Networks, Coordination and
Cooperation
•
•
•
Nicholas Weller
USC Department of Political Science and School of
International Relations
Collaborators:
•
Daniel Enemark, USC Law School
•
Mathew McCubbins, USC Marshall, Law and Political
Science
•
Mohan Paturi, UCSD Computer Science
Central questions
• How does network structure affect a group of
people’s ability to solve collective action
problems?
• What aspects of structure affect collective
action?
• Answers can help us to understand the
conditions when collective action problems
can be solved and how institutions can
aid/impede solutions
Collective action requires
coordination
•
Research about collective action focuses on
cooperation. But, coordination is still needed.
•
•
“Because every ongoing social process possesses a multiplicity
of equilibria, opportunities to cooperate and the concomitant
problem of coordinating to one of these equilibria are
omnipresent (Niou and Ordeshook 1994, p. 210).”
Implicitly, the focus on cooperation assumed that
coordination was easy (or easier)
•
“Multiple equilibria are a major obstacle to cooperation that was
downplayed by the early emphasis on 2X2 games.” (Koremenos
et al. 2001)
•
Role
of
communication
In settings where coordination is important each individual’s
•
What affects this assessment?
best course of action depends on assessment of others’
likely action.
•
•
•
•
“Secure and cheap tools of communication lower transaction costs for the
organization of collective action, with social media in particular allowing like-minded
members to find one another and to make their true beliefs known in a semi-public
setting.” (Lynch 2011)
“Before Egypt shut off the Internet and mobile phones, before it even started blocking
Twitter and Facebook, those tools were used to coordinate and spread the word about
the demonstrations that were scheduled for January 25. Without these mass
organizing tools, it’s likely that fewer people would have known about the protests, or
summoned the kind of courage that’s made possible by knowing you’re not the only
one sticking your neck out.” http://www.fastcompany.com/1722492/how-social-mediaaccelerated-the-uprising-in-egypt
Solidarity leaders in Poland transmitted information via foreign radio networks with
details about their strike activities, which would then be broadcast in news reports
throughout the country (Chong 1993, p. 135)
Communication seems important, but how?
Network as Communication Structure
•
•
Network can be used to model communication
between actors; can represent arbitrary structure
of communication
•
•
Nodes: actors in a network
Edges: presence of communication
Why use a network?
•
Allows modeling of arbitrary structure of
communication
Possible Networks with 4
actors
Everyone
hears
everyone
Coordination on a Network
•
•
•
Communication: embed subjects in a network
•
•
Node == actor
Edge == communication and constraint
Coordination: multiple solutions to each task
Cooperation: some players will have to accept
less earnings for group to solve a problem
•
•
Asymmetric benefits to coordination
Costs to take an action
Experimental Basics
• Task: Color the nodes of a network
•
•
Color nodes differently than neighbors graph coloring
Color nodes same as neighbors consensus
• There are multiple outcomes that satisfy the
condition for a proper coloring.
• Global solution as a result of local actions
• Task is easy to explain good for
experiments
•
•
•
•
•
•
Experimental Basics,
II
16 subjects
3 minutes to solve problem
$1 baseline payment iff successful
Colors change for each session and differ for
subjects
Decisions are asynchronous and instantly
known
Within group design
Subject Information
Subjects know:
Number of local neighbors
Number of edges for each neighbor
Color of neighbors
Time elapsed in session
Whether a network is colored correctly
How and what they get paid
Subjects DON’T know
Structure of entire network
Who their local neighbors are
Symmetric vs. Asymmetric Coordination
McCubbins, Paturi and Weller. 2009. “Connected Coordination: Network Structure and Group
Coordination.” American Politics Research
Symmetric vs Asymmetric
•
•
Symmetric (pure) coordination: subjects
each receive the same amount for a
solution
Asymmetric (impure, battle of sexes): for
the group to solve the problem ½ of the
subjects must receive the lower of two
payoffs
•
•
Baseline payoff is $1
Bonus payoff ranges from $1 to $4
Expectations for Symmetric and
Asymmetric Coordination
Greater number of edges within networks will
lead to faster solutions
Greater number of edges will also reduce
impact of asymmetric coordination
Time, Connectivity, and Asymmetry
Costly coordination
•
If there is a cost to take an action to achieve
coordination, then the task involves both
cooperation and coordination.
•
•
Every player would rather have others pay the cost
to achieve coordination, but all are better off if
coordination occurs (similar to Stag Hunt or
Assurance Game)
Two key decisions in this game:
•
•
Initial move: only pay the cost to move if probability
of successful completion is sufficiently high
Subsequent moves: if initial moves do not lead to
coordination. Do players pay to move again?
•
•
Experiment Overview
Subjects Know
• 16 subjects in each network
• Cost to choose color (0, 5, 10, 20, 30, 50)
• Within and between group design
• All groups had multiple treatment conditions, order
varied
• 3 minutes to coordinate
• $1 iff successful, $0 if not; costs for taking an action
deducted from the $1 or $0
• Number of neighbors and their degree; color of the neighbor
at any moment
• Subjects quizzed on all of this to ensure compliance
Subjects Don’t Know
• Anything beyond their local neighborhood
• Who the local neighbors are; they change randomly for each
trial
• Progress of the global coordination task
Expectations
1.
Costs will slow coordination
1.
increases in cost will further slow coordination
2.
Costs increase the time to the first move because players are
waiting to see if someone else will incur the initial cost and
attempt to lead the group to a solution (i.e. Strategic Delay, Choi
et al. 2008, Chong 1991 idea of delay in assurance game)
3.
Costs increase efficiency (i.e. players take fewer actions to
achieve coordination.
4.
Networks with more edges will be solved faster than networks
with fewer edges, c.p.
5.
Networks with higher degree variance will be solved more
quickly, c.p.
Costs slow coordination
Effect of Increasing Costs on
Coordination
Costs cause delay in time to first
move
Costs reduce number of moves
More edges = faster solutions
24
edge
s
56
edge
s
“Leaders” = faster coordination
24 edges
0 degree
variance
15 edges
11.5 degree
variance
Conclusion
•
•
•
•
Collective political action requires both coordination and
cooperation
Communication is crucial to solving these types of
problems
Communication structure (network) mediates effects of
costs and asymmetry
Communication structure affects coordination via
multiple paths
•
•
Amount of information (number of edges), BUT
adding edges can also make problem more difficult
Presence of leaders (degree variance)
•
Looked at two common modifications to
pure coordination games – asymmetric
preferences and costs to take an action.