The Story of Psychology (24 page)

Fechner spent the next nine years in plodding experimentation, collecting data to confirm the law. Despite the mystical and poetic aspects of his personality, in the laboratory he was the very model of a compulsive and rigorous researcher. He tirelessly had subjects lift weights, look at lights, listen to noises and tones, look at color samples, and so on, and pronounce them either different or the same. Over those years he experimented with a wide range of intensities of each kind of stimulus, using
three methods of measuring such judgments. With just one of those methods he tabulated and computed no fewer than 24,576 judgments.
³⁹
He considered this first systematic exploration of the quantitative relationship between the physical and psychological realms a new scientific specialty and named it “psychophysics.”

Of the three methods of experimental measurement that he used, he had borrowed two from predecessors and perfected them, and invented the third himself. Until then, no one had ever used such careful, quantitative, and precisely controllable methods to explore psychological responses. His methods were soon widely adopted, and are in constant use today in every laboratory of psychophysical research.

One is the method of limits, which Fechner called the “method of just noticeable differences.” To determine the threshold of a stimulus, the experimenter presents stimuli one at a time, starting with the most minimal and increasing the magnitude until the subject can perceive them. To determine the j.n.d., the experimenter presents a “standard” stimulus and a “comparison” stimulus, increasing the difference by small steps until the subject says it is perceptible.

A second is the method of constant stimuli, which Fechner called the “method of right and wrong cases.” The experimenter presents identical stimuli time and again—either single ones at the threshold, or pairs of stimuli that are very similar. The subject replies “Yes” (meaning that he perceives it, or that the two are different), or “No” (he does not perceive it, or the two are not different). The subject’s responses yield averages, and these indicate how likely it is that, at any given stimulus level or difference between stimuli, the subject will perceive the stimulus or the difference between two stimuli.

The third, Fechner’s original contribution, is called the method of adjustment, which he called the “method of average error.” Either the experimenter or the subject adjusts the comparison stimulus until it seems (to the subject) identical with the standard stimulus. There is always some error, however minuscule, to one side or the other. Every error is recorded, and after many trials the average error is computed; it, too, is a measure of the j.n.d. This method established the useful principle that measuring the variability of data can be as informative as measuring the central tendency.

In 1860, Fechner published the fruits of his work in the two-volume
Elements of Psychophysics.
He was fifty-nine, an age at which scientists rarely produce their most original work;
Elements
, however, was truly original and had an immediate impact. Interest was intense and wide-
spread—not in the panpsychism it espoused but in its experimental and quantitative methodology. As Boring once said of Fechner’s failure and triumph, “He attacked the ramparts of materialism and was decorated for measuring sensation.”
⁴⁰
Some psychologists, to be sure, regarded psychophysical methodology as a dreary topic. Years later the great William James wrote:

But many others did not share this view. Even though debate raged over the validity of Fechner’s assumption that all j.n.d.’s are equal, his methods were generally considered a genuine breakthrough. The time was ripe for quantitative research on the relation between stimulus and response; almost at once many psychologists began using Fechner’s three methods, which firmly linked the body’s physical mechanisms to the subjective experiences they aroused.
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(Fechner himself, though he continued to write in defense of psychophysics, devoted most of the rest of his long life to aesthetics, paranormal phenomena, statistics, and panpsychic philosophy.)

Later psychologists have found fault with or even disproven every one of his findings, yet his methods are not only still useful but fundamental to sensory measurement. Boring sums up Fechner’s paradoxical achievement:

A
ccording to most authorities, psychology was born on a December day in 1879. All that had gone before, from Thales to Fechner, had been the evolution of its ancestors.

The birth, a quiet affair, went unheralded. At the University of Leipzig that day, in a small room on the third floor of a shabby building called Konvikt (“hostel” or “retreat”), a middle-aged professor and two younger men were setting up apparatus for an experiment. On a table they positioned a chronoscope (a brass clocklike mechanism with a hanging weight and two dials), a “sounder” (a metal stand with an elevated arm from which a ball would fall onto a platform), and a telegrapher’s key, battery, and rheostat. They then wired together the five pieces of apparatus, the circuitry being no more complicated than that of a present-day beginning electric train set.
¹

The three were Professor Wilhelm Wundt, a long-faced, austere, densely bearded man of forty-seven, and two young students of his, Max Friedrich, a German, and G. Stanley Hall, an American. The set-up was for Friedrich’s benefit; with it he was going to collect data for a Ph.D. dissertation on “the duration of apperception”—the time lag between the subject’s recognition that he has heard the ball hit the platform and his pressing of the telegraph key.
²
It is not on record who made the ball drop that day and who sat at the key, but with the first
clack
of the ball on the platform, the click of the key, and the registration of elapsed time on the chronoscope, the modern era of psychology had begun.

One could argue, of course, that it began in the 1830s, with Weber’s work on just noticeable differences, or in 1850, with Helmholtz’s measurement of the speed of nerve transmission and Fechner’s first psychophysical experiment, or in 1868, with Donders’s reaction-time studies. Or even, as Robert Watson has suggested, in 1875, since in that year the University of Leipzig granted Wundt the use of the room in Konvikt to store and demonstrate his apparatus, and Harvard University made a small room in Lawrence Hall available to William James for his experiments.
³

But 1879 is the year recognized by most authorities, and for good reason. That was when the first experiment was conducted in the room in Konvikt that Wundt thenceforth called his “private institute.”
⁴
(In German universities, a formally organized laboratory is called an institute.) Within a few years the laboratory had become a mecca for would-be psychologists and was considerably enlarged and designated the university’s official Psychologisches Institut.

Largely because of the institute, Wundt is considered not just one of the founders but the principal founder of modern psychology. It was there that he conducted his own psychological research and trained many graduate students in his laboratory methods and theories, and from there that he sent forth cadres of new psychologists—he personally supervised nearly two hundred dissertations—to the universities of Europe and America. In addition, he wrote a number of scholarly articles and massive tomes that established psychology as a field of science with an identity of its own. He himself was the first scientist who can be properly called a psychologist rather than a physiologist, physicist, or philosopher with an interest in psychology.

Perhaps most important, Wundt restored the study of conscious mental processes to psychology. They had been its core from the time of the Greek philosophers, and still were for the English associationists, who, like all their predecessors, explored them through the traditional method of introspection. But the German mechanists, seeking to make psychology scientific, had rejected introspection on the grounds that it was subjective and dealt with unobservable phenomena. A scientific approach to psychological phenomena, they held, dealt only with the physical aspects of neural responses and, in the words of one of them, was a “psychology without a soul.”
⁵

It is true that long before the first experiment in Wundt’s laboratory
both Fechner and Donders had used experimental means to measure certain mental responses. But it was Wundt who fully developed the methods that would be used by the next two generations of psychologists, and it was he who became the leading proponent of the view that mental processes could be experimentally studied. He had, in fact, begun espousing this view as early as 1862, in the introduction to his
Contributions to the Theory of Sense Perception:

He drew an analogy between psychology and chemistry. Just as the chemist learns from experiments not only how a substance is affected by others but also what its own chemical nature is,

As many as a dozen years before the first experiment in his laboratory, Wundt was known as a bridge builder who sought to link physiology and mental processes. Word of his views had even reached America, where in 1867 the young William James wrote to a friend:

(James did not manage to meet Wundt that summer but did so many years later, by which time he himself was a leading figure in psychology.)

Some contemporary historians, critical of the Great Man approach to history, would say that the new science of psychology was created not by Wundt but by the general social and intellectual milieu of the mid-nineteenth century and by the state of development of the behavioral and social sciences. The animal psychology included in Darwin’s
On the Origin of Species
(and later in his
Expression of the Emotions in Man and Animals
), the sociological studies of Auguste Comte, the growing number of reports by anthropologists on the life, language, and ideas of preliterate peoples, and other related factors had created an atmosphere in which it was possible to think that human nature could be scientifically studied.