Researchers at Northwestern University have used data from 1.5 million questionnaire respondents to determine that there are four personality types. They also claim that people's personalities can change over time. Here's a break down of the personalities:
- Average. People in the average cluster are described as extroverted and high in neuroticism. Women are more likely to be in this personality type and it’s the most common, according to the research.
- Reserve. The reserve type isn’t very extroverted or neurotic. Instead, they’re agreeable and conscientious, as well as emotionally stable. Those in both the reserve cluster and the average cluster are not very open."
- Self-centered. These people are described as very extroverted and aren’t considered very agreeable, conscientious, or open. As people age, the amount of those who fall into the self-centered category declines dramatically in both men and women. "These are people you don't want to hang out with," researchers note.
- Role Models. This type scores high in every trait—extroversion, openness, agreeableness, and conscientious—except neuroticism. People are more likely to be in the Role Model category as they age, and women are more likely to be in this group than men.