Some established theories tell us that the size of the brain is linked to the person's intelligence. However, we didn't know that its shape can also say a lot about our personality, until this new study is published in the journal Social Cognitive and Affective Neuroscience.
According to researchers of this new study, neurotic people may have a thicker cortex than those who are more open-minded. It's the first research that clearly links personality traits to differences in brain shape.
Researchers studied the connection between the shape of the brain, and the “big five” personality traits. These traits are neuroticism, agreeableness, extraversion, conscientiousness and openness to experience. Psychologists consider these traits to comprise the major dimensions of personality.
Experts gathered 507 healthy young volunteers, and underwent brain scans for the study. The researchers then examined the brain scans. They focused on the cortex, the outermost layer of the brain, which is also composed of grey matter. The researchers found some variations in cortical thickness, surface area and number of folds.
The results revealed a profound association between three measures of the cortex such as thickness, area and folding. These measures also came with different personality traits.
“This is a clear pattern with thickness going in the opposite direction than area and folding, as a function of different personality traits,” Dr. Luca Passamonti, a Cambridge neuroscientist and lead author of the study, told The Huffington
Researchers learned that neurotic people had a thicker cortex, with reduced surface area and folding. On the other side of the spectrum, those high in openness to experience had a thinner cortex with increased surface area and folding.
“We are continually shaped by our experiences and environment, but the fact that we see clear differences in brain structure which are linked with differences in personality traits suggests that there will almost certainly be an element of genetics involved,” study co-author Dr. Nicola Toschi said in a statement
. “This is also in keeping with the notion that differences in personality traits can be detected early on during development, for example in toddlers or infants.”
Particular brain differences are even more observed in individuals with mental health conditions.
“Understanding the ‘healthy’ brain and more specifically how variability across personality traits relate to brain structural measures as thickness, area, and folding may help us to develop better model to understand ― and consequently treat ― the diseased brain,” Passamonti said.
It’s not yet established, for one, whether personality traits determine brain shape, or vice versa. It’s also unclear how these brain differences might factor into mental illness.
“We don’t know whether what we see is driven by genes, environment or both,” he said. “What we know it the most likely possibility is that a complex interaction between genetic predispositions and bad environmental factors are risk factors for many neuropsychiatric disorders.”