Is There Any Truth To Personality Tests? We Took A Couple To Find Out

By far the most popular personality test is the so-called Myers-Briggs Type Indicator (MBTI), which is reportedly used by 89 of the Fortune 100 companies to analyze the qualities of job applicants. While clearly an upgrade on the Spartan approach, critics of the test say it’s too categorical as it assigns each person a fixed personality type. In contrast, most research suggests that personalities are far messier than this and can’t be placed into neatly labeled boxes.

After about seven pain-free minutes in my company, the MBTI has apparently sussed my type and condensed my entire identity to four simple letters. Turns out I’m an INFP (more on that later). I can’t help but wonder what became of my sort in Sparta.

The invention of personality types

The origins of the MBTI are somewhat bizarre, and go back to the 1920s when an American writer named Katherine Briggs – who had no background in clinical psychology – became obsessed with the influential book Psychological Types by Swiss psychoanalyst Carl Jung. In the book, Jung postulates that all people can be classified as either “perceivers” or “judgers”, effectively dividing the world into two camps.

Stressing that his theories were based on nothing more than his own observations and not backed up by any scientific research, Jung went on to propose that those in the perceiver group could be further divided into “sensors” and “intuitors”, while judgy individuals could be split into “thinkers” and “feelers”. This adds up to a total of four main types, each of which can then be separated into “introverts” and “extroverts”.

Although scientific findings do not speak in favor of the Myers-Briggs test, this test is unfortunately very often used in practice.

Prof. Mathias Allemand

Not wishing to be misinterpreted, Jung wrote that in reality, “every individual is an exception to the rule”, and that no one actually fits entirely into any one category. Despite this, Briggs used the personality types framework to sort the kids in her neighborhood into different pigeonholes.

Later, during the 1940s, Briggs’ equally unqualified daughter Isabel Briggs Myers developed the idea further and devised the earliest iteration of what would later become the MBTI. 

Do personality types really exist?

The current version of the MBTI is a 93-item questionnaire that places people into one of 16 personality types. Each of these is made up of four dichotomous sub-types, depending on whether a person is categorized as introverted or extroverted, sensing or intuiting, thinking or feeling, and judging or perceiving.

Results are displayed as a four-letter combination. For instance, “ESTJ” corresponds to the extroverted-sensing-thinking-judging type. 

Simplistic though that may seem, an estimated 2 million people take the MBTI each year in order to learn their type, usually with the intention of figuring out which profession is for them. The big problem with this, however, is that the framework is completely unsupported by scientific analysis.

For instance, studies have indicated that the test has zero success at predicting which people will perform best at different jobs, while others have shown that around 50 percent of users get a different outcome each time they take the test. Speaking to IFLScience, Professor Mathias Allemand – a psychologist at the University of Zurich – laments that “although scientific findings do not speak in favor of the Myers-Briggs test, this test is unfortunately very often used in practice.”

Am I in the right job?

With a century of pseudoscience to back it up, the MBTI confidently spits out the four letters that define me – along with one-16^th of the rest of the world. From now on, you can address me as he/him/INFP – or Introverted-Intuitive-Feeling-Perceiving, to use my full label. A report tells me that people matching my profile are “mediators”, meaning we are “poetic, kind, and altruistic people, always eager to help a good cause.”

I certainly sound like a nice guy, but what kind of job would suit a sensitive soul like mine? As it turns out, my report informs me that “with their curiosity and their love of self-expression, many INFPs dream of becoming writers.” I have to admit, the MBTI has certainly nailed me there.

Reading on, I discover that “many people with this personality type choose careers that are focused on service, such as counseling, psychology, teaching, health care, social work, massage therapy, or physical rehabilitation.” Having spent several years working in mental healthcare, one could say I’m the quintessential INFP.

The science of personality

Despite the apparent accuracy of my MBTI result, it’s worth noting that I don’t always feel like writing or helping people. Some days I wish I’d become a beekeeper, while I also still secretly dream of being the heavyweight boxing champion of the world. Neither of these are likely to happen any time soon, but my fickle fancies do highlight the unreliability of personality types. 

It's also worth noting your personality is not necessarily set in stone either. Research has shown that the use of psychedelic drugs, or even organ transplants, can appear to modify personalities, and there are even ways you can consciously do it yourself.

It’s for this reason that you won’t find any actual psychologists using the MBTI or any other type-based personality test. Instead, researchers tend to take a trait-based approach to personality, and have developed frameworks to gauge the extent to which people are prone to expressing certain characteristics.

In particular, the so-called five-factor model (FFM) – also known as the Big Five approach – stands out as a highly robust tool for measuring people’s personalities. According to Allemand, Big Five personality tests don’t attempt to place anyone into fixed categories, but “show how people see their pattern of behaviors and experiences ‘in general’.”

“They say little about how you behave in a particular situation and what you are currently experiencing. But they do say something about what your general tendencies are,” he explains. For instance, rather than assuming that people are either introverts or extroverts, the FFM shows where an individual falls on a continuum that stretches from one extreme to the other.

Why only five traits?

The idea that your entire persona can be boiled down to just five characteristics might seem a little simplistic, but the FFM is backed up by several decades of research. “The Big Five framework is derived from the psycho-lexical and factor-analytical tradition of personality psychology, among others,” says Allemand. 

“The psycho-lexical approach assumes that language is a 'window to personality' and that the most important individual differences in personality are encoded in natural language. Especially adjectives such as active, agreeable, anxious, assertive, or artistic are suitable for describing differences between people,” he explains.

Efforts to create the FFM began in the 1960s, when researchers scoured the dictionary for every word that could be used to describe a person’s personality. Thousands of terms were selected, yet by painstakingly questioning volunteers about these attributes over many years, psychologists were able to identify certain characteristics that seemed to be grouped together. By the nineties, this huge list of phrases had been crunched to just five personality traits that collectively encompass the entire range of linked adjectives.

“Statistical methods such as factor analyses were used to determine as few 'personality factors’ as possible and to reduce the number of words,” explains Allemand. “Those research efforts often found five factors in the data.”

Long story short, the Big Five traits are: extraversion, conscientiousness, agreeableness, openness to experience, and neuroticism. Personality tests based upon this model therefore reveal the degree to which a person possesses each of these five characteristics.

The Big Five in practice

Unlike the MBTI, the FFM can actually be used to make predictions about how people’s lives will turn out. For instance, individuals with higher levels of the trait conscientiousness have been shown to live longer and enjoy more fulfilling interpersonal relationships.

The same trait has also been identified as a general predictor of job performance, with those displaying greater conscientiousness typically making better workers. Likewise, lower levels of neuroticism have been linked to superior professional outcomes, while the remaining three traits are associated with success in specific occupations. Extraversion, for example, correlates with a greater talent for sales and management roles.

On a population-wide level, Big Five traits can even have an impact on politics. Surprising as that may sound, one study found that countries with higher general levels of openness to experience tend to have more democratic institutions. Importantly, there’s also evidence to suggest that the same five traits are relevant across different cultures and nationalities.

Taking my own FFM personality test, I learn that I have an agreeableness level of 72.9 percent, making this my strongest trait ahead of openness to experience, for which I clock in at 69.2 percent. I’m also 54.3 percent extroverted and 42.4 percent conscientious, while my level of neuroticism is 30.1 percent.

Unlike my MBTI result, this score can’t tell me much about what career I should pursue, but does at least provide some meaningful insight into the various aspects of my character. And it’s still definitely better than the Spartan personality test.

This feature first appeared in Issue 20 of our digital magazine CURIOUS. Older issues of CURIOUS are free for all users. To access new issues, become an All Access Member.