Sunday, March 25, 2012

Large brain size favourable for having friends

It appears you need a large brain if you want to maintain a large social network. Especially one brain area seems to be of importance, as British scientists found a correlation between size of this area and the number of friends one has. According to the researchers, the ability to make friends and maintaining them is a complex process which calls for the need of a large social and cognitive brain. By discovering how it works, it also tells us something about how our social skills evolved.

Prefrontal cortex
Our brain is divided into various areas that specialize in certain tasks. Some areas in the outer layers of the brain, known as the cortex, play a role in social and cognitive behaviour, while parts deeper in the brain are involved with more primitive processes including emotions such as fear and joy. During their experiments, the British scientists scanned the brains of 40 volunteers and correlated their findings with the number of friends they have. What they found is that people with a high number of friends also tend to have a larger brain area called the orbital prefrontal cortex. It was already known that the prefrontal cortex is important for complex cognitive and social behaviour, as well as creating a personality for yourself.

Mentalising
Scans showed that volunteers with more friends and a larger orbital prefrontal cortex were better at 'mentalising' certain tasks. That basically means they were able to understand how other people feel. Normally, human beings can only keep track of the mental states of five people. Understanding how others feel is important for making and keeping friends, and their experiments show why brain size and number of friendships are correlated to each other. And friendship is more than just that when it comes to brain involvement. We need to be able to distinguish between friends and people we just know exist, calling for a complex set of brain qualities that are fairly unique to humans.

Evolution
Not only does this study tell us something about how our brain turns us into the social beings that we are, but it also gives us a trace of our evolution. We know that somewhere during the evolutionary process, life became more complex with increased social interactions. Humans are not the only social beings: other animals with highly evolved brains also show social behaviour. However, we appear to be the most advanced of all animals, and evolution of the prefrontal cortex, the most frontal part of the brain, may explain how that happened over the course of millions of years. A previous study revealed how our brains developed during more recent evolution, by analysing the shape of skulls.

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