SNA of Kin-Based social-economic networks

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    A Social Network Analysis Approach to Modeling Social-Economic Complexity in

    Traditional Kin-Based Systems

    Brian D. Jones

    IntroductionThis paper explores changes in the organization of kin-based social-economic

    networks utilizing methods from Social Network Analysis. Social Network Analysis

    (SNA) is a growing approach to investigating large, complex data sets comprised oflinked actors. SNA provides tools for the researcher interested in network topology, that

    is, the morphology and structure of a network. Analytical software provides a means to

    visualize large data sets as sociograms, and more importantly, to quantify many of theircharacteristics. Some important network variables include group cohesion, number of

    components (cliques), brokerage roles of actors, measures of centrality, information

    diffusion, and measures of prestige and rank. Although these variables have clearapplication to anthropological theory, social network analysis has remained primarily a

    research tool among sociologists.The networks I will describe are intended to model changing social-economic

    organization among traditional (non-state-level) kin-based social groups. A constantpower-law based economic organization underlies the model. Power-law distributions

    typify many complex social and economic networks and are referred to in the literature as

    scale-free because they express the same organization at any scale of analysis (Barabsiand Albert 1999). Scale-free networks consist of actors among whom many are loosely

    linked to others, and very few are quite strongly linked. Such relationships express

    themselves as straight lines on log-log plots that summarize the number of links and theircumulative proportion in a population (Bentley 2003). Power-law distributions are

    considered ubiquitous, appearing in a variety of networked systems as diverse as moderncorporate organizations, Hollywood actor networks, numbers of sexual human partners,

    connections between airline hubs, the electrical power grid structure, and university

    research funding (Barabasi 2002, Bentley and Maschner 2007: 15-4).Barabasi and Albert (1999) established that that scale-free organization typifies

    networks that grow over time based on a rich get richer algorithm. This means that the

    probability of a new actor linking to an existing one is based on the proportion of links

    the established actor already controls. Thus, if one university has a long-standing trackrecord of attaining NSF grants, it has a greater probability of receiving new ones. I use

    this underlying principle to model traditional human economies because it has become

    increasingly evident that even the simplest foraging economies are underlain by a highdegree of variation in terms of individual hunted meat yield, or access to trade partners

    (e.g. Bentley 2003: 39-40). Bentley (2003) has determined the existence of scale-free

    social-economic organization among Somali and Gabbra pastoralists, and in the size ofNeolithic long barrows, while Maschner and Bentley (2003) discuss scale-free

    organization among Northwest Pacific house floor sizes as it relates to social rank.

    In all of these cases, the presence of scale-free relationships points to the existence ofsignificant variation in levels of social prestige, rank (Frieds positions of valued status

    [1967: 109]) and/or social stratification (Frieds unequal access to basic resources

    [1967: 186]). Other classic examples would likely include the Trobriand Kula exchange

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    network in which one or two high-status participants have hundreds of trade partners,

    while most have one or two (Malinowski 1920). Among foragers, where social pressuresmay exist to promote cooperation rather than competition, differential prestige among

    actors will nevertheless likely be present because of the rich get richer phenomenon

    inherent to growing networks. I would anticipate, for example, that among Khoisan

    women, very few have collections of beaded necklaces acquired through social contactsthat weigh in the kilogram range, while most have tens of grams of beads in their

    possession. In the scenarios explored here, each model is seeded with 2 linked trade

    partners, each with an initial 50% probability of acquiring the next partner. Thisparticular power law relationship results in a best linked actor with between about 44

    and 86 incoming links after all of the 1,000 trade ties have been established (based on a

    1-sigma range of 15 sampled networks). The exact number varies in each iterationbecause of the probabilistic nature of the model.

    In addition to a scale-free economic organization, the model is grounded in a simple

    kinship-based organization. Each actor in the model represents an 8-person householdconsisting of two grandparents, a married couple and four sub-adult children. In the

    model, the spouse who marries into the household represents a directed link in, while themarriage of a son or daughter into another family represents a directed link out (Fig. 1).

    Such households could be patrilocal or matrilocal in organization, such that a daughtermarries in, in the first example, or a son marries out in the second. The simple

    assumption for the model is that each household produces a marriageable son and

    daughter. This is meant to represent a mean condition in a stable population. It isassumed that two of the four subadults would not survive to adulthood. While the model

    could have been created to reflect more variability, this modal form was selected for the

    sake of simplicity. The 8-person household size of each actor in the network of kin isused to calculate larger-scale populations.

    The complete model consists of 1,000 actors representing a population of 8,000individuals. Three related computer programs were written using FreeBasic, an open-

    source variant of the BASIC computer language. The program permits the user input of

    certain variables, such as the number of exogamous bands, or the proportion of elite inthe population. Graphic output is produced, largely to reassure the user that the program

    did what it was asked to do (Fig. 2). The programs produce three types of additional

    output in the form of ascii text files. These include a comma-delimited csv file that can

    be imported into a spreadsheet or database, and network and partition files that can beread by Pajek social network analysis software (de Nooy et al. 2005). These files

    summarize the network, characterizing the kinship and economic links of each actor, or

    family unit. Every actor produces an outgoing economic link and an outgoing kinshiplink. All actors receive one kinship link, but may receive many or no economic ties (Fig.

    3).

    The model was developed to examine the effects of increasing kinship restrictions onthe topology of the resultant social network. Kinship restrictions are utilized to model

    change between very open, exogamous systems as occur among small-scale foraging

    societies, through tightly-controlled endogamous ranked systems where an elite classmakes up as little as 1% of the population, as might occur among chiefdom levels of

    socio-political organization. Two basic systems are thus explored. The first models

    exogamous societies with a decreasing number of clans. Beginning with 100 clans, 99%

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    of the population is potentially marriageable, while with just two clans (essentially a

    moiety-based system) only 50% of the population is marriageable. The second systemexamines the effects of prestige-based rank on the network. A transitional system is

    explored in which actors are ranked into two moieties, but marriage remains exogamous

    (e.g. following a Natchez marriage pattern [Tooker 1963]). Increasing restrictions on

    marriage, now based on rank rather than clan affiliation, are then further explored byincorporating endogamous marriage rules. Models start with a ranked endogamous

    moiety-based system, and then examine social organizations in which an endogamous

    elite represent an ever-shrinking portion of the population, while the pool of commonersgrows proportionally.

    I use increasing marriage restriction rules as a proxy of increasing social complexity,

    and secondarily, growing population density. If we allow the simple assumption that atleast 200 individuals are required within a human breeding population to maintain long-

    term viability (Wobst 1974), then group size must increase to compensate for the

    decreasing proportion of available marriageable partners. This relationship issummarized in Table 1. It indicates that marriage regulations may become more

    restrictive only as populations grow.

    Table 1: Modeled Relationship Between Marriage Restriction and Base Populationassuming a 200-person minimum breeding population

    exogamous endogamous

    100 clans 10 clans 2 clans 25% elite 10% elite 5% elite 1% elite

    % marriageable 99% 90% 50% 25% 10% 5% 1%

    minimum population 202 222 400 800 2,000 4,000 20,000

    modeled family actor units 25.25 27.78 50 100 250 500 2500

    The changes observed can be seen as paralleling different levels of socio-politicalorganization. Where few or limited marriage restrictions exist, the modeled exogamous

    clan-based societies can be described as bands in Services (1962) original

    terminology. Such societies are centered on small, mobile kin groups, loosely linked toothers across a landscape. These societies may have rather low group numbers, falling

    between at least 200 and 400 individuals.Social systems anchored in moiety-based marriage restrictions and those in which an

    endogamous ranked elite represent a portion of the population falling between about 50%

    and 10% are best described as tribes. Tribal societies are typically settled in villages

    with populations in the hundreds to one or two thousand. As modeled based on theimposed marriage restrictions, these societies are expected to number between, at a

    minimum, 400 and 2,000 members. Finally, large endogamous ranked systems where the

    elite represent a small portion of the overall population (e.g. less than 10%) are bestdescribed as chiefdoms. In this case, elite marriage partners are likely to come from

    affiliated neighboring villages, or potentially from within a single large urbanized center,

    such as Cahokia. Such social systems are likely to number in the thousands or tens ofthousands.

    While these dated terms have been the subject of much anthropological debate since

    Service first described them, they provide a heuristic, if simplistic, framework for

    understanding some of the underlying goals of this study. No attempt was made to model

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    specific societies, such as Algonquian or Iroquoisan social organizations that I have

    discussed elsewhere (Jones 2010), rather, my intent was to examine more generalnetwork dynamics that likely relate to these, and many other kin-based systems. My

    primary goal to introduce some of the advantages of a social network analysis approach

    to studies of social complexity and I hope that the reader will consider how my general

    conclusions may relate to their own specific areas of interest.

    Methods

    Three basic measures were made of the modeled networks. The first ranks actors interms of in-coming network links. This measure is referred to as the indegree or

    simply popularity of a vertex (actor) (de Nooy et al. 2005: 189). The number of

    incoming links is easily quantified for each actor and provides a measure of socialprestige. Sorting the indegrees of all network actors provides a way to assess each actors

    rank within the population. Arbitrary cut-offs permit the ranked list of actors to be

    divided into classes of elites and commoners based on the desired proportion of eachin a given model simulation. Rank divisions only apply to the second group of models,

    not to clan-based kinship systems.The second measure determines how well the network is integrated. The simplest

    measure of integration is the network diameter. The diameter is most often understood(somewhat confusingly) as the longest shortest path between all vertices in the

    network. A shortest pathway through other actors links every two actors in a social

    network. The diameter therefore represents the longest of all of these most efficient pathsthrough the entire network. The diameter is measured in terms of the number of steps

    required to reach a desired point. This term reflects the popular concept of six degrees

    of separation, between two individuals. The difference is that degrees of separationusually indicates the average distance between all actors in a network. (This measure has

    only recently been mathematically verified to be 6.6 among the global human network, ashas long been suggested in the popular press.) Average network distance is a useful

    value because it reduces much of the variation inherent in modeled networks. The

    average network distance is generally significantly less than its actual diameter (forexample, the diameter of the global human social network is about 29). Both measures

    are used here to quantify network integration.

    A third measure of network integration is the proportion of actors not reachable from

    another actor. This can occur in loosely integrated networks, and is also more likely innetworks with directed links between actors. In undirected networks, information

    between actors can move either direction along a link (such undirected links are referred

    to as edges), but in directed networks, links define the direction of movement (these arereferred to as arcs). The networks modeled are all directed networks, so under some

    conditions, actors may fall out of reach of other actors within the network. When

    networks become fragmented in this way, information can no longer pass to all of itsmembers, and the network can be qualified as broken or poorly integrated.

    These measures can all be provided by a single function within Pajek (Net>Paths

    between two vertices>Distribution of distances>From all vertices). Simulations were runthrough the BASIC programs based on each model parameter. The resultant .net files

    were then analyzed within Pajek. Because there was no way to iterate this process

    automatically, this study is limited to the analysis of 10 samples from each of the nine

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    model parameters. Resultant raw data was incorporated into Excel spreadsheets for

    statistical analysis and visualization.Because of the probabilistic nature involved in the creation of each network, some

    variation in the results of each test is expected. Nevertheless, the sample of 10 networks

    under each condition proved sufficient to assess levels of significance between model

    parameters. Additional program output (partition files in the .clu format) was used todefine both clan and elite-commoner sub-networks within Pajek. These partitions

    allowed the data to be visualized more effectively with Pajeks Draw function (Figure

    4). In some cases, commoner sub-networks were extracted from the complete networkusing the partition files (Operations>Extract from network>Partition) to permit additional

    analysis of the sub-network. Pajeks Net>Partitions>Degree>Input function was utilized

    to produce vector files that were used to scale vertices in the draw window based ontheir number of incoming links. Image files were exported to Encapsulated PostScript

    (.eps) from within the Draw window (Export>2D>EPS/PS).

    Results

    The baseline for all model comparisons consists of a network with no marriagerestrictions and a perfectly even distribution of trade links. This perfect world network

    consists in part of a ring-formed chain-like trade network. In graph theory terms, suchnetworks are described as highly clustered, that is, actors are exclusively connected to

    their nearest neighbors (Watts 2003). The network also consists of random kinship links.

    While the raw trade network has an average distance of 500 steps between its actors, therandom kin ties produce a small world effect (Watts and Strogatz 1998) that create

    shortcuts, reducing the average network distance to just 8.66 steps (Figure 5). The

    network diameter (longest of all most efficient paths between actors) is just 14 steps. Aswe constrain the network, these distances will increase, indicating a drift from a nearly

    random network to one in which there is increasing organization.The first model consists of 100 exogamous clans, seeded by the two pre-established

    trade relationships used throughout all of the systems examined. This model of a very

    open exogamous clan organization with few marriage restrictions is intended to modelsmall-scale social-economic organization as might be found among highly mobile

    foraging societies. Less restricted marriage rules such as these are expected under low

    population density conditions where finding an appropriate mate may be logistically

    challenging. In North America, Paleoindian and Early Archaic foraging groups werelikely organized in this way. This network organization expresses a significant increase

    in average network distance, which is now about 11.7 steps between any two actors.

    Most of this change is actually associated with the introduction of the scale-free tradingnetwork rather than the increased restriction on marriage partners. The introduction of the

    100 exogamous clans under a balanced trade scenario results in no significant change

    from the perfect world results noted above.As marriage restrictions are further increased in the exogamous 10-clan system,

    there is an insignificant decline (p=0.477 based on a 2-tailed T-test) in the average

    network distance to 11.62. In fact, the same average distance is expressed by the systemwith just two exogamous clans. This indicates that none of these exogamous models

    have any significant effect on the network structure once a power-law economic

    organization is introduced.

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    A subtle, though significant (p=0.0012) change does occur in the system when

    identity based on rank is first introduced. This marks an important change in the valuesystem of the society, as suggested by Frieds (1967) original definition of rank as

    indicating access to positions ofvaluedstatus. Until this time, clan affiliation was

    randomly based, and no realized social value was placed on ones prestige. Some clan

    members enjoyed many trade links, while others had few, but this did not affect onessocial identity per se. The ranked 2-clan (moiety) system divides actors into two

    groups based on the number of trade links they receive. The half of the population that

    receives the most trade partners belongs to the elite clan, and the half that controls theleast belongs to the commoner clan. While this organization seems peculiar, it is not

    unprecedented in the ethnographic literature (e.g. as expressed in the ranked Natchez

    moiety). Based on the power law distribution of trade links, about two-thirds of actorsreceive no trade link at all, while the remaining third receive one or more links. The net

    effect of a bimodal social organization is that the commoner class is isolated from

    incoming trade links, while the elite class receives them all. Under exogamous marriagerules, the isolated commoners are reunited with the dense elite network. The net effect is

    that the average distance between actors in the network is actually reduced slightly fromthat of the unranked exogamous system.

    The next scenario reflects a second value transition within the society. In thisscenario, the elites redefine the marriage rules and enforce an endogamous system to

    better maintain control over the trade network. Instead of elites marrying commoners,

    elites now marry one another, and commoners do the same. This small change in therules results in a drastic reorganization of the social-economic network. Under

    endogamous marriage rules, the commoners now form an isolated kin-network with all

    trade links directed toward the elite group. This network is likely to be comprised of anumber of disassociated loops with an average (but highly variable) network distance of

    about 170+/-50. The elite enjoy a complex, dense small-world network of kinship andtrade ties. This close network has an average network distance of about 10.15+/-0.18.

    Not only does this represent a very effective communication network, it also controls

    100% of the trade economy. The 1000 trade links are divided unequally among the 500elite, but provide a mean per-capita wealth of 2 trade ties.

    As a whole, the endogamous network comprised of a 50% elite, 50% commoner ratio

    must be considered broken. Its average network distance is 30.38, and is highly

    variable (+/-17.2). Thus, while the elite sub-network may be enjoying an optimalstructure, the network as a whole is fragmented and communication between many of its

    members based on exchange and kin networks cannot occur. On average, 39.8+/-4.5% of

    the networks members cannot be reached by its other members. Such a disrupted social-economic structure is not likely to function for any length of time.

    There are two options for change. The first is to return to the prior system of ranked

    exogamy. This will require the elite to relinquish their complete control over theeconomic wealth in trade partners. The second option is to increase the size of the

    commoner network by redefining the cutoff point for elite status. This option actually

    benefits both the elites and commoners. The commoners need to attract additionalmembers from among the elite if they hope to participate in the full social-economic

    network. The elites can increase their per-capita wealth in trade ties by shrinking their

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    numbers so that only those with the greatest number of trade links are counted among

    themselves.The net effect of these two goals is likely to move the network in the direction of

    additional increased restrictions on marriage. As the definition of who qualifies as an

    elite becomes narrower, network functionality is gradually restored. Under the power-

    law that underlies this particular system, the benefits of a smaller elite to the overallnetwork are only realized after the elite comprise less than 33% of the network. After

    this point, some individuals receiving trade links will be counted among the commoners.

    At first, their numbers are few and the links they provide are also limited, but by the timethe network defines the elite class as comprising the upper 20% of incoming trade wealth,

    the number of isolated network actors falls on average well below one individual (0.26+/-

    0.41).At this point, the network can be seen as restored. With a 20% elite, the average

    network distance is still high and remains quite variable (23.6+/-3.5). Elite wealth is

    reduced to about 88% of the total (that is, the commoners now have access to 12%), andper-capita trade ties have increased to 4.4. As the definition of elites is constrained to

    the wealthiest 10% of the population, the average network diameter drops to 17.3+/-1.2.Elite per capita wealth is increased to about 7 links, and the commoners now have access

    to about 31% of the trade network. When the elite comprise 5% of the population, theaverage network diameter drops to 15.5. Elite per capita wealth in incoming trade links

    is raised to about 10 links, and the commoners have access to about 49% of the total trade

    economy. At 1% of the population, the average network diameter is 12.6, and variationabout the mean is quite low (+/-0.28), indicating the establishment of a relatively robust

    and efficient network. Elite per capita wealth averages close to 21 incoming links, while

    the commoners control nearly 80% of the remaining network. After this point,increasingly narrowed definitions of the elite continue to reduce the average network

    slightly, but even at 0.2% of the population (two individuals in a thousand) the value is11.97+/-0.23, and additional change comes very slowly as the limit is approached. This

    limit can be calculated using an exogamous network with no marriage restrictions and an

    initial seed of two trade links. Its value is 11.81+/-0.26 based on a sample of 10 suchnetworks, which is not significantly different from the sample of 0.2% elite networks at

    this sample size. In sum, the effectiveness of ranked endogamous networks with elites

    making up to 1% or less of the overall population begins to approach that observed under

    exogamous conditions.

    Discussion

    The societies modeled above go through two important social transitions based on 1)a revaluation of prestige and a redefinition of identity based on rank and 2) a redefinition

    of marriageable partners based on rank. In the first transition, group membership is

    linked to ones level of prestige. This is a critical value change that marks the emergenceof rank as an aspect of identity. In the second transition, endogamy provides a means for

    one group to monopolize its economic status. The transition to an endogamous marriage

    custom redefines group solidarity so that the definition of us and them becomes moreexplicit. Neither of these should be seen as simple transitions, as they are likely to

    conflict with the established sense of cosmological order, as expressed in most moiety

    organizations.

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    In non-judgmental terms reflecting the efficiency of the social networks in question,

    the first transition is a good one, because it reduces average network diameter, and thusincreases the effectiveness of communication between its members. This strategy

    appears to increase small world network dynamics by effectively combining a pseudo-

    random kin network with a power-law-based economic network. The second transition is

    disastrous, however. In this case, through separating the two kinship networks, thestrongly biased economic network only reaches half the members of the population. The

    society is rent asunder, and communication to half of its members becomes severely

    compromised. This may explain why such social constructs are very uncommon in theanthropological literature.

    Should the new endogamous rank-based identity structure remain intact (rather than

    reverting to the effective exogamous system typified by the example of the Natchez), theonly way to repair the fabric of society is to reduce the overall proportion of those

    defined as elites. This benefits the commoners by allowing some members with

    incoming trade ties to be included in its kin network, reestablishing opportunities forsociety-wide communication. The benefit to the elite class is an increase in per capita

    wealth, at the cost of giving up some control over the economic system. In this way, theelite become more elite and can differentiate themselves more strongly from the

    commoner class.A notable transition in the behavior of the new network occurs when the proportion of

    elite approaches 1% of the population. At this point, the network is quite well integrated

    (with an average diameter of about 12.5) and very few members are likely to be isolatedfrom the overall network. As summarized in Table 1, such a restricted marriage system is

    only sustainable in societies numbering about 20,000 members, that is, within chiefdoms.

    In fact, the transition to a ranked endogamous social organization is unlikely to occuruntil a local population reaches at least 4,000 members (a 5% elite class), at which point

    the transition to a very restricted endogamous elite can occur without compromising theoverall social network stability. Ranked endogamous societies numbering less than 4,000

    members (that is, with an elite proportion between 50% and 5%) are simply unlikely to

    sustain themselves for any period because of the inherently unstable and fragmentednature of the resultant kinship and economic networks.

    Importantly, a tipping point occurs in the economic organization of endogamous elite

    networks with an elite class comprising less than 5% of the overall population. At this

    time, elite control over the economic portion of the network rapidly falls below 50%. At4% of the population, the elite control on average 45.3% of the economy, but at 2% they

    have access to only 35.4% and at 1% only 26.2% (based on 10 sampled networks). This

    indicates that in the system modeled above, when the elite comprise less than 5% of thesociety, the commoner class begins to control the majority of the economy.

    While this transition is occurring, the commoner class sub-network is becoming

    increasingly effective on its own. When the elite represent 5% of the population, thecommoner network diameter approximates that of the full network (average

    diameter=16.5+/-0.4 vs. a complete network of 15.5+/-0.7). While the difference

    between the two values is significant (p=0.0013 with a 2-tailed T-test), the ranges overlapat 1-sigma. With a 1% elite, the difference between the two networks is less than 1

    degree of separation, and there is little incentive for the commoners to continue to take

    part in the portion of the trade economy controlled by the elite. They now control on

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    average 73.8% of the economy. At this point, it is increasingly likely that the commoners

    will abandon the elite, unless other strong incentives keep them in the system.

    Conclusions

    The use of a Social Network Analysis approach has proven effective at examining a

    social-economic model designed to explore the network dynamics of a kin-based socialorganization overlain by a power-law-structured economy. The modeling process itself is

    rewarding, as it challenges one to deconstruct traditional (non-state-level) social-

    economic dynamics into just a few critical variables. The variables selected in this modelwere related to the definition of marriageable partners and the degree of social value

    placed on prestige. These alone appear to have a significant effect on the efficiency of

    the social networks examined, as measured by their average network diameters (degreesof separation between actors). Actor prestige was evaluated by the calculation of

    incoming economic links and provided a means of establishing the rank of each actor.

    The measure of network diameter quantified the efficiency of the movement ofinformation across the entire network. Other factors measured by the Pajek SNA

    software included the proportion of actors unreachable by the rest of the network, whichprovided a measure of network viability. The proposed relationship between increased

    marriage restrictions and degree of social complexity is, to my knowledge, a new one, butit appears to have functioned well as a central variable in the models explored here.

    Underlying the organization of all of the networks examined was a power-law

    distribution in economic ties between actors. This structure was selected because itappears to underlie many natural and human systems that add elements over time. The

    nature of the power law was arbitrarily established, and was based on seeding a growing

    economic network with just two active participants. A more equitable power lawdistribution could have been modeled by seeding the trade network with a greater number

    of actors, but the simplest organization was selected. Only by seeding the populationwith more than 100 or so initial trade partners can one move beyond the general rule that

    only about a third of the population receives any incoming economic links at all. The

    primary effect of altering the strength of the power-law distribution in the economy is onthe point at which the commoner class controls more than 50% of the economy. In the

    model presented above, this transition occurred when the elite class was comprised of the

    wealthiest four to five percent of the population. Given a more equitable distribution of

    wealth, the commoners will control the majority of the economy sooner (for example,with 300 seeded trade relationships, the commoners will already control over 50% of

    trade ties when the elites comprise about 10% of the population).

    The models examined suggest that exogamous kin systems become only slightlymore efficient as marriage restrictions (based on a reduction in the number of clans) are

    introduced. A system comprised of just two exogamous clans is not very different in its

    network topology than a system comprised of 100 clans. Interestingly, a subtle, butsignificant improvement in exogamous network efficiency occurs when individuals

    become ranked based on their level of economic prestige, and when that rank defines

    their band membership. Such moiety-based exogamous ranked kinship systems typifiedgroups such as the Natchez, likely descendants of a Mississippian chiefdom society.

    An important result of this study is the recognition that at some time, under a system

    of endogamous elite marriage and as marriage restrictions are increased (as the definition

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    of who qualifies as an elite is narrowed), some point will be reached where the

    commoners control the majority of the economy. If at this point their own kinshipnetwork is well enough integrated, the commoners may elect to remove themselves from

    the elite-controlled network at little organizational cost. A similar balance of elite vs.

    commoner control of the economy may underlie the dynamics of many traditional

    chiefdom-level organizations. The network study presented here may provide at least apartial explanation of the observed fragility of such systems in the archaeological record.

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    Figure 1: The 8-individual kinship organization representing a single actor in thenetwork. Assumes a stable modal population where two children survive to reproduce.

    The example shown is patrilocal, with females marrying out and into family units,

    forming the kinship links between actors.

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    Figure 2: Sample output of BASIC program used to produce the network models. The

    output summarizes a 10% elite endogamous kinship network seeded with two trade

    partners. The total number of incoming links and the calculated rank of the first 30 actorsare summarized on the right.

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    Figure 3: The modeled kin-based economic network simplified with 12 actors.

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    Figure 4: Example of Pajek Draw output of 50% elite endogamous network (elite: red,commoner: green). Size of vertex reflects the rank of the actor. Note the isolated

    commoner kin chains resulting from this organization.

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    Average Network Diameter: "degrees of separation"

    11.0111.6211.6211.718 .6 6

    30.38

    23.62

    17.2715.51

    12.6412.33 11. 97 11. 81

    0

    5

    10

    15

    20

    25

    30

    35

    4045

    50

    perfe

    ctworld

    100cla

    ns

    10cla

    ns

    2cla

    ns

    rank

    edcla

    ns

    50%

    elite

    20%

    elite

    10%

    elite

    5%elite

    1%elite

    0.5%

    elite

    0.2%

    elite lim

    it

    Figure 5: Average Network Diameters of the Modeled Networks.