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ABSTRACT: Using aggressive behavior, animals of many species establish dominance hierarchies in both nature and the laboratory. Rank in these hierarchies influences many aspects of animals' lives including their health, physiology, weight gain, genetic expression, and ability to reproduce and raise viable offspring. In this chapter, we define dominance relationships and dominance hierarchies, discuss several model species used in dominance studies, and consider factors that predict the outcomes of dominance encounters in dyads and small groups of animals. Researchers have shown that individual differences in attributes, as well as in states (recent behavioral experiences), influence the outcomes of dominance encounters in dyads. Attributes include physical, physiological, and genetic characteristics while states include recent experiences such as winning or losing earlier contests. However, surprisingly, we marshal experimental and theoretical evidence to demonstrate that these differences have significantly less or no ability to predict the outcomes of dominance encounters for animals in groups as small as three or four individuals. Given these results, we pose an alternative research question: How do animals of so many species form hierarchies with characteristic linear structures despite the relatively low predictability based upon individual differences? In answer to this question, we review the evidence for an alternative approach suggesting that dominance hierarchies are self-structuring. That is, we suggest that linear forms of organization in hierarchies emerge from several kinds of behavioral processes, or sequences of interaction, that are common across many different species of animals from ants to chickens and fish and even some primates. This new approach inspires a variety of further questions for research.
Advances in genetics 01/2011; 75:51-81. · 3.39 Impact Factor
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Ivan D Chase
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ABSTRACT: Researchers have developed a variety of techniques for the visual presentation of quantitative data. These techniques can help to reveal trends and regularities that would be difficult to see if the data were left in raw form. Such techniques can be of great help in exploratory data analysis, making apparent the organization of data sets, developing new hypotheses, and in selecting effects to be tested by statistical analysis. Researchers studying social interaction in groups of animals and humans, however, have few tools to present their raw data visually, and it can be especially difficult to perceive patterns in these data. In this paper I introduce a new graphical method for the visual display of interaction records in human and animal groups, and I illustrate this method using data taken on chickens forming dominance hierarchies.
This new method presents data in a way that can help researchers immediately to see patterns and connections in long, detailed records of interaction. I show a variety of ways in which this new technique can be used: (1) to explore trends in the formation of both group social structures and individual relationships; (2) to compare interaction records across groups of real animals and between real animals and computer-simulated animal interactions; (3) to search for and discover new types of small-scale interaction sequences; and (4) to examine how interaction patterns in larger groups might emerge from those in component subgroups. In addition, I discuss how this method can be modified and extended for visualizing a variety of different kinds of social interaction in both humans and animals.
This method can help researchers develop new insights into the structure and organization of social interaction. Such insights can make it easier for researchers to explain behavioural processes, to select aspects of data for statistical analysis, to design further studies, and to formulate appropriate mathematical models and computer simulations.
Frontiers in Zoology 02/2006; 3:18. · 4.46 Impact Factor
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ABSTRACT: We performed experiments with cichlid fish to test whether several basic aspects of dominance were the same in isolated pairs as in pairs within a social group of three or four. We found that the social context, whether a pair was isolated or within a group, strongly affected the basic properties of dominance relationships. In particular, the stability of relationships over time, the replication of relationships in successive meetings, and the extent of the loser effect were all significantly less in socially embedded pairs than in isolated pairs. We found no significant winner effect in either isolated or socially embedded pairs. These findings call into question many current approaches to dominance that do not consider social context as an important factor in dominance behavior. These findings also cast serious doubt on the validity of empirical and theoretical approaches based on dyadic interactions. Among these approaches are game theoretic models for the evolution of aggressive behavior, experimental designs evaluating how asymmetries in attributes influence the outcome of dominance
Behaviour 10/2003; 140(10):1193-1217. · 1.57 Impact Factor
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ABSTRACT: 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.
Proceedings of the National Academy of Sciences 05/2002; 99(8):5744-9. · 9.68 Impact Factor
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I D Chase
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ABSTRACT: Dominance hierarchies near linearity (containing mostly transitive and few intransitive triads) are common in many species. Analysis of the possible sequences for forming dominance relationships shows that two ensure transitivity, and two others produce either transitive or intransitive triads. Experiments with chickens show that in groups of three and four they most often use the two sequences that ensure transitivity and thus linear hierarchies. Examination of such sequences may help explain the formation of near linear hierarchies in other species.
Science 05/1982; 216(4544):439-40. · 31.20 Impact Factor
