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Personality 101: The Trait Approach & the Lexical Hypothesis


Human personality is a well-known concept in both academic and non-academic circles. This concept has raised the most diverse conclusions in both circles: from well-established factorial solutions to classifications of people based on what the Sorting Hat from Hogwarts would estimate. For a long time now, research in psychology has gained plenty of knowledge about human personality and its implications in everyday life, but this knowledge is either unknown or misunderstood by the general population. This situation calls for efforts to close this gap between what is known based on science and what is assumed to be true based on our random and subjective experience. The following 101 series explores the most consensual contemporary conceptualization of personality, the creative steps scientists took to arrive at this conceptualization using the lexical hypothesis, the specificities of this contemporary conceptualization by looking at each one of the Big Five traits, and the implications of each trait for individuals and societies.

The Personality 101 series is divided into 5 chapters:

  1. Personality 101: The Trait Approach and The Lexical Hypothesis

  2. Personality 101: Conscientiousness

  3. Personality 101: Agreeableness and Extraversion

  4. Personality 101: Emotional Stability

  5. Personality 101: Openness to Experience

Personality 101: The Trait Approach and The Lexical Hypothesis

Thirty-one-year-old Robert often feels restless. He has problems sitting at a desk for more than a few minutes, cannot get organized, loses his keys and wallet, and forgets about his plans for the evening. He fails to achieve up to his potential at work. During the conversation, his mind wanders and he interrupts others, blurting out what he is thinking without considering the consequences. He gets into arguments. His mood swings and periodic outbursts make life difficult for those around him. Now his marriage is in trouble (John, 2021).

This is a typical description of someone’s personality in a clinical setting. It conveys a good idea of how Robert is: disorganized with things and time causing evident consequences in his work, disorganized in speech, restless and impulsive. With this small paragraph, a clinician might already have an idea of what Robert is and what the goals would be in clinical intervention. However, something is lacking here. Surely, a short paragraph cannot summarize the wholeness of a human being, all their intricacies and idiosyncrasies; besides, the paragraph lacks some mention of the positive characteristics, too. Despite the risk of losing information, the task of trying to summarize someone's personality is useful, it helps with making life decisions easier: decisions like the search for a job, choosing a career, a partner, an adequate therapeutic procedure, and even one’s friends and hobbies.

What is needed is to summarize the personality of someone with the least loss of information possible, i.e. a descriptive model or a taxonomy of personality. “One of the central goals of scientific taxonomies is the definition of overarching domains within which large numbers of specific instances can be understood in a simplified way” (John, 2021, p. 38). In plain words, a taxonomy about personality would be useful because it will allow the interpretation of the massive amount of information contained in one person’s behaviour using a very small group of categories. In this article, the best taxonomy for personality is going to be introduced along with the methodology followed to design it.

A taxonomy of human personality has been searched for a long time. Even in Ancient Greece Theophrastus would ponder: “why is that, while all Greece lies under the same sky and all the Greeks are educated alike, it has befallen us to have characters variously constituted?” (Theophrastus, 1909, p.77). The most famous of the ancient attempts is Hippocrates' taxonomy in which he believed that different proportions of four bodily fluids or humour would manifest in the way people think, feel, and behave. A predominance of blood constituted a sanguine or social character, phlegm constituted a phlegmatic or easygoing character, black bile constituted a melancholic or analytical character, and yellow bile constituted a choleric or extraverted character (Chiao, 2018).

A Room with Mirrors, Photo by Дмитрий Хрусталев-Григорьев (Хрусталев-Григорьев, 2021)

Before going into more taxonomies of traits a note of recognition must be conceded to many other conceptualizations of personality that are not trait-based. Whereas the trait approach is one of the most frequently used nowadays, many authors in the history of psychology proposed models based on their own scientific and theoretical framework (Funder, 2012). Freud’s framework, for instance, is based on the psychosexual development of the person, and he would argue that personality suffers many changes during childhood, also known as the stages of psychosexual development, but once adolescence arrives, personality becomes rather stable. Another key aspect of his theory is the division of personality into three components: the less conscious aspect, the id; the conscious experience of the person, the ego; and the social demands internalized in the individual, the super-ego (Funder, 2012).

Later, other authors would propose different psychological processes as important components of human experience. Jung proposed the collective unconscious, the Anima and the Shadow as crucial mechanisms of the human psyche. More humanistic perspectives, like the ones championed by Abraham Maslow, Carl Rogers or Positive Psychology, focused on self-actualization processes, the acceptance of one's own experience, the hierarchies of motivations and needs, and the positive aspects of psychology like strengths and virtues (Funder, 2012).

These are important contributions but some of them are elusive to scientific investigation, meaning that it is hard to apply the scientific method to answer the questions they pose. This is why, currently, they do not receive the same attention as the trait approach, and though there are some attempts to understand them, their significance is not as universal as the trait approach (Mastnak, 2021).

The most basic tenet of the trait approach is, understandably, the trait. According to Allport (1931), a trait has more than a nominal existence, is more than a generalized habit, is dynamic, it can be empirically or statistically found, is not unrelated to other traits, is not a moral quality, is not disproven if other behaviors appear in the behavioral repertoire of an individual, and it can be spotted in the individual and also in the population. Therefore, a trait is something real, can be found using statistical tools, and it is not disproven if other behaviors or emotions that go against this trait appear. This last feature of traits reveals an important nuance: a trait is the natural tendency of an individual, what the person would do almost spontaneously, the default mode of operating; this does not mean that, in a particular situation, an individual could not show behaviors, feelings, or thoughts that deviate from this natural tendency (Fleeson & Law, 2015). Practically, this means that an extravert can sometimes act as an introvert, and vice versa.

Marilyn Diptych, by Andy Warhol

Once the concept of trait has been cleared, let’s look at some of the attempts to define a taxonomy of personality in the modern history of Psychology. Raymond Cattell, a British-American psychologist, proposed 16 factors, or overarching categories obtained by means of statistical procedures, that comprise traits like Warmth or being outgoing and supportive, Social Assertiveness or being uninhibited and bold in social situations, Introversion or being reserved and clear-headed, and Independence or being self-sufficient (Cattell & Mead, 2008). His theory led to the development of the Sixteen Personality Factor Questionnaire (16PF) that is still being used in vocational and educational settings. Another well-known theory of traits is the Eysencks’ theory of personality, in which there were only two bipolar factors accounting for all the variation in human personality: extroversion-introversion, and emotional stability-instability (Furnham et al., 2008).

The methodology used by these authors to obtain such taxonomies is mostly based on the following process. The author would first get enough information about the topic by reading or gathering the conclusions obtained after years of experience in therapy and consultation. Once they think they have a solid theoretical framework from which to talk about personality, they will enumerate a set of traits that could explain and summarize humans across time and places. Although this is an oversimplification of the process, it serves one purpose: to show that, although it may be helpful for the patients of the author, it is not replicable or its replicability could be easily questioned. Therefore, since human personality is a universal phenomenon, a taxonomy that could replicate itself across contexts and individuals is needed (Mischel, 1996).

There is a different process that overcomes the limitations of the previous one. This is the so-called lexical hypothesis, proposed by Galton (1949), which states that every important human phenomenon must be somehow represented in the lexicon of a language, and since most languages are easily translated to others, the universality of the phenomenon could also be guaranteed. Based on this proposition, what authors would normally do is gather all the words used in a particular language for the phenomenon of interest from a representative sample of words in that language (some examples include dictionaries but also the transcripts of contemporary famous TV shows and movies), then they would ask a group of experts to analyze this list and determine which words are better at capturing the phenomenon under study (Ashton & Lee, 2007; Oreg et al., 2020; Parrigon et al., 2017). This implies discarding synonyms and uncommon words from the sample. Later, they would approach a representative sample of individuals to categorize the phenomenon of interest (e.g. personality) according to the words established in the previous step. This will allow, by using proper psychometric and statistical techniques (i.e., factorial and multivariate statistical analyses), both to filter the best words that will be used and to create a refined measure of the phenomenon.

The Last Bookstore, Photo by Jaredd Craig (Craig, 2018)

As of now, the scientific consensus is that the lexical hypothesis is the best solution found so far for the classification and understanding of personality (DeYoung et al., 2007). In fact, one of the most famous and used taxonomies used at the moment, both in research, educational, clinical, and vocational settings, is the Big Five Taxonomy of personality, initially proposed by Costa & McCrae (1992), and that have been further developed ever since. This taxonomy summarizes personality in five overarching traits: Conscientiousness, Agreeableness, Emotional Stability, Openness to Experience, and Extraversion. Each one of this will be further developed in the following posts of this 101 series.

One important note of warning is that, although this Big Five solution has proven to be very useful, the traits that conform it should not be understood as casual entities of human behaviors, instead they should be understood according to their real nature: a descriptive explanation of human personality. They do not explain casual relationships, they describe personality, they summarize it so that it can be easier to understand it (Fajkowska & Kreitler, 2018). A second note is that these traits are not separable and completely distinguishable entities in and of themselves, they are correlated and there is some degree of overlap between some of them (Van der Linden et al., 2012).

A final note, and the most important one, is that this taxonomy is based, as almost everything else in Psychology, on self-reports accounts. This is an important issue because, as Jung would say, “you are not what you say you’ll do, but what you do” (PsycholoGenie, 2014). This fact poses a challenge, specially in personality research: are the tests really measuring psychological phenomena if they rely solely on self-report accounts? Are scientists not purposefully biasing their findings because self-reports suppose cheaper costs in research than observational or experimental reports (Galic et al., 2016; Olino & Klein, 2015)? These questions are fueling some alternative research directions, like gathering behavioral data by means of wearables, cameras, and smartphones which, as of now, are both showing coincidences with the already extant research on the topic, and pushing its boundaries forward (Ihsan & Furnham, 2018).

Woman using her Apple Watch, Photo by Solen Feyissa (Feyissa, 2020)

Personality psychology is an important and flourishing branch of Psychology. Its aim is to better understand human behaviors, thoughts, and emotions so that its knowledge would allow people to make better informed decisions in their life. Throughout history, personality has raised many questions to philosophers, writers, thinkers, and scientists and there have been many attempts to understand it. Though the validity of some of them could be recognized from a phenomenological point of view, the scientific method is not yet capable of working with them. Now, the consensus obtained in science is that the best solution found so far is the lexical hypothesis, as manifested in the relevance and extended use of the Big Five Theory of personality. These five traits have been proven useful in the description of many aspects of the human experience and their research is still a burgeoning theme in Psychology, though they are not free of limitations and improvements. Contemporary technologies are being gradually incorporated in the study of personality and their conclusions are solidifying the field and incorporating new findings. Only time will show how far the study of personality will get, and it is almost breathtaking to think that it all started with a man pondering why there were so many differences in people that were born under the same Ancient Greek sky.

Bibliographical References

Visual Sources

Craig, Jaredd. (2018). The Last Bookstore [Photograph]. Unsplash.

Feyissa, S. (2020) Woman using her Apple Watch [Photograph]. Unsplash.

Warhol, Andy (1962). Marilyn Diptych [Silkscreen on Canvas]. Tate Gallery, London.

Хрусталев-Григорьев, Дмитрий. (2021). A Room With Mirrors [Photograph]. Unsplash.


Author Photo

David Saeteros

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