The personality traits that people use to describe themselves and others seem pretty self-explanatory, right? You probably use terms such as extraversion (and its reverse, introversion) often, along with many other trait labels for people: “I’m very conscientious at work,” or “My mother is so neurotic!” These are everyday terms.

Not surprisingly, researchers in psychology also use these terms; they measure these traits all the time. You can even test yourself on the internet to find out where you stand on many traits. Most psychologists agree that the most important traits—the so-called “Big Five”—are extraversion, conscientiousness, neuroticism, openness to experience, and agreeableness. When you use these terms, you might assume they have agreed-upon definitions.

This is only partly true. The same trait can have somewhat different definitions depending upon what behaviors are included in its measurement. Psychology researchers are sometimes aware of this, sometimes not. Also, it turns out that researchers developed their various personality scales based on what they thought each trait means. So, different measures of the same trait can include somewhat different behaviors.  Hmmm, we wondered: What do non-psychologists (that is, regular people) think these traits mean?

It was simple to ask the question. But like many conversations with your mother, it took a lot of work to unravel the nuances of meaning. With colleagues Katja Schlegel, Vanessa Castro, and Mitja Back, we asked over 400 people of all ages to tell us. Without providing any definitions, we asked what behaviors would lead them to label someone as extraverted, conscientious, neurotic, open to experience, or agreeable. No rules were imposed; they could write down anything they wanted.

Then we sorted their answers into categories and ranked the categories based on how often certain behaviors were named. Finally, we compared the categories to the ways in which these traits are measured in four personality measures widely used by researchers. These researcher-made measures always define a personality trait in terms of a collection of behaviors that together add up to the trait being measured.

The categories suggested most often by our research participants did capture a common thread in the researchers’ measures. For example, the most commonly used category for extraversion was “outgoing/social.” For agreeableness it was “friendly/kind/compassionate”; for conscientiousness, “planful/detail oriented”; for neuroticism, “nervous/anxious”; and for openness to experience, “risk taker/willing to try new things.” These definitions supplied by our participants are very similar to the way researchers measure these traits.

But sometimes our participants mentioned behaviors that the researchers don’t include in their measures of a trait. For example, researchers’ measures don’t paint extraverts as attention-getting, domineering, or self-centered the way our participants sometimes did. They saw conscientious people as friendly, kind, and compassionate, but researchers’ measures don’t include items like these. Neurotic people were seen by our participants as being more dysfunctional and weirder than one would think from the researchers’ measures. For agreeableness, our participants often mentioned being weak-willed and approval-seeking (a ‘pushover’), but the researchers’ scales do not. Finally, for openness to experience, a number of our participants mentioned being outgoing and social, but the researchers’ measures didn’t include these characteristics as part of openness.

We saw the reverse pattern as well, where the researchers’ measures included behaviors that participants did not mention at all, or not much. Researchers included lack of self-control and impulsivity, as well as self-consciousness, as aspects of neuroticism, but our participants did not say that. Researchers described the agreeable person as trusting, and also modest (honest, humble), but our participants didn’t. Finally, under openness to experience, researchers included having intense emotional experiences, using one’s imagination a lot, and having artistic tendencies, but those concepts never came up in our participants’ responses.

What’s the bottom line here? Who is wrong, ordinary people or the researchers? The answer is that no one is wrong. The labels we use for personality traits are concepts, not facts. Definitions are human-made. We discovered that different humans make different definitions for the very same trait. Not only do people sometimes differ from researchers, but in all probability people differ from each other, just as researchers differed from each other when they devised items to put on their personality scales.

The bottom line is to always delve deeper into what people mean when they talk about personality. Next time your friend uses a trait term, you might want to follow up with: “what exactly do you mean?” That might trigger an enlightening conversation.

For Further Reading:

Hall, J. A., Schlegel, K., Castro, V. L., & Back, M. (2019). What laypeople think the Big Five trait labels mean. Journal of Research in Personality, 78, 268-285.


Judith Hall is University Distinguished Professor of Psychology at Northeastern University in Boston, MA. She works at the social-personality boundary studying nonverbal communication, interpersonal accuracy, and the empathy concept.