Limits...
Escaping the tragedy of the commons through targeted punishment.

Johnson S - R Soc Open Sci (2015)

Bottom Line: It is well known that cooperation among many players faced with a social dilemma can be maintained thanks to the possibility of punishment, but achieving the initial state of widespread cooperation is often much more difficult.We show here that there exist strategies of 'targeted punishment' whereby a small number of punishers can shift a population of defectors into a state of global cooperation.We conclude by outlining how the international community could use a strategy of this kind to combat climate change.

View Article: PubMed Central - PubMed

Affiliation: Warwick Mathematics Institute, Centre for Complexity Science , University of Warwick , Coventry CV4 7AL, UK.

ABSTRACT
Failures of cooperation cause many of society's gravest problems. It is well known that cooperation among many players faced with a social dilemma can be maintained thanks to the possibility of punishment, but achieving the initial state of widespread cooperation is often much more difficult. We show here that there exist strategies of 'targeted punishment' whereby a small number of punishers can shift a population of defectors into a state of global cooperation. We conclude by outlining how the international community could use a strategy of this kind to combat climate change.

No MeSH data available.


(a) As figure 1b (all players initially defect), but now the ‘single file strategy’ is applied. (b) As in figure 1b, but under the ‘groups strategy’ with ν=10 and θ=80%. (See the main text and figure 2 for descriptions of these strategies.) (c) Difference between figure 1a (all players initially cooperate) and figure 3a. (d) Difference between figures 1a and 3b. (e) Speed v=N/τ, where τ is the number of time steps required to achieve global cooperation, for the situation in figure 3a. (f) Speed v for the case of figure 3b.
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RSOS150223F3: (a) As figure 1b (all players initially defect), but now the ‘single file strategy’ is applied. (b) As in figure 1b, but under the ‘groups strategy’ with ν=10 and θ=80%. (See the main text and figure 2 for descriptions of these strategies.) (c) Difference between figure 1a (all players initially cooperate) and figure 3a. (d) Difference between figures 1a and 3b. (e) Speed v=N/τ, where τ is the number of time steps required to achieve global cooperation, for the situation in figure 3a. (f) Speed v for the case of figure 3b.

Mentions: As noted above, players with the ability to punish others have the freedom to decide whom to punish. It may seem fairest to punish all defectors equally, but when these are numerous this approach dissipates the total punishing capacity. Consider, instead, the following rule. A defecting player i is only deemed at fault at time t if the one immediately before her in the ordering, player i−1, cooperates at time t. This rule, which we shall refer to as the ‘single file strategy’, is illustrated in figure 2a. According to this view, the number of players considered at fault, nf, will be smaller than the total number of defectors when these are in the majority, while the scenario becomes identical to the previous one when almost all the players cooperate. In figure 3a, we show the results for simulations in which punishers adopt this strategy. As in figure 1b, all players initially defect. The region of global cooperation is now significantly larger than in figure 1b: harmony can be achieved at much lower values of punishment π, particularly if rationality β is high. Because at any one time only a very small number of defectors are deemed at fault, even a low level of punishment is sufficient to make them cooperate. As each new player switches state, it passes on the burden of responsibility to another one down the line, resulting in a cascade of defectors becoming cooperators. A secondary effect is that, as the ranks of cooperators grow, the total punishment they are able to inflict increases, although as we show in the electronic supplementary material this is not essential for the mechanism to work.Figure 2.


Escaping the tragedy of the commons through targeted punishment.

Johnson S - R Soc Open Sci (2015)

(a) As figure 1b (all players initially defect), but now the ‘single file strategy’ is applied. (b) As in figure 1b, but under the ‘groups strategy’ with ν=10 and θ=80%. (See the main text and figure 2 for descriptions of these strategies.) (c) Difference between figure 1a (all players initially cooperate) and figure 3a. (d) Difference between figures 1a and 3b. (e) Speed v=N/τ, where τ is the number of time steps required to achieve global cooperation, for the situation in figure 3a. (f) Speed v for the case of figure 3b.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555856&req=5

RSOS150223F3: (a) As figure 1b (all players initially defect), but now the ‘single file strategy’ is applied. (b) As in figure 1b, but under the ‘groups strategy’ with ν=10 and θ=80%. (See the main text and figure 2 for descriptions of these strategies.) (c) Difference between figure 1a (all players initially cooperate) and figure 3a. (d) Difference between figures 1a and 3b. (e) Speed v=N/τ, where τ is the number of time steps required to achieve global cooperation, for the situation in figure 3a. (f) Speed v for the case of figure 3b.
Mentions: As noted above, players with the ability to punish others have the freedom to decide whom to punish. It may seem fairest to punish all defectors equally, but when these are numerous this approach dissipates the total punishing capacity. Consider, instead, the following rule. A defecting player i is only deemed at fault at time t if the one immediately before her in the ordering, player i−1, cooperates at time t. This rule, which we shall refer to as the ‘single file strategy’, is illustrated in figure 2a. According to this view, the number of players considered at fault, nf, will be smaller than the total number of defectors when these are in the majority, while the scenario becomes identical to the previous one when almost all the players cooperate. In figure 3a, we show the results for simulations in which punishers adopt this strategy. As in figure 1b, all players initially defect. The region of global cooperation is now significantly larger than in figure 1b: harmony can be achieved at much lower values of punishment π, particularly if rationality β is high. Because at any one time only a very small number of defectors are deemed at fault, even a low level of punishment is sufficient to make them cooperate. As each new player switches state, it passes on the burden of responsibility to another one down the line, resulting in a cascade of defectors becoming cooperators. A secondary effect is that, as the ranks of cooperators grow, the total punishment they are able to inflict increases, although as we show in the electronic supplementary material this is not essential for the mechanism to work.Figure 2.

Bottom Line: It is well known that cooperation among many players faced with a social dilemma can be maintained thanks to the possibility of punishment, but achieving the initial state of widespread cooperation is often much more difficult.We show here that there exist strategies of 'targeted punishment' whereby a small number of punishers can shift a population of defectors into a state of global cooperation.We conclude by outlining how the international community could use a strategy of this kind to combat climate change.

View Article: PubMed Central - PubMed

Affiliation: Warwick Mathematics Institute, Centre for Complexity Science , University of Warwick , Coventry CV4 7AL, UK.

ABSTRACT
Failures of cooperation cause many of society's gravest problems. It is well known that cooperation among many players faced with a social dilemma can be maintained thanks to the possibility of punishment, but achieving the initial state of widespread cooperation is often much more difficult. We show here that there exist strategies of 'targeted punishment' whereby a small number of punishers can shift a population of defectors into a state of global cooperation. We conclude by outlining how the international community could use a strategy of this kind to combat climate change.

No MeSH data available.