The internet has created the illusion of mass intimacy but how many Facebook friends is too many?
The asnwer, says Robin Dunar, is 151

It’s the internet world now, so you can speak to anyone anywhere in the world – right? Blog away, and every Tom, Dick and Harriet from Anchorage to Cape Town can admire your wit, marvel at your wisdom and might even offer a comment in return. Sign them up to your Facebook site, where you can now boast 300,500,1000 friends.

But how well do you really know all these peopl? Would you really respond with a cheque for £50 to an em-ail plea from one of them? OK, OK, I know a suprising number of people get hoodwinkey by 15-year old Nigerian spammers on a franky old village internet connection, but I’ll warrent that most of you aren’t so gullitile – and it’s precisely because you don’t treat everyone on your Facebook list as equally worthy of interest.

The bottom line is that our social worlds are actually very small. It’s easy to add friends to your social network site (or SNS in the trade) but it’s another thing whether you’d really lay down your life for all of them. The reason is simple: our brains aren’t big enough to allow us to have deeply meaningful relationships with more than a handful of people. There is a general relationship between brain size and social group size in monkeys and apes, and that relationship predicts a natural group size of just 150 for us human beings, now known as Dunbar’s number (thanks to some anonymous internet wit).

In fact, 150 – give or take a few – turns up in all sorts of obscure and not so obscure places. It was the average size of villages in the Domesday Book and 18th-century England, as well as in traditional small-scale societies today. It’s the average size of parishes among community-focused sects such as the Amish and the Hutterites, and the typical size of companies in most armies around the world.
When Brigham Young sent his fledgeling 5,000 Mormons of f to found Salt Lake City and the Mormon state, he did so in groups of 150.

It’s the average number of people to whom most of you send Christmas cards – not the number of cards, but the number of people in the households to which you send your cards. It’s the number of relations, friends and aquaintances you think enough of to be worth the time, effor and expense of writing out a card.

Dunbar’s number seems to demarcate a clear boundary between those with whom you have relationships of trust, obligation and reciprocity and those you don’t.
Beyond lie the many people whom you recognise by sight, might even be happy to have a passing conversation with, but whom you really wouldn’t count among your personal friends.
We are able to remember the names and faces of many of these “outsiders”, but we don’t have significant past histories with them.

But even within the hallowed circle, all is not equal. In fact, your social world consists of a series of circles of friendship, running from an inner core of about five intimates, through a series of layers of increasing size but declining intimacy until we arrive at the cliff edge at 150.

One slightly curious feature of this social world is the extent to which we people it preferentially with kin. Kinship, it seems, still has a singularly strong hold over us. We have examined large numbers of personal social networks – all laboriously and generously listed by long-suffering subjects in our studies – and there is a very striking tendecy for the number of friends to be inversely related to the number of kin included. Especially so from those who come from very large extended families, who as a result have fewer friends.
And kin are interesting for another reason if we don’t actively keep up our friendships, they gradually but inexorably slide down through the layers until eventually they will drop off the edge of the 150. But not so kin.
Not only are we stuck with them from birth (or marriage), but we can ignore them and abuse them and they will still come to our aid in a way that no similarly abused friend would ever do.

But for the rest, it is the opportunities that we have to interact that lie at the core of building relationships. We have to work at it in ways that only seem to work well if we do it face-to-face. There is no substitute, it seems, for doing stuff together if you really want to get to know someone to the point where you have a reciprocal level of intimacy, trust and obligation. It’s got something to do with triggering deeply buried emotional responses that need to be physically triggered by touch, smell and sight.

And this is where the virtual world of the internet lets us down. Yes, we can list 1,000 names on our social network site, but names is precisely all they are unless we have first grappled with them in the flesh.
The bottom line is that a touch is worth a thousand words. In real life, we gain signals about an individual’s true feelings and honesty from a touch taht we simply cannot replicate virtually on the internet.

And that’s why it is easy to be deceived by that terribly nice young man in Nigeria. In real life, ever senistive to subtle hard-to-disguise signals of the underlying intentions, we would never fall for this so quickly. It’s the way someone smiles at you that we notice, not just the fact that he smiled.

For those who don’t fall prey to scammers, our internet world is not that different from our everyday life. Most of the traffic on a website, or the texts that stream out of the mobile phones of our children, are directed at small numbers of individuals. And when we hit the keyboard on our own SNS, we seem to assume we are speaking directly to that handful of intimates.
We think we are engaged in one of those intimate late-night conversations. But on social network sites many other are peering in. It’s another version of those infuriatingly public mobile phone calls on trains.

For some, that’s the whole point: for them, a blog or an SNS is just a lighthouse beaming out its message to the anonymous world, a form of exhibitionism that offers its own pleasures. But the lesson that the world is full of voyeurs whom you don’t necessarily want to see the photos of your drunken behaviour in Ibiza takes time to learn. That’s why, in the end, SNSs have introduced options for censoring who has access to what parts of your life.

In real life, our social network consists of semi-isolated sets of people – family, work friends, the group with whom we play football at the weekend, the painting class we attend on Tuesdays and sometimes go on outings with. Most of us maintain different personas for each of these worlds, for they are just sufficiently isolated from each other to allow us to do that. The internet has cut a swath right through taht. Everyone from Granny to the stranger with whom we carelessly swapped addresses at that party now see the same “us” whether we like it or not. Defriending has become a necessary part of the SNS toolkit.

The internet has had another unexpecteed effect. Those indefinably special friendships of the late teens adn early twenties reappear casually on Friends Reunited. Forged in the white-hot heat of the emotionally most turbulent period of our lives, there is something deeply enduring about these relationships. Not a few old flames have been rekindled, sometimes fatally disturbing current relationships.

This is a reminder that some deepy meaningful relationships can remain half-buried in our minds, for ever occupying slots in a way that prevents later friends reaching those coveted innermost five positions of greatest intimacy. More evidence, perhaps, that our social world is limited by our capacity to manage relationships.