Social network size in humans

Human Nature (Impact Factor: 1.96). 04/2003; 14(1):53-72. DOI: 10.1007/s12110-003-1016-y

ABSTRACT This paper examines social network size in contemporary Western society based on the exchange of Christmas cards. Maximum
network size averaged 153.5 individuals, with a mean network size of 124.9 for those individuals explicitly contacted; these
values are remarkably close to the group size of 150 predicted for humans on the basis of the size of their neocortex. Age,
household type, and the relationship to the individual influence network structure, although the proportion of kin remained
relatively constant at around 21%. Frequency of contact between network members was primarily determined by two classes of
variable: passive factors (distance, work colleague, overseas) and active factors (emotional closeness, genetic relatedness).
Controlling for the influence of passive factors on contact rates allowed the hierarchical structure of human social groups
to be delimited. These findings suggest that there may be cognitive constraints on network size.

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    ABSTRACT: This is a report on results from research that tested a hypothesis stating the aggregate phenomenon known to social science as clan-level social complexity can be explained computationally using the following theoretic components: human metabolic and bio-reproductive theory, nutrient seeking (foraging) behaviors, evolutionary theory, and a spatial ecology. To test this hypothesis an agent-based model was created wherein each agent had an artificial chromosome containing eleven genes (8-bits per gene) ten of which had independently inheritable, graded, and expressible traits like draught tolerance, temperature sensitivity, a robust metabolism, and improved fecundity in small-group settings, for example. The agents could move freely within a diverse 2D ecology, enjoyed caloric and water metabolic costs, and had human-like 28-day reproductive cycles with gestation and nursing metabolic adjustments. One simulation in particular ran for more than 200 agent generations of 6,421 simulated years. Reported here are results of that simulation, the changes that occurred in three of the eleven genes in the agent population under test as a consequence of artificial evolution, and how "sociality" may have begun to emerge in the population.
  • Computers in Human Behavior 08/2014; 37:377-384. DOI:10.1016/j.chb.2014.04.033 · 2.27 Impact Factor
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    ABSTRACT: We describe the interim state of development of a prototype, multi-agent system (MAS) studying the Peopling of the Western Hemisphere. The model is part of a computational analysis of proxy evidence associable with late Pleistocene human migrations. In particular, we examine an out-of-Europe migratory theory some suggest occurred late in the Pleistocene. The migratory theory we examine is the Bradley-Stanford Solutrean-Clovis Hypothesis [2], [3]. To date, natural decay and terrestrial location has produced only limited circumstantial [10], genomic [8], and lithic [17] evidence supporting conclusions pertaining to this specific theoretic event. The work described here constitutes the foundation steps for a coherent body of computational social science whose intent is a thorough investigation of the several hypothesized routes often suggested as migratory thoroughfares for early hunter-gatherer peoples into the Western Hemisphere. We use a biologically detailed, temporally articulated, spatially accurate, and empirically driven MAS.
    3rd World Congress on Social Simulation, Kassel, Germany; 09/2010

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