Introduction
Animal behavioral ecologists have long proposed that greater environmental patchiness changes the optimal strategy for a variety of social behaviors (e.g. MacArthur and Pianka 1966).
Following this lead, primatologists and human behavioral ecologists generally propose a relationship between group size and movement and whether resources are dispersed or clumped in space (e.g. Crook 1970; Jarman 1974; Wrangham 1980; Winterhalder and Smith 1981; Slobodchikoff 1984; Terborgh and Jansen 1986; Kelly 1995). While some ecological models focus on the effects of group size on predation risk, or inter-group competitive ability to monopolize resources, other have focused on cooperation and feeding competition (e.g. MacDonald 1983; White and Wrangham 1988; Chapman et al. 1995; Janson and Goldsmith 1995; Creel 1997). When patches are large feeding competition should be lower, and optimal group size will increase if there are advantages to grouping (Clark and Mangel 1986). Applications of this logic to human foraging societies are tempting. For example, Kelly (1995: 215) following Horn (1968) predicts that hunter-gatherer group size should increase with increased environmental patchiness.In a similar manner, animal ecologists have proposed (and provided some evidence) that levels of resource patchiness affect movement patterns of foraging species
M.A. Janssen (is)
School of Sustainability, Arizona State University, Tempe, USA
e-mail: Marco.Janssen@asu.edu
K. Hill
School of Human Evolution and Social Change, Arizona State University, Tempe, USA e-mail: kim.hill@asu.edu
© Springer International Publishing Switzerland 2016 159
J.A. Barcelo and F. Del Castillo (eds.), Simulating Prehistoric and Ancient Worlds, Computational Social Sciences, DOI 10.1007/978-3-319-31481-5_3
(e.g. Hart 1981). The general prediction is that movement should be less frequent in patchy environments because foragers should stay within a patch until foraging gain rates drop below some critical value before moving on (Charnov 1976).
While most hunter-gatherer mobility models predict that mobility decreases with more abundant resources (an intuitive outcome if movement is costly), Kelly also predicted that more patchy environments should result in less frequent mobility for hunter-gatherer societies (1995: 120) even when resource density is held constant.In this paper we explore these predictions using agent-based modeling, and examine how optimal group size, movement frequency, are affected by more dispersed or more clumped resource distributions, when the absolute number of resources in the environment is held constant. We also examine the effect of targeted camp movement (vs. random) on the return rate that can be obtained in more patchy environment. The model uses real measured parameters from a modern foraging society to create an agent-based model, which subsequently allows us to simulate a more patchy or less patchy environment in order to determine how those changes affect optimal group size and mobility.
3.2