Chapter IV Institutionalizing experimental psychology: The model in Leipzig in the 1880s. To make the "experimental ideal" work for psychology, Wundt needed a specific research program which justified experimental psychology as a separate discipline. He had been making arguments for this since 1862; now he had to get an international community of researchers to join him in the effort. Otherwise, psychology would continue to be only a minor part of philosophy, and psychophysical methods would interest only the physicists and sensory physiologists who occasionally used them. To establish a separate experimental discipline of psychology, Wundt sought to relate a theory of mind (at least a preliminary or heuristic model) to a well-defined, quantitative and easily reproducible experimental methodology. He had such a program in his Leipzig laboratory during the 1880s. A. The work of the Leipzig Institute: What was at its heart? What kinds of experiments were carried out in Wundt's Institute? And what were they intended to prove or discover? Edwin G. Boring gave one survey of the Institute's publications. He began with the remark that Wundt actually defined experimental psychology for the time being, because the work of this first laboratory was really the practical demonstration that there could be an experimental psychology . Practically all the work from the Leipzig laboratory was published in the Philosophische Studien (1881-1903) and there is not very much in this journal that did not come either directly from Leipzig, or from Wundt's students so soon after leaving Leipzig that they still represented the intentions of Wundt. 1 "All the work from the Leipzig laboratory" refers to the five or so doctoral dissertations from Wundt's Institute each year, as well as to a few research reports by more advanced researchers. Many dissertations which Wundt sponsored were not published in Philosophische Studien, but nearly all the experimental studies were. Following his apt historical remarks, Boring proceeded to classify the work in the Institute in a way that obscures its uniqueness: he draws almost no distinction between Wundt's Institute and the laboratories of contemporary sensory physiologists. Boring classified 109 experimental articles into four categories: (1) more than one-half on sensation and perception, with the proportion increasing toward the end of the series; (2) one-sixth on reaction times, concentrated in the 1Edwin G. Boring, A history of experimental psychology , 2nd ed. (NY: Appleton-Century-Crofts, 1950), 339-340. Hereafter Boring. period before 1890; (3) one-tenth on attention and feeling, especially in the 1890s; and (4) somewhat less than one-tenth on association. Dividing the first category further, he found that vision received the lion's share, nearly a quarter of all the experimental studies in the journal. The next most important area of sensation was auditory perception. In the area of tactile sensation, so important in the history of psychophysics (the Weber law, etc.), there were only a few studies. A couple of researchers published on sense of taste, and there were no articles on the sense of smell. A sixth sense, the "time sense," was represented by three different researchers' studies of the perception or estimation of temporal intervals. Boring strongly identified with the Wundtian tradition, but his own research specialty was psychophysics, studies of sensation and perception that were not primarily concerned with the issues involved in the other three categories. He suggested that reaction-time experiments represented the core of the work of the early Institute but concluded that that line of research ultimately failed when it proved impossible to measure separately the times required by different mental functions. Boring neglected to emphasize how important this "failed program" was to the development of laboratory psychology. The failure was by no means total, as Metge-Meischner, for example, has argued. 2 2Anneros Metge, "The experimental psychological research conducted at Wundt's Institute and its significance in the history of psychology," in Advances in historiography of psychology , ed. Georg Eckardt and Lothar Sprung (Berlin, GDR: Deutscher Verlag der Wissenschaften, 1983), 43-49. A separate discipline of psychology needed an area of study that it could call its own. When Wundt came to Leipzig, studies of sensation and perception were primarily identified with physiology, and Wundt would change that identification only partially. Research on sensation and perception in the Leipzig Institute, in the large picture, was preliminary or ancillary to investigations of complex central nervous processes. Reaction-time experiments sought to measure those processes directly. Leipzig researchers worked in hot pursuit of the parameters and laws of mental chronometry, and Wundt's theory of mental processes implied that reaction-time experiments could serve as the model for investigating many mental phenomena, including attention, association, feeling, and emotion. B. The research program: Reaction-time studies . 1. Reaction-time studies before the Leipzig Institute. Chapter Two of this dissertation told how astronomers, trying to gain ever more accurate simultaneous measurements of position and time for a given celestial event, came up against the phenomenon of the personal equation. No matter how careful the observers, they could differ in reporting a given event by as much as a half-second. This dilemma interested Wundt, and his "complication experiment" sought to explain the discrepancies and develop some standard measurement of reaction times. By 1866 Wundt was taking credit for the discovery that the observed time of a reaction was significantly greater than the time required for a nervous impulse to travel from sense organ to the brain plus that required to travel back to the reacting muscle. 3 In other words, a good chunk of the time was taken up by central nervous processes. For a young physiologist declaring a new scientific psychology, that was a crucial finding. It only remained to discover a way to investigate those central processes experimentally. 4 At about this time such investigations were made possible by the appearance of an accuate instrument to measure the "speed of thought." The Swiss astronomer Adolph Hirsch (1830-1901) began doing experiments with a chronoscope (a very accurate stop-clock) which had been developed by his precision mechanic, Mathias Hipp (1813-1893). 5 The Hipp chronoscope (see Figure 4.1) registered time intervals to the one-thousandth second. With minor improvements, it remained a standard piece of apparatus in psychology laboratories for at least fifty years after Hirsch published his reaction-time measurements in the early 1860s. 6 3Solomon Diamond, "Wundt before Leipzig," in Wilhelm Wundt and the making of a scientific psychology , ed. Robert W. Rieber (NY: Plenum Press, 1980), 3-70; 49. 4The following discussion is based on the chapter "Reaction time" in Robert S. Woodworth, Experimental psychology (NY: Henry Holt, 1938), 298-339. 5A. Hirsch, "Expériences chronoscopiques sur la vitesse des différentes sensations et de la transmission nerveuse," Bulletin de la société des sciences naturelles, Neuchâtel, 6 (1861-63), 100-114; A. Hirsch, "Ueber persönliche Gleichung und Correction bei chronographischen Durschgangs-Beobachtungen," Untersuchungen zur Naturlehre des Menschen und der Thiere, 9 (1863), 200-208. 6Michael M. Sokal, Audrey B. Davis, and Uta C. Merzbach, "Laboratory instruments in the history of psychology," Journal of Hirsch determined the times for some simple reactions, in which the subject signaled, e.g. pressed a telegraph key, upon perceiving a stimulus: visual stimulus 200 ms (milliseconds) auditory stimulus 150 ms electric shock 140 ms It was of great interest to astronomers that visual perception required more time; astronomical photography was then in its infancy, and precision-timed observations still required eye-ear coordinated reports. At Utrecht, the physiologist Franciscus Cornelis Donders (1818-1889) proposed a way to measure the time taken by different mental functions. His technique, the "subtraction method," was essentially this: find the time for a simple reaction to stimulus (such as those Hirsch did); run another reaction which is set up in the same way but which involves a more complicated mental process; then subtract the first time from the second to get the "physiological time" required by that additional mental process. 7 the history of the behavioral sciences, 12 (1976), 59-64; 61-63. 7The first presentation of such experiments was the medical dissertation of Donders's student: J. J. de Jaager, De physiologische tijd bij psychische processen (Utrecht, 1865), trans. as "Reaction time and mental processes," in Origins of psychometry , ed. and trans. J. Brozek and M. S. Sibinga (Nieuwkoop, Netherlands: de Graff, 1970). Donders communicated the results more widely in his articles, particularly Franciscus Cornelius Donders, "Die Schnelligkeit psychischer Processe," Archiv für Anatomie und Physiologie (1868), 657-681; trans. "On the speed of mental processes," Acta psychologica, 30 (1969), 412-431. Donders's experiments rely on the assumption that each part of the reaction (sensation, perception, discrimination, choice, reaction movement) takes a specific amount of time, and that "physiological time" for particular mental processes can be determined if experiments can be devised in which there is first no such process and