Culture and Ecology of Chaco Canyon and the San Juan Basin

A Broader Perspective 335Assuming that male and female terrestrial huntergathererscontribute 50 percent to the total food consumedby a group and that the division of labor is suchthat males and females focus on different species andorganize independent work parties, it was possible toestimate the minimal group size for foragers at 18.98persons, or at 9.49 if the sexual division of labor wascollapsed. When the male-female division of laborcollapses, group sizes decrease to about half theminimal size of groups with a 50:50 division oflabor.The greater the dependence of the group onterrestrial animals, the greater the proportion of thediet that is obtained by males. When the malesassume greater responsibility for the procurement ofterrestrial animals, the minimal group size increaseslinearly as does the percentage of their contribution tothe total diet until thresholds are reached. For thosedependent on plant resources, this threshold is reachedat a 49 to 50 percent contribution, and there seems tobe no bias toward collectors. For animal-dependentgroups, the threshold occurs when 77 percent of themale contribution to all food is reached. After that,the male contribution may continue to increase, butthe group 1 size decreases. When the group sizemodel was compared to the ethnographic data, themodel worked for cases that meet assumptions, butthere was considerable variability among cases thatviolated one or more of the assumptions.Once mobility is no longer an option due toincreasing population, changes in labor organizationwould occur at the same time that mobility becomesincreasingly ineffective. Mobile residential workgroups that originate in sedentary settings are largerthan the maximum dispersed components of residentiallymobile people at similar locations. Yet there isa dramatic decrease in the area occupied by sedentarypeople relative to that occupied by mobile people.When stress occurs, one way to obtain more food is toincrease the labor input. Within an ethnic group,intensification operates throughout the range of socialsegments; it operates best among larger groups whenthey are constrained in geographic expansion and thearea available for use becomes smaller.Binford (2001:318-332) found that G. Johnson's(1978, 1982) value of six decisionmakers per segmentof population did seem to result from an organizationalfactor. The number of nuclear families in thesmallest groups of hunter-gatherers at foraging campsclosely matched this number during periods ofcollapsed division of labor. The average groupconsisted of 10.5 persons (mUltiply dependency ratioof 1.75 by six), which compared fairly well with theaverage of the smallest node in the bimodal distributionfor cases dependent on terrestrial plants, andwith 10.23, the number derived from the minimalmobility model. When doubled, so that six men andsix women supported 21 persons, the results Were notthat different from 17.49, the average group size inthe ethnographic data, and 20.47, the number derivedfrom the minimal mobility model. Binford concludedthat the minimal decision group and the minimalmobility group numbers fit the same pattern. Thefamily was the basic organizational scale for group 1units; the household is the basic unit only when it islarger than the group 1 size or the household equalsthe family. Examples of the latter are mountedhunters and net-hunting mutualists who have verylarge group 1 units. A third pattern in which theorganizational number of six occurs was found amongthose hunters who reduce risk by pooling theirconsumable products (Winterhalder 1990).Aggregated Residential Units. Group 2units, or aggregated residential units, were notnecessarily built on group 1 units. The socialorganization of hunter-gatherers in these residentialunits is based on segments that work together incooperative units. Based on his terrestrial model, forgroups obtaining most of their food from plants,group 2 size increases as subsistence diversityincreases. The nonpacked groups are organized interms of networks; the family is the unit that decideswith whom to cooperate and where to locatethemselves with regard to maximum subsistencesecurity. The composition of these larger units variesthroughout the year as segments participate indifferent tasks and reunite with others at a later date inrisk-pooling cooperative associations. Within thelarger group, these associations are not necessarily tiedthrough kinship; rather, the task at hand and theabilities of the participants affect the choice ofpartners. Thus, the composition of the aggregatedresidential group changes as different segments movearound the landscape. More than two work groupsmay be organized each day as the packing threshold(when maximum diversity in niche breadth is reached)is approached (Binford 2001:422).