ABSTRACT
Studies of these forces, of their propensities in humans and other species, for sexuality and aggressivity, gained momentum in the 20th century. Systematic observation and experimentation for the sake of reducing ignorance and gaining information and understanding of the structural and functional components involved in the phenomena of “sexuality,” at biological and behavioral levels, is of quite recent origin as history goes, a matter of less that 200 years. In this overview of key advances in knowledge concerning sexual functions, the first were based on studies of biological organisms other than humans; social tolerance for direct studies of human subjects and modes of procedure for doing so are relatively late developments. Such studies, and public awareness of them have frequently evoked opposition from social conventions and from individual and social anxieties. Explorations in unconventional areas, yielding new
insights, merit illustration in a history of neuroscience. Among key steps marking the 20th century’s growth of knowledge concerning sexual phenomena, the North American contributions to the flow have taken two separate channels: the social, observational human stream, and the experimental rapids of ablations and endocrines. This chapter takes each in turn and only hints at the revolutionary social consequences.
