines the nature of the object and determines its behaviour (a Muslim behaves the way they do because they are conscientious). Consequently, only a static description of the psychological universum (in the category of traits) is possible.
McCrae mentions several equations describing physical laws and discusses the principle of energy conservation. But this principle transferred onto the field of personality psychology has nothing in common with those laws because it concerns the stability of the dimension and not the dynamics of changes.
Conjecturing a very liberal analogy, determining it as being whimsical, McCrae (2009) mentions five main physical forces that push and pull all objects in the physical universe. They are: gravitation, electric charge, magnetism, and strong and weak nuclear force. Similarly, five traits push and pull people toward various—attention!—courses of behaviour. Jokes aside, a significant difference can be seen—surely, the mentioned physical forces do not only regulate the course of behaviour. They regulate something more—namely, they regulate behaviour. Gravitation does not only regulate the manner of falling but also falling itself. Personality traits, on the contrary, only regulate the course of behaviour. The content of the behaviour remains unknown.
It is worth pointing out that extraversion on the one hand was compared to mass (as an abstract dimension, independent from what the mass belongs to and whom extraversion belonged to), and, on the other hand, to basic physical forces (to which gravitation also belongs). However, these are completely different categories. From the point of view of the differentiation conducted by Lewin, significant differences can be seen. Comparing extraversion to mass is close to the Aristotelian spirit, while the comparison to force moves towards Galileian physics. Mass is the property of the studied object; gravitation is a force that acts between objects. If the comparison of extraversion to mass does not give rise to any doubt, comparing it to force is relatively doubtful. The psychological universum proposed by McCrae’s Aristotelian physics of traits is a static universum. In the Big Five model there is no room for dynamics—dynamics that surely are the basic subdiscipline of modern physics.
The integration of knowledge on personality posited by McCrae requires the change in paradigm of the physics of personality from the Aristotelian to the Galileian, postulated by Lewin
Dynamic aspects of the personality were usually connected with motivation and as such are acknowledged to be one of the historical sources of contemporary personality psychology (McAdams, 1997). In the Big Five Theory, motivational aspects belong to so-called” characteristic adaptations (McAdams & Pals, 2006; McCrae & Costa, 2003), thus, in the metaphor of the commented article of McCrae (2009), they are closer to the chemistry of personality.
Nevertheless, it seems that the trait model is incapable of overcoming the limitations of Aristotelian physics. A change in paradigm of trait physics means the necessity to introduce the laws describing the action of forces into personality physics. From the point of view of the Big Five Model, it is not a change in paradigm but merely its supplementation. Traits (after the introduced modification) shall remain the same as they are at present.
The law of metaphorical analogy—the patronage of such a modification can be traced back to the ancient Greek philosopher Empedocles who was mentioned in psychology of personality by Emmons (1995), among others. Empedocles saw the entire universe as being composed of four elements (earth, air, fire, and water), which constitute an analogy to the traits of the Big Five Model. However, the vision of Empedocles already contained an explanation of changes, therefore, apart from the elements, he introduced two forces (love and strife) into his concept. Thanks to this he explained not only what the world is like, what it is composed of, and what the coming to be and change consists of.
Attention should be turned to the fact that the forces proposed by Empedocles that explained the dynamics of the world were equally as universal as the elements, therefore, they corresponded to the simplicity of physics rather than the richness of chemistry posited by McCrae (2009). The vision of Empedocles was also an early harbinger of the physics of Galileo—changes took place not because that was the nature of the changing object but because that object entered into interaction with the forces. An equivalent of the elements of Empedocles are the five personality traits. What corresponds to the forces of Empedocles?
Five personality traits and ten values: Towards Galileian personality physics
The introduction of the motivational value theory of Schwartz into personality trait physics can be a step towards changing the Aristotelian paradigm to the Galileian
The Schwartz value theory fulfils (to the same extent as the trait theory) two, formulated by McCrae and also previously mentioned here, criteria of similarity of psychological constructs (traits) to physical sizes. The third criterion is fulfilled better by the Schwartz value theory than the trait theory. Seeing that Schwartz (1992, 2006) proposes a catalogue of 10 values, through analogy to the Big Five personality traits, they shall be referred to as the Big Ten values.
Value as a cognitive representation of motivational goals is abstract similarly to traits. In the same way as the Big Five describes the universum of traits, the Big Ten describes the universum of motives. Both abstract constructs are manifest in various behaviours, which sometimes, at first instance, seem dissimilar.
Ten value types are a universal catalogue. Big Ten was verified in numerous studies, including in representative groups already in four editions of the European Social Survey. The number of respondents has reached hundreds of thousands. The grand scale of the research on values in the Schwartz’s model is comparable in psychology perhaps only with studies on personality traits in the model of Costa and McCrae. Advanced statistics were performed in the research on values—not only simply factor analysis, which McCrae writes about, but also multigroup confirmatory factor analysis within an invariance study (Davidov, Schmidt, & Schwartz, 2008), which has not been performed to date in any trait questionnaire.
The two mentioned properties of the Big Ten authorize, in principle, equal treatment of the Big Five and Big Ten models as approaches to two different aspects of personality: traits (the elements of Empedocles) and motives (the forces of Empedocles).
On the grounds of the Schwartz’s model, it is possible to formulate laws other than Aristotelian laws resulting from belonging to a class. The Schwartz’s value model contains not only classification of values (defined in motivational terms) but also description of relation between values.
The key to Schwartz’s (1992) thesis concerns the structure of values in the form of a circular continuum, organized by the rule of similarity (values located close to one another on the wheel can be fulfilled jointly) and the rule of conflict (values located on the opposite sides of the wheel cannot be fulfilled jointly). Based on the circumplex structure thesis, a hypothesis can be formulated about the sinusoid pattern of relations between an external variable and the whole system of values (Schwartz, 2006), which can be seen as an example of mathematical clarity and generality of the physics of personality.
What is more, rules of the value structure constitute the germ of laws in the Galileian spirit. Two directions of recently conducted research are particularly promising and close to the physics of personality in the Galilean spirit. The first of those concerns the development of the value structure in childhood. Research started by Döring, Blauensteiner, Aryus, Drögekamp, and Bilsky (2010) presents the development of the circumplex structure of values by, as a first step, isolating two dimensions and then carrying out the differentiation of values aimed at the Big Ten circumplex model. The emerging structure of values results from Galilean interactions between partly innate needs and culture within which socialization takes place.
The other direction of research and theory development is related to laws governing a change in values. Research done both in the laboratory (Maio, Pakizeh, Cheung, & Rees, 2009) and in natural conditions (Bardi, Lee, Hofmann-Towfigh, & Soutar, 2009) indicates that an intraindividual value change mirrors the circumplex structure of values so that conflicting values change in opposite directions and compatible values change in the same directions, in accordance with the sinusoidal hypothesis. Such results allow us to determine regularities behind a change in values (Bardi & Goodwin, 2011).
Both the mentioned research directions are the first but, nevertheless, quite considerable step toward the Galilean physics of personality, in which the object’s behaviour is explained not through his or her belonging to a class, but based on laws governing relations between objects.
The elegant classification of 10 values is comparable to the classification of five personality traits constituting a supplement of the static description of personality by the dynamic aspect. Furthermore, the structure of the value theory is described in a way that exceeds the limitations of Aristotelian physics of personality. In the interpretation that has been propounded herein, they are rather proper to the first level of personality according to the classification of McAdams and Pals (2006), that is, the physics of personality in the metaphor of McCrae (2009).
Footnotes
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Jan Cieciuch is a researcher (PhD) at the Faculty of Psychology, University of Finance and Management in Warsaw. His interests include personality and developmental psychology and methodology and philosophy of science. He is currently undertaking research on values and traits in cross-cultural and developmental perspective. Address: Faculty of Psychology, University of Finance and Management, ul. Pawia 55, 01-030 Warsaw, Poland. Email: