There are two different types of extroverts — 'agentic' and 'affiliative' — each with distinct brain structures, new research finds.
Agentic extroverts are 'go-getters': the kind of outgoing people who are persistent, assertive and focused on achievement.
The other kind of extroverts have a softer side.
Affiliative extroverts tend to be more affectionate, friendly and sociable.
Both types of extroverts share distinct brain anatomy as well as displaying distinct differences, the new research finds.
Dr Tara White, the study's first author, said that extroverts in general are keen to share:
"These are people just sharing with you how they tend to experience the world and what's important to them.
The fact that that's validated in the brain is really exciting. There's a deep reality there.
This is the first glimpse of a benchmark of what the healthy adult brain looks like with these traits."
For the study, researchers scanned the brains of 83 people to look for similarities and differences in key areas of the brain.
They found that both types of extroverts had more gray matter in the medial orbitofrontal cortex.