Are you sociable and affectionate? Are you always trying to please people? It might be because you have more brain tissue in certain parts of your brain, according to a team of researchers from Cambridge University and the University of Oulu in Finland.
The scientists studied the link between brain structure and personality in a group of males by scanning their brains and having them answer questions that rated their "social reward dependence," a measure of their emotional warmth and sociability. Turns out, the more gray matter a man has in the orbitofrontal cortex and ventral striatum regions of his brain, the higher his social reward dependence tends to be. And here's what's neat: Those same brain regions have previously been linked to the processing of simple rewards.
"It's interesting that the degree to which we find social interaction rewarding relates to the structure of our brains in regions that are important for very simple biological drives such as food, sweet liquids, and sex. Perhaps this gives us a clue to how complex features like sentimentality and affection evolved from structures that in lower animals originally were only important for basic biological survival processes," says Dr. Graham Murray, a psychiatrist who worked on the study.
But keep in mind, he says, that trying to understand why some people are warmer or more social than others is complex, and this study is only correlational—meaning that we know brain structure and personality are related, but "it cannot prove that brain structure determines personality. It could even be that your personality, through experience, helps in part to determine your brain structure."
The research appears in the European Journal of Neuroscience. —Heather Wax