Human Adult Neurogendering: Brain Plasticity and Sex Difference Research
ABSTRACT: This paper analyses the extent to which the growing research on neuroplasticity in the 20th century related to neuroscientific investigations into sex differences. In the late 19th century, William James formulated the notion of a malleable brain that is responsive to exterior influences. At the same time, however, the influential work of Santiago Ramón y Cajal led to an adoption of the view of a static adult brain. The latter concept shaped neuroscientific theories for the next century: the idea of human adult neurogenesis became a neuroscientific fact only around the turn of the 21st century. Parallel to the slow stabilization of the various concepts of brain plasticity, the number of neuroscientific investigations into sex differences increased significantly. Most of these studies reported functional or structural differences between female and male brains and asserted their congenital nature. Focusing on the second half of the 20th century, this paper will analyze the relationship between plasticity research, neuroscientific investigations into sex differences, and the communication of related findings to a broader public. Drawing on clinical and cognitive neuroscientific publications as well as on personal papers of 20th-century neuroscientists, I will address the following questions: Was the idea of innate sex differences resistant to the concept of neuroplasticity? How far did the social female/male dichotomy influence how neuroscientists approached sex/gender? How, if at all, did neuroscientists embrace the idea that gender might leave its material marks on initially unsexed human brains?