Introvert vs Extravert: What the Science Actually Says

“I’m such an introvert” has become a popular way to describe everything from disliking parties to needing a nap after a phone call. There are books, memes and mugs about it. The science behind the idea is solid. The popular version is a little off, and the gap between the two is worth understanding, because it changes what the label can tell you.

Start with the toy at the top: an evening out, and a social battery that drains or charges depending on where you sit on the scale.

Where the words came from

The Swiss psychiatrist Carl Jung popularised introvert and extravert in 1921. For Jung, the difference was about the direction of a person’s attention: outward to the world of people and things, or inward to thoughts and feelings. It was a broad, almost philosophical idea.

Modern psychology kept the words and changed the meaning. In research today, extraversion is one of the Big Five personality traits, measured by questionnaires and studied in hundreds of thousands of people. It describes how much you’re drawn to people, activity and stimulation. People high in it tend to be sociable, talkative, energetic and assertive, and to seek excitement. People low in it, introverts, tend to be quieter, more reserved, and happier with less going on.

Like every Big Five trait, it’s a scale, not a box. There’s more on the other four in the complete guide to the Big Five.

Introvert doesn’t mean shy

This is the most common mix-up.

• Shyness is anxiety about social situations: worry about being judged, saying the wrong thing or being embarrassed.
• Introversion is about preference and energy: social time uses energy, and quiet time restores it.

They’re separate. An introvert can be confident, charming and a good public speaker, then want a quiet evening to recover. An extravert can love company and still feel anxious in it. In Big Five terms, shyness is closer to neuroticism, the tendency to feel anxiety, than to introversion.

It matters because the two call for different responses. Shyness can be eased with practice and confidence. Introversion isn’t a problem to be fixed at all.

Most people are ambiverts

Because extraversion is a scale, most people fall somewhere near the middle: they enjoy company and time alone, depending on the day, the people and how tired they are. People sometimes call this being an ambivert. It isn’t a separate type, just the crowded middle of the scale.

The middle can be a good place to be.

Where it comes from

Twin studies suggest roughly 40 to 50% of the differences between people in extraversion are linked to genes. One influential idea, from the psychologist Hans Eysenck in the 1960s, was that introverts’ brains are more easily aroused by stimulation, so they seek less of it, while extraverts seek more to reach a comfortable level.

Eysenck’s idea led to one of psychology’s odder experiments. Put a few drops of lemon juice on people’s tongues and measure how much they salivate. In several studies, introverts produced more saliva, as if their bodies responded more strongly to the same stimulus. The details of the arousal theory are still debated, and newer ideas focus on how strongly people respond to rewards. But the basic picture, that introverts and extraverts experience the same situations differently, has held up.

Extraversion is fairly stable through adulthood, though it can shift a little, and everyone acts more extraverted in some situations than others.

What it predicts

Extraversion is linked to:

• Positive emotion. Extraverts report feeling enthusiastic and happy more often, one of the most consistent findings about the trait.
• Social life. More friends, more social activity, and more time in groups.
• Some jobs. Performance in roles built on influencing people, such as sales and management, though as Grant’s study shows, more isn’t always better.

It does not mean introverts are less happy in any simple way, worse at relationships or less capable. Introverts often have fewer but closer friendships, and do well in work that rewards focus and careful thinking.

Introverts and leadership

Leaders are often extraverted, and extraverts are more likely to be seen as leader material. But being picked and doing well aren’t the same.

In 2011, Adam Grant, Francesca Gino and David Hofmann studied pizza delivery stores and lab teams. When team members were passive, extraverted leaders did better. When team members were proactive and full of ideas, introverted leaders did better, apparently because they listened and let good ideas through, where extraverted leaders felt threatened or talked over them. The best leader depends on the team.

Acting out of character

What happens when people act against their type?

When researchers ask people to act more extraverted for a while, many people, including introverts, report feeling more positive at the time. One study found that the lift was followed by more tiredness a few hours later. The takeaway isn’t that everyone should be an extravert. It’s that people can stretch beyond their comfort zone when it matters to them, and that the stretch may need paying back with rest.

The psychologist Brian Little calls these free traits: acting out of character in the service of something you care about, like a shy professor who is a lively lecturer. He also points out that it helps to have “restorative niches”, places and times to be your natural self afterwards.

Planning a week around your battery

The “social battery” in the toy is a metaphor, but it’s a useful one, because it suggests planning rather than willpower.

If you’re towards the introverted end, look at your week as a budget. A wedding, a team offsite or a family visit uses a lot; a quiet evening, a walk or an hour with a book refills it. You can still do the big events. You’ll enjoy them more if you don’t schedule three in a row, if you build in a gap before and after, and if you give yourself permission to leave a party at ten rather than one.

If you’re towards the extraverted end, the budget runs the other way. A week of working from home, or a stretch of solo study, can leave you flat and unmotivated. Building in company, even a call or working in a café, often does more for your mood and productivity than another hour at the desk.

Most people in the middle need some of each, and notice it most when they’ve had too much of one.

What the popular version gets wrong

• “Introverts hate people.” They don’t. They often prefer smaller groups and deeper conversations, and need time to recover.
• “You’re one or the other.” Most people are near the middle, and everyone behaves differently in different settings.
• “Introverts are deep thinkers, extraverts are shallow.” Neither trait is linked to intelligence.
• “It’s an excuse.” The trait describes what you find draining, not what you’re able to do.

Making it work

• Introverts: protect time to recharge, especially before and after big social events. Choose depth over breadth in socialising if that suits you. Needing solitude isn’t being antisocial.
• Extraverts: build in people and variety, even in solo work. Watch that you leave space for quieter voices.
• Teams and families: mix ways of contributing. Agendas sent in advance, written input and a moment of silence before discussion all help quieter people say what they think.
• Everyone: the trait describes your comfort zone, not your limits. Skills like public speaking or listening can be learned from either end.

Where are you?

The free introvert or extravert test takes about five minutes and places you on the scale, with what it means at work and with friends. For the full picture, the Big Five test measures extraversion alongside the other four traits.