Oxford University researchers found maintaining friendships requires more brain power. Their study concluded that people with real friends have to use more cognitive skills to understand what someone else thought。
Scientists discovered a link between the number of friends people had and the size of their orbital prefrontal cortex, which is a region of the brain found just above the eyes。
The conclusions, published in the journal Proceedings of the Royal Society B, shows for the first time that competency in social skills is determined by the size of peoples' brains。 英国《皇家学会生物学分会学报》刊登了这一结果，这一研究也是首次指出社交技能是由人们的大脑大小所决定的。
"We found that individuals who had more friends did better on mentalising tasks and had more neural volume in the orbital frontal cortex, the part of the forebrain immediately above the eyes," said Prof Robin Dunbar, who led the study。
"Understanding this link between an individual's brain size and the number of friends they have helps us understand the mechanisms that have led to humans developing bigger brains than other primate species."
"The frontal lobes of the brain, in particular, have enlarged dramatically in humans over the last half million years."He added: "Of course, the amount of spare time for socialising, geography, personality and gender all influence friendship size, but we also know that at least some of these factors, notably gender, also correlate with mentalising skills."
"脑部的前额叶部分，特别是在过去的50年里有着显著增大。" 他还补充道："当然，参与社交活动的闲暇时间、地域、个性和性别都影响朋友数量，但我们也知道，其中有部分因素， 尤其是性别，与心智化能力相互影响。"
"Our study finds there is a link between the ability to read how other people think and social network size."
Tests were conducted on 40 people, with scientists taking anatomical Mr images of their brains to measure the size of their prefrontal cortex, which is used for high-level thinking. They were all volunteer postgraduate students of "broadly similar ages with potentially similar opportunities for social activities"。
Participants were asked to make a list of people they had social – rather than professional – contact with over a seven day period. They also took a test to determine how competent they were at 'mentalising', which is the capacity to understand what another person is thinking, a crucial aspect in how people handle the social world。
Dr Joanne Powell, from the University of Liverpool, added: "Perhaps the most important finding of our study is that we have been able to show that the relationship between brain size and social network size is mediated by mentalising skills. What this tells us is that the size of your brain determines your social skills, and it is these that allow you have many friends."