1. Computer-Mediated Communication
Collaborative Editing, Online Collective Action and Game Theory

2. Computer-Mediated Communication — Cheshire & Fiore
Announcements
Assignment #2 and Due Dates
Thurs Nov 13th (Assn 2)
Presentations Dec 2nd and Dec 4th
Final Projects Due Tuesday December 16th
Next Week
No Readings or Reviews
In-class activities
Office hours moved to 3-4pm today
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

3. Highlighting a few good points and issues:
Who is the target audience in a collective action problem?
NPR example
Incentives and “crowding out” effects
Monetary versus other incentives
Mycroft: Heinlein vs. Conan Doyle
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

4. Computer-Mediated Communication — Cheshire & Fiore
“… [we] note that administrative and coordinating elements seem to be growing at a faster pace than the bulk of articles in the encyclopedia [Wikipedia]”
Viégas et al. 2007
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

5. “Talk” Pages on Wikipedia
(Viégas et al. 2007)
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

6. “Emergent” Order and Coordination
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

7. Designing for Social Psychological Incentives
Outcomes for Collective Action
Contribution
Size
Membership
Diversity of
Contribution
Standardization
Behaviors
Social psychological incentives
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

8. Using Game Theory to Understand Collective Action
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

9. Types of Social Dilemmas
Different social dilemma games
make different use of the payouts:
T>R>P>S Prisoner’s Dilemma
T>R>S>P Chicken
T>P>R>S Deadlock
R>T>P>S Stag Hunt B
Coop.
Defect
3 (R)
5 (T)
Reward
Temptation
Sucker
Punishment
3 (R)
0 (S)
Ebay example A
0 (S)
1 (P)
5 (T)
1 (P)
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

10. When are Social Dilemmas Useful in the Study of CMC?
Wherever we find mixed-motive situations and collective action…
Standards Wars
And Intperpersonal
Interactions
Online Tagging Systems (folksonomies), Collaborative Editing Systems
Del.ic.ious
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

11. Forms of Interaction in Social Dilemmas
N-person PD
2-person repeated PD
Public Good
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

12. Computer-Mediated Communication — Cheshire & Fiore
The N-person PD
“No one wants to pay taxes because the benefits are so diffuse and the costs are so direct. But everyone may be better off if each person has to pay so that each can share the benefits”
cf. Schelling 1973; Axelrod 1984
N-person game is same idea as a standard 2-person, except you now have to account for a new parameter (k) which represents the minimum coalition necessary to produce the optimal outcome.
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

13. Computer-Mediated Communication — Cheshire & Fiore
Vaccinations, Invisible Hands, Halloween Parties and other Scary Things.
Vaccinations: if they are optional, what proportion need to get them to reduce public risk?
Invisible Hand: Adam Smith’s idea is essentially about collective behaviors guiding shared outcomes
Parties: Showing up on time versus showing up late
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

14. Computer-Mediated Communication — Cheshire & Fiore
2-person repeated PD
“…there are many opportunities for mutually rewarding activities by two senators. These mutually rewarding actions have led to the creation of an elaborate set of norms…among the most important of these is the norm of reciprocity [helping out a colleague and getting repaid in kind]”
- Axelrod 1984
Same idea as a standard PD, except now you have repeated interactions with same partners over time. This one change accounts for all the interest, because it allows cooperation to emerge even if individuals behave with rational self interest.
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

15. Computer-Mediated Communication — Cheshire & Fiore
C C C C C C C C C = 0
versus
D D D D D D D D D = 45
C C C C C C C C C = 27
versus B
Coop.
Defect
3 (R)
5 (T)
3 (R)
0 (S) A
0 (S)
1 (P)
5 (T)
1 (P)
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

16. Strategizing in repeated PD games
Consider two individuals who interact repeatedly over time
No mechanisms for enforceable commitments.
No way to be sure what the other will do on each ‘turn’.
No way to eliminate the other player or leave the interaction.
No way to change the other player’s payoffs.
What strategy might you use if you had to play this game over and over again with others?
Always Cooperate?
Always Defect?
Something more complicated, perhaps using past behavior?
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

17. Computer-Mediated Communication — Cheshire & Fiore
CMC PD tournament 2008!
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

18. Computer-Mediated Communication — Cheshire & Fiore
CMC PD tournament 2008!
Work in groups to develop PD strategies
Use IPDLX open-source PD software
Used for tournaments by PD “professionals”
Works with Java 1.4, 1.5, 1.6, any platform
Tournament will be in class on Tuesday —Actually, TWO tournaments:
One where you enter your one best strategy
One where you enter any and all strategies
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

19. Computer-Mediated Communication — Cheshire & Fiore
Tournament format
Round-robin: each strategy plays each other strategy and itself once
Winner has the most cumulative points
Each game will have n turns
n is unknown and potentially variable
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

20. http://courses.ischool.berkeley.edu /i216/f08/ipdlx08.zip
Software details…
/i216/f08/ipdlx08.zip
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

21. Computer-Mediated Communication — Cheshire & Fiore
Software details…
public class CMCSample extends Strategy {
private final static String _abbrName = "CMCS";
private final static String _name = "CMC Sample Strategy";
private final static String _description = "Not a proper strategy...";
...
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore

22. Computer-Mediated Communication — Cheshire & Fiore
Software details…
public double getMoveDecision() {
// Default move
double move = COOPERATE;
// Do some magic ...
// ... end magic.
// Return your move for this round
return move; }
11/21/2018
Computer-Mediated Communication — Cheshire & Fiore