The role of American zoologists and behavioural ecologists in the development of animal sociology, 1934–1964

Abstract

This review considers a period of great activity in the study of animal behaviour in North America during the 30 years preceding the formation of the Animal Behavior Society (ABS) in 1964. Special attention is paid to the history of some of the main ideas of animal sociology. The importance of relating animal behaviour to the natural conditions of existence was re-emphasized in this period. Important centres of investigation are mentioned, with some emphasis on the Department of Zoology at the University of Chicago, particularly on the leadership provided by W. C. Allee and A. E. Emerson, two of the founders of modern animal sociology, and on the relevance to behaviour of Sewall Wright's shifting balance theory of evolution. Major contributions were made dealing with the origin of sociality, social organization, social development, physiology of behaviour, social control in population regulation and the evolution of behaviour. Many major principles of animal sociology were developed or elaborated in North America. Examples include the Allee principle of undercowding, Emerson's concept of dynamic social homeostasis, and the basic similarities in the principles of socialization in birds and mammals, particularly in relation to sensitive periods in development. In the physiology of behavioural development there was Roger Sperry's theory of specific chemical affinities between neurons in the developing central nervous system, related to the inheritance of basic behavioural patterns. Another important concept was the role of embryonic hormones in the development of sexual differences in behaviour. On another level there was Allee's principle of the general dominance of cooperation and mutualism at low population densities, contrasted to the increasing importance of competition at high population densities, with social disorganization under extreme crowding. From the statistical consequences of Mendelian heredity, Wright found that the most favourable conditions for continued adaptive evolution, including social evolution of animals, were of a large population subdivided into many partially isolated local populations, with natural selection taking place at all levels of organization, among populations as well as between individuals. An attempt is made to trace the network of stimulating interrelations and the intellectual heritage during this period among investigators of animal behaviour, especially as relating to the history and gradual formation of the ABS and its precursors. The precursor groups of the ABS emphasized animal sociology (sociobiology in the broad sense of the biology of social relations) from the start.