A Cultural History of Causality by Kern Stephen;

Author:Kern, Stephen;
Language: eng
Format: epub
Publisher: Princeton University Press

PHYSIOLOGY OF EMOTIONS

Jealousy, revenge, and greed are complex emotions that develop over time. As such, they were well suited to motivate murder in novels, but they did not lend themselves to rigorous research by the experimental physiologists who concentrated at first on the more basic emotions, such as fear, anger, and shame. Therefore the history of that research provides a conceptually somewhat remote context for the emotions that I surveyed in this chapter. Still, by way of conclusion I will sketch that history because it is part of the broader cultural context for thinking about the causal role of emotions.

In the late nineteenth century, experimental physiologists found emotions such as fear and anger interfering with experiments designed to study other phenomena and so developed ways of working around them. As the historian Otniel Dror concluded, “Emotion signified the collapse of the laboratory’s ideal of the animal-machine, of reliable control, predictability, replicability, and standardization.”25 In time, these interfering emotions became the subject of new research into how they affect phenomena such as digestion, blood pressure, metabolic rates, and blood sugar levels. This research was made possible by a series of new technologies for measuring physiological phenomena and making a visible record of the results.

In 1847 Carl Ludwig invented the kymograph to record changes in blood pressure on a revolving drum covered with sooted paper. This invention inaugurated the birth of modern physiology.26 While earlier in the century Müller had concluded that the time between a nerve stimulus and a muscular response in frogs was “infinitely small and unmeasurable,” the invention of more precise instruments and the refinement of experimental methods allowed that time to be measured. In 1850 Hermann von Helmholtz adapted an instrument patterned after Ludwig’s kymograph to measure and record with unprecedented precision the velocity of a nerve impulse, a measurement that was crucial for the experimental study of the physiology of emotions.27 Subsequent physiologists adapted other technologies to measure simple emotional reactions and create more precise permanent records of them as graphs and charts.

In the early 1860s the French physiologist Étienne-Jules Marey invented several graphic inscriptors that fulfilled four crucial requirements for more precise scientific experimentation.28 They captured movements produced by physiological processes without interfering with them, made those movements visible without sacrificing their complexity, showed their temporal and spatial dimensions and the forces that produced them, and made a permanent and visible representation of them so they could be studied at a later time by more than one person. With these technologies Marey brought the precision of experiments in physics to physiological research. His first invention, the sphygmograph (1860), measured blood pressure by means of a lever with one end on the pulse of the wrist and the other attached to a stylus that scratched a line on a piece of moving, soot-blackened paper. It facilitated study of the precise sequence of the wrist pulse, the externally palpable heartbeat, and cardiac contractions. Other technologies Marey invented to study physiological processes include the thermograph to measure heat changes

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