Laboratories of Experimental Psychology

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 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.

1 Henri, V. (1893a). Les laboratoires de psychologie expérimentale en Allemagne [Laboratories of experimental psychology in Germany]. Revue Philosophique de la France et de l’Etranger, 36, 608–622.

2 Let us take this occasion to present our thanks to Drs. Ebbinghaus, Martius, Müller, and Wundt for the gracious welcome that they extended to us. 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 “Appun Tonmesser”,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

3 Translator’s note: in German in the text (also applies to all italicized footnoted terms that follow). Appun tone measurer.

4 Translator’s note: sound pendulum.

2 AN 1893 FRENCH DESCRIPTION OF GERMAN LABORATORIES 3 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

4 AN 1893 FRENCH DESCRIPTION OF GERMAN LABORATORIES 5 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 (binaurale Schwebungen);

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 spokes the 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

5 W. Wundt, Physiologische Psychologie, [Physiological psychology] V. I, p. 429 (4th Edition).

6 Loeb, Unters. Üb. den Fühlraum der Hand [Investigations of how spatial relationships can be detected by the hand] (Pflüg. Arch. F. Physiologie, Vol. 41, pp. 107–127).

6 AN 1893 FRENCH DESCRIPTION OF GERMAN LABORATORIES 7 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 complementary7; 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 time8; 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

7 Wundt, Physiol. Psychologie, V. I, p. 441 in a footnote (4th edition).

8 Meumann, Beiträge sur Psychologie des Zeitsinnes [Contributions to the psychology of the time sense] (Phil. Stud., VIII, pp. 431, 511, and IX, pp. 264–307). 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.

A study that has a few points in common with the preceding one is that of Mentz on the influence of rhythm on pulse and respiration; the goal of this study, which has been under way for two semesters, is to study the changes produced in pulse and respiration by a ticking metronome, depending on whether or not the subject pays attention to the sound of the metronome, and on whether the metronome is set to tick at a lower or a higher speed. At the same time Mentz is investigating what feelings are connected to the different speeds of the metronome, with particular emphasis on the transition from the pleasant to the unpleasant and on the positions of these indifference points (Indifferenzpunkt) depending on the subject’s various dispositions: tired or not, before or after a meal, etc.

When two tuning forks with almost the same number of cycles per second are made to vibrate simultaneously, vibrations or interferences (Schwebungen)9 occur, their number per second being equal to the difference in the two tuning forks’ number of cycles per second; these vibrations also occur when each of the tuning forks is made to vibrate next to only one ear and the intensity of the sounds produced is reduced until the vibrations of one tuning fork cannot be transmitted by the air to the ear on the opposite side. This already fairly old observation has led in recent years to a discussion between Scripture10 and [616] Schaeffer11; the first of these two authors explains this phenomenon by the production of vibrations in the central organs, thus holding that they are of cerebral origin; the second, on the contrary, says that the vibrations of one of the tuning forks is transmitted to the ear on the opposite side through the bones of the skull, and thus the external production

9 Translator’s note: beats.

10 Philos. Stud., VII, p. 630, and VIII, p. 638.

11 Zeitschr. Für Psychol. U. Physiol. D. Sinnesorg., V. II, p. 111, IV, p. 348, and V, p. 397.

8 AN 1893 FRENCH DESCRIPTION OF GERMAN LABORATORIES 9 of vibrations. The solution to this question, says Wundt12, is of great importance; indeed, if the first hypothesis is correct, this would imply that stimulation is propagated along the acoustic nerve in the form of oscillations with the same period as the oscillations of the sound itself; for this reason, a methodical study has been undertaken in the laboratory on the production of vibrations from one ear to the other. The sounds produced by two electric tuning forks located in different rooms are transmitted through rubber tubes into a third room where the subject is located; the ends of each of the tubes are inserted into the subject’s ears, who must then say whether or not he hears vibrations.

A question that is in direct connection with the previous one is that of whether the acoustic nerve is directly excitable by sonic vibrations; this question was raised by Ewald13, who made observations on pigeons whose entire auditory organ had been removed; according to him, these pigeons continued to react to sounds, and consequently could hear; in July 93, Ewald sent a similar pigeon to the Leipzig laboratory and Wundt, with his students, undertook a series of experiments to determine whether this pigeon reacted to sounds and tones of different pitches; for comparison, the same experiments were performed in parallel on a healthy pigeon. After the end of these experiments, which lasted about three weeks, the pigeon had to be submitted to an anatomical examination to determine exactly how and where the acoustic nerves had been cut. These two studies will perhaps lead to a new theory of audition, more precise than all those devised thus far.

The two studies that remain for us to examine are on the esthetics of proportions of length in geometric figures and on [617] the esthetics of color combinations; the first is already finished14 and the second has only just begun. Two different methods can be used in research of this kind: the method of choice and the method of comparison; in the first, the subject must indicate which in a series of geometrical figures he finds most agreeable; in the second, the subject is presented with two figures and he must say which of the two is the more agreeable. This method requires a much more considerable number of experiments than the first, but it makes it possible to obtain a continuous ranking of a certain number of figures in order of pleasantness, a result that can be obtained only imperfectly using the

12 Wundt, Ist der Hörnerv direct durch Tonschwingungen erregbar? [Is the acoustic nerve directly excitable by sound vibrations] (Philos. Stud., VIII, p. 641.)

13 Ewald, Physiologische Untersuchungen über das Endorgan des Nervus Octavus [Physiological investigations of the end-organ of the eighth nerve], p. 23.

14 Witmer, Zur experimentellen Aesthetik einfacher räumlicher Formverhältnisse [On the experimental aesthetics of simple relationships between spatial forms] (Philos. Stud., IX, pp. 96–145 and 209–264). method of choice. The study of the esthetics of geometric shapes has been performed, mainly using the method of choice; the most important result is that in a series of simple geometric figures, two are preferred: one where the ratio of lengths is 1 to 1, and one where this ratio is 1 to 1.635, which is very close to the golden ratio of 1 to 1.618; the variations for the different figures and for different people are very small.

The study of the esthetics of color combinations cannot be performed using the method of choice because of contrast effects, which are of capital importance; the method of comparisons must therefore be used. In the study which is underway in the laboratory, the colors used are simple colors, obtained by transparency through gelatin sheets15; the subject is shown two transparent squares on a black background, and he must say which of the two pleases him the most; each of these squares is formed of two rectangles of different colors. These experiments, which will continue for around two more semesters, are the first after those of Fechner, and it is to be hoped that they will yield interesting results.

Such, roughly speaking, are the studies undertaken this year at the Leipzig laboratory. A comparison with the studies that had previously been performed reveals a quite notable difference: first, the muscular sense and gustatory sensations were studied for the first time in the laboratory; the sense of time was submitted to a very complete study, much more precise than those that had previously been performed; and finally, a new branch of psychology, the study of feelings, was broached; we have seen, [618] indeed, that two students have been at work specifically on feelings, and that furthermore, three other students have included the question of feelings in their studies, in connection to different sensations; this new direction was in part provoked by the thesis of Lehmann16, which was published last year; in this thesis, Lehmann constructed a new theory on the transition from pleasure to pain, on the basis of two experiments; according to this theory, this transition occurs not at the crossing of an indifference point (Indifferenzpunkt), as Wundt says, but at a certain moment when the pleasure linked to a sensation begins to diminish, new sensations begin which lead to pain; when the intensity of the first sensation increases, this feeling of pain prevails: feelings of pleasure and pain thus coexist at a certain moment.17 The question of feelings is to be revisited in the winter of 1893-1894, and the laboratory is to acquire a plethysmograph for this research; it

15 See Kirschmann, Ueber die Herstellung monochromatischen Lichtes [On the production of monochromatic light] (Philos. Stud., VI, p. 543–552).

16 Lehmann, Die Hauptgesetze des menschlichen Gefühlslebens [The principal laws of feeling-life in humans], 1892.

10 AN 1893 FRENCH DESCRIPTION OF GERMAN LABORATORIES 11 may thus be hoped that in a few years the psychology of feelings will be extended and made more precise by new experiments.

The second laboratory of experimental psychology in Germany is that of Göttingen, founded in 1879 by G. E. Müller; this laboratory was long a private possession of Müller, and it began to receive a subsidy of 500 marks (625 francs) for devices only a few years ago.

The laboratory consists of five rooms, including one darkroom, with all the others well lit and connected together electrically. Most of the devices have been acquired in the last three years by a student in the laboratory; in describing them I will follow the same order as above. For the study of visual sensations, the laboratory possesses devices analogous to those of the laboratory in Leipzig, as well as demonstration devices from Hering. For auditory sensations, there are no special devices; for the muscular sense, there is first a series of boxes with weights, built according to Fechner’s18 model, and then an ergograph and a Mosso19 ponometer, and finally a device from Schumann for the study of the per-[619]-ception of arm movements; in this device the movement of the arm can be registered on a recording cylinder, such that all of the changes in the velocity of movement can be known exactly. The psychometric devices include: a Hipp chronoscope with a control hammer and accessory devices for stimulation and reaction, a Schumann chronograph, in which the cylinder is set in movement by a small water engine with adjustable speed—the vibrations of a tuning fork, at 250 cycles per second, are registered on the cylinder. The laboratory possesses two Schumann devices for the study of the sense of time: the first20 is composed of a horizontal axis that can be set in rotation by a clockwork movement; on this axis are three circular disks which bear a certain number of platinum points that can be adjusted at will; below the axis, opposite each disk, is a cupola with mercury; the axis of the device communicates

17 See loc. cit., p. 181.

18 See Fechner, Psychophysik, I, p. 96.

19 See Mosso, La Fatigue.

20 See Schumann, Ueb. Die psychol. Grundlagen der Vergleichung Kleiner Zeitgrössen [On the psychological processes used in the comparison of small time-durations] (Zeitschr. F. Psych. U. Phys. d. Sinnesorg., IV, p. 50). with one of the poles of a battery and the mercury with the other pole via a telephone, such that when one of the platinum points touches the mercury the telephone makes a sound. This device not being sufficiently precise and furthermore being unwieldy to use, Schumann constructed another: it is a graduated circle roughly 30 centimeters in diameter, around which six contacts can be moved; as the stem that moves around the center of the circle passes in front of the contacts, it produces a closure of the current and as a result causes the telephone to sound; the stem’s movement is very regular, being propelled by a Helmholtz electro-magnetic motor21, which includes a regulator; the precision obtained with this device is perfect, as the mean error does not exceed a thousandth of a second; it can thus be used to check the measurements of the Hipp chronoscope.

Beyond these devices, the laboratory possesses devices for physiology and physics, which are greater in number than in the laboratory of Wundt.

In summary, in the laboratory there are many new devices; but most of them remain shut away in cupboards, unused, since the number of students is very limited. Indeed, the laboratory’s personnel consists of G.-E. Müller, director; Schumann, assistant, and only two students, because at the University of Göttingen it is much more difficult to present a doctoral thesis [620] on a topic in experimental psychology than in Leipzig, and students who wish to prepare a thesis are not readily admitted to the laboratory; furthermore, this laboratory is still little known abroad.

The studies carried out in the laboratory are published in the Pflüger’s Archiv of physiology and in the Zeitschrift für Psychologie und Physiologie der Sinnesorgane. Up until now only four studies have been performed: the first, by Müller and Schumann, on the comparison of lifted weights22; the goal was to study the psychological factors upon which the comparison of two lifted weights depend; the muscular force with which each of the weights is lifted is of great importance: hence, when one repeatedly lifts first a weight A, and then B which is heavier than A, and at some point one replaces B with a weight C which is equal to A, then C is lifted much more quickly than A and seems much lighter. The authors have performed a large number of experiments using the method of true and false cases to study the influence of the application of muscular force; the most important result is that the greater the muscular force applied to lift a given weight, the lighter it seems, which runs counter to the theory of the sense of innervation. When one wishes to compare

21 See Cyon, Methodik. d. physiolog. Experimenten [Methodology in physiological experiments], p. 404.

22 Müller and Schumann, Ueber die psychologischen Grundlagen der Vergleichung gehobener Gewichte [On the psychological processes used in the comparison of lifted weights] (Pfl. Archi., v. 45, pp. 36–112).

12 AN 1893 FRENCH DESCRIPTION OF GERMAN LABORATORIES 13 two nearly equal weights, one lifts both of them with the same muscular force, and the lighter weight is lifted more quickly than the heavier; according to the authors, it is this difference in speed that leads us to this or that judgment regarding the comparison of weights.

Next, two studies were performed by Schumann, the first on memory for groups of similar sonic impressions that follow one another in a regular fashion 23, and the second on the comparison of short intervals24 (Meumann subjected the latter to a critique, perhaps too severe), and Schumann intends to take up the question of the sense of time anew with the new device that was described above. Finally, the last study to have been performed in the laboratory is that of Müller and Schumann 25 on memory and association: it is, so to speak, a continuation of Ebbinghaus’s work on memory; subjects learn syllables in series, and then are shown a syllable and are asked to speak the syllable or the word that is [621] associated to it immediately; at the moment when the syllable is shown a current is interrupted, and as a result the Hipp chronometer is set in movement; the subject closes the current, and thus stops the chronoscope, by pronouncing the word. The number of times that a series of syllables must be read to be learned is thus determined, as is the time taken to associate one syllable to another, and finally the relation between the two associated syllables is observed; this study is not yet finished, and is being continued by Müller and a student in the laboratory.

In summary, the laboratory in Göttingen is still at the beginning of its formation; the resources there are excellent, but it is difficult to have more than four subjects for a study.

In 1888 Dr. Martius founded the third laboratory of experimental psychology in Germany, in Bonn; this laboratory is Martius’s private possession; it is located in a space belonging to the laboratory of physics. In total it includes five large, well-lit

23 Schumann, Ueber das Gedächtnis für Komplexe reglemässig aufeinander folgender gleicher Schalleindrücke [On memory for groups of sound impressions presented in regular succession] (Zeits. f. Ps. u. Phys. d. Sinnes, I, pp. 75–80).

24 Schumann, Ueb. d. psycholog. Grundlagen d. Vergleichung Kleiner Zeitgrössen [On the psychological processes used in the comparison of small time-durations] (Zeitsch. f. ps. u. Ph. d. Sinn., IV, pp. 1–70).

25 See Zeitsch. f. ps. u. Ph. d. Sinn., VI, p. 81. rooms and two darkrooms; the devices found in the laboratory are the same as those in the Leipzig laboratory—it can be said that it is a smaller version of the Leipzig laboratory; the original devices in the laboratory are first of all that of Martius, used for reactions to sounds of different pitches; it is composed of a resonance chamber 26, upon one of whose sides strings of varying thickness are stretched; at the moment when one of the cords is made to vibrate, the current is interrupted and the chronoscope is set in movement; by reacting, the subject stops the chronoscope. The second new device is a rotating disk, whose rotation is propelled by a small water motor, with a pair of little fins which allow the speed to be made regular and also to be varied in very small steps; a special system gives the number of rotations per second.

The personnel of the laboratory consists of Martius and two students, with the largest number of students in the laboratory at one time so far being five; the cause for this small number is here once again the question of examinations; Martius not being qualified as an examiner for doctoral degrees, it is difficult to present a thesis on a subject in experimental psychology in Bonn.

The studies carried out in the laboratory are published in the Philoso-[622]- phische Studien: these include, first, the studies of Martius on the apparent size of objects, on motor reactions, on reaction times to sounds of different pitches, and on the influence of the intensity of auditory stimulation on the duration of reactions 27; then that of Marbe on the fluctuations of attention28 and on the mixing of black and white. The latter has not yet been published; it was performed using the new rotating disk described above; a disk with black and white sectors is made to turn, and the speed required for it to appear in a uniform gray is determined; next the variations in speed with changes in the size of the sectors or the lighting of the disk are studied; the mixing of white and black can be said to occur more easily when the minimum speed is lower.

In summary, this laboratory greatly resembles that of Leipzig, as much by the devices it contains as by the kind of studies that have been performed there.

26 See Philos. Stud., VI, p. 403.

27 Martius, Scheinbare Grösse der Gegenstände [The apparent size of objects] (Ph. St., V, pp. 601–618); — Musculäre Reaction u. Aufmerksamkeit [Muscular reaction and attention] (Ph. St., VI, pp. 167–217); — Reactionsz. u. Perceptionsdauer der Klänge [Reaction time to, and perceptual durations of, tones] (Ph. St., VI, pp. 394–417); — Einfl. d. Intensität der Reize auf die Reactionszeit der Klänge [The influence of stimulus intensity on the reaction time to tones] (Ph. St., VII, pp. 469–487).

28 Marbe, Schwankungen der Gesichtsempfin. [Fluctations in visual sensations] (Ph. St., VIII, pp. 615–638).

14 AN 1893 FRENCH DESCRIPTION OF GERMAN LABORATORIES 15

There is one laboratory left for us to look at, that of Berlin, on the subject of which, unfortunately, we have little to say: it was founded a few years ago by Dr. Ebbinghaus, receives no regular subsidy, it occupies two rooms, and is organized mainly for demonstrations; the number of devices found there is very limited: a Hipp chronoscope with a few accessory devices; a series of boxes of the same size, but varying weight; a support upon which an arm can be immobilized, such that it is possible to lift a weight simply by bending the elbow; and finally a few devices for optics and physics. No special studies have been carried out in this laboratory; the eight students who frequented it this year performed experiments to familiarize themselves with the devices and methods of experimental psychology; but Dr. Ebbinghaus hopes that in two years there will be quite a large space and a regular subsidy, which will allow him to perform original studies.

VICTOR HENRI.