Scientists identify four personality types

Personality tests are very popular, but if you ask psychologists for work, they will tell you that the results are not much better than the astrological signs. But a new study, based on vast sets of personality data representing 1.5 million people, has convinced one of the most critical critics of personality tests to conclude that there may be personality types distinct.

In a report published Monday in the journal Nature Human Behavior, researchers at Northwestern University, Illinois, identify four types of personality: reserved, model, egocentric and average.

The new approach was in no way the basis of widespread personality tests like the Myers-Briggs, who spits a personality type with acronyms like INTJ, for introversion-intuition judgment or ESFP (c & # 39; that is to say, to perceive extroverted sensations). ).

"The social psychology community is in tune with the personality assessments of Myers-Briggs Type," said Alexander Swan, a psychologist at Eureka College in Illinois who is a reviewer of the test.

This test, developed in the 1940s, is based on the idea of ​​the Swiss psychoanalyst Carl Jung that people can be grouped into archetypes. (These archetypes were not empirical discoveries, but the evaluation of Jung's literary motives and his observations of the people he knew.) The Myers-Briggs tests generate one of 16 archetypes for each user, but the questions are poorly written. And several studies show that personality types are inconsistent and can not predict professional success or other characteristics.

People were trying to gorge each other for thousands of years. "These ideas go back to ancient Greeks like Hippocrates, etc.," said Martin Gerlach, a postdoctoral researcher studying complex systems at Northwestern University.

Gerlach and his colleagues Luís A. Nunes Amaral and Beatrice Farb are trying to propel these old ideas in the field of Big Data. They took a relatively new approach: not to adhere to Jungian theories, but to analyze four huge sets of data.

They also enlisted the help of North West psychologist William Revelle, who was skeptical about the idea of ​​personality types. He was first a critic of the group's study. "I will be very direct," he said. "My first reaction was that it does not make sense."

Social psychologists dispute the existence of personality types. Features are another matter. Personality traits "can be measured consistently across ages, cultures," said Amaral, director of the Northwestern Institute of Complex Systems. The five most established traits, or Big Five, are the franchise, the professional conscience, the extroversion, the agreeableness and the neurosis.

Swan agreed that the Big Five is "a good model." Long questionnaires, usually 100 or more questions, determine whether people score low or high on these characteristics. "I see myself as someone who is full of energy" or "I tend to keep grudges".

The results give a value for each of the five traits, which indicates that a person has a high level of approval, for example, or little neurotism. The big flaw of the Big Five lies in the self-declaration: do we really know if we are full of energy? Do we honestly answer our grudges? But the promoters note its coherence; Self-assessments often correspond to peer assessment.

Given that five values ​​are assigned to each person who passes a Big Five test, the study authors had to work in a five-dimensional space to search for models. "I've heard of people able to visualize five dimensions in their head," said Amaral. "I am certainly not one of them.

Thus, scientists used a sophisticated machine learning algorithm to identify clusters of traits, or what Revelle called "dough sizes" in this 5-Am population. At the first attempt, Amaral said he was completely wrong.

Imagine a watermelon sitting next to grapes. If the only tool you have is a melon baller, you can pick up the grapes, but go after the watermelon and you'll cut it into little balls that did not exist before. The first model of the authors of the study was like that of the melon baller. They carved the 5-D space into a dozen types of artificial personalities.

Revelle cut them down. "I do not believe in these types of personality," he says. No cigar, remembers Amaral. They re-checked the model and the psychologist was right.

Scientists have finally developed a more robust model for selecting smaller groups (such as "role model" and "self-centered") and keeping the larger ("medium") intact. Revelle asked them to apply the tool to two additional sets of data on personality traits. They found four guys here too.

This finally convinced Revelle – the four personality types appeared as expected wherever they looked. In total, this research represents personality traits for 1.5 million people in the United States and Great Britain.

The new study "presents a very strong argument for personality types defined by Big-Five personality trait patterns," said John A. Johnson, a psychologist at the University of Pennsylvania. Johnson has collected data on the personality traits of more than 500,000 people. He made these datasets available to the authors of the study, but was not otherwise involved in this research.

"What is unique in this study is the choice of the five major domains as a starting point," he said, "rather than certain theoretical types derived from the imagination of the theorist."

Amaral and his colleagues named clusters only after locating clusters. The role models were high in each trait but neuroticism. They also appeared with increasing frequency as older people grew older. "These people are not mean, not rude, but kind and polite and treat people with respect," said Amaral. The reserved type was not open and not particularly extrovert, but otherwise pleasant and conscientious.

Amaral expressed it in a "non-technical" way: some people are "jerky". Teenage men were more likely than average to be egocentric, but this proportion decreased with age.

"These 18-year-olds will grow up," Revelle said. "Except that some people do not grow up and become high politicians."

Johnson said that he was not surprised by the links between personality type, age, and sex. "Personality changes very slowly over time in the direction of greater maturity: more friendliness, awareness and emotional stability," he said.

Swan was not so convinced by the usefulness of these categories. "Having one of their groups called average is low," he said. He struggled to see why it would be useful to describe someone this way. Labeling a category as egocentric, however, was a credit to the authors of the study. "You will not find that in the Myers-Briggs type tests," he said, because his results are still "very good things."

Revelle said he was convinced that these types exist, but he is not sure what to remember from this observation. "Myers-Briggs was very successful because people like to say," Oh, I'm a this", Added Revelle. "It's a complete mistake."

He proposed a metaphor for the map of the United States population. Many people live in New York, Los Angeles, Houston and Chicago, the four most populous cities. And it is sometimes useful for someone to identify as a New Yorker. But you miss the majority of the United States if you focus only on these metropolitan areas. In addition, the city closest to you is only a descriptor, even in the context of location. "Do you prefer that the person live in the north or south or live in New York or Chicago?

It's the same with the identity of someone. "What is the real utility of these?" He declared. I do not think we really answered that. "

Not yet anyway. Revelle is currently collecting personality data at SAPA-Project.org. (You can take this test here.) And Gerlich wants to know if the people they called "models" are more successful in their work.

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