"Masters" of Time: Chrono-Biologizing Sleep in the 20th Century

Abstract

In 20th century Western societies, the question if human beings could "master" their sleep and sleeping time became increasingly relevant. Scientists from several fields set out to find the principles of basic body rhythms, debating about the effects of "cosmic forces," the influence of light and temperature, and the power of will and habits. To conduct their experiments, these researchers turned places like hospital rooms, caves, or bunkers into chronobiology laboratories. It is argued that the now dominant concept of a "clock" inside the body regulating the alternating phases of sleeping and waking was only one of various possible answers to the question of the how, why, and when of sleep. In the course of the 20th century, experts found very diverse, even contradictory explanations for diurnal rhythms, depending on the context they lived in and technologies they worked with. By conceptualizing experimental spaces not as neutral instances of verification, but as epistemically productive, it is pointed out that the science of sleep did not follow a linear path towards a biological truth called "body clocks" but contributed to the sometimes contingent "making" of scientific concepts that generated reliability only within a specific historical context.