你的社交有上限

If you’ve ever been romantically rejected by someone who just wanted to be friends, you may have delivered a version of this line: “I’ve got enough friends already.” Your implication, of course, being that people only have enough emotional bandwidth for a certain number of buddies.

如果你曾经被委婉地拒绝了，人家只想和你交朋友，你可能会这样说：“我已经有足够多的朋友了。”当然，你的意思是人们的感情只够应付一定数量的朋友。

It turns out that’s not just an excuse. There are well-defined limits to the number of friends and acquaintances the average person can retain. 

事实证明，这不仅仅是一个借口。普通人能维持的朋友和熟人的数量的确有明确的限制。

But the question about whether these limits are the same in today’s digital world – one in which it’s common to have social media profiles, or online forums, with thousands of followers – is more complicated.

但是当今的数字世界里，在社交媒体或在线论坛拥有成千上万粉丝的账号很常见。这种情况下这些限制是否还成立成为了一个更复杂的问题。

According to British anthropologist Robin Dunbar, the “magic number” is 150. Dunbar became convinced that there was a ratio between brain sizes and group sizes through his studies of non-human primates.

据英国人类学家罗宾·邓巴说，这个“神奇数值”是150。通过对非人灵长类动物的研究，邓巴坚信在大脑大小和群体规模之间存在一个比例。

This ratio was mapped out using neuroimaging and observation of time spent on grooming, an important social behaviour of primates.

这一比例是他通过神经成像和观察灵长类动物在梳毛（一种重要的社交行为）上所花费的时间测算出的。

Dunbar concluded that the size, relative to the body, of the neocortex – the part of the brain associated with cognition and language – is linked to the size of a cohesive social group. This ratio limits how much complexity a social system can handle.

新大脑皮层是大脑中与认知和语言相关的一部分。邓巴得出结论，新大脑皮层的尺寸与身体的比例与一个有凝聚力的社会群体的大小有关。这个比例限制了一个社会系统的复杂度。

Dunbar and his colleagues applied this basic principle to humans, examining historical, anthropological and contemporary psychological data about group sizes, including how big groups get before they split off or collapse. They found remarkable consistency around the number 150.

邓巴和他的同事把这个基本原理应用到人类身上，研究了关于群体大小的历史、人类学和当代心理学数据，包括群体在分裂或瓦解前能有多大。他们发现这个数字都不可思议的在150左右。

According to Dunbar and many researchers he influenced, this  rule of 150 remains true for early hunter-gatherer societies as well as a surprising array of modern groupings：offices,communes, factories, residential campsites, military organisations, 11th Century English villages, even Christmas card lists.

150人法则不仅适用于早期原始社会，也符合现代数量惊人的社会群体：办公室、公社、工厂、宿营地、军事组织、11世纪的英国乡村，甚至圣诞节贺卡清单，据邓巴以及受其影响的研究人员的说法。

Exceed 150, and a network is unlikely to last long or cohere well. But 150 alone doesn’t tell the whole story.

超过150人的交际网不容易长久或者稳定联结。但是，仅仅150人也不足以说明全部事实。

Other numbers are nested within the social brain hypothesis too. According to the theory, the tightest circle has just five people – loved ones. That’s followed by successive layers of 15 (good friends), 50 (friends), 150 (meaningful contacts), 500 (acquaintances) and 1500 (people you can recognise). People migrate in and out of these layers, but the idea is that space has to be carved out for any new entrants.

其他数字也是在社会脑假设（Brothers.L于1990年提出的一种脑认知进化理论）之中，根据这个理论，最紧凑的社交圈只有五个人，也就是你爱的那些人。随后的层次分别是15人（挚友）、50人（朋友）、150人（有意义的联系）、500人（点头之交）以及1500人（你能认出的人）。人们在这些不同的层次中进出转移，但它的理念是社交空间必须为新入者腾出位置。

Dunbar isn’t sure why these layers of numbers are all multiples of five, but says, “this number five does seem to be fundamental to monkeys and apes in general”.

Dunbar不确定为什么这些层次的人数都是5的倍数，但他说道“大体来说，数字5似乎对于猴和类人猿来说是很基础的。”

Of course, all of these numbers really represent range. Extroverts tend to have a larger network and spread themselves more thinly across their friends, while introverts concentrate on a smaller pool of “thick” contacts. And women generally have slightly more contacts within the closest layers.

当然，以上这些数据仅代表着我们的社交范围。性格外向的人往往拥有更大的人际关系网，放在朋友身上的精力也会更加分散。而性格内向的人则专注于较小的“亲密”圈。而且通常女性最亲密层次的联系人比男性多。

Certain organisations have taken these ideas to heart. The Swedish Tax Authority, for instance, has restructured their offices to stay within the 150-person threshold.

某些组织已经接受了这些理念。例如，瑞典税务局已对其办事处进行了（人员）重组，以保持在150人的范围内。

Not everyone subscribes to the social brain hypothesis. Some are sceptical about the possibility of deriving a magic number for social interaction at all. Still, it can be a useful exercise for thinking through communities and evolution.

并非所有人都赞同社交脑假说。有些人质疑根本不可能得出这一神奇数字。尽管如此，这一数字还是能被看作的一次有用的实践，我们能以此来完全理解社群和进化。

Among those who agree that a Dunbar-ian number can be found, some contest whether it’s 150. Research on varied social groups in the US suggests that their social networks cluster around 290 in size. And these numbers may be significantly skewed by outliers.

在那些认为邓巴数字存在的人之中，有人质疑这个数字是否为150。在美国针对不同社会群体的研究表明，他们的社交关系网的大小集中在290人左右。并且，这些数字可能极大地被离群索居者拉低了。

One argument is that the number of social connections isn’t normally distributed (or shaped like a bell curve), so a few people with massive numbers of contacts may be throwing off the average.

有一种论点认为社会关系的数量并不是正态分布的（或者说不是呈钟形曲线分布的），所以一些社交广泛的人可能会超过平均水平。

More and more people are preaching the gospel of small being better when it comes to online social life. Scale may be one of the issues with the massive social networking sites that now dominate our lives. 

当谈到网络社交生活时，越来越多的人在宣传小社交圈更好的道理。规模可能是目前占据人们生活的社交网站的问题之一。

Thus far, the research of Dunbar and colleagues on online relationships suggests that these are similar to offline relationships in terms of numerical restrictions.

到目前为止，Dunbar和他的同事关于网络关系的研究表明，线上人际关系与线下人际关系相似。

Dunbar and colleagues also have performed research on Facebook, using factors like the number of groups in common and private messages sent to map the number of ties against the strength of those ties.

Dunbar及其同事还在Facebook上进行了研究，利用发送的普通消息和私人消息中的群组数量等因素，根据关系的强度映射出关系的数量。

When people have more than 150 friends on Facebook or 150 followers on Twitter, Dunbar argues, these represent the normal outer layers of contacts (or the low-stakes connections): the 500 and 1500. For most people, intimacy may just not be possible beyond 150 connections.

Dunbar认为，当人们在Facebook上有超过150个好友或在推特上有超过150个关注者时，这代表了正常的外层联系数（或者说低风险的联系）：500和1500。对大多数人来说，超过150的联系范围之后，亲密关系便不可能存在。

“These digital media – and I’m including telephones in there – are really just providing you with another mechanism for contacting friends,” Dunbar says.

Dunbar说：“这些数字媒体(也包括电话)真的只是向你提供了另一种和朋友联络的机制。”

Even the possibility of anonymity online doesn’t seem to Dunbar to be substantially different to the offline world. He compares anonymous internet interactions to the use of confessionals in the Catholic church.

即使对于Dunbar来说，网络匿名的可能性也不会本质上不同于现实世界。他将匿名的网络互动比作天主教教堂忏悔室里的忏悔。

It isn’t a close relationship, but it is one that recognises the benefits of confidentiality among quasi-strangers.

它不是亲密关系，反而它认可对陌生人保密信息有益处。

“It’s extremely hard to cry on a virtual shoulder,” Dunbar deadpans. “Having a conversation isn’t like a lighthouse; it is not just blinking away out there and maybe someone is listening, and maybe somebody is not.”

Dunbar不带感情严肃地说 ：“在一个虚拟肩膀上哭泣太难了。与人交流并不像灯塔——它的光可以直接照亮那个地方而你在说话时有人可能在听也可能没有。”

In this view, the non-physical, non-real-time nature of internet relationships means that they can’t challenge “real-world” ones in meaningful ways. Face-to-face relationships, with all the non-verbal information that is so critical to communication, remain paramount.

这样看来，网络社交的虚拟特性意味着它无法从真正意义上威胁到现实社交。面对面社交，涵盖了除语言表达之外的一切信息，这些信息对社交的重大影响，终究无法被超越。

But Dunbar’s own research suggests generational differences in this regard. Those aged 18–24 have much larger online social networks than those aged 55 and above.

但Dunbar的研究提出了年龄差的问题，18～24岁的青年与55岁及以上的中老年人相比，有着远超后者的庞大社交网络.

And the primacy of physical contact in the social brain hypothesis may apply less to young people who have never known life without the internet, for whom digital relationships may be just as meaningful as analogue ones.

在社交大脑假说中，身体接触的重要性可能并不适用于从未离开过互联网的年轻人们，因为对他们来说，数字关系与模拟关系的意义可能是相同的。

It makes sense that there’s a finite number of friends most individuals can have. What’s less clear is whether that capacity is being expanded, or contracted, by the ever-shifting ways people interact online.

大部分人能够拥有的朋友数量有限，这是情理之中的事。目前尚未可知的是，随着人们的线上互动方式不断变化，这个数量是会扩大还是减少。

新闻来源：https://www.bbc.com/future/article/20191001-dunbars-number-why-we-can-only-maintain-150-relationships