Sociology 204: Social Networks

• Angelina Grigoryeva (O: Wallace 225, OH: Th 1-2pm)
• Glenn Harrison (O: Wallace 121, OH: M 1:30-2:30pm)
• Mariana Campos Horta (O: Wallace 225, OH: Th 3:45-4:45pm)
• Patrick Ishizuka (O: Wallace 227, OH: Th 4-5pm)
• Sophia Li (O: Wallace 119, OH: W 1-2pm)

This course provides students an introduction to the study of social networks. We will focus on understanding the causes and consequences of the patterns of relationships between individuals. Topics will include the small-world puzzle (six degrees of separation), the strength of weak ties, and the spread of diseases and fads.

Student grades will be based on the following:

• In-class midterm exam: 25%

The midterm exam will take place on March 13, 2013 during the regular class time. If you have a conflict during this time, please read the change of exam time request policy.

• In-class final exam: 45%

  This in-class final exam will cover the material from the entire semester. The final exam will be on Friday, May 17 from 9am to noon in McCosh Hall 10. If you need to reschedule the exam time, please follow the standard university rescheduling policies for final exams.

• Homework/Precept: 30%

  Each precept session will have an assignment that will serve as the basis of the discussion. Some assignments will involve data collection and analysis, while others will involve writing. Hard copies of these assignments will be due in class each Wednesday. If you cannot be in class on Wednesday, you can email your assignment to the leader of your precept, but they must receive it by 10am on Wednesday. If you do not turn in your assignment on time, you can still turn it in at your precept for a reduced grade (20% penalty). After your precept, you will not be able to submit your assignment for a grade unless you have a letter from the Dean of your college.

Numeric grades will be converted to letter grades at the end of the semester based on a standard scale. Any requests for re-grades must comply with the re-grading policy. This course counts towards the requirements for the Certificate in Information Technology and Society.

There is one text for the class: Six Degrees: The Science of a Connected Age by Duncan Watts. Other readings are available on the web or from blackboard. To understand the flow of ideas, students should do the readings for each lecture in the order that they are listed on the syllabus.

In this course we will be using Piazza for online class discussion. You will not be required to post, but the system is designed to get you help quickly and efficiently from classmates, the preceptors, and the professor. Rather than emailing questions to the teaching staff, I encourage you to post your questions on Piazza. Find our class page at: https://piazza.com/princeton/spring2013/204/home.

A note on the use of open access scholarship: Because of the prohibitive cost of academic journals, many of assigned readings for this course are available only to people with access to a university library. I have marked these closed access articles with a . Fortunately, some of the more recent scholarship in this area is freely available to everyone in the world. I have marked these open access article with a . It is my hope that eventually I will be able to construct this syllabus using exclusively open access scholarship. In the meantime, copies of many of the closed access articles can be found through Google Scholar.

Course introduction (2/4/13)

• No reading assigned.

The connected age and the small world problem (2/6/13)

• Watts, Preface and Chapter 1.
• Milgram, S. (1967). The small world problem. Psychology Today, 1:62-67. (Available from Blackboard)
• Travers, J. and Milgram, S. (1969). An experimental study of the small world problem. Sociometry, 32(4):425-443.
• Kleinfeld, J.S. (2002). The small world problem. Society, 39(2):61-66. (Available from Blackboard)

There will be no precept during the first week of the course.

More on the small world problem and some history (2/11/13)

• Granovetter, M. (2003). Ignorance, knowledge, and outcomes in a small world. Science, 301:773-774.
• Dodds, P.S., Muhamad, R., and Watts, D.J. (2003). An experimental study of search in a global social networks. Science, 301:827-829.
• Watts, Chapter 2.
• Erdos-Reyni random graph animation by Uri Wilensky. (optional)

Understanding the small world phenomena (2/13/13)

• Watts, Chapter 3.
• Watts, D.J. and Strogatz, S.H. (1998). Collective dynamics of 'small-world' networks. Nature 393, 440-442.
• Watts, D.J. (1999). Networks, dynamics, and the small world phenomenon. American Journal of Sociology, 105(2):493-527.
• Watts-Strogatz small world model animation by Eytan Bakshy and Lada Adamic. (optional)

Assignment 1: Six degrees of Wikipedia

Degree distributions and power laws (2/18/13)

• Watts, Chapter 4, 101-114.
• Barabasi, A.L. and Bonabeau, E. (2003) Scale-free networks. Scientific American, 50-59. (Available from blackboard)
• Barabasi, A.L. and Albert, R. (1999) The emergence of scaling in random networks. Science, 286:509-512.
• Barabasi-Albert random graph animation by Eytan Bakshy and Lada Adamic. (optional)
• Liljeros, F. et al. (2001). The web of human sexual contacts. Nature, 411:907-908 with comment and rejoinder.

Foci (2/20/13)

• Gladwell, M. (1999). Six degrees of Lois Weisberg. The New Yorker.
• Watts, Chapter 4, 114-129.
• Feld, S.L. (1981) The focused organization of social ties. American Journal of Sociology, 86(5):1015-1035.

Assignment 2: Hubs and foci

Social search (2/25/13)

• Watts, Chapter 5.
• Lee, N.H. (1969). The Search for an Abortionist: Preface, Chapter 1, and Chapter 5. (Available from blackboard).

Spread of disease in networks (2/27/13)

• Watts, Chapter 6.
• Bearman, P.S., Moody, J.M., and Stovel, K. (2004). Chains of affection: The structure of adolescent romantic and sexual networks. American Journal of Sociology, 110(1):44-91.
• Helleringer S. and Kohler, H.P. (2007). Sexual network structure and the spread of HIV in Africa: evidence from Likoma Island, Malawi. AIDS 21:2323-2332 with comment and reply.

Assignment 3: Is it really a small world?

The madness of crowds (3/4/13)

• Watts, Chapter 7.
• Asch, S.E. (1955). Opinions and social pressure. Scientific American, 193(5):31-35. (Available on Blackboard)
• Easley D. and Kleinberg, J. (2010). Networks, Crowds, and Markets: Chapter 16.
• Tierney, J. (2007). Diet and fat: A severe case of mistaken consensus. New York Times.

Thresholds, cascades, and predictability (3/6/13)

• Gladwell, M. (1996). The tipping point. The New Yorker.
• Watts, Chapter 8.
• Granovetter, M. (1978). Threshold models of collective behavior. American Journal of Sociology, 83(6):1420-1433.
• Watts, D.J. (2002). A simple model of global cascades on random networks. PNAS, 99:5766-5771. (skim)

Assignment 4: Information cascades and mistaken consensus

Cascades and fads in cultural markets (3/11/13)

• Hedstrom, P. (2006). Experimental macro sociology: Predicting the next best seller. Science, 311:786-787.
• Salganik, M.J., Dodds, P.S., and Watts, D.J. (2006). Experimental study of inequality and unpredictability in an artificial cultural market. Science, 311:854-856.
• Salganik, M.J., and Watts, D.J. (2008). Leading the herd astray: Experimental study of self-fulfilling prophecies in an artificial cultural market. Social Psychology Quarterly, 71:338-355.

Midterm Exam (3/13/13)

• 50 minute in-class midterm exam.

There will be no precepts the week of the midterm. Have a great spring break.

Strength of weak ties (3/25/13)

• Granovetter, M. (1973). The strength of weak ties. American Journal of Sociology, 78(6), 1360-1380.

Weak ties and complex contagion (3/27/13)

• Centola, D. and Macy, M.W. (2007). Complex contagion and the weakness of long ties. American Journal of Sociology, 113(3):702-734.
• Centola, D. (2010). The spread of behavior in an online social network experiment. Science, 329(5996):1194-1197.

Assignment 5: Strength of weak ties on Facebook

Core discussion networks of Americans (4/1/13)

• Fountain, H. (2006). The lonely American just got a bit lonelier. The New York Times, July 2.
• McPherson, M., Smith-Lovin, L., and Brashears, M.E. (2006). Social isolation in America: Changes in core discussion networks over two decades. American Sociological Review, 71(3):353-375.
• Fischer, C. (2009). The 2004 GSS finding of shrunken social networks: An artifact? American Sociological Review, 74(4):657-669.
• McPherson, M., Smith-Lovin, L., and Brashears, M.E. (2009). Models and marginals: Using survey evidence to study social networks. American Sociological Review, 74(4):670-681.

Friends of friends (4/3/13)

• Strogatz, S. (2012). Friends you can count on. New York Times, September 17.
• Feld, S. (1981). Why your friends have more friends than you. American Journal of Sociology, 96(6):1464-1477.
• Christakis, N.A. (2010). How social networks predict epidemics. TED Talk.
• Christakis, N.A. and Fowler, J.H. (2010). Social network sensors for early detection of contagious outbreaks. PLoS ONE 5(9):e12948.

Assignment 6: Core discussion networks of Princeton students using this questionnaire

Know your epidemic: Networks, sampling, and the sizes of the groups most at-risk for HIV/AIDS (4/8/13)

• Bernard, H.R. et al. (2010). Counting hard-to-count populations: The network scale-up method for public health. Sexually Transmitted Infections, 86:ii11-ii15.
• Salganik, M.J. et al. (2011). Assessing network scale-up estimates for groups most at risk of HIV/AIDS: Evidence From a multiple-method study of heavy drug users in Curitiba, Brazil. American Journal of Epidemiology, 174(10):1190-1196.

Know your epidemic: Networks, sampling, and the characteristics of the groups most at-risk for HIV/AIDS (4/10/13)

• Salganik, M.J. and Heckathorn, D.D. (2004). Sampling and estimation in hidden populations using respondent-driven sampling. Sociological Methodology, 34:193-239. (skim)
• Salganik, M.J. (2012). Commentary: Respondent-driven sampling in the real world. Epidemiology 23(1):148-150.
• McCresh et al. (2012). Evaluating respondent-driven sampling. Epidemiology 23(1):138-147.

Assignment 7: Network scale-up study of Princeton students using this questionnaire

Digital traces of communication (4/15/13) [To be changed because of a special guest lecture by Jake Hofman]

• Wikipedia page on sensitivity and specificity.
• Wuchty, S. (2009). What is a social tie? PNAS, 106(36):15099-15100.
• Eagle, N., Pentland, A., and Lazer, D. (2009). Inferring social network structure using mobile phone data. PNAS, 106(36):15274-15278 with comment and reply.
• Jones, J.J., et al. (2013). Inferring tie strength from online directed behavior. PLOS One, 8(1):e521168. (Note: When reading this paper, please read the Materials and Methods section after the Introduction and before Results.)

Obesity is contagious . . . maybe (4/17/13)

• Thompson, C. (2009). Are your friends making you fat? New York Times Magazine, September 13.
• Watch James Fowler on The Colbert Report.
• Christakis, N.A. and Fowler, J.H. (2007). The spread of obesity in a large social network over 32 years. New England Journal of Medicine, 357:370-379.
• Kolata, G. (2011). Catching obesity from friends may not be so easy. New York Times, August 8.
• Lyons, R. (2011). The spread of evidence-poor medicine via flawed social-network analysis. Statistics, Politics and Policy, 2(1): Article 2.

Assignment 8: Spying with digital traces

Experimental studies of contagion (4/22/13)

• Nickerson, D.W. (2008). Is voting contagious? Evidence from two field experiments. American Political Science Review, 102(1):49-57.
• Sacerdote, B. (2001). Peer effects with random assignment: Results for Dartmouth roommates. Quarterly Journal of Economics, 116(2):681-704.

What Facebook knows (4/24/13)

• Simonite, T. (2012). What Facebook knows. MIT Technology Review, June 12.
• Bakshy, E., Rosen, I., Marlow, C., and Adamic, L. (2012). The role of social networks in information diffusion. Proceedings of the 21st international conference on World Wide Web (WWW), 519-528.
• Bakshy, E. Eckles, D., Yan, R., and Rosenn, I. (2012). Social influence in social advertising: Evidence from field experiments. Proceedings of the 13th ACM Conference on Electronic Commerce (EC), 146-161.

Assignment 9: Experimental study of contagion on Facebook

Friendship formation (4/29/13)

• Small, M.L. (2010). Unanticipated Gains: Origins of Network Inequality in Everyday Life: Preface, Chapter 1, Chapter 3 (excluding postscript), Chapter 8. (Available from Blackboard)
• Uzzi, B. and Dunlap, S. (2005). How to build your network. Harvard Business Review, 83(12):53-60. (Available from Blackboard)

Homophily (5/1/13)

• Kossinets, G. and Watts, D.J. (2009). Origins of homophily in an evolving social network. American Journal of Sociology, 115(2)405-450.
• Wimmer, A. and Lewis, K. (2010). Beyond and below racial homophily: ERG models of a friendship network documented on Facebook. American Journal of Sociology, 116(2):583-642.