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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.


Average cooperation and movement.Matrix of plots of the average cooperation <c> as a function of vision ν for different agents’ types of movement (columns) and levels of importance of social capital θ (rows), when the spatial distribution of beached whales is uniform. The maximum standard error of the average of cooperation of all experiments represented in the plots is 0.056.
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pone.0121888.g008: Average cooperation and movement.Matrix of plots of the average cooperation <c> as a function of vision ν for different agents’ types of movement (columns) and levels of importance of social capital θ (rows), when the spatial distribution of beached whales is uniform. The maximum standard error of the average of cooperation of all experiments represented in the plots is 0.056.

Mentions: In the last set of experiments, we relaxed the assumption that agents move following a random walk. Now, we assume Lévy flight movement much more similar to real human mobility patterns discussed in the literature [31–33,35]. As we have just described in the Methods section, we have implemented a truncated Cauchy function for the agents’ step length per tick, with a minimum step length of 1, corresponding to a movement of one patch distance, and a maximum equal to the half of the side of the 2D square world. In order to compare this truncated power law distribution of step length with the original random walk of fixed step length of 4 (patches), we choose the Cauchy parameters such that the average length is fixed for a complete run. In particular we have explored a set of truncated Cauchy functions of {4, 6, 8} average step lengths whose results are shown in Fig 8. Now, the first row of plots corresponds to the random walk movement, identical to the results showed in Fig 6, and is used as a benchmark for comparing the effects of the increasing average step lengths of the Cauchy functions depicted in the remaining rows.


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)

Average cooperation and movement.Matrix of plots of the average cooperation <c> as a function of vision ν for different agents’ types of movement (columns) and levels of importance of social capital θ (rows), when the spatial distribution of beached whales is uniform. The maximum standard error of the average of cooperation of all experiments represented in the plots is 0.056.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0121888.g008: Average cooperation and movement.Matrix of plots of the average cooperation <c> as a function of vision ν for different agents’ types of movement (columns) and levels of importance of social capital θ (rows), when the spatial distribution of beached whales is uniform. The maximum standard error of the average of cooperation of all experiments represented in the plots is 0.056.
Mentions: In the last set of experiments, we relaxed the assumption that agents move following a random walk. Now, we assume Lévy flight movement much more similar to real human mobility patterns discussed in the literature [31–33,35]. As we have just described in the Methods section, we have implemented a truncated Cauchy function for the agents’ step length per tick, with a minimum step length of 1, corresponding to a movement of one patch distance, and a maximum equal to the half of the side of the 2D square world. In order to compare this truncated power law distribution of step length with the original random walk of fixed step length of 4 (patches), we choose the Cauchy parameters such that the average length is fixed for a complete run. In particular we have explored a set of truncated Cauchy functions of {4, 6, 8} average step lengths whose results are shown in Fig 8. Now, the first row of plots corresponds to the random walk movement, identical to the results showed in Fig 6, and is used as a benchmark for comparing the effects of the increasing average step lengths of the Cauchy functions depicted in the remaining rows.

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.