Cooperation in organisms, whether bacteria or primates, has been a difficulty for evolutionary theory since Darwin. On the assumption that interactions between pairs of individuals occur on a probabilistic basis, a model is developed based on the concept of an evolutionarily stable strategy in the context of the Prisoner's Dilemma game. Deductions from the model, and the results of a computer tournament show how cooperation based on reciprocity can get started in an asocial world, can thrive while interacting with a wide range of other strategies, and can resist invasion once fully established. Potential applications include specific aspects of territoriality, mating, and disease.

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The Evolution of Cooperation

This paper reports on the development of social network analysis, tracing its origins in classical sociology and its more recent formulation in social scientific and mathematical work. It is argued...

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Social Network Analysis

This book introduces the non-specialist reader to the principal ideas, nature and purpose of social network analysis. Social networks operate on many levels, from families up to the level of nations, and play a critical role in determining the way problems are solved, organizations are run, and the degree to which individuals achieve their goals. Social network theory maps these relationships between individual actors. Though relatively new on the scene it has become hugely influential across the social sciences. Assuming no prior knowledge of quantitative sociology, this book presents the key ideas in context through examples and illustrations. Using a structured approach to understanding work in this area, John Scott signposts further reading and online sources so readers can develop their knowledge and skills to become practitioners of this research method. A series of Frequently Asked Questions takes the reader through the main objections raised against social network analysis and answers the various queries that will come up once the reader has worked their way through the book.

What is social network analysis

Statistical physics has proven to be a fruitful framework to describe phenomena outside the realm of traditional physics. Recent years have witnessed an attempt by physicists to study collective phenomena emerging from the interactions of individuals as elementary units in social structures. A wide list of topics are reviewed ranging from opinion and cultural and language dynamics to crowd behavior, hierarchy formation, human dynamics, and social spreading. The connections between these problems and other, more traditional, topics of statistical physics are highlighted. Comparison of model results with empirical data from social systems are also emphasized.

Statistical physics of social dynamics

Linear hierarchies, the classical pecking-order structures, are formed readily in both nature and the laboratory in a great range of species including humans. However, the probability of getting linear structures by chance alone is quite low. In this paper we investigate the two hypotheses that are proposed most often to explain linear hierarchies: they are predetermined by differences in the attributes of animals, or they are produced by the dynamics of social interaction, i.e., they are self-organizing. We evaluate these hypotheses using cichlid fish as model animals, and although differences in attributes play a significant part, we find that social interaction is necessary for high proportions of groups with linear hierarchies. Our results suggest that dominance hierarchy formation is a much richer and more complex phenomenon than previously thought, and we explore the implications of these results for evolutionary biology, the social sciences, and the use of animal models in understanding human social organization.

https://www.pnas.org/content/pnas/99/8/5744.full.pdf

Individual differences versus social dynamics in the formation of animal dominance hierarchies

Aggressive interactions and inter-contest interval: how long do winners keep winning?.

Groups in many species of mammals and birds form hierarchies: these hierarchies are frequently linear or near linear in moderate size groups. Two models have been proposed, both implicitly and explicitly, in the literature to explain the process of hierarchy formation. One explanation contends that animals win their places in a hierarchy through a round robin competition, and the other states that there is a high statistical correlation between position and rank on some trait or composite of traits thought to predict dominance. It is demonstrated here that both models require stringent mathematical conditions to predict linear and near linear hierarchies and that available data indicate that these conditions are not met. Most of the data cited are from studies of dominance in chickens, but the same mathematical conditions are necessary to generate linear and near linear hierarchies by the round robin and correlational models in any species. Thus, the findings presented here have application to any species of animals forming linear and near linear hierarchies.

Models of hierarchy formation in animal societies

The author investigates the theory, methods, and findings of animal behaviorists and social scientists studying dominance hierarchies in small groups. In both disciplines: (1) the literature argues that the explanations of hierarchy structure are based upon differences in individual characteristics among group members; (2) although critical examination reveals that these explanations require stringent conditions to account for commonly occurring kinds of hierarchies in humans and animals, the available data indicate such conditions are not met; and (3) the hierarchy-formation process has not been adequately studied. In an attempt to alleviate the current problems in hierarchy research, I present the results of a particular animal study and develop a general explanation as to how hierarchy structures arise. This approach applies to both humans and animals and serves as a model of how the cumulative patterns of interactions among individuals produce group social structures.

Social Process and Hierarchy Formation in Small Groups: A Comparative Perspective

Put in one sentence, the central message of this article is: There are theoretical reasons and empirical evidence to suggest that the performance of cooperative and noncooperative behavior by animals in many situations is best explained by considering both fitness benefits and the contributions of other group members to cooperative behavior. The formal model presented here indicates one way in which fitness benefits and the actions of other group members can be combined to yield predictions about the performance of cooperative and noncooperative behavior. This model is contrasted with the population genetics models applying to cooperative and noncooperative behavior. These latter models predict only the presence or absence of cooperative and noncooperative behavior from fitness considerations; they do not predict the actual, quantifiable amount of each kind of behavior, and they do not recognize the possibility that the amount of a behavior may be adjusted in a manner contingent upon the behavior of other...

https://www.jstor.org/stable/pdfplus/2460803.pdf

Ivan D. Chase

Papers

Individual differences versus social dynamics in the formation of animal dominance hierarchies

Aggressive interactions and inter-contest interval: how long do winners keep winning?.

Models of hierarchy formation in animal societies

Social Process and Hierarchy Formation in Small Groups: A Comparative Perspective

Cooperative and Noncooperative Behavior in Animals