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Introduction
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Methods and Results
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Discussion
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References
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Previous investigators have usually failed to recognize the adaptive value of the reproductive postponement state and have, instead, characterized it as "social pathology." For example, Calhoun characterized males in a reproductive postponement state as "completely passive . . . . They ignored all of the other rats of both sexes, and all the other rats ignored them. Even when the females were in estrus, these passive animals made no advances to them . . . . They were fat and sleek, and their fur showed none of the breaks and bare spots left by the fighting in which males usually engage. But their social disorientation was nearly complete (1).
The reproductive postponement state is one of several systemic states, each mediated by a different hormonal balance, each triggered by different environmental and social stimuli, and each appropriate to a different situation in the life history of the individual. Each state is an all-or-nothing phenomenon; the animal is always in one state, and only that state. Other states include the courtship reproductive state, pregnancy state, lactation state (the latter two only in females), a reproductive postponement state that occurs during winter for the animals living in temperate zones, and an emigration reproductive state. Analyzed in terms of systems theory, each state is a stable rhythmic limit cycle (11). [Note: My most detailed analysis was never published but may be found here.]
The detailed hormonal effects of reproductive states, including where and how the hormones act upon the motivational systems of social behavior in the nervous system, have been reviewed elsewhere (12). According to this analysis, one may distinguish a general set of reproductive states, analyzed best in terms of systems theory, which affect, in turn, a series of specific motivational systems of social behavior organized in the nervous system (offense, patrol/marking, male sexual behavior, female sexual behavior, parental behavior). Whereas reproductive states, on the one hand, involve the entire organism, are mutually exclusive, and have a time course of weeks or months, the motivational systems, on the other hand, involve portions of the nervous system, may interact simultaneously, and have a time course of activity that ranges from minutes to hours or days.
In primates, there is also evidence for the operation of a reproductive postponement state. Whereas rhesus monkeys who are reproductively active and dominant have high levels of androgens, other monkeys who have been defeated have greatly depressed levels of androgens and correspondingly decreased levels of reproductive activity (13). Similarly, in rhesus monkeys, the corticosteroid response to ACTH is low in dominant animals, but greatly elevated in animals who have been defeated (14). Data for other species has not been as clear as those for the rhesus monkey (15, 16 17). In infant monkeys, social stress leads to elevated corticosteroid levels which, we may assume, would retard the onset of sexual maturity just as it does in rodents; this has been shown in both rhesus monkeys (18) and squirrel monkeys (19).
In this paper we will consider the evidence supporting the existence of a reproductive postponement state in humans. Since the motivational systems of social behavior are quite similar in rodents and primates (20), it seems likely that the operation of a reproductive postponement state, which acts by hormonal control of these motivational systems, is probably similar in humans as well.
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