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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.


Parameter importance.A random forest with mtry = 18/3 (where 18 is the number of parameters) and ntree = 300 (for this value the MSE is stabilised) has been implemented. The permutation-based MSE reduction is used as the criterion of importance to rank the model parameters. By randomly permuting predictors (i.e. parameters) and observing how much the MSE grows, the more important a predictor, the more increase in the MSE is expected.
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pone.0121888.g005: Parameter importance.A random forest with mtry = 18/3 (where 18 is the number of parameters) and ntree = 300 (for this value the MSE is stabilised) has been implemented. The permutation-based MSE reduction is used as the criterion of importance to rank the model parameters. By randomly permuting predictors (i.e. parameters) and observing how much the MSE grows, the more important a predictor, the more increase in the MSE is expected.

Mentions: To solve the overfitting problem and to get a better understanding of the model parameters, we have used a Random Forests implemented with the “randomForest” R package [61]. Fig 5 shows the parameter importance using the Mean Standard Error (MSE) reduction of each permuted parameter over the OOB dataset [60]. The interpretation of these results is much more trustworthy because these importance predictions with a Random Forests are more stable and robust to changes in data [61]. The results confirm the importance of the mutation parameter along with prob-beached-whale, social-capital-versus-meat-sensitivity, vision, beached-whale-distribution and distance-walked-per-tick (all of them with over 20% increase in the MSE), which govern the main hypothesis of the model, from indirect reciprocity to the beachings and agents’ movement.


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)

Parameter importance.A random forest with mtry = 18/3 (where 18 is the number of parameters) and ntree = 300 (for this value the MSE is stabilised) has been implemented. The permutation-based MSE reduction is used as the criterion of importance to rank the model parameters. By randomly permuting predictors (i.e. parameters) and observing how much the MSE grows, the more important a predictor, the more increase in the MSE is expected.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0121888.g005: Parameter importance.A random forest with mtry = 18/3 (where 18 is the number of parameters) and ntree = 300 (for this value the MSE is stabilised) has been implemented. The permutation-based MSE reduction is used as the criterion of importance to rank the model parameters. By randomly permuting predictors (i.e. parameters) and observing how much the MSE grows, the more important a predictor, the more increase in the MSE is expected.
Mentions: To solve the overfitting problem and to get a better understanding of the model parameters, we have used a Random Forests implemented with the “randomForest” R package [61]. Fig 5 shows the parameter importance using the Mean Standard Error (MSE) reduction of each permuted parameter over the OOB dataset [60]. The interpretation of these results is much more trustworthy because these importance predictions with a Random Forests are more stable and robust to changes in data [61]. The results confirm the importance of the mutation parameter along with prob-beached-whale, social-capital-versus-meat-sensitivity, vision, beached-whale-distribution and distance-walked-per-tick (all of them with over 20% increase in the MSE), which govern the main hypothesis of the model, from indirect reciprocity to the beachings and agents’ movement.

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.