The Core of Hxaro Exchange

... exploring Gravity Solutions

Starting from the gravity solution for the hxaro exchange system, we will show how to read the results of such a solution and demonstrate how specific features contained in the solution can be exploited to answer questions of theoretical importance.

The morphing procedure moves those actors who have exchange relations with other camps into the center of the total system. The solution above shows these new locations together with the links for which this new solution represents a low energy state. While the image above presents all empirical information that has produced the new solution, it has the disadvantage of not being easily readable.

One way to enhance the readability is to omit the ties and to mark the different domains which are populated by the members of a specific camp. This is shown below.

These convex hulls of the camp populations reflect more intuitively what has happened to the original camp locations: the inhabitants of the red camp stay relatively close together - even the most central red actor does not invade any area of the other camps. This is different for the blue and green and two members of the yellow camp.

If our focus is on defining the core of the exchange system, a conservative solution is to look at the domain overlap - the intersection of the the camp domains. This is the area of interpenetration. Actors who are positioned inside this area have links which constitute much of the total intercamp exchange. The area of intersection - the core - is pink in the image below.

The gravity solution has provided us with a core domain of the hxaro system. Individuals located in this domain are of central importance for connecting different camps by hxaro exchange.

We can now use this formal definition of the core together with additional information and try to answer an important theoretical question about the nature of the hxaro exchange system. A question of great theoretical importance to anthropologists is to which degree hxaro is a kinship phenomenon. For the following images we use a classification of the hxaro exchanges which makes use of additional information on who has consanguineous kin relationships with whom among the Kung. This provides us with three types of links:

The image below contains all links of the core population only.

While the image above could be used to trace all links in which a core member is involved, it is still too complex to give an easy answer to our question. Again we omit the links from the visualisation and provide some summary information with the help of tiny pie-charts, one for each member of the core domain: the size of the pie chart stands for the number of reported exchanges of a specific actor, the composition of the pie gives information on the specific mixture of exchange-only, kin-based exchange and 'unused' kinship relations (kin only) these actors have.

Having identified the core of the system und used an independent classification of exchanges by kinship, we find that almost all of the core actors of hxaro exchange conduct a considerable part of their exchanges based on kinship relations, and are at the same time also involved in pure exchanges (exchange only).

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Lothar Krempel, MPI für Gesellschaftsforschung, Lothringerstr.78, 50677 Köln, Germany
email: krempel@mpi-fg-koeln.mpg.de