Ask Professor Pelly is a column in which the Pelican science team answer your science-y questions

Bradan asks: How scientifically accurate is the popular Myers-Briggs personality test?

In case you don’t know, the Myers-Briggs Type Indicator (MBTI for short) is a popular personality questionnaire that assigns you to one of 16 categories. Each category has a four-letter “name” with each of the four letters signifying a different “preference pair”. The Myers-Briggs website outlines the four pairs:

* Extraversion or Introversion: “Opposite ways to direct and receive energy”

* Sensing or iNtuition: “Opposite ways to take in information”

* Thinking or Feeling: “Opposite ways to come to conclusions”

* Judging or Perceiving: “Opposite ways to approach the outside world”

Taking the test will place you on one side of either of these dichotomies and may even give you a “clarity index” to tell you how strongly you fit either side. For example, you may be classified as an Extraverted Intuiting Feeling Judging person, or an ENFJ. Some versions of the test take this further and attach a title to this result. For example, INFP is classified as “Healer” and ESTP as “Promoter”, which is a great excuse when your mum asks you why you spend your Saturday nights hanging around Northbridge giving people entry tokens.

The Myers-Briggs personality test was developed during the early 20th century by Mother-Daughter team Katharine Cooks Briggs and Isabel Briggs Myers. The test is based on the work of psychiatrist Carl Jung. His 1923 book Psychological Types outlines the I/E, N/S and T/J dichotomies seen in the modern MBTI test. Jung’s ideas weren’t developed through research – back in his day, you could declare a lot of stuff to be scientific truth as long as you had some kind of doctorate. Briggs took Jung’s type system and added the Judging and Perceiving dichotomy – again, no research – and created the MBTI system as we know today.

In short, the MBTI system is based on a 1923 theory that some psychiatrist just kinda came up with, and hasn’t really been updated since. So no, the Myers-Briggs Personality test is not particularly scientific.

But let’s give it some leeway here. So what if its development wasn’t up to modern standards – is it still useful in a modern context? If it’s so bad, why is a personality test from nearly 100 years ago still so popular?

Modern research has been done on the MBTI to see if it holds up – and there are aspects that do! Aspects of the MBTI can be seen in the Five Factor model personality test, which describes personality along factors of Openness to experience, Conscientiousness, Extraversion, Agreeableness and Neuroticism. The Extraversion and Conscientiousness factors of the Five-factor model mirror the E/I and J/P dichotomies of the MBTI.

However, the S/N and T/F dichotomies don’t hold up as well. The MBTI positions Sensing as “[preferring] real information coming from the five senses” and iNtuiting as “[preferring]

information coming from associations”. These are both core functions of perception, and the idea that these are even opposites has no scientific basis. It’s like if a test asked if you preferred tasting or hearing.

The Thinking/Feeling dichotomy has also been criticised – research has shown that logical and emotion-based reasoning happen independently and are again not opposites.

The MBTI has also been criticised for how vague and non-conclusive its results are. Many of the type descriptions are broad enough to lend themselves to the Forer effect, where people believe general statements about personality apply specifically to them. This effect is commonly believed to explain popular belief in astrology and fortune telling, which doesn’t exactly bode well for the MBTI’s scientific validity. The Forer effect is reinforced by how uniformly positive the types are. Unlike the Five Factor model, where you can be classified as closed-minded, neurotic, unconscientious or disagreeable, the MBTI stays very nice about everything. This is useful because the MBTI isn’t really about measuring personality, at least not any more.

You’ve probably never taken a real Myers-Briggs Personality Test.

The newest iterations of the MBTI, the MBTI®Form M Step I™ questionnaire and MBTI®Form Q Step II™ results booklet, are owned by The Myers-Briggs Company. Myers-Briggs tests may only be carried out by MBTI Certified Professionals; certification costs between US$1180 for an online course or up to US$2295 for an in-person training workshop. The Form M tests themselves cost US$400 for a pack of 10 and the Form Q results profiles cost upwards of US$92 each. In contrast, the NEO PI-3 personality test, based on the Five Factor model, costs $70 for a pack of 10 questionnaires.

These tests are marketed towards businesses, and the Myers-Briggs company website lists benefits such as “Nurture and retain top talent” and “Reduce workplace conflict”. The MBTI isn’t a scientific tool as much as it is an HR tool. It has remained popular throughout the decades due to marketing, not due to its value as an instrument.

You can take a Five factor-based personality test here. Or, if you want something with nice and tidy results you can put in your Instagram bio, you can find your astrology birth chart here, your Hogwarts house here, or what sandwich you are here. Heck, even take an unofficial MBTI-style test here – just take your results with a bucketful of salt.

If you want to know more about the MBTI and its criticisms, check out the article Evaluating the validity of Myers‐Briggs Type Indicator theory: A teaching tool and window into intuitive psychology by Swan and Stein (2019). It goes into depth not only on criticisms but also on what the MBTI’s popularity says about our society.

Have a burning science question you want our team to answer? Email us at pelicanscience@guild.uwa.edu.au

Words by Zoe Castleden, Science Editor

Zoe is an ENFP, a Scorpio, a Ravenclaw, and a hamburger with lettuce instead of buns.