The Coevolution of Group Size and Leadership: An Agent-Based Public Goods Model for Prehispanic Pueblo Societies

Abstract

We present an agent-based model for voluntaristic processes allowing the emergence of leadership in small-scale societies, parameterized to apply to Pueblo societies of the northern US Southwest between AD 600 and 1300. We embed an evolutionary public-goods game in a spatial simulation of household activities in which agents, representing households, decide where to farm, hunt, and locate their residences. Leaders, through their work in monitoring group members and punishing defectors, can increase the likelihood that group members will cooperate to achieve a favorable outcome in the public-goods game. We show that under certain conditions households prefer to work in a group with a leader who receives a share of the group's productivity, rather than to work in a group with no leader. Simulation produces outcomes that match reasonably well those known for a portion of Southwest Colorado between AD 600 and 900. We suggest that for later periods a model incorporating coercion, or inter-group competition, or both, and one in which tiered hierarchies of leadership can emerge, would increase the goodness-of-fit.

Modeling Historical Land Cover and Land Use: A Review fromContemporary Modeling

“…It is estimated that the world's extension of pre-agriculture forests was of 61.51 million km 2 , of which 15.51 million km 2 were lost prior to about 1500 A.D. The historical LCLUC models are relatively scarce and were mostly developed during the past two decades in several parts of the world, mainly in China, the USA, Europe and South America (Figure 1 [7,34,37,39,[62][63][64][65][66][67][68][69][70]). Historical models of change have distinct disciplinary origins and use different space-time scales.…”

“…The second group, with less numerous contributions, includes agent-oriented models attempting to understand the socio-environmental processes and their relation to LCLUC [7,15,39,40,64,76,77]. In general terms, the study areas of these models are small, ranging from a couple to hundreds of square kilometers.…”

“…Several works have recognized that LCLUC and the intensification of agricultural practices in response to demographic growth can lead to severe change in local or regional environmental conditions [7,8]. Such intensification of agriculture can lead to problems for population persistence [1,3,[9][10][11] and even cause the collapse of civilizations [7,[12][13][14][15][16][17][18].…”

“…Other models include decision-making by local communities and the influence of such decisions in land administration [31]. Modeling environmental conditions that determine processes of change is difficult because of the numerous biophysical, socioeconomic and cultural variables involved [7,15,17]. These models apply from the scale of individual parcels to that of large extensions and are used for predicting and explaining both the systems and the effects that human processes have on these systems [27].…”

Long and spatially variable Neolithic Demographic Transition in the North American Southwest

“…Regional population size limits the maximum sizes that social groups within the region can attain (1). Social group size in turn influences the capacity of groups to innovate and maintain innovations (2,3), and changes the conditions of the contest within societies between defection and its suppression, affecting efficiency in production of public goods and therefore social organization (4)(5)(6)(7).…”