Two Different Types of Extroverts Have Different Brain Patterns

There are two types of extroverts: "agentic" go-getters and "affiliative" people persons. Now, scientists have mapped the similarities and differences in the brain between these two types of extroverts.

Everyday experiences show that there are two types of extroverts. There are the gregarious "people-persons" who find reward in sharing affect and affiliation with others. And then there are also the ambitious "go-getters" who flash smiles in their pursuit of achievement and leadership agendas. While the two personalities overlap, though, these personalities have distinct signatures in the anatomy of the brain.

"These are people just sharing with you how they tend to experience the world and what's important to them," said Tara White, one of the researchers, in a news release. "The fact that that's validated in the brain is really exciting. There's a deep reality there."

In this latest study, the volunteers were first screened for mental and physical health and then were given standard personality tests that measured scores of both kinds of extroversion. Then, the volunteers underwent MRI scans designed to detect the volume of grey matter in different regions of their brain.

The scientists found that higher degrees of either kind of extroversion correlated with higher grey matter volumes in the right and left medial orbitofrontal cortex, even after controlling for possible confounding factors. People with high agentic extroversion scores, though, also had other regions with larger grey matter volumes: the parahippocampal gyrus, the precentral gyrus, cingulate gyrus and caudate. Among men in the study, the nucleus accumbens also had larger volumes.

The findings reveal that while both types of extroverts had higher volumes in one key brain region, agentic extroverts also had higher volumes in several other areas. The findings reveal the differences in these extroverts and also provide a developmental benchmark from which to better understand these different types of people.

The findings are published in the journal Cognitive, Affective & Behavioral Neuroscience.

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