Seeking truth in personality science: reconciling trait theory and psychological type John B. Lloyd

School of Pharmacy, University of Sunderland, Sunderland, UK

ABSTRACT Two rival paradigms compete for acceptance as representing objective reality concerning the structure of the human personality: the Five- Factor (Trait) model and the Myers-Briggs (Type) model. In this review, the common features of the two schemes are identified and the points of difference examined. It is concluded that a harmonised scheme could be achieved if both sides gave some ground. The Type community could relinquish its contention that every individual has a clear either-or preference for (for example) Extraversion or Introversion. It could also acknowledge the speculative nature of Type Dynamics. The Trait community could relinquish the value- judgements inherent in its current scheme and accept that (for example) introversion is not merely a deficit of extraversion but a distinct quality with positive potential. Given the many similarities of the two present paradigms, a unified approach would have a good claim to be the best current portrayal of personality.

ARTICLE HISTORY Received 7 June 2021 Accepted 5 December 2022

KEYWORDS Myers-Briggs Type Indicator (MBTI™); Big Five; Five- Factor model; personality traits; Psychological Type

Introduction

This review examines and evaluates a long-running conflict in personality psychology: that between advocates of the Five-factor Trait-based model and those of the Myers- Briggs Type Indicator (MBTI™) approach. Both models have a long history, and within their respective communities both have the settled status of what Kuhn (1962) designated a “paradigm”, a theoretical framework that can be deployed with no need for recurrent justification. Both models are widely used in academia and the corporate world. Within the academic community Trait dominates, continually providing the basis for numerous empirical investigations. Type is much used in staff development by corporate human resources departments, and in some religious contexts.

The author is a retired biochemistry academic, with a lifetime’s exposure to controver- sies in his own specialism and a fascination with how they are eventually resolved. One such, now half a century ago, is still vivid in his memory. The battle was fierce and wound- ing, raging for two decades. The two principal protagonists were both intelligent and dis- tinguished scientists, one a respected establishment figure; the other a more unconventional character who ran a personally-owned laboratory. Eventually, the latter won the day and his theory now forms the basis for the accepted orthodoxy.

Some features of the Trait-Type divide are not unusual: one side can be designated mainstream (Trait), the other fringe (Type); and debate can become heated and lose

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CONTACT John B. Lloyd [email protected]

MENTAL HEALTH, RELIGION & CULTURE 2022, VOL. 25, NO. 9, 817–828 https://doi.org/10.1080/13674676.2022.2158794

objectivity. But other features are less common. Among these are a high degree of com- monality in their explanatory models, an overlap that neither side seems keen to acknowl- edge. Each group appears to accept and use its own theoretical basis as a largely unquestioned paradigm. The published literature of each group rarely contains any mention of its opponents; comparative studies of the two models are sparse.

There is an asymmetry in the relationship of the two groups. Mainstream personality psychology is scornful and dismissive of the MBTI™, frustrated by what it sees as the unwillingness of the Type community to acknowledge its scheme’s flawed nature; and irri- tated by the continued popularity of Type among human resources personnel serving businesses and non-profit organisations (see Moyle & Hackston, 2018). The Type commu- nity’s response to this antagonism has been understandably defensive. Rebuttals of the criticisms have been attempted, but, judging by the paucity of citations, these rarely penetrate beyond the boundaries of the Type community itself. An exception is the recent work of Moyle and Hackston (2018), which robustly challenges some of Type’s detractors. Despite the hostile climate Psychological Type remains stubbornly convinced that it offers a truer description of reality than the Five-Factor model of personality. Its fol- lowing is loyal and committed. At the present time dialogue between the two camps is almost non-existent. A notable exception is the extensive research output of Adrian Furnham (see Furnham, 2022), which consistently acknowledges the integrity and validity of the MBTI™.

Norcross et al. (2006) publishedanevaluationof an extensive rangeofpsychological treat- ments and tests. A panel of “experts”was asked to indicate how “discredited” they regarded each item, using a five-point scale from “1, not at all discredited” to “5. certainly discredited”. MBTI™ was ranked the fourth least discredited of the 25 psychological tests. This seeming endorsementof its validity is surprisingandseemsatoddswith currentprofessionalopinions.

Before proceeding to a more detailed analysis, a further point must be made. Much of the hostility between Trait and Type centres around their deployment in staff evaluation and staff development. Psychological Type is clear and explicit that the MBTI™ should never be used for staff selection, but this has not prevented it being criticised for its unsuitability in this context. Moyle and Hackston (2018) devote much of their defence of Type to this issue. However, the focus of the present review is different. The goal of all science is to describe reality as accurately as possible. We are here concerned with whether the infinite variety of the human personality can meaningfully be subject to classification. All theories are valueless unless they begin to account for what is regularly observed. As the physicist-theologian John Polkinghorne (1930–2021) put it: epistemology models ontology. Certainly that should be its intention.

This review follows the author’s previous commentaries on the Trait-Type controversy. Lloyd (2007, 2012a) examined the criticisms levelled at Psychological Type by, respect- ively, some Christian theologians and the mainstream personality psychology community. Conversely, Lloyd (2015) reviewed criticisms of the Five-Factor model. Some overlap with these papers in the present writing is inevitable but is kept to a minimum.

Clearing the ground

The two models of human personality considered here both assume that the study and classification of human personality is a study of something real. In the second half of

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the twentieth century serious doubts were expressed about this. Indisputably individual people behave in different ways, but personality implies that there are relatively stable predispositions in each of us that influence our behaviour. But is this the case? This is a large issue that spawned a huge literature that was well documented and evaluated by Krahé (1992). Currently, there is wide agreement that personality differences are real but are not the sole determinants of a person’s behaviour, which is also influenced by each situation encountered. Behaviour on every occasion is not a mechanical sequence of cause and effect determined solely by personality. Behaviour is chosen, often in defiance of our predispositions, because we know what the situation requires. Neverthe- less, at least as often, an individual’s personality shows through in their behaviour.

Another criticism of attempts to classify human personality asserts that because every individual is unique, the endeavour is futile. Paul’s (2004) The Cult of Personality is a com- prehensive condemnation of the evils of personality testing: it is equally negative about Psychological Type and the Five-Factor model. Its principal focus is on the misuse of these instruments in the recruitment and deployment of staff, a concern equally vociferously expressed in the official Psychological Type literature, which emphasises that its use in companies should be limited to staff development and employee self-understanding. A fascinating feature of Paul’s book is the detailed account of the personal histories of the principal players in twentieth-century personality psychology. Similar in style, but focusing solely on Psychological Type is Emre’s (2018) What’s Your Type? This too majors on a detailed biography of Myers and Briggs and their work, is unremittingly nega- tive and polemical about Psychological Type, but disappointingly light on detailed criti- cism of the instrument itself.

The discipline of taxonomy has been of immeasurable value in the development of bio- logical science. Noticing and recording similarities between groups of plants, animals and microorganisms were fundamental to the subsequent formulation of evolutionary theory. To place a species in a family of similar species in no way negates its uniqueness. This is why the attempt to classify human personalities is laudable. It will not directly generate theories about the origin of personality characteristics but, if successful, may eventually lead to such.

Trait and type: similarities and differences

The Five-Factor model of personality postulates five independent components of person- ality, each designated a Trait. These Big Five Traits are Extraversion, Openness (to Experi- ence), Agreeableness, Conscientiousness, and Neuroticism (or its desirable converse, Emotional Stability). Individuals are assessed for the strength of each Trait, and this com- posite profile provides a snapshot summary of their personality.

The Myers-Briggs scheme postulates four cognate pairs of personality components. These are designated Extraversion/Introversion, Intuition/Sensing, Feeling/Thinking, and Judging/Perceiving. Each individual is deemed to have a preference for one or other com- ponent of each pair.

As briefly mentioned above, there is a remarkable congruence between the personality characteristics identified by the two taxonomic schemes. Thus, degree of Extraversion is one of the Five-Factor Traits, while Type has Extraversion/Introversion as one of its four binary polarities. Likewise, the Trait of Openness (to Experience) correlates with Type’s

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Intuition; Trait’s Agreeableness with Type’s Feeling; and Trait’s Conscientiousness with Type’s Judging. It is not surprising that when a given population sample was tested with both Psychological Type and a personality Trait instrument, there was a high degree of correlation between the above-mentioned pairs (Furnham, 1996; Furnham et al., 2003; McCrea & Costa, 1989). More recently, Furnham (2022) has re-examined this question, using the NEO-PI-R test to measure the Big Five dimensions. Once again, there was a good correlation between the two measures of Extraversion, between Judging (MBTI) and Conscientiousness (Big Five), and between Feeling (MBTI) and Agree- ableness (Big Five). The correlation between Intuition (MBTI) and Openness (Big Five) was less impressive. But on the whole it still seems that the Five-Factor Model and Psycho- logical Type are to a large extent identifying essentially the same human characteristics.

Both schemes use questionnaires to evaluate an individual’s personality characteristics. Par- ticipants are asked to respond to a series of statements by either agreeing or disagreeing with them. Unsurprisingly an examination of questionnaires from the two camps reveals a remark- able degree of overlap in content. It would be instructive to examine the instruments used to evaluate, for example, MBTI’s Extraversion and Big Five’s Extraversion, to seewhether the imper- fect correlation can be traced to subtle differences in the qualities they seek to identify.

Given the very different provenance of the two schemes (discussed below), these com- monalities are truly remarkable and should be an encouragement to both the Trait and Type communities that they are on the right track in seeking to identify major com- ponents of human personality. This congruence also narrows down the areas of dispute between the two taxonomic schemes and provides hope for dialogue and perhaps compromise.

However, there are substantial differences between the two explanatory schemes.

1. The Big Five model posits an additional personality component, Emotional Stability. This discrepancy is not serious, as both parties might agree that their four or five per- sonality components may be an incomplete listing, which future work might amplify or correct. There has already been significant work done on the extent of correlation between the Five Factor model’s Neuroticism and each of the four polar axes of MBTI™ (Furnham, 2022; Furnham & Crump, 2014). The more recent of these publications (p. 1513) concludes that “Neurotics are Introverted Sensers, and associated with Percei- vers” (thus Myers-Briggs ISP).

2. The Big Five model sees the factors as human qualities that manifest themselves in overt behaviours. Personality Type sees them as predispositions1 for particular pat- terns of behaviour. These Preferences are not directly inferable from observed behav- iour, which in a mature individual will derive as much from circumstances as from predisposition.

3. The Big Five model regards the factors as intrinsically positive attributes, so that a high score for (for example) Extraversion is admirable and a low score is a deficiency. By con- trast, Personality Type holds that each preference is one of a cognate pair, both of which have both positive and negative potential. Thus extraverted and introverted behaviours are both valuable in the right context but can be a liability in other contexts.

4. Psychological Type theory holds that each individual has, by nature, a preference for either Extraversion or Introversion, for either Intuition or Sensing, for either Thinking

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or Feeling, for either Judging or Perceiving. From this, it is deduced that there are 16 Psychological Types, and that everyone can be identified with one of these. By contrast, the Five-Factor model simply allocates scores to each of the five factors: there is no pigeon-holing.

We turn now to a review of the literature in which the paradigms are criticised by adherents of its rival paradigm. The literature is sparse: as already noted, neither group pays much attention even to the existence of the other.

Specific criticisms of psychological type

Incoherence

In their recent attack on Psychological Type, Stein and Swan (2019, Abstract) conclude that Type theory “lacks agreement with known facts and data, lacks testability, and pos- sesses internal contradictions”. This harsh and sweeping criticism is perhaps justifiable if Type Theory is taken to embrace not simply the basic postulates already alluded to, but also the elaborate superstructure that has been built upon it. In Type literature, the latter is designated Type Dynamics, which is ramifying and constantly increasing in detail. It postulates complex relationships between the four dual-polarities. Added to that are elements from Jung’s writings that are equally conjectural. I submit that Type needs to distinguish more clearly between its basic postulates and the speculative material that has accreted around it in recent decades. Reynierse (2009, p. 18) agrees:

It is only the eight individual MBTI preferences that have demonstrated validity – not type dynamics or the type categories formed by type dynamics. The time has come for the type community to abandon their enthusiasm for type dynamics and to discard it.

A seemingly un-noticed example of internal contradictions is seen in MBTI Step II, an extension of MBTI™ in which each of the preference pairs (e.g., Extraversion/Introversion) is further divided into five subsets. Each subset is regarded as independent of the others, and each can be scored. A logical implication of this exercise is that the overall score for Extraversion/Introversion is a composite. However, this negates the core Type postulate that each individual prefers either Extraversion or Introversion (Lloyd, 2012a).

These are serious and valid criticisms of Type. However, I do not believe that Stein and Swan (2019) provide convincing evidence that the fundamental postulates of Type are incoherent. They are no more so than the basic postulates of the Five-Factor model.

Every person is unique

The Type model insists that each individual prefers (for example) either Extraversion or Introversion, whereas the Trait model envisages a continuous spectrum of extraversion from high to low. Type identifies four either-or axes, of which Extraversion-Introversion is one, the others being Sensing-Intuition, Thinking-Feeling and Judging-Perceiving. Thus, Type theory holds that every individual human being belongs to one of 16 Types. To some of its critics, this is patently absurd. Imagine, says Essig (2014), a Myers-Briggs

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Weight Indicator, in which everyone is identified as either obese (O) or anorectic (A). Weight is a continuum, not to be defined by its extremes, and surely so too is personality.

This criticism of Psychological Type requires careful analysis. In its crudest form, it is an attack on any attempt to classify personality. However, the uniqueness of each individual is not invalidated by, for example, the identification of a small number of human blood groups or the normal and mutant alleles of numerous human genes. There is no cogent reason why personalities cannot be classified and commonalities identified.

Moreover, Type theory seeks to identify a person’s Preference/predisposition for, say, Extraversion or Introversion. It is not directly inferable from the individual’s behaviour, which will be dependent on the demands of each context encountered. Extraverts can learn to introvert, and certainly Introverts must frequently extravert when their work or other responsibilities demand.

It has been pointed out (Harvey & Murray, 1994) that, if the Psychological Type model is correct, the scores on an instrument designed to measure Extraversion and Introversion (for example), should be bimodal, with two peaks, one clearly in the Extraversion and one clearly in the Introversion region, whereas if the Five-Factor model corresponds to reality, the distribution of scores should be unimodal, with one peak around midway between high and low scores. This matter has been investigated on several occasions (see Bess & Harvey, 2001; Moyle & Hackston, 2018), with contradictory results. However, the issue is perhaps not as critical as has been supposed. It would not greatly damage the Psychological Type model if the identification of individuals as either (for example) Extravert or Introvert were seen as an easy-to-grasp simplification, denoting on the Extra- vert or Introvert side of the continuum. After all, people are happy to describe themselves as right- or left-handed, despite there being a spectrum, with only a few truly ambidextrous.

One corollary of the either-or feature of Type theory is the identification of 16 Person- ality Types, each of which can be encapsulated in a prose summary of its chief features. These descriptions are sufficiently distinct, so that most people can easily identify with one of them much more than with any of the other 15. Once again, it is important to recall that Psychological Type seeks to identify predispositions rather than overt behaviours.

Provenance of the theories

The Type and Trait models arose independently. Type has a dual provenance: Jung (1971) and the amateur psychologist mother and daughter, Katherine Briggs and Isobel Myers (Myers & Myers, 1980). The Five-Factor model arose by an evolutionary process as a Highest Common Factor from the conclusions of two or more generations of personality psychologists (Goldberg, 1992).

It is understandable, but seriously mistaken, to judge scientific theories by their origin and history. Certainly, a trained and disciplined scientist is more likely than an enthusiastic amateur to come up with a correct explanation of some phenomenon. But there are many exceptions. And even the professional will often admit that the correct solution came to him or her as a brainwave, rather than by logical deduction.

What matters is not the origin of a hypothesis, but the extent to which it explains the observations being studied. Theories about human personality should be judged by this criterion and no other.

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A comfort blanket

Paul (2004, p. 131) asks why “so many people fall in love with the Myers-Briggs”. She con- cludes that one of its principal attractions is “its reassuring confirmation of what we already know about ourselves”. She considers that its “relentlessly positive orientation ensures that everyone’s permanent personality is a good one”. This criticism of Psycho- logical Type discerns correctly that Type sees positive potential in both poles of each pair of preferences but ignores Type’s insistence that one’s preferences are no sure guide to appropriate behaviour. This point is developed in a subsequent section below, but here it is sufficient to insist that level of acceptability by the general public is no basis for determining the validity of a hypothesis. Sometimes the truth is unpalatable, and sometimes it is affirming.

Unworthy motivations

Several authors ponder the question of why Type remains so popular when it has been repeatedly rejected as invalid by psychology professionals. Pittenger (2005, p. 219) attri- butes its popularity to “the publisher’s marketing campaign”, and more recently Stein and Swan (2019, p. 3) believe it is because Psychological Type exists in a parallel universe “gov- erned mostly by commerce”, seeming “to prioritise what sells over what is correct”. This financial explanation is consistent with Grant’s (2013, p. 5) comment that “thousands of people have invested time and money in becoming MBTI-certified trainers and coaches”.

While these assertions are impossible to prove or disprove, it is also the case that finan- cially successful enterprises are those that offer customers a product that continues to meet their needs.

Snake oil

In the Introduction, reference was made to the frustration felt by some in the Trait com- munity that the Type model continues to attract and to be used. This leads to some intem- perate writing. Thus Essig (2014, p. 1) describes the Myers-Briggs analysis as meaningless, absurd, and “pretty much nonsense, sciencey snake oil”. His one specific criticism, dis- cussed above, hardly justifies such wholesale condemnation of MBTI.

Specific criticisms of the Five-Factor model

Psychological Type theorists have only one major disagreement with Trait theory, but it is a substantial one. It concerns the value-judgements explicit in Five-Factor terminology and implicit in the interpretation of its scoring. Its simplicity is seen as simplistic and its implications incompatible with the observed realities of human personality. The author has discussed this topic elsewhere (Lloyd, 2015), and what follows necessarily overlaps to some extent with that material.

Both Type and Trait models identify Extraversion as a key component of human per- sonality. The Five-Factor model identifies examples of extraverted behaviour (and praises them as admirable), without inferring anything about an individual’s innate preferences.

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The admirability of extraverted behaviour is therefore common ground for the Five- Factor model and Psychological Type. But the two models lead in different directions when Introversion is considered. For the Five-Factor model Introversion is simply a lack of Extraversion. It can therefore see only negatives about those who score low on Extra- version; they must try harder to overcome their disability. In the Type model, Introversion possesses its own strengths, such as the ability to work creatively and contentedly in soli- tude for long periods. Thus, Type is as positive about the introverted personality as about the extraverted: both predispositions bring many benefits to the individual and to society. The last two decades have seen an increasing assertiveness by self-identifying introverts. The titles of their books (Cain, 2012; Laney, 2002) signal an intense frustration with the perceived bias of the Five-Factor model.

So exactly what does Type theory propose for the relationship between Extraversion and Introversion? First, that introverted behaviour is as valuable in its place as extraverted: each is the more appropriate mode in any given life-context. Consequently, each individ- ual should learn to become adept at deploying extraverted and introverted behaviour: ideally this versatility develops with increasing maturity (Lloyd, 2012b). And secondly, each individual has an innate predisposition for either extraverted or introverted behav- iour: one comes more naturally and easily than the other. An analogy is right- and left- handedness, where the (rarely occurring) ideal is to be ambidextrous.

Trait theory’s value judgments are seen not only with Extraversion. Although the terms Extraversion and Introversion are not inherently value-laden, the designations of the other four Factors are explicitly and unambiguously so. Openness to Experience, Agreeableness, Conscientiousness and Emotional Stability are terms that clearly signal approval; they are all positive desirable qualities. Type theory has no problem with this. The problem lies with the descriptions of low scorers, who are seen as simply displaying a relative lack of these good human qualities. Table 1 demonstrates this from current textbooks.

By contrast, Type theory employs non-evaluative terminology for the three Traits Open- ness to Experience, Agreeableness and Conscientiousness. These are, respectively, Intuition, Feeling and Judging, and each is paired with a cognate quality that is regarded as equally positive (see Table 2).

I have elsewhere (Lloyd, 2015) expanded on the inability of the Five-Factor model to recognise the complementary and equally positive qualities often possessed and dis- played by individuals who score low on, for example, Openness to Experience, Agreeable- ness or Conscientiousness. To be dismissed as closed-minded, disagreeable or

Table 1. Qualities deemed characteristic of low-scorers for Five-Factor Traits. Trait Characteristics of low-scorers*

Extraversion Reserved; sober; unexuberant, aloof, task-oriented, retiring, quiet; silent; unassertive, unadventurous, unenergetic; timid; quiet; reserved; shy; aloof; restrained; withdrawn

Openness Conventional; down-to-earth; narrow interests; unartistic; unanalytical; unimaginative; uncreative, uninquisitive, unreflective; unsophisticated; commonplace; shallow

Agreeableness Cynical; rude; suspicious; uncooperative, vengeful; ruthless; irritable; manipulative; unkind; selfish; distrustful; stingy, cruel; quarrelsome; unfriendly

Conscientiousness Aimless; unreliable; lazy; careless; lax; negligent; weak-willed; hedonistic; disorganised; irresponsible; impractical; frivolous

Emotional Stability Worrying, nervous, insecure, inadequate, hypochondriacal, angry, tense, envious, unstable, discontented, self-pitying, temperamental; demonstrating anxiety, hostility, depression, self-consciousness, impulsiveness and vulnerability, reflecting a tendency to experience negative emotions

*Data are taken from Lloyd (2015), which also details sources.

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irresponsible is immensely wounding. The denigration of (for example) introversion by Trait theory, and its celebration by Psychological Type, is almost certainly a major reason why the latter remains so popular.

So, is it possible to decide whether Trait or Type has got it right about the taxonomy of human behaviours and predispositions? In an earlier section of this article, Extraversion/ Introversion was explored as an exemplar; we therefore now take another Five-Factor model Trait: Agreeableness. As we have already seen, this maps closely to Psychological Type’s Feeling. In both schemes, it denotes the attractive human qualities of kindness, empathy, generosity and compassion. For Trait theory, that is the sum total. For Type theory, however, Feeling is paired with Thinking, not as opposites, but as contrasting behavioural predispositions. Thinking denotes a cool-headed, logical approach to issues and decisions, a passion for justice and truth even at the expense of treading on vulner- able toes.

Type affirms the value of both Feeling and Thinking, endorsing the generally accepted principle that wise decision-making about many issues requires both heart and head to be consulted. One without the other can result in unwise and damaging actions