If your social life leaves something to be desired, it might be your brain structure that’s to blame.

　　A ‘Facebook feature’ deep in the temporal lobe governs the number of friends you are likely to make, scientists have found.

　　The amygdala, a small almond-shaped structure, has for some time been linked to empathy and fear responses.

　　But a study suggests that the larger the amygdala, the wider and more complex is its owner’s network of friends and colleagues.

　　Volunteers aged between 19 to 83 were asked to complete questionnaires which measured how many regular social contacts they had, and in how many different groups.

　　Magnetic resonance imaging scans found a positive link between big amygdalas and the richest social lives. Professor Lisa Barrett, a psychologist at Northeastern University in Boston, Massachusetts, reported the findings in the journal Nature Neuroscience.

　　She said they were consistent with the social brain theory, which suggests the human amygdala evolved to deal with an increasingly complex social world.

　　Other studies of primates have shown that those living in larger groups tend to have larger amygdalas. The findings was published in a new study in Nature Neuroscience.

　　Dr Lisa Barrett, Professor of Psychology at Northeastern University, who took part in the research, said the amygdala got bigger to cope with mankind's more hectic social life.

　　She added: 'Further research is in progress to try to understand more about how the amygdala and other brain regions are involved in social behaviour in humans.'

　　Her colleague Dr Bradford Dickerson, an associate Professor of Neurology at Harvard Medical School said: 'This link between amygdala size and social network size and complexity was observed for both older and younger individuals and for both men and women.'

　　Recently US scientists reported on the case of a woman whose amygdala had been destroyed by a medical condition.

　　As a result the 44-year-old mother of three felt no fear and constantly put herself in danger. Over the years she had been threatened with a knife, held at gunpoint and assaulted.

　　如果你的社交生活不盡人意，那可能得怪你的大腦結構。

　　科學家們發現，大腦顳葉深處的“交際特征”決定了你可能交到的朋友個數。

　　人們一度認為杏仁核與同理心和恐懼反應有關。杏仁核是大腦內一個小的杏仁狀組織。

　　但是一項研究顯示，一個人的杏仁核越大，他的朋友圈和同事圈就越大越復雜。

　　參與該研究的志愿者年齡介于19歲到83歲之間，研究者請他們填寫調查問卷，以得出他們經常聯系的朋友個數以及有多少種不同類別的朋友。

　　磁共振成像掃描顯示，杏仁核的大小與社交生活的豐富程度成正比。美國東北大學的心理學家麗莎•貝瑞特教授在《自然神經科學》雜志上發表了以上調查結果。東北大學位于馬薩諸塞州波士頓市。

　　貝瑞特教授說調查結果與社會腦理論相符，該理論認為人類杏仁核的進化是為了應對愈來愈復雜的社交世界。

　　其他對靈長類動物的研究發現，群居動物的杏仁核要更大一些。這些研究成果發表在《自然神經科學》的一項新研究報告中。

　　東北大學的心理學教授麗莎•貝瑞特博士參與了這項課題，她說人類的杏仁核變大是為了應付日益繁忙的社交生活。

　　她接著說：“我們目前正在進行更深層次的研究，來進一步了解杏仁核和其他腦部區域如何影響人類的社會行為。”

　　她的同事布拉德福德•狄克生博士說：“我們觀察了人們的杏仁核大小與社交圈大小和復雜程度之間的關系。我們的觀察對象有老有少，有男有女。”狄克生博士是哈佛大學醫學院的神經病學副教授。

　　美國科學家們觀察了一位因病導致杏仁核受損的婦女，最近他們就觀察結果作了報告。

　　報告顯示，這位已經是三個孩子母親的44歲的女人從來感覺不到恐懼，并經常將自己置于危險的境地。這些年來，她遭受過匕首威脅，被人拿槍指過頭，還曾經慘遭毆打。

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