Introvert, extravert or ambivert? Extraversion is a scale, not two boxes

Personality research has no separate groups called introverts and extraverts. It has Extraversion, a continuous scale on which everyone has a position, and most people sit somewhere in the middle. "Introvert" and "extravert" are handy names for the two ends; "ambivert" is a name for the middle.

Where the words come from

Carl Jung popularized the terms between 1910 and 1921, when his book Psychological Types described two opposite attitudes: energy turned toward the outer world or toward the inner one. Jung thought in types. Trait psychology kept the words and dropped the boxes: for Hans Eysenck and for the Big Five, Extraversion is a dimension, and "ambivert" describes people in its middle range (Grant, 2013).

The spelling question has a short answer. "Extraversion" with an a is Jung's spelling and the one used in research; "extroversion" with an o entered everyday use almost at once (Kaufman, 2015). Both mean the same thing.

Why not two boxes

Psychologists have statistical methods designed to tell whether a characteristic splits people into categories or spreads them along a scale. A meta-analysis of 317 such findings found five dimensional results for every categorical one, and no domain, normal personality included, where categories were supported overall (Haslam and colleagues, 2020).

In practice, splitting people into introverts and extraverts puts those just below and just above the middle into opposite groups, though they resemble each other far more than either resembles the far end of their box. That is why our test gives you a position on the Extraversion scale rather than a label.

What Extraversion actually measures

In everyday speech "introvert" often means shy. The trait measured by questionnaires is broader. In the IPIP-NEO, the public questionnaire our test uses, Extraversion is the sum of six facets: friendliness, gregariousness (enjoying crowds), assertiveness, activity level, excitement-seeking and cheerfulness (IPIP).

Two people with the same score can get there by different routes. One loves parties but never speaks up in meetings; the other happily leads a team and prefers quiet evenings alone. The trait score is an average, and the facets show where it comes from. The most solid common thread is mood: in a large meta-analysis Extraversion was the trait most closely tied to positive emotions, with a correlation of .44 across almost 13,000 people (Steel, Schmidt and Shultz, 2008).

The situation matters as much as the trait

A trait describes how you behave on average, not at every moment. William Fleeson asked people to report several times a day, for two to three weeks, how they were behaving. Over the days, almost everyone passed through nearly every level of every trait: withdrawn moments and outgoing ones in the same person. Yet each person's average was very stable from one week to the next (Fleeson, 2001). Someone low in Extraversion is not always withdrawn; they spend more of their time there, on average, than someone high in it.

Do ambiverts have an advantage?

The idea spread through a study by Adam Grant of 340 call-center staff selling by phone. People in the middle of the scale sold more over three months than those with low or high scores (Grant, 2013). It is an interesting result, and it should be read for what it is: one sample of very young workers (19 on average), a four-item Extraversion scale, and an effect the author himself calls small to medium. We found no preregistered replication. It is a plausible idea, not a rule.

Precise percentages also circulate: "two thirds of people are ambiverts", "a third are introverts". We found them in no primary source, and they could not be precise anyway: on a continuous scale they depend entirely on where you draw the lines.

So which are you?

The more useful question is not which group you belong to but where you sit on the scale, and on which facets. The test below measures Extraversion along with the other four traits and shows your position compared with a large sample. What each level means is on the Extraversion page.