Story of Psychology - Morton Hunt [71]
which says that the ratio between the just noticeable stimulus, δ (R), and the magnitude of the standard stimulus, R, is a constant, k, for any sensory system. Known as Weber’s Law, it is the first statement of its kind—a quantitatively precise relationship between the physical and psychological worlds. It was the prototype of the kind of generalization that experimental psychologists would be looking for from then on.
Neural Physiology: von Helmholtz
In 1845, a handful of young physiologists, most of them former students of Müller’s, formed a little club, the Berliner Physikalische Gesellschaft (Berlin Physical Society), to promote their view that all phenomena, including neural and mental processes, could be accounted for in terms of physical principles. It was one of the group, Du Bois-Reymond, who had earlier stated the mechanist doctrine mentioned above, “No forces other than the common physical-chemical ones are active within the organism.”
Du Bois-Reymond brought to the club a friend, Hermann Helmholtz (1821–1894), who was surgeon of a regiment stationed in Potsdam.28He was a shy, serious young man with a broad forehead and large intense eyes; neither by personality nor position did he seem likely to become the front-runner for the society’s radical theory. But within a few years he was just that. His research on nerve transmission, color vision, hearing, and space perception clearly showed that the neurological processes underlying mental functions are material and can be experimentally investigated.
Helmholtz never thought of himself as a psychologist; his major interest was physics. Although the first twenty years of his career were devoted largely to physiology, his goal during that period was to explain perception in terms of the physics of the sense organs and nervous system; in so doing, he exerted a major influence on experimental psychology. Ironically, in his own time Helmholtz’s best-known scientific achievement was one that took him only eight days and that he himself considered minor—the invention of the ophthalmoscope, with which doctors could for the first time view the living retina.
Although Helmholtz became one of the leading scientists of his century—his achievements earned him elevation to the nobility (hence the “von”)—he was totally unlike the scientist he most admired, the ferociously competitive, dour, reclusive Isaac Newton. Toward fellow scientists he was courteous and generous, if rather formal, and in private life he was a remarkably normal middle-class Herr Professor; his biography offers no frissons. He got a good grounding in the classics and philosophy from his father, a poorly paid teacher of philosophy and literature at the Potsdam gymnasium; went through medical training, wrote his dissertation under Müller, and served five years as a regimental surgeon; married when he received his first academic appointment and had two children; was widowed, married again, and had three more children. His career consisted of ever-better posts at ever-better universities, constant research and writing, and growing status and acclaim. He engaged in no priority fights and only one scientific controversy, and his only recorded indulgences were classical music and mountaineering.
Helmholtz began his research career during his obligatory service in the military. Since it was peacetime, he had plenty of leisure, and