Modeling Group Size and Scalar Stress by Logistic Regression from an Archaeological Perspective

Abstract

Johnson’s scalar stress theory, describing the mechanics of (and the remedies to) the increase in in-group conflictuality that parallels the increase in groups’ size, provides scholars with a useful theoretical framework for the understanding of different aspects of the material culture of past communities (i.e., social organization, communal food consumption, ceramic style, architecture and settlement layout). Due to its relevance in archaeology and anthropology, the article aims at proposing a predictive model of critical level of scalar stress on the basis of community size. Drawing upon Johnson’s theory and on Dunbar’s findings on the cognitive constrains to human group size, a model is built by means of Logistic Regression on the basis of the data on colony fissioning among the Hutterites of North America. On the grounds of the theoretical framework sketched in the first part of the article, the absence or presence of colony fissioning is considered expression of not critical vs. critical level of scalar stress for the sake of the model building. The model, which is also tested against a sample of archaeological and ethnographic cases: a) confirms the existence of a significant relationship between critical scalar stress and group size, setting the issue on firmer statistical grounds; b) allows calculating the intercept and slope of the logistic regression model, which can be used in any time to estimate the probability that a community experienced a critical level of scalar stress; c) allows locating a critical scalar stress threshold at community size 127 (95% CI: 122–132), while the maximum probability of critical scale stress is predicted at size 158 (95% CI: 147–170). The model ultimately provides grounds to assess, for the sake of any further archaeological/anthropological interpretation, the probability that a group reached a hot spot of size development critical for its internal cohesion.

Sizes of Permanent Campsite Communities Reflect Constraints on Natural Human Communities

“…Partitioning the data sets into what seem to be natural subclusters suggests an even closer fit, with peaks at ∼140 and ∼107 for the small and large data sets, respectively. There is considerable evidence for the existence of a natural community size of approximately 150 in both ethnographic (Alberti 2014;Dunbar 2008) and online (Fuchs et al 2014;Gonçalves, Perra, Vespignani 2011;Haerter, Jamtveit, and Mathiesen 2012;Pollet, Roberts, and Dunbar 2011) environments, and the fact that the average camp community size in the present samples is in this same area adds support to the claim that this is an optimal or preferred community size. More generally, analysis of the substructuring patterns in both data sets suggests peaks at values that approximate the observed social layering values of 50, 150, and 500 observed in natural communities.…”

Leadership solves collective action problems in small-scale societies

“…Collective action problems become more frequent and difficult to solve as group size increases [7,87]. In larger, dense communities, the costs of monitoring for free-riding increase, and conflicts between group members tend to become more frequent [88,89]. Group members may prefer more institutional leadership when this helps solve the problems of life in large, dense communities [4,90,91].…”

How to Make a Polity (In the Central Mesa Verde Region)

“…. [which] can ameliorate scalar stress by promoting an effective communication flow and by fostering in-group consensus and cohesion” (Alberti 2014:2; see also Adler and Wilshusen 1990). Coward and Dunbar (2014:388) suggest that more or less universal appearance of such structures is due to the fact that “elaborating the ‘settings’ for social interaction [with ritual facilities for example] simplifies social interactions and performance by off-loading the social information necessary for effective interactions from human memory into the material environment.”…”