The Personality Test Psychologists Actually Trust

The Enneagram and MBTI are two well-known personality tests. Neither, however, is the personality theory that the field of psychology endorses today. Rather than sorting people into distinct types, psychologists are far more inclined to study the degree to which different facets of personality are present.

The Enneagram Personality Test

The Enneagram holds that personality can be divided into nine categories: Type One is the Perfectionist, Type Nine is the Peacemaker, and so on. As far as I understand it, the Enneagram lacks a solid theoretical foundation. Like MBTI, it has not been accepted because it isn't backed by enough data — and it has even been labelled a "pseudoscience".

In scientific research, scientists typically form testable hypotheses based on observation, then verify or refute those hypotheses through experiments and data analysis. The single most important link in scientific research is data, and what psychologists prize most is research data. The Enneagram groups people into nine sets, which may well serve as an observation about, or a hypothesis concerning, humankind — yet to this day only a handful of studies support the reliability of Enneagram theory. The reason we feel the Enneagram describes our own personality so accurately may well be that we are swayed by the Barnum effect and confirmation bias, which lead us to misjudge just how accurate these personality tests are.

The Big Five Theory

Like MBTI, the Enneagram overlooks an important fact: a person's personality traits — extraversion or conscientiousness, for example — follow a normal distribution. Most people's traits sit somewhere around the middle of the average, and only a tiny minority are extremely extraverted or extremely introverted. Most of us are somewhere in between, behaving differently at different times and in different situations, and cannot be forced into the box of "extravert" or "introvert".

The Big Five theory proposes that people have five personality traits: Openness to Experience, Conscientiousness, Extraversion, Agreeableness and Neuroticism. Unlike theories built on "types", the Big Five stresses that every person possesses all five of these traits. Like height and weight, everyone has these attributes; the difference lies in the degree to which each is present.

People high in Openness to Experience tend to be more curious and more willing to embrace new things. People high in Conscientiousness go about tasks more diligently and methodically. People high in Extraversion enjoy socialising more. People high in Agreeableness are easier to get along with and more understanding of others. People high in Neuroticism, meanwhile, frequently experience negative emotions.

You might be curious: where did these five personality traits come from? To identify humankind's personality traits, psychologists first gathered data through questionnaires made up of a large number of statements describing personality — for example, "I like going to parties", "I usually spend my weekends with friends", "I am very careful in what I do". They then calculated the correlations between the different statements. We can imagine that people who strongly agree with "I like going to parties" will mostly also agree with "I usually spend my weekends with friends", because both relate to one's degree of extraversion. After comparing the correlations between the various statements, psychologists grouped the highly correlated statements together, and from this finally arrived at the Big Five's five personality traits.

Beyond having enjoyed years of data support, the Big Five's strengths also include its relationship with mental health and academic achievement. People high in Neuroticism are more prone to anxiety disorders and depression, while people high in Conscientiousness tend to perform better academically.

Of course, the Big Five theory has its shortcomings too. First, it is a data-driven psychological theory. The Big Five can only match the patterns in the data; it offers no explanation of why a person comes to display these personality traits or behavioural patterns. If someone enjoys socialising, the Big Five explains this by saying they are a person high in extraversion — yet the very reason they are judged to be high in extraversion is, in turn, that they agreed in the questionnaire with the two statements "I like going to parties" and "I usually spend my weekends with friends". In other words, the Big Five theory can only offer a circular explanation; it cannot fully deconstruct a person's personality within the theory itself.

Readers should also be mindful when interpreting the results of a personality test. Bear in mind that psychological theories are group-based and may not accurately describe any one individual. The fact that most people high in Conscientiousness perform well does not mean someone low in Conscientiousness can never excel academically. If you are taking a personality test to understand yourself better, then — whatever kind of test it is — never let the result hold back your own growth and outlook.