INFO 6940: Special Topics: Analytic Social Systems
Tue/Thu 2:55-4:10 PM, Location: 301 College Ave (large conf room)
3 credits, S/U Optional
Professor: Paul Ginsparg (452 Phys.Sci.Bldg,
Office hours: Wed 1-2 PM (or by appointment)
Course website: http://www.infosci.cornell.edu/Courses/info6940/2012sp/ (this page)
This course will cover recent research on the structure and analysis
of social and technological networks, and some of the background
material necessary to understand it. Topics are likely to include
random graphs and small-world properties, cascades and critical
phenomena, heavy-tailed distributions, game-theoretic models of
behavior, decision-making, clustering and communities, social networks
and the web, and reputation systems.
The early part of the course will be more lecture-centric, using some
of the more advanced sections of the
Easley/Kleinberg text (Networks,
Crowds, and Markets), and additional material from the research
literature. It will then transition to a mixture of lecture and
discussion of more recent selections from the research literature.
There will also be some overlap with topics in Info 6850, albeit with
less mathematical emphasis. The goal is to make the current literature
accessible to students with less formal mathematical background.
Prerequisite: graduate standing. Introductory-level background in
probability and statistics. Some basic programming experience might
also be helpful for manipulating network datasets.
Note: Can be used for graduate core credit for formal analysis of
Lecture 1 (Tue 24 Jan 12)
Course overview (Graph theory, Game theory, Strategic Interaction, Information Networks, Population Models, Structural Models, Aggregate Behavior)
Intro chapters 1,2,3 from
NYTimes: Separating You and Me? 4.74 Degrees
re some recent local work
Lecture 2 (Thu 26 Jan 12)
Finished chpt 3 of E/K, including
"advanced material" on
Betweenness Measures and Graph Partitioning.
Plan is to complete chpt 4
next Tues, and begin discussion of articles mentioned in lecture 1.
(After class, I also mentioned these 2002 articles
Uncloaking Terrorist Networks ,
Mapping Networks of Terrorist Cells;
see also this blog entry
Another addendum: by coincidence Dunbar joined the networkers network over
the weekend, arXiv:1201.5722
(Sex differences in intimate relationships, et al. + Barabási, Dunbar)
Lecture 3 (Tue 31 Jan 12)
Threaded into discussion of
an early popular description of the "network contagion" mentioned on Thurs can
be found here:
Obesity Can Be Contagious (Jul 2007), and a more recent popular article
questioning the results is this one:
(Jul 2011: 'Critics now wonder how the "social contagion" studies ever passed
The first of the technical articles is described in this blog entry:
Contagion, Confounding: Pick Any Three (Apr 2010),
explaining that equally good explanations can be found without invoking contagion or influence.
The latter mentions these technical articles (just for a flavor, not yet to be
read in detail):
Even before the recent set of technical articles disputing the
C/F network contagion media hype, there was already some popular backlash
against the notion of causative network effects, e.g. from spring '10:
Has a Plague of Social
Illness Struck Mankind? (Apr, 2010) and
Doubts About the
Social Plague Stir in the Human Superorganism (Apr, 2010)
Note added, for a discussion of modularity and how it is used together with
link betweenness centrality to find optimal community structure,
Lecture 4 (Tue 2 Feb 12)
Finish up from last time (modularity, selection vs social influence in
Wikipedia edits), then discussion of
Note: see Networks Journal
for 7 Feb noon discussion of above
Lecture 5 (Tue 7 Feb 12)
Finish up discussion of
(see also this follow up
and also some of
(please have another look before class, specifically assortative mixing)
(Re the second, note also
Why Your Friends Have More
Friends Than You Do (Feld, 1991))
Then we'll finish Part I of the book with discussion of sections 5.4,5.5 of
(at the end of the 3rd week, you're supposed to be familiar with all of chapts 1--5 of the course text)
Lecture 6 (Thu 9 Feb 12)
finish finishing chapter 5
(covered 5.4, 5.5, on weaker forms and generalizations of structural balance).
The Role of Social Networks in Information Diffusion
In parallel with earlier discusions (which updated Milgram's small world to 2011 on-line social data), this one effectively updates Granovetter's strength of weak ties
and their contribution to diffusion of novel information
to modern electronic large-scale datasets.
Also mentioned that you might start perusing
(or go back further, or check some recent conf proceedings) for student
presentations of articles to class.
Lecture 7 (Tue 14 Feb 12)
For the next two weeks we'll be covering population models of network dynamics,
focusing on the latter parts of chpts 17
and 18 of the text, and some related
articles to be posted. You should be familiar with all of 16-18 by end lecture
Lecture 8 (Thu 16 Feb 12)
Finish chpt 17, some of chpt 18 (popularity...)
"Is Justin Timberlake a Product of Cumulative Advantage?"
Lecture 9 (Tue 21 Feb 12)
Finished chapter 18 on network effects, specifically section 18.7
(and was planning to discuss some articles involving recommender systems and
their possible benefits and drawbacks, continuing the discussion also of the
Watts et al experiment, deferred to Thurs).
Here are the older (INFO 2950) problems
I mentioned re the Polya urn and related.
I also used this slide (from INFO 4300) re
Amazon/Wikipedia power laws, based on this (INFO 2950) problem on the "Long Tail".
Additional popular refs re power laws for cities:
of cities (Glaeser),
Lecture 10 (Tue 23 Feb 12)
The next focus will be the structural network models of chapters 19-21,
covered most of 19.1-19.4 .
Discussed a bit of this article posted last week
(How the Scientific Community Reacts to Newly Submitted Preprints: Article
Downloads, Twitter Mentions, and Citations), but not in extensive detail for
reasons mentioned. Spent more time discussing
We will also start on the logistics for student presentations.
Week of 27 Feb - 2 Mar
- The video of Jon Kleinberg's public talk I mentioned is here:
"What can Facebook, Amazon and Google teach us about society and about ourselves?" (20 Jul 2011)
- You should also make sure you've absorbed all of chpts 1-5, 16-18 (material
from lectures 1-9), and try to read 19-21 to get a jump on the material for the
next few lectures. Feel free to look at the exercises, and we can discuss in
class any that are particularly interesting.
- As mentioned two weeks ago (lecture 6 above), you should also peruse some
in the text, or more recent follow-ups by same authors, or recent conference
proceedings, or arXiv:cs.SI
or keyword search of topics that interest you,
for student presentations of articles to class, which we'll start after the
break. Please email me your choice, or set of possibilities, so we can settle
on a schedule.
- Note also that the CAM "Network Journal Club", noon 28 Feb Rhodes 657, will discuss the
Bakshy et al. article (updating
Granovetter) we discussed in Lecture 6, as well as
on homophily in adoption of health behavior.
- Note this CAM colloquium, Thu 1 Mar 2012, 655 Rhodes Hall,
3:30pm: Sam Arbesman, "The Half-Life of Facts?, it is about
"patterns and regularities to how facts change over time".
Lecture 11 (Tue 6 Mar 12)
We finished cascading behavior, role of weak ties, collective action, and
"bilingual" extensions (sections 19.3-19.6 and 19.7C).
We will also discuss some of the choices for presentation, to help guide 2nd
half syllabus. Please come prepared with your selections.
Lecture 12 (Thu 8 Mar 12)
We will cover epidemics, specifically sections 21.7-21.8.
We will also continue discussing the choices for presentation, to help guide
2nd half syllabus. Please come prepared with your selections.
Lecture 13 (Tue 13 Mar 12)
Finished the discusion of coalescent phenomena (including discussion of
geometric series, see older (INFO 2950) problem, and
Tied up some lingering loose threads re info cascades from sections 19.7A,B,
and mention of SIR class models (21.3, 21.4).
Lecture 14 (Thu 15 Mar 12)
Will complete the technical discussion of small-world phenomena, sections
20.3-20.7, and finalize schedule for presentations after the break.
(so far: Leo: 3 Apr (visualization), Alistair: 5 Apr (Digg); Elizabeth: 10 Apr (effect
of exposure to preferences), Shion: 12 Apr (mix at mixers);
Wei: 17 Apr, Matt: 19 Apr (assortative happiness)
Xiying: 24 Apr, Jaeyoon: 26 Apr );
Spring Break (19-23 Mar 12)
Note: so far in the book we've covered Part I (chpts 1-5), Part V (chpts 17,18,
will return to 16), Part VI (chpts 19-21)
Lecture 15 (Tue 27 Mar 12)
After completing some final details on sect 20.7, will review chpt 16 (Bayes
Theorem) in preparation for part VII on
aggregate behavior, probably covering chpts 22-24 in next few lectures.
Lecture 16 (Thu 29 Mar 12)
Completed review of chpt 16 (Bayes etc) and then chpt 22 (covered only to 22.2,
so 22.3- next week).
See also notes on expected number of steps to avalanche,
as discussed in class.
Lecture 17 (Tue 3 Apr 12)
Covered 22.3 (Aggregate beliefs and the wisdom of crowds).
Lecture 18 (Thu 5 Apr 12)
Finish Chpt 22.4-22.10 (Markets and Information), and likely cover 23.7-23.10
(voting as information aggregation) next week
- Alistair will discuss this article:
Information Spread (info cascades
in digg and twitter)
Iowa Electronic Markets (IEM
e.g., 2012 presidential election market
Some Intrade links:
i) How it Works (note contracts are for $10 shares).
ii) Republican Presidential Nominee in 2012: Romney at $9.52/share (95.2% chance),
Santorum at $0.08/share (.8% chance, 103 shares available to buy [think even will occur], 70 shares available to sell [think event won't occur]).
iii) President in 2012: Obama at $6.08/share (60.8% chance)
Lecture 19 (Tue 10 Apr 12)
- Liz will present
"To Switch or Not To Switch" (Zhu
et al, 2011) about how an individual's choices can change after exposure to others' preferences.
(In advance of class, these articles dealing with confirmation and conformity
in recommender systems are also potentially of interest:
"Is Seeing Believing?"
(Cosley et al., 2003)
provides some high level background on
recommender systems and influence, and
"I will do it, but i don't
like it" (Schwind et al, 2011),
is a shorter treatment of how information
evaluation and selection is affected by exposure to preference-consistent or
We'll also finish some last details of chpt.22 (Markets and Information;
though 22.6-22.9 still pending),
and start covering 23.7-23.10 (voting as information aggregation).
Lecture 20 (Thu 12 Apr 12)
Lecture 19 (Tue 17 Apr 12)
Lecture 20 (Thu 19 Apr 12)
Lecture 21 (Tue 24 Apr 12)
(So far we've covered roughly Parts I,V,VI,VII of the text, focusing on the more advanced
material. The lecture plan for the remaining two weeks is to cover the first
half of Part II (game theory), emphasizing the advanced material in chpts
Lecture 22 (Thu 26 Apr 12)
is a brief description of Boczkowski's work I mentioned re the
"mismatch between supply and demand of news in the elite media"
(see also his IS colloquium here last year)
Covered 6.5-6.8 (more on Nash equilibria)
Lecture 23 (Thu 1 May 12)
Lecture: finished 6.8 - 6.10 (A,B)
(Re George Price, see Death of an Altruist
[also this radiolab audio link]
Re "Predicting X from Twitter is a popular fad within the Twitter research
subculture", see this critical bibliography of election prediction using
Lecture 24 (Thu 3 May 12)
Lecture: evolutionary game theory: chpt. 7
(Note: a recent observation
about prediction markets)