notes
weak ties as social glue
14 october 2003
Trying to find uniform ways to characterize a social group at a small scale and at a large scale is somewhat akin to trying to reconcile quantum mechanics with cosmology. At the small group level, it is an individual's strong ties with other individuals which characterize the group. This is perhaps what Wellman and Frank suggest with the phrase, networked individualism. However, in looking at large groups, weak ties exert a much stronger influence, as suggested by Granovetter. For example, we tend to think that because we select all our friends by choice, we must also transitively reason that our friends select their friends by choice, and so on. That means our friends-of-friends network should have a fantastically wide range. However, as Newman shows in "Ego-centered networks and the ripple effect," these extended networks are smaller than expected. Why?
Newman does not directly answer this question, only suggesting that it is a mathematical characteristic of the network structure. He exhibits mathematical formulae to calculate the range of a person's friends-of-friends network by factoring in overlap between different circles of friends. Granovetter's account of weak ties offers a perfect explanation. The reason why there is overlap, is because our seemingly 100% free-willed choices of friends is actually subtly influenced by a preference for weak, but common characteristics. These characteristics are not so dominating as to make us feel we can't just pick whoever we want and work at the friendship. But consider a friend of a friend. You cannot explicitly pick that person to be a friend of a friend. However, the same weak tie that enabled your relationship with your friend can influence the choice of friend of a friend. Hence, strong ties only influence your immediate friends, but weak ties can travel many links away from you.
So it is the commonality of these weak ties that creates the overlap of friends and accounts for the narrower than expected range of your friends-of-friends network. The influence of weak ties does diminish as the number of friend-of-a-friend links are included into a circle. Because the tie is "weak," it is still plausible that a friend of a friend will completely escape the social group you belong to, and hence, you've connected to a whole new group where a different set of weak ties are at play.