The Four Personality Types According to Gerlach, Farb, Revelle, and Nunes Amaral

· November 30, 2018
A group of American researchers proposed that there are 4 types of personality based on 5 personality characteristics.

Throughout history, many theorists have elaborated their own personality theories. Recently, a group of researchers from Northwestern University in the United States analyzed data exhaustively. Their results challenged the established personality paradigms. In this sense, they discovered four personality types.

The social psychologists wanted to discover whether there are personality types. Personality traits are another matter. Personality traits “can be measured consistently across ages and cultures,” said Amaral, co-author of the study and professor of chemical and biological engineering at Northwestern’s McCormick School of Engineering.

These researchers reviewed data from more than 1.5 million surveys and found that there are at least four different personality types: average, reserved, self-centered, and role model. These four personality types are based on five basic personality traits: neuroticism, extroversion, openness, agreeableness, and conscientiousness. The new study was published in Nature Human Behavior magazine.

A controversial concept

William Revelle, professor of psychology at Weinberg College of Arts and Sciences and co-author of the study, explained that “People have tried to classify personality types since Hippocrates’ time, but previous scientific literature has found that to be nonsense”. The data from this new study shows that “there are higher densities of certain personality types”.

The concept of personality types continues to be controversial in the field of psychology. This is due to the various separate classifications that have received empirical backing. The previous attempts at defining personality types that were based on small research groups gave way to results that often weren’t able to be replicated.


Some of these emotions are related to the four personality types.

“Personality types only existed in self-help literature and did not have a place in scientific journals. Now, we think this will change because of this study,” said Amaral.

Personality types: A new focus

The new study combined a computational alternative approach with data from four questionnaires. More than 1.5 million people were surveyed and the questionnaires were obtained from John Johnson’s IPIP-NEO. The myPersonality project and the data from BBC’s Big Personality had 120 and 300 elements, respectively.

The questionnaires, developed by the research community, have between 44 and 300 questions. The participants respond to them voluntarily online. The opportunity to get information about their own personalities attracts them.

Based on this large data collection, the research team identified five traits that may have a higher level of acceptance. These are neuroticism, extroversion, openness, agreeableness, and conscientiousness. After developing new algorithms, they discovered four personality groups or types.

Different personality types

  • Average: Average people are high in neuroticism and extroversion but also low in openness. According to the researchers, women tend to have a higher probability of having an average personality.
  • Reserved: Reserved people are emotionally stable but not very neurotic. They’re not particularly extroverted but are somewhat agreeable.
  • Role model: These people score low in neuroticism and high in all the other traits. According to the researchers, these people are reliable and open to new ideas. They’re good at being in charge of things. Women have a higher probability of belonging to this group.
  • Self-centered: Self-centered people score high in extroversion but below-average in openness, agreeableness, and conscientiousness.

Our personality changes throughout our life

The researchers explain that as people mature, their personalities change. For example, older people tend to be less neurotic but also more conscientious and agreeable than people under the age of 20.

“When we look at large groups of people, it’s clear there are trends, that some people may be changing some of these characteristics over time,” said Amaral.