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Effect of resource spatial correlation and hunter-fisher-gatherer mobility on social cooperation in Tierra del Fuego.

Santos JI, Pereda M, Zurro D, Álvarez M, Caro J, Galán JM, Briz i Godino I - PLoS ONE (2015)

Bottom Line: According to ethnographic sources, the Yamana developed cooperative behaviour supported by an indirect reciprocity mechanism: whenever someone found an extraordinary confluence of resources, such as a beached whale, they would use smoke signals to announce their find, bringing people together to share food and exchange different types of social capital.The model provides insight on how the spatial concentration of beachings and agents' movements in the space can influence cooperation.We conclude that the emergence of informal and dynamic communities that operate as a vigilance network preserves cooperation and makes defection very costly.

View Article: PubMed Central - PubMed

Affiliation: INSISOC, Universidad de Burgos, Escuela Politécnica Superior, Edif. "La Milanera", Burgos, Spain.

ABSTRACT
This article presents an agent-based model designed to explore the development of cooperation in hunter-fisher-gatherer societies that face a dilemma of sharing an unpredictable resource that is randomly distributed in space. The model is a stylised abstraction of the Yamana society, which inhabited the channels and islands of the southernmost part of Tierra del Fuego (Argentina-Chile). According to ethnographic sources, the Yamana developed cooperative behaviour supported by an indirect reciprocity mechanism: whenever someone found an extraordinary confluence of resources, such as a beached whale, they would use smoke signals to announce their find, bringing people together to share food and exchange different types of social capital. The model provides insight on how the spatial concentration of beachings and agents' movements in the space can influence cooperation. We conclude that the emergence of informal and dynamic communities that operate as a vigilance network preserves cooperation and makes defection very costly.

No MeSH data available.


Related in: MedlinePlus

Pruned regression tree for average cooperation within the time limit.The CART uses the LHS data. Each decision node shows the condition used to divide the data, along with the number of runs after the split and the corresponding average of cooperation. The resulting subset on the left side satisfies the conditions while the subset on the right side does not. The maximum CART has been pruned with minsplit = 20 (i.e. the minimum number of observations that must exist in a node to try a split) and cp = 0.01 (i.e. complexity parameter).
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pone.0121888.g004: Pruned regression tree for average cooperation within the time limit.The CART uses the LHS data. Each decision node shows the condition used to divide the data, along with the number of runs after the split and the corresponding average of cooperation. The resulting subset on the left side satisfies the conditions while the subset on the right side does not. The maximum CART has been pruned with minsplit = 20 (i.e. the minimum number of observations that must exist in a node to try a split) and cp = 0.01 (i.e. complexity parameter).

Mentions: A CART has been fit to the LHS data in order to enlighten the relationship between model parameters and the stationary behaviour as much as possible. The R package “rpart” [62] has been used to grow the CART tree until each node contains a small number of instances and then use cost-complexity pruning to remove irrelevant leaves. The resulting tree (after pruning) is too large to be easily understood since all parameters are important to a greater or lesser extent, so we have pruned the tree to improve interpretability using the parameters minsplit = 20 and cp = 0.01. The resulting pruned CART is showed in Fig 4.


Effect of resource spatial correlation and hunter-fisher-gatherer mobility on social cooperation in Tierra del Fuego.

Santos JI, Pereda M, Zurro D, Álvarez M, Caro J, Galán JM, Briz i Godino I - PLoS ONE (2015)

Pruned regression tree for average cooperation within the time limit.The CART uses the LHS data. Each decision node shows the condition used to divide the data, along with the number of runs after the split and the corresponding average of cooperation. The resulting subset on the left side satisfies the conditions while the subset on the right side does not. The maximum CART has been pruned with minsplit = 20 (i.e. the minimum number of observations that must exist in a node to try a split) and cp = 0.01 (i.e. complexity parameter).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390331&req=5

pone.0121888.g004: Pruned regression tree for average cooperation within the time limit.The CART uses the LHS data. Each decision node shows the condition used to divide the data, along with the number of runs after the split and the corresponding average of cooperation. The resulting subset on the left side satisfies the conditions while the subset on the right side does not. The maximum CART has been pruned with minsplit = 20 (i.e. the minimum number of observations that must exist in a node to try a split) and cp = 0.01 (i.e. complexity parameter).
Mentions: A CART has been fit to the LHS data in order to enlighten the relationship between model parameters and the stationary behaviour as much as possible. The R package “rpart” [62] has been used to grow the CART tree until each node contains a small number of instances and then use cost-complexity pruning to remove irrelevant leaves. The resulting tree (after pruning) is too large to be easily understood since all parameters are important to a greater or lesser extent, so we have pruned the tree to improve interpretability using the parameters minsplit = 20 and cp = 0.01. The resulting pruned CART is showed in Fig 4.

Bottom Line: According to ethnographic sources, the Yamana developed cooperative behaviour supported by an indirect reciprocity mechanism: whenever someone found an extraordinary confluence of resources, such as a beached whale, they would use smoke signals to announce their find, bringing people together to share food and exchange different types of social capital.The model provides insight on how the spatial concentration of beachings and agents' movements in the space can influence cooperation.We conclude that the emergence of informal and dynamic communities that operate as a vigilance network preserves cooperation and makes defection very costly.

View Article: PubMed Central - PubMed

Affiliation: INSISOC, Universidad de Burgos, Escuela Politécnica Superior, Edif. "La Milanera", Burgos, Spain.

ABSTRACT
This article presents an agent-based model designed to explore the development of cooperation in hunter-fisher-gatherer societies that face a dilemma of sharing an unpredictable resource that is randomly distributed in space. The model is a stylised abstraction of the Yamana society, which inhabited the channels and islands of the southernmost part of Tierra del Fuego (Argentina-Chile). According to ethnographic sources, the Yamana developed cooperative behaviour supported by an indirect reciprocity mechanism: whenever someone found an extraordinary confluence of resources, such as a beached whale, they would use smoke signals to announce their find, bringing people together to share food and exchange different types of social capital. The model provides insight on how the spatial concentration of beachings and agents' movements in the space can influence cooperation. We conclude that the emergence of informal and dynamic communities that operate as a vigilance network preserves cooperation and makes defection very costly.

No MeSH data available.


Related in: MedlinePlus