Your brain structure determines personality

Washington:A study says that one's personality is related to the size of different parts of brains.

Colin DeYoung at the University of Minnesota (UM) and colleagues wanted to find out the correlation between different personality factors and brain structures.

For the study, psychologists divided all personality types into five factors: conscientiousness, extraversion, neuroticism, agreeableness, and openness / intellect. Then, 116 volunteers answered a questionnaire to describe their personality, followed by a brain-imaging test that measured the size of different parts of the brain.

The researchers used a computer program to warp each brain image to compare the relative sizes of different structures. Several links were found between the size of certain brain regions and personality.

For example: "Everybody, I think, has a common sense of what extraversion is - someone who is talkative, outgoing, brash. They're more motivated to seek reward, which is part of why they're more assertive," says DeYoung.

That quest for reward is thought to be a leading factor in extraversion. Earlier studies had found parts of the brain that are active in considering rewards.

So DeYoung and his colleagues reasoned that those regions should be bigger in people who are more extraverted.

Indeed, they found that one of those regions; the medial orbitofrontal cortex - it's just above and behind the eyes - was significantly larger in study subjects with a lot of extraversion.

The study found similar associations for conscientiousness, which is associated with planning; neuroticism, a tendency to experience negative emotions that is associated with sensitivity to threat and punishment.

And agreeableness, which relates to parts of the brain that allow us to understand each other's emotions, intentions, and mental states.

Only openness / intellect didn't associate clearly with any of the predicted brain structures.

"This starts to indicate that we can actually find the biological systems that are responsible for these patterns of complex behaviour and experience that make people individuals," says DeYoung, said a university release.

However, he points out that this doesn't mean that your personality is fixed from birth; the brain grows and changes as it grows. Experiences change the brain as it develops, further changing the personality.

The research appears in Psychological Science, a journal of the Association for Psychological Science.