Social Networks
(Demography 180)

Spring 2018

Professor Dennis Feehan
Office: 2232 Piedmont Ave, Room 210
Email: my last name at berkeley.edu
Class meetings Tu/Th 11am-12.30pm, 141 McCone
Class number: 41045
Office hours: Tu 3-4pm, 210 Dept. of Demography

RRR week review session:
Thursday, May 3rd, 11am-12.30pm (usual class time)
McCone 141 (usual class room - to be confirmed)

Final exam: May 10, 8am, McCone 141


Piazza page
Bcourses page
Lecture slides

Overview

The science of social networks focuses on measuring, modeling, and understanding the different ways that people are connected to one another. In this class, we will use a broad toolkit of theories and methods drawn from the social, natural, and mathematical sciences to learn what a social network is, to understand how to work with social network data, and to illustrate some of the ways that social networks can be useful in theory and in practice. We will see that network ideas are powerful enough to be used everywhere from CDC and UNAIDS, where network models help epidemiologists prevent the spread of HIV, to Silicon Valley, where data scientists use network ideas to build products that enable people all across the globe to connect with one another.

Calendar

Theme Week Date Topic Materials
Intro 1 1/16 Intro / what social networks are / class info
1/18 Personal networks; social connectedness and social isolation in America; survey data collection
Homophily / Tie strength I 2 1/23 Basic graph theory: definitions, types of networks, types of network data Homework 1
1/25 Strength of weak ties; social capital
Homophily / Tie strength II 3 1/30 Networks in context; homophily Personal networks lecture notebook
2/1 Positive and negative relationships
Affiliation networks 4 2/6 Working with entire network data; quantifying network structure: degree distributions, average path length, clustering Working with whole network data notebook
2/8 Affiliation networks; foci; group membership; one-mode projections of bipartite networks Structural balance notebook
Network models 5 2/13 Intro to mathematical network models; the Erdos-Renyi model and its predictions Erdos-Renyi random networks notebook
2/15 Intro to mathematical network models; the Erdos-Renyi model and its predictions Homework 2
Small worlds 6 2/20 Small worlds
2/22 Search in small worlds / Scale-free networks
7 2/27 Midterm review
3/1 Midterm
Search in small worlds, scale-free networks 8 3/6 Midterm recap; finish search in small worlds
3/8 Scale-free networks Homework 3
Simple contagion 9 3/13 Diseases and simple contagion in general; SIR model
3/15 SIR model on networks Centrality and SIR model notebook
10 3/20 Centrality, influence, and network disease models Homework 4
3/22 Sexual networks, concurrency, and HIV
11 3/27 SPRING BREAK
3/29 SPRING BREAK
Complex contagion 12 4/3 Social influence, herding, and cascades
4/5 Threshold models and complex contagion
13 4/10 Complex contagion cont. Homework 5
Empirical studies of contagion 4/12 Complex contagion cont. Complex contagion notebook
14 4/17 Can your friends make you fat? Experimental and observational studies of complex contagion
Cooperation and collaboration 4/19 Cooperation and collaboration Homework 6
15 4/24 Guest lecture: Ugur Yildirim (Cooperation in networks)
4/26 Guest lecture: Abigail Jacobs
5/1 READING WEEK
5/3 READING WEEK
5/10 Final exam! 8am, McCone 141

Requirements

Lectures

Lectures will introduce and develop key theoretical and technical concepts in the study of social networks. To illustrate these ideas, some of the lectures will have a live lab component, where we will interactively discuss and work through an analysis in a Jupyter notebook. These live labs will help us explore and develop intuition about key concepts in the course.

The lectures are organized so that the first set of material, up to the mid-term exam, is a survey of the core theories, concepts, and methods needed to be familiar with social networks. After the mid-term, the lectures will turn to an exploration of how these core ideas have been used, modified, and deepened in several different topic areas.

You are responsible for all of the material covered in lectures, as well as any announcements made there.

Required readings

The course readings will include selections from the textbook Networks, Crowds, and Markets by Easley and Kleinberg; chapters from popular science books written by leading network researchers, and several journal and newspaper articles.

The readings serve two purposes: (1) they provide an introduction and reference for key concepts that we will need to study social networks; (2) they illustrate how social network ideas get used in real world research and applications across many different disciplines. You are expected to do the reading before each class.

PDFs of each of the readings will be posted on the bCourses site.

Homework

There will be a total of 5 to 7 homework assignments. You can drop the homework with the lowest score. Together, the homeworks are worth 40% of your final grade. These homeworks are a critical part of the learning you will do in this class: they give you an opportunity to explore the topics we cover in the readings and in lecture on your own. They also give you a chance to practice your writing and your data analysis and programming skills. The format for each homework will ask you to provide some written arguments and to solve some problems by writing Python code in a Jupyter notebook. It can be helpful and educational to discuss the assignments with other students in the class, but (1) all of the work should be your own (i.e., you are not allowed to just copy code, answers, or arguments); (2) you should make a note of the names of the other students you worked with when handing your assignments in.

Exams

There will be two in-class closed book examinations. The mid-term examination will be held on March 1, 2018 during normal class time in our normal classroom; the timing of this midterm is designed to assess your mastery of the core concepts in social networks. The final will be held during the final exam period (exact date/time TBD). The final exam will be cumulative.

Quizzes

I will post a small number (4-5) quizzes on bCourses over the semester. These quizzes will be 5-10 multiple choice questions; the goal of these quizzes will be to ensure that you are staying up to date with the reading and lecture materials covered in the class. The quizzes will be a total of 10% of your grade.

Summary

Component % of grade
6 Homeworks (you can drop your lowest score) 40
4 Quizzes 10
Mid-term exam 20
Final exam 30

Detailed schedule

Week 1: Introduction to social networks

Intro to mathematical network models; the Erdos-Renyi model and its predictions

Lectures:

Reading:

Homework 1

Week 2: Homophily and tie strength I

Lectures:

Reading:

Week 3: Homophily and tie strength II

Lectures:

Reading:

Week 4: Affiliation networks

Lectures:

Readings:

Week 5: Network models

Lectures:

Readings:

Homework 2

Week 6-7: Small worlds

Lectures:

Readings:

Week 7: Catch-up, review, and midterm

Lectures:

Week 8: Search in small worlds and scale-free networks

Lectures:

Readings:

Homework 3

Weeks 9-10: Simple contagion

Lectures:

Reading:

Spring break

Homework 4

Weeks 12-13: Complex contagion

Lectures:

Reading:

Homework 5

Week 14: Empirical studies of contagion

Reading:

Homework 5

Week 15: Guest lectures

Reading:


Reading list

Easley, D., & Kleinberg, J. (2010). Networks, crowds, and markets: Reasoning about a highly connected world. Cambridge University Press. https://www.cs.cornell.edu/home/kleinber/networks-book/

Epstein, H. (2008). The invisible cure: Why we are losing the fight against AIDS in Africa. Macmillan.

Watts, D. J. (2003). Six degrees: The science of a connected age. WW Norton & Company.