1242 



HORMONAL REGULATION OF BEHAVIOR 



several species of North American gulls in 

 the process of pair formation. The hostility 

 which precedes pairing is associated with 

 the establishment of their territories. Pair- 

 formation activities seem to be followed 

 by a reduction of intersexual hostility and 

 the gradual emergence of sexual behavior. 

 According to Tinbergen (1953), the pre- 

 nuptial behavior of the female appeases the 

 male, suppresses her escape behavior and, 

 together with the courting by the male, fa- 

 cilitates the synchronization of sexual be- 

 havior patterns. 



The selective value of aggressiveness has 

 been discussed by Collias ( 1944) and Car- 

 penter (1958). Selection may operate on the 

 level of the individual, with the more ag- 

 gressive ones usually having precedence to 

 food, mates, and cover. On the group level 

 the more socially stable units conserve en- 

 ergy and may leave more progeny. 



III. Historical Background 



The discovery of a social organization 

 based on agonistic behavior was made by 

 Schjelderup-Ebbe (1913) during a study of 

 calls or sounds made by chickens. Later he 

 summarized observations of the domestic 

 fowl and other birds (Schjelderup-Ebbe, 

 1935). Many of these were repeated by 

 Sanctuary (1932) and Masure and Allee 

 (1934a), working with chickens. Masure 

 and Allee (1934b) also observed common 

 pigeons and shell parakeets and discovered, 

 contrary to Schjelderup-Ebbe, that some 

 birds do not show absolute dominance, but 

 rather bidirectional pecking (called peck- 

 dominance in the earlier reports). Allee 

 (1936) summarized these initial observa- 

 tions and suggested a plan for analytical 

 studies, which included alteration of the 

 physiologic state by hormonal treatment. 

 Noble and his associates (Noble, 1939a, b; 

 Noble and Curtis, 1939; Noble and Borne, 

 1940; Noble and Wurm, 1940; Noble and 

 Greenberg, 1941) made extensive studies of 

 behavior which stimulated a general in- 

 terest in the relationship between the endo- 

 crines and social behavior in fishes, am- 

 phibians, reptiles, and birds. The social 

 organization in baboons was described by 

 Zuckerman (1932), and in monkeys by 

 Maslow (1934). Carpenter (1934) reported 



the virtual absence of a dominance order 

 in the howler monkey. Yerkes (1939) 

 observed dominance relations between uni- 

 sexual and heterosexual pairs of chimpan- 

 zees and related changes in dominance- 

 submission to the sexual status of the 

 female. 



Since this early period, many investi- 

 gations have been directed at a clarification 

 of the relationship between the gonadal 

 hormones and social, but particularly ago- 

 nistic, behavior. Something of the progress 

 that has been made will be apparent from 

 what follows. However, many reviews al- 

 ready exist^ and in this place a particular 

 effort will be made to present a contempo- 

 rary cross-sectional view of the subject 

 that will contain an indication of the many 

 problems that are in need of study. 



IV. Methods 



Many experimental techniques have been 

 used in studies of agonistic behavior. As 

 would be expected, they vary greatly, de- 

 pending on the species, the question it is 

 hoped the experiments will answer, and the 

 connotation of aggressiveness that is ac- 

 cepted. Potter and Allee (1953), Kislack 

 and Beach (1955), Scott and Fredericson 

 (1951), and Scott (1958b) considered ag- 

 gressiveness as a tendency to start fights. 

 According to this view, the levels of aggres- 

 siveness would be measured by latency, i.e., 

 the time between the meeting of two indi- 

 viduals in a test situation and the first overt 

 display of agonistic behavior. However, the 

 term as it is used in this chapter refers to 

 the ability to be self-assertive or to display 

 independence of action (Collias, 1944) . Ag- 

 gressiveness in this sense is a tendency 

 whereas aggression is an activity. Factors 



^ Comprehensive reviews of aggressive behavior 

 among vertebrates, including a discussion of hor- 

 monal factors, have been prepared by Collias (1944, 

 1950). Social organization and related phenomena 

 in vertebrates were considered bv Allee, Emerson, 

 Park, Park and Schmidt (1949), Allee (1952), Tin- 

 bergen (1953) and Scott (1956, 1958a). General in- 

 formation bearing on the territorial behavior of 

 vertebrates has been brought together by Bourliere 

 (1952) and Carpenter (1958). Other reviews deal 

 with the social behavior of fishes (Aronson, 1957; 

 Baerends, 1957), birds (Hinde, 1956a), ungulates 

 (Darling, 1952), other lower mammals (Hediger. 

 1952), and subhuman primates (Carpenter, 1952) 



