US scientists crack secrets of personality

Humanity: Data was collected from over a million surveys asking people to describe their personality.

Should we pay attention to personality tests? American scientists have used big data to split humanity into four distinct personality types. Science like this has a controversial history.

Reserved. Role model. Average. Self-centred. Every single person can be categorised into one of these types. Yes, even you.

That is, according to a landmark study which analysed the data of 1.5 million people. But how exactly did scientists reach this conclusion?

Each personality type is determined by a combination of five different traits: neuroticism, extraversion, openness, agreeableness and conscientiousness.

Every person can be ranked on each. High scores on all besides neuroticism and you are a “role model”. Someone with low scores on all but extraversion is “self-centred”, low neuroticism and openness ratings indicate a “reserved” personality.

“There is very little to say about average,” quips the study’s author Luis Amaral — although this is the categorisation of the typical person.

Personality tests have long been controversial. “My first reaction was this is nonsense,” admitted co-author William Revelle. But repeated experiments and the weight of data soon convinced him.

The findings are the latest twist in a science which is thousands of years old.

Ancient Greek physician Hippocrates also believed in four basic traits, or “humours”. They were: sanguine, choleric, melancholic and phlegmatic. Early medicine taught that these traits could be influenced by changes in diet.

In 1921, Carl Jung theorised distinct personality categories in the book Psychological Types. The book remains obscure, but it inspired the most influential personality test ever created: the Myers-Briggs test.

The test splits people into 16 types. It is used across the world to assess employees, students and even romantic partners — over two million people take it every year.

But for all its popularity, some remain cynical. “As many as three quarters of test takers achieve a different personality type when tested again,” writes Annie Murphy Paul in The Cult of Personality Testing. “The sixteen distinctive types described by the Myers-Briggs have no scientific basis whatsoever.”

Should we pay attention to personality tests?

Not my type

Absolutely, some argue. The maxim “know thyself” has long been a feature of Western philosophy. Engaging with these tests help us come to terms with who we are. They also provide a crucial lesson: other types of people see the world in different ways to ourselves. This builds empathy with others in an increasingly individualistic society.

Nonsense, others respond. Carl Jung also said this: “every individual is an exception to the rule.” No test will ever categorise the unique aspects of each person. Some say the tests are enlightening; in fact, they are deadening — a depressing symbol of corporate culture in which life itself is reduced to a string of digits.

You Decide

  1. Do solid personality types actually exist?
  2. Is it good to be average?


  1. Study the graphs at the top of this article. Each one shows a personality type and the combination of traits that make it up. Rank yourself on each trait: either high, low, or somewhere between the two. Which personality type do you think is the best fit for you? Discuss with your classmates.
  2. Do some research into the Myers-Briggs personality test, starting with the links in Become An Expert — you could even complete the test yourself. Do you think that it can accurately categorise different people? Would it be wrong to force employees and students to take the test?

Some People Say...

“The unexamined life is not worth living.”


What do you think?

Q & A

What do we know?
These four personality types are not set in stone, and researchers say that they can change with age. Furthermore, the vast majority of those surveyed in the study were from the UK or the US. The scientists hope to widen their research to see if different languages and cultures have an influence on personality types.
What do we not know?
One of the key weaknesses of personality tests is that the data comes from personal testimony — therefore individuals may rate themselves higher on certain attributes that they believe to be desirable. This means that personality tests cannot be totally accurate, as the data they are based on is not entirely impartial.

Word Watch

“A robust data-driven approach identifies four personality types across four large data sets,” published in Nature Human Behaviour.
Often abbreviated to OCEAN, these are the “big five” personality traits that are accepted by most psychologists around the world.
Optimistic and positive — enthusiastically seeks social engagement.
Independent, decisive and values a fact-based view of the world. Has also come to mean bad-tempered and irritable.
Introverted and deep thinkers. Also refers to feeling of deep sadness and depression.
Relaxed and easy-going. Can also mean unemotional and being calm under pressure.
Carl Jung
(1875-1961) Swiss psychiatrist and psychoanalyst.
Named after the mother-daughter duo who invented the test: Katharine Cook Briggs and Isabel Briggs Myers.

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