Do you consider yourself to be a people-person? Do you crave the company of others, are you warm and sentimental? Well, if you are, then it could come down to the structure of your brain.
Graham Murray led a team of researchers from Cambridge University and Oulu University in Finland who have discovered that the greater the concentration of tissues in certain parts of the brain, the more likely someone is to be highly sociable. Earlier studies have linked these same areas of the brain to processing simple rewards like sweet tastes and sex.
Publishing in the European Journal of Neuroscience, Murray and the team recruited 41 male volunteers who had their brains scanned by MRI scanners and were also asked to fill out a questionnaire to find out about aspects of their personality. They were asked to rate themselves on statements like ‘I make a warm personal connection with most people', or 'I like to please other people as much as I can'. The results of the questionnaire provide a measure of how sociable someone is, called the social reward dependence.
They found that people with higher social reward dependence scores tended to have a greater concentration of grey matter in both the orbitofrontal cortex (the outer strip of the brain above the eyes), and in the ventral striatum (a deep structure across the centre of the brain).
Eating energy-rich sweet foods and sex are vital for survival while social interactions are not necessarily so, but it could be that emotions like sentimentality and affection in humans evolved from structures in the brain that make animals seek out and satisfy these more basic needs.
This research could also shed light on understanding what causes various psychiatric disorders which make social interactions difficult, like autism or schizophrenia. So far Murray and his team have found a correlation between brain structure and personality, but exactly how the two are linked is still to be uncovered.