AN 1893FRENCH DESCRIPTION OF GERMAN LABORATORIES 1
Laboratories of Experimental Psychology
In Germany
By Victor Henri (1893)[1]
[608]Fifteen years have passed since Dr. Wundt’s founding of the first laboratory of experimental psychology. During this relatively short interval, the new science has made great progress, its goal and its methods have grown more precise, and the number of laboratories has considerably grown, such that, at the present moment, there are sixteen laboratories in America, four in Germany, two in England, and one in each of the following countries: France, Italy, Switzerland, Belgium, Holland, Denmark, Sweden and Romania; which makes a total of more than 30 laboratories, more than half of them in America. In this article I propose to give a description of the four laboratories in Germany and the work performed in them.[2]
I
I shall describe the four laboratories in order of the date of their creation: I shall thus begin with that of Leipzig, created by Wundt in 1879. Up until the month of July 1892, it was located within the University itself; it was composed of seven rooms, only two of which were separate; the others were placed one after the other in a sequence, such that it was necessary to move through all of the rooms in order to get to the final one where the laboratory was found; there was thus a continual coming and going through four of the rooms, which caused much disturbance and reduced the number of studies that could be performed at one time. At the end of the 1891-1892 academic year, as the demolition of the University had begun, the laboratory was transported into the old Trier institute, where it would be located [609] during the five years of the construction of the new University.
The laboratory consists of 11 separate rooms, with their doors along a long hallway; one of them is occupied by the library, another is the director’s office, and there are nine rooms, including one darkroom, for experiments; all of them are connected together electrically, with the electricity generated in a central station composed of 60 Meidinger cells.
The laboratory receives an annual subsidy of 1500 marks (1875 francs) for devices; each device was acquired or constructed for the studies conducted in the laboratory. In the description I will classify them according to the purpose they serve.
For the study of visual sensations, the laboratory possesses rotating disks of different sizes, making it possible to obtain mixtures of colors; a spectroscope; a heliostat; a series of prisms and lenses; and finally a device for the study of geometrical illusions which was just constructed: it is a large square plate of glass, 50 centimeters on a side, which can be moved in any direction using micrometric screws; a sheet of cardboard can be placed behind this plate, and on this cardboard certain lines or points can be traced according to the illusion that is to be studied; certain points on the plate are marked, such that of the figures that are to be compared with each other, one is drawn entirely on the cardboard, while the other to the contrary is drawn partly on the cardboard and partly on the plate of glass; by moving the latter the size of the second figure can be varied.
For the study of auditory sensations, the laboratory possesses a series of tuning forks with resonance boxes, electric tuning forks, three “AppunTonmesser”,[3] which make it possible to obtain quite pure sounds varying from 32 to 1024 cycles per second; and two devices which produce sounds of different intensities: in the first, used by Starke, the sound is produced by a ball that falls onto a small board from a certain variable height, a special system allows the exact measurement of this height and makes it possible to let the ball drop without pushing it; in the second device (Schallpendel)[4], constructed by Kämpfe, the sound is produced by the impact of the ball of one pendulum against a plane surface situated in the pendulum’s median plane; by varying the angle separating them, sounds of the same kind, but different intensities, can be obtained.
Then follows a whole series of devices used to measure the duration of mental acts. These devices are: a Cattell chronometer, [610] two Hipp chronoscopes, and two devices for controlling this chronoscope; each of these devices consists of a hammer that falls from a certain height and that, as it falls, first closes an electric current and then interrupts it; this current sets the chronoscope in movement as it passes through it; knowing the time between the closing and the opening of the current, one can see whether the time indicated by the chronoscope in fact corresponds to it; for more precise measurements of reaction time the laboratory possesses a Wundt chronograph: it is a cylinder 32 centimeters in length and 20 centimeters in diameter which turns swiftly around its axis; on this cylinder the vibrations of a tuning fork which vibrates at 500 cycles per second are marked, and next to this are marked the times at which stimulation and reactions occur. Beside these devices used to measure time there are a series of devices used to produce visual, auditory, tactile, or olfactory stimulation such that at the moment when the stimulation is produced, the current is closed; and also devices for registering the reaction either with a finger, with the lips, or with spoken words.
To these psychometric devices we may add the Wundt pendulum, which is used to produce stimulation of two different kinds simultaneously, such as for example visual stimulation, produced by a needle that sweeps around a dial at a certain speed, and auditory stimulation, produced by the striking of a bell: the subject has to determine the position of the needle that corresponds to the striking of the bell; auditory stimulation can be replaced with tactile stimulation.
For the study of the sense of time (Zeitsinn), the laboratory possesses two devices: the first and older of the two, that of Estel, and the second, quite recent one of Meumann, which, it can be said, is a perfection of the first; the goal of these devices is to produce openings and closings of a current at time intervals that can be set in advance; the essential piece in these two devices is a graduated circle upon which contacts can be laid out. A rigid stem turns around an axis that is located at the center of the circle, and as it passes in front of the contacts it opens or closes the current; in the first device, the movement is communicated by a clockwork mechanism with a weight; in the second, the movement is produced by a clockwork mechanism with springs, of Balzar, and in this device the same movement can be transmitted to a Balzar recording cylinder. Beyond these devices, the laboratory possesses devices for physiology and physics, and finally demonstration devices for teaching.
[611]Let us now look at the internal organization of the Leipzig laboratory and the studies that are performed there.
During the academic year 1892-93, the personnel of the laboratory was composed of 25 people: Wundt, the director; Külpe and Meumann, his two assistants, and 22 students. At the beginning of each semester, Wundt distributes the studies that are to be undertaken at the laboratory; most of the topics are dictated by Wundt and only a small number are chosen or proposed by the students themselves; once the topics have been distributed, the next step is the designation of the students who must take part in the different studies: there are thus three to ten experimental subjects for each study. A student must first remain for at least six months as an experimental subject before obtaining a study; this is a condition that I believe to be very useful and almost necessary; indeed, the students who arrive in the laboratory are in general students who have only vague ideas on experimental psychology; during the first six months and often the first year, they familiarize themselves with the psychological devices which are shown to them in a course given by Külpe; further, by taking part in one or several studies, they learn how to perform the work, and in the end they can deal with the literature of the branch of experimental psychology that they wish to choose for their work. In the great majority of cases, the goal of the students who come to the laboratory is to prepare a doctoral thesis; the fact that it is possible to present a thesis on a topic in experimental psychology in Leipzig is the reason why there are always many students in the laboratory: this is an advantage compared with other laboratories, since experimental subjects are never lacking; but there is also a slight flaw, which is that students sometimes take more of an interest in their thesis than in the study itself and are a little too rushed.
The laboratory is open every day except Sunday, from ten o’clock to noon and from two o’clock to seven; during this time all the students can come and work in the library of the laboratory, which contains most philosophical and physiological journals and a large number of treatises and theses in psychology; each student must contribute 25 marks (32 francs) per year for the library. Those who are engaged in an original study can come to the laboratory at any hour, so that someone can always be found there from seven o’clock until midnight or one o’clock in the morning; furthermore, these students can come during vacation. The duration of studies varies greatly, but it is rare for it to be less than six months, and ordinarily it is a year or often longer; all of the studies carried out [612] at the laboratory are published in the Philosophische Studien, which has thus far produced eight and a half volumes of 650 pages each.
A glance at the studies that have been carried out since 1878 and up until 1892 shows that the largest number have been aimed at studying whether the laws of Weber and Fechner are applicable to visual and auditory sensations and sensations of pressure, to determine the psychological methods that must be applied to each of these sensations, and consequently the drawbacks and advantages of each of these methods, as well as how each must be modified according to the circumstances. Almost as numerous as these are the studies on psychometry; simple reaction times have been studied for visual, auditory, tactile, and olfactory sensations, as well the influence of habit, fatigue, intensity of stimulation, and various medications on the duration of reactions, as well as the difference in cases where the attention of the subject is concentrated on the movement to be executed or on the sensation that is to be produced—hence the distinction between motor reactions and sensory reactions; finally there have been studies on the duration of more complicated mental acts, such as the time taken for choices, recognition, and association. There are yet few precise results in this branch: simply knowing the duration of different mental acts cannot make it possible to draw conclusions on the nature of these acts and on their order of complexity, without incorporating hypotheses which as easily be admitted as rejected.
A much smaller number of studies have been carried out on visual and auditory sensations: for the first, there has been some research on contrast and its effects, on color blindness, and on the perceptibility of colors in indirect vision; for the second, a study was conducted on memory for the pitch of tones, and another on the perception of intervals. The latter led to a very long controversy between Wundt and Stumpf.
Finally, four studies have been carried out on the sense of time and two on the fluctuations of attention.
In summary, between 1879 and 1892 forty-five studies were performed in the Leipzig laboratory, the large majority of which bear either on the duration of mental acts or on the measurement of the external stimulation that produces this or that sensation or change in sensation; in short, it might be said, the elements of experimental psychology whose goal is to give a scientific description of the simplest states of awareness, while [613] attempting to deduce certain laws, but where the concern is not with purely mental processes nor with individual variations: an introduction to experimental psychology, a passage between physiology and psychology.
All of the studies that I have discussed thus far were performed in the old laboratory; let us now take a look at those that have been performed this year in the new laboratory. The twelve studies undertaken this year were:
1st Study of differential perception for spectral colors;
2nd Quantitative relationships in color contrast;
3rd The specific brightness of colors;
4th On geometrical illusions;
5th Study on the evaluation of distances using movements of the arms;
6th Study on the sense of taste;
7th Psychology of the sense of time;
8th The influence of rhythm on pulse and respiration;
9th Study on associations;
10th The production of beats from one ear to the other (binauraleSchwebungen);
11th A study on esthetic feeling with regard to lengths in geometric figures;
12th Esthetic feeling with regard to combinations of colors.
We will look at only a few of these studies in detail, focusing mainly on new results. We begin with the fifth study, on the evaluation of distances using movements of the arms, which, although incomplete and interrupted, has led to interesting results;[5] the subject was seated close to a perpendicular board in the frontal plane, and in the board there were holes laid out along the arc of a circle, with spokesthe length of the arm; little pegs could be placed in these holes, making it possible to stop the movement of the arm; the experiments were conducted according to the method of least differences; the first result obtained was that with the speed of the movement remaining constant, the smallest perceptible difference, if the movement does not exceed 60°, remains almost constant, and there is no tendency to increase the size of the movement rather than diminishing it, a result contrary to the one obtained by Loeb.[6]
[614]The second study that we will look at a little more closely is that of Kiesow on taste sensations; its goal is to study contrast phenomena and to determine the conditions under which two tastes can be complementary; the liquids used are solutions of saccharin, hydrochloric acid, sea salt, and quinine. Two types of contrast can be observed, simultaneous contrast and successive contrast; to obtain the first, the first solution is poured onto one side of the tongue, and distilled water is poured onto the other; the latter seems to have a certain taste which depends on the taste of the solution. To create successive contrast, a certain solution is poured onto a portion of the tongue, and then, sometime later, distilled water is poured on the same portion, and in this case too distilled water seems to have a certain taste; to study whether two solutions might be complementary, the experimenters mix them in different proportions and then observe whether the mixture has a certain taste or not. The most important result is that two gustatory sensations that provoke one another through the contrast effect are not always complementary[7]; hence for example saltiness and sweetness are complementary and provoke one another by the contrast effect, while on the contrary, although sweetness and sourness create a contrast, they are never complementary. Aside from these questions, Kiesow has also been studying the value of the minimum stimulation necessary to produce a gustatory sensation and the variations in these minima with the effect of cocaine, with which he covers a portion of the tongue. Finally he has made a few observations on feeling, linked to certain gustatory sensations, focusing his attention mostly on the transition from pleasure to pain.
The most important study currently underway at the Leipzig laboratory is that of Meumann on the sense of time[8]; this study was begun in the winter semester of the year 91-92, and it is not yet finished. The question of the sense of time is one of the most difficult among those dealt with by experimental psychology; the evaluation of time depends so greatly on the dispositions of the subject that it is very difficult to eliminate all the causes of error.
Meumann distinguishes the evaluation of short time intervals (less than 0.5 s), medium-length intervals, and long intervals. That which influences the evaluation of the first of these is most of all the stimulation which delimits [615] them; for the evaluation of long intervals, it is the impressions that occur within them that are of great importance. With this established, Meumann began to study the evaluation of short intervals depending on whether they are delimited by sounds that are more or less loud and of varying kinds, as well as when they are delimited by electric sparks that are more or less luminous. When the intervals are delimited by sounds, their perception is rhythmic, which leads to a new question, namely the influence of rhythm on the evaluation of short intervals; the feeling linked to these different rhythms must also play an important role for this evaluation. Aside from these questions, Meumann is also studying the esthetic feeling that occurs when an interval delimited by two sounds is divided in two by another sound. He is looking to see whether there might be some constant proportion that is preferred to others, as in the case of the division of a spatial interval. In summary, Meumann’s study touches on a very large number of questions, and will no doubt greatly advance the psychology of the sense of time.