MAS 961  ·  Techno-Identity  ·  Spring 2006

02.16 Social networks and the flow of information

The people you know are your social network. This personal network is embedded in a larger network, for you can follow the chain of connections from your friends, to their friends, to the friends of these friends of friends. We live in the age of global connectedness: with the exception of a few isolated tribes in the rainforests of New Guinea, the Amazon, and the Andaman Islands, everyone is connected to everyone else in a giant social network.

The structure of social networks has been the focus of much recent (and not so recent) research. How many hops does it take to get from one arbitrary person to another? (Milgram,Watts)? How does information and social support move through these networks and how do people understand and make use of them in everyday life (Wellman, Granovetter, Feld)? How do people communicate information about their network? And how do / should new technologies extend these connections?




Wellman, Barry and Milena Gulia The network basis of social support
Granovetter, Mark The Strength of Weak Ties
Feld, Scott The Focused Organization of Social Ties
Donath, Judith and danah boyd    Public displays of connection
Judith Kleinfeld   Could it be a big world

Duncan J. Watts, Peter Sheridan Dodds, M. E. J. Newman


Identity and Search in Social Networks

Identity and Search in Social Networks (for non-subscribers)



  I. A future of many weak ties.

In the last few years, numerous social networking sites have been built (friendster, linkedIn, Facebook, MySpace, etc. etc), some of which have become extremely popular. The premise of many of these sites is that the more connections you have and can show, the better.

Yet real world social networks have real costs. Maintaining a somewhat deeper connection with another person requires spending the time with them, and being responsible for them in some fashion, whether just to be an available ear or to truly take care of them in a time of need. A big question about social netowrking technology is whether it functions mainly to substitute numerous shallow and weak ties for fewer but deeper ones. If you are not familiar with any such sites please spend some time looking at a few of them (e.g. LinkedIn, MySpace, etc.)

The Wellman and Giulia paper talks about the social support people get from networks. Granovetter talks about the value of heterogeneous networks. Feld discusses how people balance creating larger circles of friends with the limits of their time and attention. The Donath and boyd paper examines the function of social network displays. Please read these papers and answer about the following questions:

  • How do people display social networks in everyday life (that is, not online)? Give 2 concrete, specific examples. Why do they do this? Looking at this display as a signal, what is the quality it is inferring?  What are the costs of making this signal? The benefits? Is there a cost to the receiver if it is not honest?
  • Identity in the real world is faceted: different aspects of our personality are expressed in different circumstances and around different people. For some of us, these differences are relatively minor, and bringing together people from different areas of our lives is not a problem. For others of us, these different facets are incompatible, and bringing them together is undesireable. How is this addressed in the design of today's SNSs? How might future designs address this?
  • Describe or sketch part of a social network known to you (e.g. your friends, family, acquaintances in classes, etc. - feel free to use pseudonyms or describe a network from your past, such as high school, for privacy). Networking sites use unnuanced and symmetrical links - in your description, what more nuanced description of these links would you include? For instance, there are different types of relationships - parent-child, friend-friend - and different strengths, and different flows of support and information. What of these more nuanced descriptions could be used in a publicly articulated space, and which could not?
  • Feld proposes that people have particular interests, common friends and pursuits, etc. that function as "foci" - and that connections are made when people with common foci are brought together. Some foci are highly constraining (such as being in the same family or research group) while others are lightly constraining (sharing a neighborhood or a popular taste) . Re-examine the social network you described. Can you apply this model to explain some of the groupings?
  • What are the benefits of making it more costly to add links in a social networking site?

II. The Small World Problem.

In 1966 Stanley Milgram, subsequently to become famous for his experiments showing that people are willing, under very little pressure, to inflict a great deal of harm to another person when told to do so by a person in authority, conducted an experiment of a more benign nature. He gave a set of letters to people in Kansas with instructions they be forwarded to a particular person near Boston, Mass., with the caveat that the letter should only be given, along with the same instructions, to a personal acquaintance, one who presumably was "closer" in some sense to the ultimate recipient. Although only a very small percentage of the chains were actually completed, and there is some question about the validity of the experiment, this project spawned the popular notion that people in the world are separated by at most 6 links, i.e. the six degrees of separation.

Since Milgram's time, communication technologies have seemingly reduced the distance between people even more. Email gives us an easy conduit to even the most passing acquaintance; Google provides us with an often surprising variety of information about anyone; social networking sites, themselves an homage to Milgram and the notion of a small, networked world, let us spend hours traversing chains of acquaintances. Duncan Watts and his colleagues

Read Judith Kleinberg's critique of the original experiment and Watt's et al's report on their more recent replication of it. Try finding someone in this experiment. Answer the following:

  • What is the significance of these experiments for understanding networks? Do Kleinberg's criticisms of the Milgram's work hold for Watts et al's work also? Why or why not? Why do you think they got better results for work based chains than acquaintance ones? What is the significance of the information people had about target?
  • Why is the network search question interesting (or not)? When would one really want to know who is 1, 2, 3 degrees away? What are the implications of public displays of connections for our ability to find these people? What are the benefits of making this display?

Please link your essays by Wednesday evening.