导读:最近的一项研究表明，男性和女性在20岁出头时交友广泛，在25岁后，人们所拥有的朋友的数量急速下降。
Story highlights
新闻概要
Men and women are socially promiscuous in their early 20s, according to a recent study
最近的一项研究表明，男性和女性在20岁出头时交友广泛
After the age of 25, the number of friends people have falls rapidly
在25岁后，人们所拥有的朋友的数量急速下降
Women lose friends at faster rates than men
女性失去朋友的速度比男士更快
Are you younger than 25 years old? You may want to appreciate this moment in life when your social circle is at its greatest. If you’re older, you may relate to what you read next.
你现在不到25岁吗？你可能会想感谢生命中这个时刻，你的社交圈是最棒的。如果你年纪再大点，你可能会接触到你接下来读到的情况了。
Soon after your mid-20s, your social circle shrinks, according to a recent study by scientists from Aalto University in Finland and the University of Oxford in England.
根据来自芬兰阿尔托大学和英国牛津大学科学家的最新研究成果，20来岁后不久，你的社交圈会开始缩小。
The teams analyzed data from 3 million mobile phone users to identify the frequency and patterns of whom they contacted and when, as well as overall activity within their networks.
团队分析了来自300万个手机用户的数据，判定他们联系的频率和模式，以及在他们在网络上的整体活跃度。
Men and women were found to be socially promiscuous -- making more and more friends and social contacts -- until the age of 25, after which point they started losing them rapidly, with women losing them at an initially faster rate than men. The average 25-year-old woman contacts about 17.5 people per month, while a man contacts 19 people.
男性和女性在25岁之前不断交友，社交联系频繁，处于泛交状态。之后他们开始快速失去朋友，最初女性失去朋友的速度快于男性。25岁的女性每月联系17.5个人，而25岁的男性每月联系19个人。
No, Facebook friends don’t count.
不，脸书上的朋友不计入其中。
This decline continues for the rest of your life, or at least until retirement, where it plateaus, probably due to reduced data among this age group.
在余生中，朋友的数量会继续下降，至少退休之前是这样的。数据突然停滞的原因，也许是在这个年龄群体中可采集的数据减少。
Why does it happen? It comes down to investments.
为什么会发生？归根结底是投资问题。
What’s it worth?
什么是值得的？
The theory is that around this age, people begin to decide who is most important -- and valuable -- in their life and make a greater effort to hold on to those friends.
关于这个年纪的理论表明，人们开始决断在他们生命中谁是最重要的或者说是最有价值的，从而为了保住这些朋友作出更大的努力。
"People become more focused on certain relationships and maintain those relationships," said Kunal Bhattacharya, a postdoctoral researcher at Aalto University who co-authored the study. "You have new family contacts developing, but your casual circle shrinks."
阿尔托大学博士后Kunal Bhattacharya共同主导了这项研究，他说“人们更在在意某些关系并努力去维持这些关系，你建立了新的家庭联系，但是你的日常生活圈缩小了。”
This applies to both partners and friends, and it stems largely from people wanting to settle down and raise a family.
这同时适用于伴侣和朋友，主要源于人们想安定下来建立家庭。
"At the beginning of this age range, women are more focused," Bhattacharya said, meaning women are more intent on finding the correct partner. once they believe they have, they invest more time in nurturing that relationship and lose others of less value.
Bhattacharya说“在这个年龄段初期，女性更加注重这点。”这意味着女性更加想要找到合适的伴侣。一旦她们认为自己拥有了，就会投入更多的时间去培养这段关系，失去一些其他没那么有价值的人。
"once you’ve made decisions and found the appropriate people, you can be much less socially promiscuous and invest your time in these people," added Robin Dunbar, a professor of evolutionary psychology at the University of Oxford who co-authored the paper. "But they can’t be just anybody," he added.
该论文的共同作者Robin Dunbar，也是牛津大学进化心理学教授补充道，“一旦你做出了决定并找到了合适的人，社交会更慎重，把时间投入到选择的人身上，而不是随意的任何人。”
Narrowing down the people you’re close to includes friendships as well as life partners, particularly for women, due to the support and help they can provide in times of need.
缩小亲近的朋友和人生伴侣的圈子，尤其是对女性来说，主要是由于他们在需要的时候可以提供的支持和帮助有限。
"Women have this idea of a best friend, who is similar to a romantic partner ... and women work hard at these relationships," Dunbar said. "Particularly with friendships, if you don’t invest in them or see those friends, they will decay and quite rapidly drop."
Dunbar认为“女性对最好的朋友的定义，几乎是一个浪漫的伴侣。女性对这些关系付出巨大的努力。特别在友谊方面，如果不花时间维持关系或去见见这些朋友，关系就会变淡并很快失去。”
Middle-age reversal
中年逆转
Trends were seen to change slightly in people’s late 30s: Men begin losing buddies at a faster rate. "You get a secondary switchover later in life," said Dunbar.
在人们30岁以后，趋势看起来有轻微的改变：男性开始以更快的速度失去伙伴。Dunbar说，“在以后的生活中发生第二次的转变。”
By the age of 39, the average man was contacting 12 people, while women were calling 15 people each month.
到39岁时，男性平均每月联系12个人，而女性每月联系15个人。
Others argued that had the teachers at the schools in China had guns, the children might have been protected. Or if more people at the Orlando nightclub had guns, fewer than 49 people might have died.
还有人认为，如果中国学校里的老师有枪，那么孩子们可能会受到保护。或者如果在奥兰多酒吧里有更多的人有枪，可能死亡人数会少于49人。
Initial numbers of contacts during younger years are higher for men, but by these later years, they soon drop contacts faster than women, and their totals become lower.
最初更年轻的时候男性月平均联系人数更高，但是在之后的这些年，与女性相比，男性更快的与朋友失去联系，直到每个月的联系人数反而少于女性。
"You see this [reduction] in them about seven years later," Dunbar said. "It’s the women who make up their mind very early on."
“从7年后他们的下降趋势来看，” Dunbar说，“女性很早就做出了决定。”
The grandmother effect
祖母效应
Though the team emphasized that the rapid loss of friends happens in both men and women, experts generally consider this formation of an "inner circle" to be more important to women, mainly due to them having children.
尽管团队强调朋友的快速流失同时发生在男性和女性身上，专家通常认为这种“核心圈”的模式因孩子的缘故对女性来说更重要。
"You make the effort in return for some benefits," said Dunbar, who believes that at this point, people will prioritize those who are more useful to them.
“你会为了某些回报而做出努力” Dunbar说，他相信人们会优先对待对他们更有用的人。
"That investment will help certain aspects of your life," Bhattacharya added.
“这些投资会对你生活的某些部分有所帮助，” Bhattacharya补充道。
At this point, contacts such as mothers, mothers-in-law, close friends and family come into play as they help people raise their children, known as the grandmother effect.
此时，联系母亲、伴侣的母亲、亲近的朋友和家人可以在帮助人们养孩子上发挥作用，被称为祖母效应。
"It’s the ’tend and befriend’ idea, meaning relationships become more important when you have children," said Michael Price, director of the Center for Culture and Evolution at Brunel University London who was not involved in the study. "You’re now investing in offspring for the rest of your lives."
“这种‘照料与结盟’理念，意味着当你有孩子以后关系会变得更加重要，” 并未参与这项研究的英国布鲁内尔大学文化演变中心主任Michael Price说道，“你正在为你以后的生活投资后代。”
In an evolutionary aspect, such such networks are believed to help women raise children.
从进化的角度来看，这样的网络被认为会帮助女性养育后代。
Price believes that men instead value more individualistic criteria, such as their achievements or status, once they have a family. "It’s well established that close, personal relationships are more highly valued by women in general, while men value status more," he said.
Price认为一旦男性拥有家庭后，会更加重视个体标准，如他们的成就或地位。他说道，“经证实，通常来说女性更重视亲密私人的关系，而男性更重视社会地位。”
Though the study was an opportunity to analyze a large data set across many age groups within a population, Price noted that it did not reveal much about the quality of the relationships being counted or what people were actually talking about. "The quantity doesn’t reveal the quality of the relationships," he said.
尽管这项研究通过年龄对人群进行划分并分析了大量数据，Price强调其并没揭示统计关系的质量或者人们实际上所谈论的内容。他说，“数量并没有展现出关系的质量。”
Is the future online?
未来会是线上的吗？
For many years, social networks have been raising people’s "friend" count, making millennials believe they have hundreds or even thousands of friends. But even with these added means of communication, experts believe the time taken to invest in a true close-knit friendship will continue to keep the trend going. Although it may become more international, the value of face-to-face friendship may never change.
多年来，社交网络增加了人们朋友的数量，使得千禧一代（1984-1995年出生）自认为他们有成百上千的朋友。但即使是这些通讯手段增加，专家认为投入在真实亲密的友谊上的时间将使这个趋势持续下去。尽管通讯可能变得越来越国际化，面对面的友谊从未改变。
"Our natural psychology is small, very small, like a village," Dunbar said. "The internet may allow you to keep relationships going over a much wider geographical area, but [for now], a shoulder 2,000 miles away isn’t as good to cry on.
“我们自然的心理很小，非常小，像个小村庄，” Dunbar说，“网络能让你跨越一个非常大的地域范围保持一段关系，但至今为止，千里之外的肩膀并不能让你在哭泣时依靠。”
