The types of personalities are a subject that has long fascinated the human race. Are you ENFP or ISTJ, in the Myers Briggs school of thought? Maybe a challenger or perfectionist, according to the Enneagram Institute? What house would the sorting hat put you in in the "Harry Potter" world — Gryffindor like the titular character?
Even though personality type tests abound online, experts have long said the idea that there are distinct types of personalities and that you can only be one isn't true. In reality, personality exists along a continuum of traits, in particular what are referred to as the big five: openness, agreeableness, extraversion, neuroticism and contentiousness, Jack Mayer, Ph.D., psychology professor and director of the Personality Lab at the University of New Hampshire, tells TODAY.com.
In fact, much of the research on personality focuses more on traits rather than types.
"There is so little research on (personality) typologies," Mayer explains. "We can say a lot about personality traits because that's how 99% of how the field operates in scholarly, academic work. Now, if you get outside of academic work, plainly as you go read online, you're going to encounter all kinds of typologies, everything from Enneagram to horoscope types."
That said, there is one major study, published in 2018 in Nature Human Behaviour, that established four personality types: average, reserved, role models and self-centered.
"(This article) was so interesting and raised a little bit of attention" because it showed psychologists that research into personality types was possible, Mayer says — but he stresses that its findings are "a far cry from" the personality tests of pop culture.
Tests like Myers Briggs and the astrology universe have a narrative element to them, which perhaps makes them more attractive to people trying to understand their personality, Mayer says. Still, the four personality types identified in the 2018 study do a fairly good job of breaking down personality.
"There's an adaptive quality to these four types," Mayer explains. "Maybe we need to flesh them out."
Adds Jonathan Adler, Ph.D., psychology professor at Olin College of Engineering: "Whether or not these models become the definitive personality type model, it is a step forward."
Different traits help to predict your personality type
Researchers at Northwestern’s McCormick School of Engineering examined data from 1.5 million participants who answered questionnaires about the "big five" personality traits. These five traits are commonly accepted to be major indicators of personality. As they looked at the data, it appeared that people clustered around four different areas, and those emerged as the different personalities.
“The findings suggest there are types,” Luis Amaral, Ph.D., professor of chemical and biological engineering at Northwestern University McCormick School of Engineering and an author of the paper, tells TODAY.com. “These (types) are more of an attractor for these personality traits.”
Personality type is based on how you rate on five traits
People fall into one of the four types based on how they rank on the big five personality traits. According to Psychology Today and Psych Central, these are defined as:
- Openness: how willing you are to have intellectual, creative and new experiences.
- Agreeableness: how respectful, compassionate, kind and trusting towards others you are.
- Extroversion: how outgoing or introspective you feel; introversion is the opposite of extroversion.
- Neuroticism: how likely you are to experience negative feelings such as anger, anxiety, irritability and depression.
- Contentiousness: how organized, responsible, productive, optimistic and emotionally stable you are.
Understanding how high or low someone ranks on each of the traits can be useful and predict things about people, such as risk of mental illness or likelihood of divorcing. But it's not an exact science.
“Everyone has variation on the big five,” Adler says. “When you look at the whole picture of personality — including the traits, but at other levels as well — it still looks largely dimensional, not categorical.”
The four personality types include:
- Average: The most common type are people who are high in neuroticism and extraversion while lower in openness.
- Reserved: People in this type are not open or neurotic, but they are emotionally stable. They tend to be introverted, agreeable and conscientious.
- Role models: These people are natural leaders with low levels of neuroticism and high levels of agreeableness, extraversion, openness and conscientiousness. They listen to new ideas and are reliable.
- Self-centered: While these people score high in extraversion, they rank below average openness, agreeableness and conscientiousness.
The researchers also found that personality isn’t static; people evolve. Teen boys tend to be overly represented in self-centered personality while older people make up a large portion of the role models.
“Certain facets are changing,” Amaral says. “As people mature and grow, their personality also matures and grows. I think there is a positive message that people mature, and they move to more desirable characteristics.”
Even though it might sound bad to be neurotic, average people experience varying levels of neuroticism. “We shouldn’t think about each one of the characteristics as the higher, the better. If you are extremely open-minded, that just means you believe everything,” Amaral said.
Because these personality types reflect people without mental illness, future research may examine people with mental illness to see if they also fall within these types or if more types emerge.