The Psychological Laboratory
James McKeen Cattell (1898)
First published in Psychological Review, 5, 655-658.
Posted August 2000
During the past quarter three papers have appeared that are of interest to all students of psychology 1] They are so accessible that an abstract is scarcely needed, but some comments may be profitable, more especially if they lead to further discussion.
Professor Titchener describes the Cornell
laboratory and the general needs and functions of a psychological laboratory
with the skillful hand to which we are accustomed. The members of the
Psychological Association who attended the
As Professor Titchener asks for discussion and criticism I shall take up one or two topics. The large ground plan and the description of the laboratory show that, in addition to a lecture-room and rooms for the director and assistant, there will be, when the laboratory is complete, eight rooms. There are, or will be, a small workshop, two dark rooms, a reaction room, a room for the 'physiological processes underlying affective consciousness,' rooms for haptics, and for taste and smell, and a large room for optics and acoustics. Now, I should find the laboratory more useful if the large rooms devoted to vision and hearing were each divided into two or three small rooms, and all the rooms named after the senses were called x. For research a large room cannot be used simultaneously for more than one purpose, and nothing seems to be gained by setting up all the work on vision, for example, in one room. In some years there may be several researches in progress [p. 656] on vision and none on hearing, and conversely. For instruction it is not desirable to drive a flock of twenty students successively into different rooms. They should use the available space of the laboratory, apparatus set up permanently, as an optical bench or chronograph, where it stands, movable pieces, as a perimeter or tuning-forks, where there are convenient places. A room for taste and smell can scarcely be used continuously for research, and a special room is not needed for an hour's instruction in the course of a year. Doubtless Professor Titchener does not hesitate to violate the names of his rooms and use them to the best advantage. I only make these remarks for those who may plan a laboratory on the Cornell model.
Professor French, in claiming that experimental psychology has no place in the undergraduate course, appears to me to fall into the common error of regarding experimental psychology as a science apart from psychology. It is, I hold, simply a method in psychology, and I do not see how an adequate course in general psychology can be given by any one who ignores this method. Recent text-books -- James, Ladd, Kiilpe, Jodl, Titchener, Ebbinghaus and others -- certainly show that the results of the experimental method are an integral part of the science of psychology. If students will follow only one course in psychology they would naturally be given a general course. If the teacher has independent interests these would be emphasized, but I should regard the subjects of James's Principles as a safe guide. This course should be given for Sophomores and Juniors, and subsequently a University should be able to offer courses in physiological, experimental, genetic, analytical, philosophical and historical psychology 3] The special student of psychology should follow all these courses, partly before and partly after taking his B.A.; other students should elect in accordance with their interests and intentions.
I am glad that Professor Titchener advocates laboratory work as an elective course for undergraduates. Still I am not quite so enthusiastic about this as I used to be. An eminent professor of physics [p. 657] recently told me that he did not want to turn his students into the laboratory until they had followed a four-hour course of lectures through the year. In psychology, where the experiments are in a way less fundamental and have scarcely as yet been perfected by the survival of the fit, this point of view is even more tenable. Perhaps an independent lecture course should be offered, and a course of supplementary laboratory work which could be elected simultaneously or the following year.
In a course of lectures on experimental psychology, demonstrations can with
much economy to the teacher and student precede, and
in some cases replace, laboratory work. Dr. Scripture's lantern seems to
perform a useful service; the mere darkening of the room has a pedagogic
function in concentrating attention. With the lantern it is possible not only
to show pictures, but also to demonstrate many of the phenomena of vision, to
exhibit words, etc., for association and memory, and to carry out actual
experiments on fatigue, reaction-time, etc. The psyche-physical methods can be
applied to sight, hearing and the perception of space nearly as well by a whole
class as by the individual student. Dr. Ward, in his course on 'Psychophysics'
Some demonstrations seem to me also desirable in a general psychological course. The student has his text-book and the lecturer may not be able to add very much, but illustrations may be given, which will greatly increase the interest of the course and be a real economy for the student. If subjects such as the senses, the accuracy of discrimination, the perception of space, illusions of sense, the elements of music, memory, the association of ideas, etc., are treated -- and they must be treated -- a demonstration or a class experiment will add as much as in physical or chemical lectures. During the years I spent at Leipzig Professor Wundt added many demonstrations to his general course, and I think to its advantage.
Dr. Scripture, from his abundant experience, is able to make many useful suggestions regarding the conduct of a psychological laboratory. Possibly he over-emphasizes the laboratory as compared with psychology. The student who intends to undertake research should understand methods of measurement and the adjustment of observations, but perhaps he should be referred to the physical laboratory. Certainly [p. 658] it is not a necessary function of a psychological laboratory to teach the use of the lathe. If the student can work in metals he has an advantage, though he is also in danger of wasting time. The calculus may ultimately become important in psychology, but as yet no one has accomplished much by its application. Dr. Scripture's ideas of profit and loss are rather material. Whether the use' of an instrument costs eight cents or three cents per hour is not as important as he seems to think. When he writes : 'The best laboratory * * * is the one that yields the largest net results in scientific research and instruction for each dollar expended,' I should only agree on condition that the last four words be omitted. The question of an expensive outfit has two sides. On the one hand, the best research can be done, and has usually been done, with simple means. On the other hand, it is bad economy for a university to spend thousands of dollars on buildings and salaries and reduce the efficiency of the laboratory to one-half by not providing a workshop and adequate instruments.
The Place of Experimental Psychology in the Undergraduate Course, F. C. French, THE PSYCHOLOGICAL REVIEW, Vol. V., No. 5, September, 1898, pp. 510-512.
Principles of Laboratory Economy, E. W. Scripture, Studies from the Yale Psychological Laboratory, Vol. V., 1897, pp. 91-104.
 When Dr. Harris writes, in his Psychologic Foundations of Education, that from the 'psycho-physiological laboratories' no 'results in pure psychology of a positive character will be arrived at,' the chief information conveyed is that Dr. Harris is concerned with a psychology that belongs to the past.
 Whether a special course in experimental psychology should be offered by a college as an elective seems to depend on the resources of the college. Vassar, with four or five hundred students, many of whom intend to become teachers, should, I think, provide such a course.
Early Psychological Laboratories 
James McKeen Cattell (1928)
First published in Science, 67, 543- 548.
Posted August 2000
for research and teaching in the sciences are of comparatively recent origin.
They may be regarded as part of the industrial revolution, for there is a close
parallel in causes and effects between the development of the factory system
and of scientific laboratories. The industrial revolution began with the
exploitation by machinery of coal and iron in
laboratory had its origin fifty years later in
Prior to the industrial revolution the artisan worked at home, sometimes with 'prentices, who were often his children. The factories, the mines and the systems of transportation, with their machinery, their skilled overseers and division of labor, their owners and entrepreneurs, their exchange of commodities and ideas, created a remarkable economy in production, so that now each individual may perhaps work half as long and consume twice as much wealth as formerly.
But there are serious drawbacks in the lack of freedom and initiative of the workman, in the loss of joy in creative work. The situation in the laboratory is similar. A professor may have many associates, assistants and students; expensive apparatus and extensive libraries may be installed; division of labor in each laboratory and among laboratories can be planned; there may be exchange of ideas and of information on the progress of research; students are taught in large groups. Production is greatly increased, perhaps quadrupled, as in the industrial system, But the scientific man is subject to administrative controls; he is no longer free; he must compromise with others and teach all sorts of students. The system is useful for the production of a large mass of routine work; it may not be favorable to creative genius.
has been called the mother of the sciences; dissecting rooms go back to the
medieval universities of
laboratories were followed by laboratories of physics and biology. I worked in
the first American biological laboratory in its early days. It was established
first laboratory of psychology was established by Wilhelm Wundt.
In an article on the
Wundt writes in the preface to the 'Physiologische Psychologie'
that it undertakes 'ein neues
Gebiet der Wissenschaft abzugrenzen,'
but he was partly anticipated by Hermann Lotze, whose 'Medizinische Psychologie' was published in 1852. Both Lotze and Wundt had a medical
education and were professors of philosophy. Their books are landmarks in the
history of our science. It was my privilege to hear the last course of lectures
on psychology by Lotze given at Göttingen
in the winter semester of 1880-81. In accordance with the custom of that
university Lotze dictated summaries which could be
written down verbatim even by one who had small psychology and less German. The
'Dictata' of that year were published and
have been translated into English. In the spring of 1881 Lotze,
then 74 years of age, migrated to
Herbart, whom Lotze succeeded at Göttingen, had tried to give a mathematical formulation to
psychology as Spinoza had to philosophy. He published the first edition of his
'Einleitung in die Philosophie'
in 1813. There followed Drobitsch, Lindner, Benecke, Volkmar and other German
most important developments for laboratory psychology were through the great
German physiologists and physicists, most of all Helmholtz,
who passed from physiology to physics. His 'Physiologische
Optik,' recently translated under the editorship
of Professor Southall and published as an act of
piety by the Optical Society, and his 'Tonempfindingen,'
of which there is an earlier translation, are classics in the history of
science. E. H. Weber became professor of anatomy at
The middle fifty years of the last century were the golden age of the German university and of science, its Wunderkind. It is marvelous what was accomplished then and there. Thus in the little corner of the field of science concerned with the psychology of the sense of vision there worked, in addition to Helmholtz and Fechner, a notable company, including Aubert, Brücke, du Bois-Reymond, Donders (in Holland), Exner, Fraunhofer, Fick, von Graefe (who examined my eyes when I was a child of eight), Hering, Hermann, von Kries, Listing, Johann Mueller, Nagel, Purkinje, Vierordt, the Webers and many more. There is no such group in the world to-day working on vision or in any other part of experimental psychology. At that time the investigation of the other senses, of movement, of the time of reaction and much else was pursued probably to greater effect than in all the innumerable laboratories of to-day.
fields so fertile in the nineteenth century were of course cleared at an
earlier time. Experiments on vision go back to Kepler,
intermissions I was a student at
When I showed Wundt an outline of the work that I proposed for a doctor's thesis on the reaction-time, including complicated responses and a study of individual differences his comment was: 'ganz Amerikanisch.' As a matter of fact I did the work in my own rooms and with my own apparatus. At that time students were expected to work in the laboratory on a subject assigned by the professor, during certain definite hours in the afternoon and with the apparatus supplied, which had to be put away neatly in the cases after a two-hour period. We used two batteries of Daniel cells and when these were set up and got into running order it was nearly time to take them apart, wash the zincs and coppers and put the fluids into bottles. As in this process we were likely to splash sulphuric acid on our clothes we kept handy a bottle of ammonia, which was very promptly applied to the stains. At that time I anticipated Dr. Watson in an observation on the conditioned reflex, for when the German student who worked with me drew a mouthful of dilute sulphuric acid through the syphon that we used, he immediately reached for the ammonia bottle and took a mouthful of that.
the early eighties Wundt's laboratory was housed on
the top floor of the Convict building, where indigent students had their
meals. He used to walk through the laboratory after his lecture, always
courteous and ready to answer questions, but, as I remember it, usually
limiting his visit to five or ten minutes. He was interested in the laboratory
as a system, and as a method of introspection, but he was not himself a
laboratory worker. His interests were very broad. His 'Logik,'
published from 1880 to 1883, contains in the second edition 1,995 pages; his
'Ethik,' also published while I was at
books and others Wundt composed on a typewriter that
I gave him, one of the first in
At the beginning of the semester students who wanted to undertake experimental work stood before Wundt in a row and from a slip of paper that he held in his hand he assigned topics in order. The year that I appeared there were six or seven of us, representing nearly as many nationalities. I was given the problem of reacting to colored lights; first when the light was seen, and second when the color was distinguished, and by subtracting one time from the other of obtaining what Wundt called the 'Apperceptionszeit.' This I could not do, but the problem was most useful to me, for it led me to realize the limitations of introspection and to base my work on objective measurements of behavior. Wundt's refusal to admit any subject to the laboratory except a psychologist who could use the results introspectively was [p. 546] also useful, for it led me to transfer the work to my rooms and make there the first psychological measurements of individual differences and to attempt to develop the useful applications of psychology -- with both of which efforts Wundt had no sympathy.
Wundt rejected as a doctorate dissertation Münsterberg's very able monograph on 'Die Willenshandlungen' because it did not coincide with
his own theories. He calls Stanley
Hall's excellent sketch of his life and work an 'erdichtete Biographie die
von anfang bis zu Ende erfunden ist.' But such things were only the
righteous indignation of the Hebrew prophet denouncing the enemies of the Lord.
The academic life in
Wundt's laboratory of psychology was international in its
reputation and influence, attracting students from all parts of the world,
Americans and Russians predominating. In 1892 it received larger quarters and
in 1897 was removed to one of the buildings vacated by the
second laboratory of psychology was organized by G. Stanley Hall at the
is a curious fact that neither of the founders of our first two psychological
laboratories was a laboratory worker. Hall's chair, like Wundt's,
was not limited to psychology; he lectured on philosophy and he also conducted
courses in pedagogy. The range of his interests was large, but it was the human
aspects of life that he cared for rather than abstract quantitative
measurements. Like James he was a man of literary genius swayed by the
emotions, which are such a large part of life and as yet such a small part of
our science. Minot, the distinguished Harvard embryologist, once said that he
envied my occupation with a science concerned with human interests. My reply
was that my experiments had as little to do with such things as his had with love and children. Hall wrote about children,
adolescence and senescence, religion and sex, the drama of life. He and James
were giants in the land, overtowering their
descendants of a work-a-day world. As Wundt
established the Philosophische Studien to publish the work from his laboratory and his
own articles on psychology and philosophy, so Hall established the American
Journal of Psychology. The early volumes give a survey of the work done in
was called upon to organize
laboratory of psychology at the
1888 I was also lecturer at
five-year period from 1887 to 1892 is distinguished for the development of
laboratories of psychology in the
in experimental psychology leading to the establishment of a laboratory was began by Professor Joseph Jastrow
professorship of psychology and the laboratory of psychology at
were James, Royce and Münsterberg
was the center of psychology. James was appointed professor of psychology at
Harvard in 1889, having been from 1872 to 1880 instructor and assistant
professor of comparative anatomy and physiology, after 1880 assistant professor
of philosophy, becoming again professor of philosophy in 1897. His great work,
'The Principles of Psychology,' was published in 1890. In a letter
addressed to me as editor of SCIENCE in 1895 James thus tells of the
development of work in experimental psychology at Harvard: 'I myself,
'founded' the instruction in experimental psychology at Harvard in 1874-5, or
1876, I forget which. For a long series of years the laboratory was in two
rooms of the
the publication of James's 'Principles of Psychology' in 1890, the
opening of the laboratories at Harvard, Yale and Cornell in 1892, and the
establishment of the American Psychological Association [p. 548] in the same
year, the earlier period of psychology in
Address on the occasion of the inauguration of the Psychological Laboratory of
First published in Mind, 15, 373-381.
Psychology cannot attain the certainty and exactness of the physical sciences, unless it rests on a foundation of experiment and measurement. A step in this direction could be made by applying a series of mental tests and measurements to a large number of individuals. The results would be of considerable scientific value in discovering the constancy of mental processes, their interdependence, and their variation under different circumstances. Individuals, besides, would find their tests interesting, and, perhaps, useful in regard to training, mode of life or indication of disease. The scientific and practical value of such tests would be much increased should a uniform system be adopted, so that determinations made at different times and places could be compared and combined. With a view to obtaining agreement among those interested, I venture to suggest the following series of tests and measurements, together with methods of making them 1]
The first series of ten tests is made in the Psychological
Laboratory, of the
The following ten tests are proposed:
I. Dynamometer Pressure.
II. Rate of Movement.
IV. Pressure causing Pain.
V. Least Noticeable difference in Weight.
VI. Reaction-time for Sound.
VII. Time for naming Colours.
VIII. Bi-section of a 50 cm. Line
IX. Judgment of 10 seconds time.
X. Number of Letters remembered on once Hearing.
[p.374] It will be noticed that the series begins with determinations rather bodily than mental, and proceeds through psychophysical to more purely mental measurements 2]
The tests may be readily made on inexperienced persons, the time required for the series being about an hour. The laboratory should be conveniently arranged and quiet, and no spectators should be present while the experiments are being made. The amount of instruction the experimentee should receive, and the number of trials he should be given, are matters which ought to be settled in order to secure uniformity of result. The amount of instruction depends on the experimenter and experimentee, and cannot, unfortunately, be exactly defined. It can only be said that the experimentee must understand clearly what he has to do. A large and uniform number of trials would, of course, be the most satisfactory, the average, average variation, maximum and minimum being recorded. Time is, however, a matter of great importance if many persons are to be tested. The arrangement most economical of time would be to test thoroughly a small number of persons, and a large number in a more rough-and-ready fashion. The number of trials I allow in each test is given below, as also whether I consider the average or 'best' trial the most satisfactory for comparison. Let us now consider the tests in order.
I. Dynamometer Pressure. The greatest possible squeeze of the hand may be thought by many to be a purely physiological quantity. It is, however, impossible to separate bodily from mental energy. The 'sense of effort' and the effects of volition on the body are among the questions most discussed in psychology and even in metaphysics. Interesting experiments may be made on the relation between volitional control or emotional excitement and dynamometer pressure. Other determinations of bodily power could be made (in the second series I have included the 'archer's pull' and pressure of the thumb and fore-finger), but the squeeze of the hand seems the most convenient. It may be readily made, cannot prove injurious, is dependent on mental conditions, and allows comparison of right-and left-handed power. The experimentee should be shown how to hold the dynamometer in order to obtain the maximum pressure. I allow two trials with each hand (the order being right, left, right, left), and record the maximum pressure of each hand.
II. Rate of Movement. Such a determination seems to be of
considerable interest, especially in connexion with
the preceding. [p.375] Indeed, its physiological importance is such as to make
it surprising that careful measurements have not hitherto been made. The rate
of movement has the same psychological bearings as the force of movement.
Notice, in addition to the subjects already mentioned,
the connexion between force and rate of movement on
the one hand and the 'four temperaments' on the other. I am now making
experiments to determine the rate of different movements. As a general test, I
suggest the quickest possible movement of the right hand and arm from rest
through 50 cm. A piece of apparatus for this purpose can be obtained from Clay
III. Sensation-areas. The distance on the skin by which two points must be separated in order that they may be felt as two is a constant, interesting both to the physiologist and psychologist. Its variation in different parts of the body (from 1 to 68 mm.) was a most important discovery. What the individual variation may be, and what inferences may be drawn from it, cannot be foreseen; but anything which may throw light on the development of the idea of space deserves careful study. Only one part of the body can be tested in a series such as the present. I suggest the back of the closed right band, between the tendons of the first and second fingers, and in a longitudinal direction. Compasses with rounded wooden or rubber tips should be used, and I suggest that the curvature have a radius of 5mm. This experiment requires some care and skill on the part of the experimenter. The points must be touched simultaneously, and not too hard. The experimentee must turn away his head. In order to obtain exact results, a large number of experiments would be necessary, and all the tact of the experimenter will be required to determine, without undue expenditure of time, the distance at which the touches may just be distinguished.
IV. Pressure causing Pain. This, like the rate of movement, is a determination not hitherto much considered, and if other more important tests can be devised they might be substituted for these. But the point at which pressure causes pain may be an important constant, and in any case it would be valuable in the diagnosis of nervous diseases and in studying abnormal states of consciousness. The determination of any fixed point or quantity in pleasure or pain is a matter of great interest in theoretical and practical ethics, and I should be glad to include. some such test [p.376] the present series. To determine the pressure causing pain, I use an instrument (to be obtained from Clav & Torbensen) which measures the pressure applied by a tip of hard rubber 5 mm. in radius. I am now determining the pressure causing pain in different parts of the body; for the present series commend the centre of the forehead. The pressure should be gradually increased and the maximum read from the indicator after the experiment is complete. As a rule, the point at which the experimentee says the pressure is painful should be recorded, but in some cases it may be necessary to record the point at which signs of pain are shown. I make two trials, and record both.
V. Least noticeable difference in Weight. The just noticeable sensation and the least noticeable difference in sensation are psychological constants of great interest. Indeed, the measurement of mental intensity is probably the most important question with which experimental psychology has at present to deal. The just noticeable sensation can only be determined with great pains, if at all: the point usually found being in reality the least noticeable difference for faint stimuli. This latter point is itself so difficult to determine that I have postponed it to the second series. The least noticeable difference in sensation for stimuli of a given intensity can be more readily determined, but it requires some time, and consequently not more than one sense and intensity can be tested in a preliminary series. I follow Mr. Galton in selecting 'sense of effort' or weight. I use small wooden boxes, the standard one weighing 100 gms. and the others 101, 102, up to 110 gms. The standard weight and another (beginning with 105 gms.) being given to the experimentee, he is asked which is the heavier. I allow him about 10 secs for decision. I record the point at which he is usually right, being careful to note that he is always right with the next heavier weight.
VI. Reaction-time for Sound. The time elapsing before a stimulus calls forth a movement should certainly be included in a series of psychophysical tests: the question to be decided is what stimulus should be chosen. I prefer sound; on it the reaction-time seems to be the shortest and most regular, and the apparatus is most easily arranged. I measure the time with a Hipp chronoscope, but various chronographic methods have been used. There is need of a simpler, cheaper and more portable apparatus for measuring short times. Mr. Galton uses an ingenious instrument, in which the time is measured by the motion of a falling rod, and electricity is dispensed with, but this method will not measure times longer than about 1/3 sec. In measuring the reaction-time, I suggest that three valid reactions be taken, and the minimum recorded. Later, the average and mean variation may be calculated 4]
VII. Time for naming Colours. A reaction is essentially reflex, [p.377] and, I think, in addition to it, the time of some process more purely mental should be measured. Several such processes are included in the second series; for the present series I suggest the time needed to see and name a colour. This time may be readily measured for a single colour by means of suitable apparatus (see MIND No. 42), but for general use sufficient accuracy may be attained by allowing the experimentee to name ten colours and taking the average. I paste coloured papers (red, yellow, green and blue) 2 cm. square, 1cm. apart, vertically on a strip of black pasteboard. This I suddenly uncover and start a chronoscope, which I stop when the ten colours have been named. I allow two trials (the order of colours being different in each) and record the average time per colour in the quickest trial.
VIII. Bisection of a 50 cm Line. The accuracy with which space and time are judged may be readily tested, and with interesting results. I follow Mr. Galton in letting the experimentee divide an ebony rule (3 cm. wide) into two equal parts by means of a movable line, but I recommend 50 cm. in place of 1 ft., as with the latter the error is so small that it is difficult to measure, and the metric system seems preferable. The amount of error in mm. (the distance from the true middle) should be recorded, and whether it is to the right or left. One trial would seem to be sufficient.
IX. Judgment of 10 sec. Time. This determination is easily made. I strike on the table with the end of a pencil and again after 10 seconds, and let the experimentee in turn strike when he judges an equal interval to have elapsed. I allow only one trial and record the time, from which the amount and direction of error can be seen.
X. Number of Letters repeated on once Hearing. Memory and attention may be tested by determining how many letters can be repeated on hearing once. I name distinctly and at the rate of two per second six letters, and if the experimentee can repeat these after me I go on to seven, then eight, &c.; if the six are not correctly repeated after three trials (with different letters), I give five, four, &c. The maximum number of letters which can be grasped and remembered is thus determined. Consonants only should be used in order to avoid syllables.
Experimental psychology is likely to take a place in the educational plan of our schools and universities. It teaches accurate observation and correct reasoning in the same way as the other natural sciences, and offers a supply of knowledge interesting and useful to everyone. I am at present preparing a laboratory manual which will include tests of the senses and measurements of mental time, intensity and extensity, but it seems worth while to give here a list of the tests which I look on as the more important in order that attention may be [p.378] drawn to them, and co-operation secured in choosing the best series of tests and the most accurate and convenient methods. In the following series, fifty tests are given, but some of them include more than one determination.
1. Accomodation (short sight,
over-sight, and astigmatism).
2. Drawing Purkinje's figures and the blind-spot.
3. Acuteness of colour vision, including lowest red and highest violet visible.
4. Determination of the field of vision for form and colour.
5. Determination of what the experimentee considers a normal red, yellow, green and blue.
6. Least perceptible light, and least amount of colour distinguished from grey.
7. Least noticeable difference in intensity, determined for stimuli of three degrees of brightness.
8. The time a colour must work on the retina in order to produce a sensation, the maximum sensation and a given degree of fatigue.
9. Nature and duration of after-images.
10. Measurement of amount of contrast.
11. Accuracy with which distance can be judged with one and with two eyes.
12. Test with stereoscope and for struggle of the two fields of vision.
13 Errors of perception, including bisection of line, drawing of square, &c.
14. Colour and arrangement of colours preferred. Shape of figure and of rectangle preferred.
15. Least perceptible sound and least noticeable difference
in intensity for sounds of three degrees of loudness.
16. Lowest and highest lens audible, least perceptible difference in pitch for C, C', C', and point where intervals and chords (in melody and harmony) are just noticed to be out of tune.
17. Judgment of absolute pitch and of the nature of intervals, chords and dischords.
18. Number and nature of the overtones which can be heard with and without resonators.
19. Accuracy with which direction and distance of sounds can be judged.
20. Accuracy with which a rhythm can be followed and complexity of rhythm can be grasped.
21. Point at which loudness and shrillness of sound become painful. Point at which beats are the most disagreeable.
22. Sound of nature most agreeable. Musical tone, chord, instrument and composition preferred.
[p.379] Taste and Smell.
23. Least perceptible amount of cane-sugar, quinine, cooking
salt and sulphuric acid. and
determination of the parts of the mouth with which they are tasted.
24. Least perceptible amount of camphor and bromine.
25. Tastes and smells found to be peculiarly agreeable and disagreeable.
Touch and Temperature.
26. Least noticeable pressure for different parts of the
27. Least noticeable difference in pressure, with weights of 10, 100 and 1000 gms.
28. Measurement of sensation-areas in different parts of the body.
29. Accuracy with which the amount and direction of the motion of a point over the skin can be judged.
30. Least noticeable difference in temperature.
31. Mapping out of heat, cold and pressure spots on the skin.
32. The point at which pressure and heat and cold cause pain.
Sense of Effort and Movement 5]
33. Least noticeable difference in weight, in lifting
weights of 10, 100 and 1000 gms.
34. Force of squeeze of hands, pressure with thumb and forefinger and pull as archer.
35. Maximum and normal rate of movement.
36. Accuracy with which the force, extent and rate of active and passive movements can be judged.
37. The time stimuli must work on the ear and eye in order
to call forth sensations.
38. The reaction-time for sound, light, pressure and electrical stimulation.
39. The perception-time for colours, objects, letters and words.
40. The time of naming colours, objects, letters and words.
41 The time it takes to remember and to come to a decision.
42 The time of mental association.
43. The effects of attention, practice and fatigue on mental time.
44. Results of different methods used for determining the
least noticeable difference in sensation.
45. Mental intensity as a function of mental time.
[p.380] Mental Extensity.
46. Number of impressions which can be simultaneously
47. Number of successive impressions which can be correctly repeated, and number of times a larger number of successive impressions must be heard or seen in order that they may be correctly repeated.
48. The rate at which a simple sensation fades from memory.
49. Accuracy with which intervals of time can be remembered.
50. The correlation of mental time, intensity and extensity.
Remarks by Francis Galton, F.R.S.
(A) One of the most important objects of measurement is hardly if at all alluded to here and should be emphasised. It is to obtain a general knowledge of the capacities of a man by sinking shafts, as it were, at a few critical points. In order to ascertain the best points for the purpose, the sets of measures should be compared with an independent estimate of the man's powers. We thus may learn which of the measures are the most instructive, The sort of estimate I have in view and which I would suggest should benoted [? for private use] is something of this kind,-'mobile, eager, energetic; well shaped; successful at games requiring good eye and hand; sensitive; good at music and drawing'. Such estimates would be far from worthless when made after only a few minutes' talk; they ought to be exact when made of students who have been for months and years under observation. I lately saw a considerable collection of such estimates, made by a medical man for a special purpose. They were singularly searching and they hit off, with a few well chosen epithets, a very great variety of different characters. I could not induce the medical man to consent to the publication of specimens of his excellent analyses, nor even of fancy specimens. Even these would have sufficed to show that if psychologists seriously practised the art of briefly describing characters. they might raise that art to a high level.
(B) The method I have long used for testing keenness of eye-sight in persons whose powers of eye-adaptation are normal, still seems to me quite effective. It is to register the greatest distance at which numerals printed in diamond type can be read. Strips of paper cut out at random from a small sheet printed all over with these numerals, are mounted on blocks set at successive distances from the eye-hole. They can easily be changed when dirty. Fair light is wanted, but that is all that is needed for ordinary test purposes.
C) I have constructed an instrument which is not yet quite as I desire , of which the first part would I think greatly facilitate [p. 381] the working with the Hipp chronograph. I had found great trouble in inducing coarse and inexperienced persons to deliver their blows aright. They bungled and struck the instrument wrongly, and often broke it. Then I made it more massive, yet still they broke it and often hurt themselves much in doing so. My present plan is to give them nothing more than one end of a long thread to hold. The other end passes round a spring reel, like the tape in a spring measuring tape. The string when left to itself will reel home much faster than the swiftest blow can travel. All that the experimentee does is to retard it; the quickest man retarding it the least. The string travels smoothly and swiftly in a straight line between two eyelet holes. A bead attached to that part of the string would make the necessary breaks of electric contact with great neatness. The thread has a stop to cheek it when it has run far enough home. My reel is nothing more than a very light wooden wheel with a groove in it, some 3 inches in diameter, and with a brass axis turning freely between fixed points. One thread passes round the axis, and is tied at the other end to an india rubber band. The other thread passes in the opposite direction round the grooved wheel, and then through the eyelet holes. The experimentee is placed well back, quite clear of the apparatus. Nothing can act better than this part of my new instrument.
(D) I now use a very neat, compact, and effective apparatus (made for me by
 Mr. Francis Galton, in his Anthropometric
 Sharpness of sight (including colour-vision) and hearing might, perhaps, be included in the list. I have omitted them because it requires considerable time to discover the amount and nature of the defect (which is usually bodily, not mental), and because abundant statistics have been published, and are being collected by oculists and aurists. [See Remark ( b )]
 See Remark ( c ).
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