Workshop “Bottom-up Evolution of Cooperation”
29th – 30th October 2015
Day 1
Introduction by Alessandro
Introductory Round
1. Presentation by Maja Schlüter, Alessandro Tavoni, and Steve Lade
 How to bridge the scale from local to global boundaries? How to model cross-scale
dilemmas? Similarities to the issue of globalization
 Collapse of cooperation when levels of resource is high. Intuitive as there is less of an
incentive to cooperate, more people defect which leads ultimately to collapse of
cooperation
 Mismatch of scales is often source of collapse of systems (f. ex. financial system)
 There is a multitude of interacting scales (more than two). Analysis of just two scales is a
starting point, but research must incorporate multiple scales eventually
 One important factor for modeling is mobility (book: Logging the globe-Patricia Marchak)
 Ostracism could be incorporated into this model as well
 Ostrom (2009): resource level has effect on cooperation (no cooperation at low and high
level)
 Form of the utility function is crucial
 Change of norms could be incorporated into the model (adaptive norms)
 Introduction of insurance or sharing mechanism, but might only be effective at medium
resource levels as there are no incentives at high or low levels.
 With variability of resource levels the time scale is very important (mismatch between
variability of resource levels and the time interval in which cooperation levels update)
2. Presentation by Andrew Tilman
 Collective benefits as a function of ostracism
 Similarity to model of market leader who establishes his position by various means
(lowering prices, etc. to prohibit others to enter)
 Heterogeneity in risk aversion could be introduced
 Individual and overall risk of resource (the latter is included in the noise term)
 In this model, there is no cooperation without ostracism
3. Presentation by Andries Richter
 Notions of fairness/upholding of social norms (evidence (f. ex. Ultimatum Game) that
sanctioning also occurs beyond the point where costs of sanctioning are lower than the
benefits)
 Using a Cobb-Douglas utility function in the analysis yields largely same results, but once
lots of noise is introduced the social optimum cannot be sustained
 No altruistic preferences are modelled, pure sanctioning model with adaptive
sanctioning preferences
 Feedback mechanism here: linear relationship between effort level and biomass (the
alpha in the model)
4. Presentation by Agostino Merico
 OGUMI app could be used for long-time horizon experiments and experiments outside
the lab (limitation however: internet connection needed)
 Type of communication in the experiment so far: face-to-face
 Logging the conversations between the players could be quite interesting
 Educational aspects could be added (for example when played with fishermen)
 Possibility to explore the effect of information provided
 Bridge between this model and the “traditional” economic models?
5. Presentation by Samir Suweiss and Paolo D’Odorico
 Tradeoff between interconnectivity and resilience
 How to quantify the modularity?
 Discussion on discounting: individual discount rate fixed (at least in the short- and
medium-run) but also very sudden changes in discount rates possible (example: 2008
Financial Crisis) -> Is a positive shock to the discount rate even possible? Important
research areas: What determines the discount rate and how can it be changed?
 Additional uncertainty of the effect of climate change makes it especially challenging
6. Presentation by Astrid Dannenberg
 Link between beliefs about INDCs and the actual pledges made
 Book by Dominic Johnson: Overconfidence and war
 Self-serving bias or just greater knowledge of the people more involved
 Overall little confidence in the INDC approach (compared to ADP approach), maybe due
to 2C target, which is already seen as unreachable by many
 Interaction between intuition and responsibility
 A question on a negotiation in which none of the respondents were involved would have
been a good control question
 Similar effects: Ownership and participatory effect
 Maybe respondents judge Paris more positively in retrospective
Discussion
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What can be the outcome of this workshop? Suggestion: Review paper about state of art models
and methods
How to go from community scale to global scale? Literature that integrates across scales not
really out there yet, at least not explicitly.
Day 2
1. Presentation by James Dyke and Patrick Doncaster
 Reason for the outrage over the proposed levy in the UK: bad timing (rising energy costs
at the same time), no alternative was presented (i.e. that the later payment for climate
change will be much more expensive)
In the model, levy is combined with insurance, thus the alternative is more present
 Caribbean parametric insurance is a good way forward

Index insurance has conceptual advantages, there are also examples of collective index
insurances today. But: Applicability to climate change might be difficult because the
shock is not idiosyncratic and the situation of climate change is expected to worsen
 No catastrophic event in this model
 Insurance would have to be implemented by all countries, premium will not come down
if only single countries implement it (as climate change is global). If the contribution is
made to an adaptation instead of a mitigation fund, it might work, because adaptation
does not incentivize free-riding by other nations (compared to mitigation)
 The model (direct insurance) is a solution to the discounting problem earlier discussed
 In this model, no social dilemma is modelled. Cooperation is in the set of mixed
strategies and the incentive for cooperation is purely economical
 Experimental testing is in plan
2. Presentation by Vítor Vasconcelos, Francisco Santos, and Jorge Pacheco
 Evidence of less cooperation with greater group size, but no consideration of possible
scale effects
 Stochastic effects play a larger role in smaller groups as the probability of having a noncooperating group is higher. However, here the population size is constant
 Intuitively, one would think that wealthy actors play a greater role as they have more
ability to contribute. In the model, the poor have a greater (peer) influence, as they are
more.
 What would change, if the threshold were global and not local? Are local institutions still
more effective if the threshold is global?
Discussion
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How sophisticated does a model have to be?
o For large population differences average out, thus model does not need to incorporate
all the difference.
o The answer depends on the research question. No general answer. Large toolbox of
elements (role of information, fussiness of threshold, reciprocity, etc.) available. Type of
research question guides choice of relevant elements.
o Introduction of stochastic variability captures complexity in an implicit way
Can evolutionary game theory be applied here? Pure replicative dynamics might be too
simplified. Local benefits are important for cooperation.
Possible way forward: willing countries form a club for a limited amount of time. They share
common benefits (for example from enhanced cooperation) as well as the costs of mitigation.
After the deadline, countries evaluate whether they managed to attract additional members and
whether to dissolve the club or not.
o By doing so the eventual threshold is only pushed into the future. However, until then
other countries might see the benefit of cooperation and join the club
o Difficult to sell as only temporary. Innovation and new technologies need long-term
incentives.
In a public good game with threshold some kind of cooperation is always possible. But unanimity
might be a utopia. There are always defectors. -> Second-best solution
Ideas for next meeting: linkage of different public goods, tradeoff possibilities between different
issues, second-best solution