Ed/ Psych 
 
 lib. 
 
 BF 
 
 38 
 
 W879p 
 
 WOODWORTH 
 PSYCHOLOGY
 
 THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 OF CALIFORNIA 
 
 LOS ANGELES
 
 PSYCHOLOGY 
 
 BY 
 
 ROBERT SESSIONS WOODWORTH 
 
 THE COLUMBIA UNIVERSITY PRESS 
 1908 
 
 :
 
 ^PSYCHOLOGY; 
 
 A LECTURE DELIVERED AT COLUMBIA UNIVERSITY 
 
 IN THE SERIES ON SCIENCE, PHILOSOPHY AND ART 
 
 MARCH 11, 1908 ,
 
 PSYCHOLOGY 
 
 BY 
 
 ROBERT SESSIONS 1WOODWORTH 
 
 ADJUNCT PROFESSOR OF PSYCHOLOGY 
 COLUMBIA UNIVERSITY 
 
 THE COLUMBIA UNIVERSITY PRESS 
 1908
 
 COPYRIGHT, 1908, 
 By THE COLUMBIA UNIVERSITY PRESS. 
 
 Set up, and published April, 1908.
 
 Ed. - Psycti. 
 Library 
 
 BF 
 
 PSYCHOLOGY 
 
 IN attempting to give a view of the present state of his 
 science a view that shall be fairly objective and free from 
 the bias of his own particular interests the psychologist 
 encounters a peculiar difficulty in that the camp of his fel- 
 lows is divided. Two standards are displayed ; two parties 
 are in the field; and their relations are not always so 
 friendly as might be expected of soldiers in a common 
 cause. Such divisions are indeed not unknown in the other 
 sciences. The descriptive and the dynamic phases of a sub- 
 ject, the study of structure and the study of function, fre- 
 quently divide the workers between them, and sometimes 
 those who hold to the one despise the other. The line of 
 cleavage is sharper in psychology than elsewhere: those 
 who define psychology as the science of consciousness 
 the "morphology of consciousness," as one has put it 
 maintain that any study which does not contribute to the 
 description of conscious life lies beyond the pale of the 
 science; whereas to those who define it as the science of 
 those functions of the organism which are roughly desig- 
 nated as mental, the examination of the consciousness at- 
 tending these functions, though valuable and suggestive, 
 does not lie at the root of the matter. This strife is indeed 
 carried on more at the level of theoretical discussion than at 
 that of practical investigation, for those who work at spe- 
 cial problems are apt to approach them from both sides. 
 There are then two general problems of psychology, and 
 
 5
 
 two general methods, one appropriate to each problem. 
 Consciousness affords a rich variety of phenomena, which 
 tempt the scientifically inclined observer to describe and 
 classify them. Even as the variety of plants, with their 
 gradations of likeness and difference, led the naturalist to 
 descriptive and systematic botany, so the multitude of sen- 
 sations and emotions, of memories and fancies, thoughts, 
 desires and decisions was sure, in time, to entice those who 
 were gifted both with scientific curiosity and with a self- 
 observant temper into an effort at setting down these mul- 
 tifarious appearances in some kind of order. The method 
 appropriate to such studies was imposed by the nature of 
 the case. As we can not enter directly into the conscious- 
 ness of our fellows, each observer must examine his own, 
 by introspection. And not all self -observation is entitled 
 to be called introspection. Since a thing can be observed 
 only when it is present, the observer of conscious facts must 
 have those facts within him at the moment of observation. 
 He must serve simultaneously as the observer and as the 
 generator of the thing observed. This creates a difficulty 
 for the introspectionist which is practically very great, and 
 theoretically insurmountable. Comte went so far as to 
 assert that it made psychology impossible. The subject 
 and the object of an observation can not be the same, he 
 said. I can not divide myself into two persons or agents, 
 one of whom does something which the other notes. And 
 without such a division, self -observation is impossible, for 
 if I do anything, I am occupied with doing it and not with 
 observing it, whereas if I set myself to observe, there is 
 nothing doing to be observed. 
 
 The antinomy of the introspective method is however not 
 quite so sharp in practise as the philosopher has asserted. 
 If it were, you could not even state with confidence that 
 the speaker's voice was audible to you. And much more 
 than this is possible. You can be sure whether the word 
 
 6
 
 "antinomy" gave rise in you, a moment ago, to a prompt 
 feeling of recognition, or to some hesitancy and disaffection 
 towards the speaker. That introspection is to some degree 
 possible arises from the fact that the consciousness of a 
 moment is not an indivisible unit, but has parts. More 
 than one process may simultaneously go on in it, and one 
 of the simultaneous processes may consist in observation. 
 Some persons frequently have the feeling of a division 
 within them, one part being engaged in watching what the 
 other is doing. 
 
 But the difficulty of introspection is only half overcome 
 by this doubleness of consciousness, for the processes that 
 go on simultaneously are not without influence on each 
 other; they often interfere with each other's completeness 
 and efficiency. If the process to be observed is easy and 
 the observation also easy, little confusion need result ; but 
 when the process to be observed is complex or absorbing, 
 as in the case of an emotion or difficult task, it becomes 
 hard to maintain the attitude of the scientific observer ; and 
 in so far as the observer's attitude is maintained, it is doubt- 
 ful whether the other process runs its normal course. Thus 
 the introspective psychology of the emotions is more prop- 
 erly the psychology of the emotions while psychologizing. 
 
 Some help comes to us here from the existence of a 
 "primary memory," from the readiness with which an ex- 
 perience can be recalled before it has fairly passed out of 
 consciousness. Just as the words of a speaker linger for a 
 while, and may, as it were, be forcibly haled back before 
 they are fully gone, to receive more careful attention than 
 they got at first, so even a poignant emotion may suggest, 
 as it starts to fade away, that here is the opportunity, so 
 long desired, of making an interesting observation. Such 
 a suggestion would hardly occur to anyone but a psy- 
 chologist, and not to him as often as might be desired. 
 
 In spite of these mitigating circumstances the possi- 
 
 7
 
 bility of two simultaneous processes in consciousness and 
 of primary memory the case of introspection is a hard 
 one, and many, even psychologists, are disposed to regard 
 its results as seldom reaching the standard of scientifically 
 observed facts. 
 
 When, in the middle of the last century, a few psycholo- 
 gists believed the time had come for the introduction of 
 experiment, they did not aim to substitute a new method 
 for that of introspection, but to provide conditions under 
 which introspection could be more precise. One improve- 
 ment consisted simply in making it first hand, in substi- 
 tuting definite observations for vague impressions derived 
 from past experience. The older psychology distinctly 
 an armchair science had been in reality less introspective 
 than retrospective. The net result of past experience had 
 been relied on, and no need had been felt for going back to 
 the individual instances. Single observations, recorded on 
 the spot, form the basis of modern psychology. We no 
 longer accept a general conclusion unless we are shown the 
 individual recorded instances on which it rests. 
 
 Along with recorded observations go repeated observa- 
 tions. The variability of conscious events is so great that 
 it is never safe to depend on single instances. For a similar 
 reason, it is now felt to be unsafe to rely on the introspec- 
 tion cf a single observer. In the earlier days, which now 
 seem to us days of happy, easy confidence, when the psy- 
 chologist had made an observation on himself, he said, not 
 "I do so and so," but "We do so and so," never doubting 
 that other minds would do the same as his. Such confi- 
 dence is now known to be misplaced. The varying self- 
 observations of many minds must be collated, and their 
 agreements, if any, separated out from the mass of dis- 
 agreement, before arriving at a description which shall 
 have a claim to universal validity. 
 
 These reforms have made introspection more conscien- 
 
 8
 
 tious, and necessity has also made it more modest. It can 
 not hope to grasp the whole of a conscious event in a single 
 observation. The attention of the observer must be 
 focused on some definite and often minute point. He 
 must not attempt to describe his experience in full, but to 
 answer the simple question, "Do you observe this yes or 
 no?" Such observations are minute, microscopic almost, 
 and attempts are made to make them genuinely micro- 
 scopic in some such way as the following. Besides the 
 observer, in whom the conscious process is to be aroused, a 
 second person is present as the conductor of the experi- 
 ment, a sort of stage manager. He prepares the apparatus 
 and other externals, and sets the observer some task, such 
 as the comparison of two physical stimuli as to their in- 
 tensity, duration, pleasureableness ; or it may be some in- 
 tellectual problem is to be solved. But, instead of letting 
 the observer alone till the task is finished, he interrupts him 
 in its midst, and questions him regarding the consciousness 
 present at that stage. Now ordinarily, with the naked 
 eye of introspection, we attend so little to the way we feel 
 while performing a mental task, to the consciousness 
 which intervenes between the grasping of the question and 
 the appearance of the answer, that we could give little ac- 
 count of it. By the intervention of the manager of the 
 experiment, it becomes possible to catch some of the fleet- 
 ing consciousness ere it disappears and so to reveal details 
 which would otherwise remain hidden. 
 
 By such devices, introspection can be made to give data 
 of sufficient precision for scientific use ; but the data are of 
 a minute and technical sort, and fail to satisfy the natural 
 curiosity of man as to the deeper and higher things in ex- 
 perience the absorbing emotions or the flights of imagi- 
 nation. In short the complaint is made that experimental 
 psychology is lacking in human interest; and should not 
 psychology, of all subjects, possess human interest? The 
 
 9
 
 psychologist too would wish to rise to these noble themes, 
 but he feels that he could not as yet deal properly with 
 them. He is comforted by the thought that the excep- 
 tional may really be less important than the ordinary run 
 of experience, for the purposes of a science of conscious- 
 ness. As history shows a tendency to descend from the 
 heroic to the routine in the experience of the race, believing 
 that only thus can the past be truly revealed, so psychol- 
 ogy, driven largely by the necessities of its method, has 
 already made a similar descent. It might well be ex- 
 pected, therefore, that an inventory of the results of in- 
 trospective psychology would be rather a dry and technical 
 affair, unsuited to the present occasion. Let me try, how- 
 ever, to set forth a few results which may have some 
 interest. A definition is first necessary. A "moment" in 
 psychology not necessarily a "psychological moment"- 
 is so much of consciousness as seems to be simultaneously 
 present; the present moment of consciousness is so much 
 experience as is being got now just now. Formerly, 
 under the influence of physical analogies and of the dogma 
 of the unity and simplicity of the mind, the moment was 
 conceived as a point, a moving point to be sure, and a point 
 that changed in quality as it moved, but a point in time, 
 leaving its past instantly behind it, and a point in breadth, 
 admitting of no simultaneous plurality. Introspection, 
 under experimental control, reveals no such mathemati- 
 cally perfect atom of consciousness. The moment is ex- 
 tended in at least two dimensions. It is extended in time. 
 Absurd as it may seem to speak of the present moment as 
 reaching back a little way into the past and even forward 
 a little into the future, this must not deter us from de- 
 scribing consciousness as we find it. So described, the 
 present moment, though it has a center corresponding 
 somewhat with the mathematical present, contains also a 
 dying away of events that have just passed the center, and 
 
 10
 
 a coming in of events that have not yet reached the center. 
 The shadows which coming events cast before them in 
 consciousness are partly of the nature of expectancies, and 
 partly due to the imperfect perception of events which 
 have already happened but are only beginning to take hold 
 of us. We live a fraction of a second, or more, behind the 
 time, and can never catch up, because time is always 
 needed for a new event to win the center of consciousness 
 from the old event that holds it. The center of the felt 
 present, the thing which most occupies the field, is always 
 a little behind the newest thing in consciousness. Nor 
 does the old event, which gives way to the new, drop in- 
 stantly out of sight; it lingers, gradually dying away; it 
 remains as something which is passing but is not yet wholly 
 past. 
 
 That the conscious moment has another dimension be- 
 sides its length in time is also clear to introspection. A 
 plurality of items may coexist within it; the contrary doc- 
 trine was not founded on empirical observation. 
 
 Yet the moment is not a bare sum of discrete items. It 
 shows internal organization. The items are related to 
 each other ; they tend to be grouped into wholes. A series 
 of sounds, physically of equal intensity and with equal in- 
 tervals between them, is not heard as such. Some of the 
 sounds receive a subjective accent, and some of the intervals 
 are subjectively lengthened, with the result that the series 
 seems to have a rhythmic form. So, a jumble of dots on a 
 plain background are seen as if grouped. The grouping 
 may change on continued examination ; but, at any one mo- 
 ment, the dots are organized in a certain form. However 
 disconnected the items presented at a moment may be as 
 physical facts, they are almost sure to appear in conscious- 
 ness as fused, contrasted, grouped or in some way related 
 to each other. 
 
 The moment is centered about some item which is tem- 
 
 11
 
 porarily the most prominent; it occupies, as we say, the 
 focus of attention, while other items lie more to the margin 
 of inattention. If one's mind is centered on a speaker's 
 thought, then the peculiarities of his voice or appearance, 
 the appearance of others near him or in more distant parts 
 of the room, extraneous noises, and one's own bodily feel- 
 ings, may still be marginally present in one's conscious- 
 ness ; though unimportant intellectually, the blend of these 
 obscure components of consciousness has its significance as 
 constituting the emotional undercurrent of the moment. 
 
 One moment shades off into another; no exact bound- 
 aries appear between them. Their sequence is not like a 
 succession of separate views, but each dissolves into the 
 next. Professor James, in a chapter which is among the 
 most successful efforts at introspective description, dis- 
 cards the old metaphors of a chain or train of ideas as en- 
 tirely inadequate, and substitutes the figure of a "stream 
 of thought." He also calls attention to the existence of 
 conscious transitions or modulations from one prominent 
 idea to the next, the transitions consisting in a variety of 
 feelings of expectancy and relationship. From all this it 
 will be seen that present conceptions of conscious process 
 differ widely from the cut-and-dried schemes which were 
 current a generation or less ago. 
 
 An important result, along quite a different line, came 
 out of Galton's inquiry into the mental imagery of va- 
 rious persons. When he asked them to think of some 
 familiar scene, some reported that a picture of the scene 
 arose within them, and appeared before the mind's eye 
 almost as if present to sense. Others had much less of 
 this pictorial consciousness; still others reported an en- 
 tire absence of any such thing. Though they recalled the 
 scene to mind, and were prepared to describe it, they did 
 not picture it to the inner sense. The same individual 
 differences appear in the process of recalling auditory, 
 
 12
 
 olfactory and tactile experience. It is the existence of great 
 individual differences in the consciousness of the same 
 facts which gives interest to this result. Men may com- 
 pare notes regarding what they have experienced, and 
 agree as to the material facts, while nevertheless their 
 modes of being conscious of the recalled facts are ex- 
 tremely diverse. 
 
 A number of recent studies of the consciousness attend- 
 ing important mental functions, such as judgment, rea- 
 soning and voluntary action, have come to negative conclu- 
 sions which yet have their value from one point of view. 
 There appears to be no definite sort of consciousness ap- 
 propriate to each of these functions, no introspective mark 
 or differentia of each. Given the starting point of a mental 
 performance and its outcome, we can not infer what con- 
 sciousness intervened. This is true even of the simple 
 case, familiar in the laboratory, in which two sense stimuli, 
 one following the other, are to be compared in intensity. 
 The old conception of the process was that when the second 
 stimulus came, an image of the first recurred to mind ; the 
 two were held up side by side in consciousness and their 
 likeness or difference read off. Experiment shows, how- 
 ever, that though this is sometimes true, more often the 
 judgment of likeness or difference arises immediately 
 on the presentation of the second stimulus, without any 
 renewed consciousness of the first. Such results show that 
 conscious process is more fluid and less diagrammatic than 
 is assumed by those who work out logical schemes of what 
 it must be. They show too that consciousness can not be 
 known by its fruits. You can not infer what consciousness 
 must be from its objective manifestations, nor even can 
 you, keeping wholly within the stream of conscious events, 
 infer what has gone before from what follows. Each bit 
 of consciousness must be known, if at all, by direct observa- 
 tion. 
 
 13
 
 Facts like these make it seem impossible to employ an 
 objective method in psychology. Many students of the 
 subject, in short one of the two great parties into which 
 psychologists are divided, repelled by the difficulties and 
 the treacherousness of introspection, have resorted to the 
 examination of objective facts connected more or less di- 
 rectly with mental life. Some have gone so far as to assert 
 that only by such means could scientific information re- 
 garding the mind be reached. As examples of such 
 studies may be mentioned folk psychology, which examines 
 language, myth and literature, art, customs and institu- 
 tions, with the object of inferring back from the products 
 of mental activity to the character of the activity. We 
 have also animal and child psychology, which endeavor to 
 deal with minds incapable of reporting introspective ob- 
 servations. Here belongs as well a large part of the work 
 done in experimental psychology, for often the person 
 experimented on does not serve strictly as an observer of 
 his inner consciousness, but has simply to react in some 
 assigned way to a situation which is presented to him. He 
 may have simply to move his finger as quickly as he sees a 
 certain light, or to move his right forefinger when red is 
 shown him and his left forefinger when green is shown 
 him, or he may have to name a presented object as 
 promptly as possible, or answer a given word by another 
 word standing in some assigned relation to it. He is not 
 asked to observe his consciousness during the process, but 
 simply to react. In another line of experiment, the per- 
 son examined is presented with two weights differing but 
 slightly, and is asked to say which is the heavier. He is 
 not asked to describe the contents of his consciousness dur- 
 ing his process of judging, but simply to judge. Or 
 again, in an experiment on memory, he is given a list of 
 disconnected words or syllables, which he studies till he 
 can repeat them in proper order ; a day later he is tested to 
 
 14
 
 see how much of the list he retains. He is not asked to 
 describe his subjective experiences while learning or recall- 
 ing these words, but is merely required to learn and recall 
 them. 
 
 Many similar experiments have been carried on in psy- 
 chological laboratories, and have been received by the 
 introspectionists with no great applause. They denounce 
 the method as unpsychological. "You are not attaining to 
 a description of consciousness by this means," they say; 
 and, in the light of the facts alluded to a few moments ago, 
 they are clearly right. From the examination of a paint- 
 ing, for example, you can not tell what was in the mind of 
 the painter when he conceived his work ; it might seem that 
 he must have had before him a mental picture of which the 
 existing painting is a copy; but among the painters who 
 have been asked regarding this, some have denied that 
 such a mental image was present, and even that they had 
 the power of forming a mental image. When we already 
 know a form of consciousness, its objective manifestations, 
 and the regularity of the connection between them, we 
 can of course infer with some degree of probability from 
 the manifestation back to the condition of consciousness. 
 But we must first know consciousness. 
 
 From all this it becomes clear why the introspective 
 psychologist accuses the objective psychologist of sailing 
 under false colors. He may be studying something, and 
 doubtless is, since he gets results which display consider- 
 able regularity and precision, but he is not studying con- 
 sciousness, and if psychology is the science of conscious- 
 ness, he is no psychologist. The introspective psychologist 
 dubs him a "psycho-physicist," or a "gnoseologist," or a 
 sort of physiologist; and mollified by the verbal distinc- 
 tion, goes his way, leaving the objective student to go his. 
 The choice of words need not detain us here. The thing 
 to notice is that a large share of those who call themselves 
 
 15
 
 psychologists are concerned with the facts which can be 
 found by the objective method. Of what nature, then, are 
 these facts? The objective wing has not taken much 
 trouble to justify its position formally; but I think it fail- 
 to say, after an examination of the detailed problems 
 which they set themselves, that they are looking for the 
 facts of mental function, that they are seeking the causes 
 and conditions of mental performances, in short that their 
 study is dynamic. They are not trying to describe con- 
 sciousness, but to unearth the causal relations which obtain 
 among mental performances and between them and their 
 physical conditions and manifestations. 
 
 It should be noted that the introspective method has not 
 much to tell of the causal relations of the conscious events 
 which it studies. For one thing, consciousness is not a 
 closed system. Physical stimuli are always breaking into 
 it from outside, and its own processes are constantly leak- 
 ing away through motor channels. The dynamics of 
 consciousness could no more be discovered by confining 
 attention to consciousness itself than the laws of plant 
 growth could be made out by studying the plant in isola- 
 tion from the soil, air and sunlight. But, what is rather 
 surprising, consciousness not only fails to reveal the ex- 
 ternal factors which determine the course of thought, it 
 does not even reveal with any completeness the internal or 
 cerebral conditions of thought, as the following simple 
 experiment illustrates. 
 
 Set yourself to add pairs of numbers the one-place 
 numbers will do as well as any. As each pair is presented, 
 the sum immediately occurs to mind. But now change 
 the problem: set yourself to multiply pairs of numbers; 
 then the appearance of a pair straightway calls up the 
 product. In one case you are 'set' or adjusted for addition, 
 and turn out sums; in the other you are set or adjusted for 
 multiplication, and turn out products. Since the numbers 
 
 16
 
 given may be the same in the two cases, and yet lead to 
 different results, it is clear that the mental adjustment has 
 much to do with your reaching the right answers so 
 promptly. But now interrupt yourself in the midst of 
 such a series of operations, and ask what consciousness you 
 have of this set or adjustment which is causally so im- 
 portant. Usually you will find nothing nothing, at least, 
 more definite than a feeling of readiness for what is com- 
 ing nothing characteristic of the exact problem which 
 you are prepared to solve. And, on the other hand, you 
 may find many things which probably have nothing to do 
 with the mental performance in question sensations, 
 images and tinges of emotion which only happen to be 
 there at the same time. It is clear that conscious process 
 does not correspond closely with mental process, if by the 
 latter term is meant the process that leads to some mental 
 result a perception, a recollection, an invention, a prefer- 
 ence, a decision, the solution of a problem. He who would 
 trace the dynamic process by which such results are reached 
 can not content himself with the introspective method, 
 though it may indeed give him valuable suggestions. 
 
 It is this sort of task which is taken up by those psy- 
 chologists who use the objective method. The essence of 
 the method consists in arousing a certain type of reaction to 
 a given situation, the conditions being standardized, and 
 the reaction, as far as possible, reduced to quantitative 
 terms. The conditions are now varied in accordance with 
 some definite plan, and the corresponding changes in the 
 reaction are noted. The relation of the changes in re- 
 sponse to the changes in the conditions is the important 
 thing. For example, it is desired to discover how the 
 sense of sight, which at first thought seems incapable of 
 giving anything more than two-dimensional pictures, such 
 as might be accurately represented in a colored photo- 
 graph, nevertheless enables us to judge of the third dimen- 
 
 17
 
 sion, of the distance of objects from us. Introspection 
 does not reveal the factors which determine the judgment. 
 Several possible factors are suggested, as hypotheses are 
 suggested in any science; such as perspective, haze, the 
 presence of intervening objects, and the slightly differing 
 views of the same object which are had by the two eyes. 
 To investigate the importance of intervening objects as 
 a factor in determining the judgment, we remove them, 
 placing the person examined in a dark room with only one 
 spot of light visible, the distance of which he has to judge. 
 We find that he does so very badly; we then restore some 
 of the intervening objects and, finding his judgment im- 
 proved, we conclude that the presence of intervening ob- 
 jects is a factor in the judgment of distance. Similarly, 
 to examine the importance of binocular vision, we compare 
 the accuracy of the judgment with one and with both eyes; 
 and finding it superior with both, finding also that the 
 stereoscope, which presents to the two eyes slightly differ- 
 ent views corresponding to what each would see in looking 
 at the object, gives a strong impression of solidity and 
 distance, we infer that the judgment of distance is 
 based largely on this difference between the two fields of 
 view. 
 
 It is the task of the dynamic psychologist to devise 
 means by which to control the conditions under which 
 a mental operation is performed and by which to gauge 
 the character and success of the operation. For control- 
 ling the conditions a great number of special devices are 
 employed, which can not easily be summarized in a few 
 words. For gauging the success of the operation, meas- 
 urement can be applied in three ways at least, as to its 
 speed, its accuracy and what may perhaps be called its 
 force or energy. As examples of the measurement of the 
 energy of mental activity may be mentioned the deter- 
 mination of the number of items of a given kind that can 
 
 18
 
 be grasped at a single glance the number being found 
 to increase greatly when the items are related in easily 
 perceived ways or of the amount that can be memorized 
 at a single reading. More common are measurements of 
 speed and accuracy. The older classics of experimental 
 psychology are largely devoted to the accuracy of sense 
 discrimination and to the speed of simple mental processes. 
 The speed is valuable as affording an index of the com- 
 plexity and difficulty of the mental operation. 
 
 In recent years, the center of gravity of investigation 
 has shifted from perception to the motor processes and 
 especially to the central processes, such as association, 
 memory and the effects of practise or training. Eye move- 
 ments, important to psychology because of their connec- 
 tion with theories of space perception and of appreciation 
 of beauty of form, and with the act of reading, have been 
 recorded photographically by psychologists, with rather 
 striking and important results. Many facts are being 
 disclosed regarding the conditions of greatest efficiency in 
 memorizing, and regarding the laws of retention and re- 
 call. In the older work, the improvement of a function 
 with practise was principally a disturbing factor, since it 
 created difficulty in the way of comparing repeated obser- 
 vations on the same person. Of late, the practise effect 
 has aroused interest for its own sake. The person tested 
 repeats the same performance time after time under the 
 same conditions, his success being measured. Almost any 
 performance will serve as the subject matter of the experi- 
 ment, since all improve with practise, though in unequal 
 measure. 
 
 The results may be presented graphically in a "practise 
 curve," which, much after the fashion of the temperature 
 curve of physicians or the curves of barometric pressure 
 and wind velocity put out by the weather bureau, shows 
 the changes in efficiency of the function with the progress 
 
 19
 
 of training. Much might be said of the results of this 
 line of study. If we analyze the lack of precision of a 
 performance into its variability, by virtue of which the 
 successive repetitions differ irregularly among themselves, 
 and its constant error, by virtue of which all the repetitions 
 differ in the same direction from the truly successful per- 
 formance, then it appears that repetition will by itself 
 reduce the variability, but will not eliminate the constant 
 error, which can only be trained out by checking up the 
 performance against the standard of success. Only repe- 
 tition gives regularity ; only correction conduces to perfec- 
 tion. When the standard of success is not very high, 
 corrected practise leads to speedy perfection. When the 
 operation is difficult or the standard of success high, as in 
 telegraplvy, the improvement, at first rapid, becomes dis- 
 couragingly slow, but after several months of continued 
 practise, may take a sudden rise, leading to a condition of 
 passable proficiency, after which further gain is slower and 
 slower, as the "physiological limit" of the individual for 
 that performance is reached. But experiment has also 
 shown that the physiological limit is seldom reached, or 
 closely approached, in the usual, non-experimental condi- 
 tions of the practise of a trade or profession. Type-setters, 
 after ten to twenty years of experience, were thought by 
 a certain investigator to be suitable subjects for an experi- 
 ment in which it was desirable that the subjects should 
 have reached their utmost efficiency. When the experi- 
 ment was begun, an immediate rise was noted which by 
 itself was not surprising. What was surprising was that 
 after this sudden jump, due to the increased stimulus of 
 the test, there came a gradual rise, a practise curve, in fact, 
 on top of ten to twenty years of practise. Similar results 
 have appeared in other lines of work. Under the condi- 
 tion of a practise experiment, a German-English vocabu- 
 lary can be learned with considerably greater speed and 
 
 20
 
 apparently also retained better than in the ordinary con- 
 ditions of school or private learning. The stimulating 
 influence of the experimental conditions lies in part in the 
 fact that the individual has a measure of his success, and 
 in part in the competitive stimulus; he competes not only 
 with others a sort of competition which is usually un- 
 equal but also with himself. Herein appears a contrast 
 between introspective and dynamic studies: whereas the 
 conditions of an introspective observation interfere to some 
 degree with the process which is observed, an experiment 
 in dynamic psychology is apt to arouse the function ex- 
 ercised to its full activity. The practical value of these 
 results both to the educator and to any man in the conduct 
 of his life and business is obvious. If one's work can be 
 made an experiment, and the success of it measured and 
 recorded, a great gain in efficiency may be expected. 
 
 Much of the newer and more exact work in one of the 
 most flourishing departments of psychology, that which 
 examines the mental capacities of various orders of ani- 
 mals, depends for its method on the study of the practise 
 effect. The questions whether an animal can learn, how 
 fast, how much, and by what means, are fundamental. 
 Considerable revision in our conceptions has been brought 
 about lately by the discovery that even protozoans can be 
 taught, that their behavior is modifiable by experience. At 
 the other end of the scale, tests show that the primates are 
 nearest to man, not only in anatomy, but as well in fertility 
 and quickness of learning, while still the highest forms 
 which have so far been carefully studied are inferior to 
 the human infant of the age of one year. The anthropoid 
 apes have not as yet received the attention they deserve. 
 The method has been employed in endeavoring to answer 
 the vexed question regarding the reason of animals. Most 
 of the discussion of this topic rested, till quite recently, on 
 anecdotes rather than on experiment. The defect of the 
 
 21
 
 anecdotal method is that, though the animal is known to 
 have learned, no observations have been made as to how 
 he learned. It may be asserted that no movement what- 
 ever, however skilled and however adaptive, can prove rea- 
 son in its performer, in the absence of knowledge as to 
 how the movement was acquired. The most wonderfully 
 skilled and adaptive of all movements are inherited, not ac- 
 quired, by the individual. The practise-curve method gives 
 at least negative information in the following way : What- 
 ever may be the full definition of reason, it is clear that 
 in practical use it involves grasping the essential feature 
 of the situation essential, that is, for the purpose in 
 hand and reacting to this feature in neglect of the un- 
 essential. Place a human being in a cage from which he 
 can escape by some concealed mechanism, and his first 
 efforts will of necessity be blind experimenting, resulting 
 finally in accidental success. Replace him in the cage, and 
 in the course of a number of trials he will observe by what 
 means his success comes, and will from that instant drop 
 all his unsuccessful gropings and do only the one thing 
 needful. No such moment of insight is revealed in the 
 process by which a dog or cat learns most of his tricks, 
 and in the case of the monkey, though the process of learn- 
 ing is rapid when the trick is simple enough, there is in 
 more difficult cases no sign of a moment of comprehen- 
 sion. The difference may however be a matter of degree 
 of the degree of complexity which the different species are 
 capable of grasping. When the thing to be learned is so 
 simple as the mere location of an object that causes pain, 
 it can be learned by a mouse in one or two trials. Harder 
 tasks, such as pulling a string, which a cat learns only by 
 a long and gradual process, are learned in a few trials by 
 a monkey. A still more difficult performance, as, for 
 example, the opening of a door by a combination of sim- 
 ple acts which must be done in a certain order, can hardly 
 
 22
 
 if at all be taught to a cat, and to a monkey only by a slow 
 process like that seen in the cat in learning the pulling of 
 a string, while an adult man learns it in from two to six 
 trials. But there are tasks yet more complicated and re- 
 condite, which even man learns only by the slow and 
 gradual process a process in which the essentials of suc- 
 cess are never recognized, though success is finally attained 
 by the gradual and unnoticed elimination of false moves. 
 Examples of this process in man are seen in the acquisition 
 of high skill in singing or playing the violin, or in handling 
 the sword or tennis racquet. Insight is not entirely absent 
 here, but insight alone does not do the work, as is seen 
 from the fact that perfect form results only from the slow 
 accretions of constant practise. 
 
 Besides animal psychology, the most cultivated among 
 what may be called the outlying fields of psychology are 
 the genetic and the pathological. Progress is being made 
 in tracing the rate of growth of the capacities of the in- 
 dividual, in correlating mental with physical growth, and 
 in assigning to hereditary endowment on the one hand and 
 to experience and training on the other their contributions 
 to the superiority or inferiority of the individual to his 
 fellows the preponderance certainly seeming to lie on the 
 side of heredity. In mental pathology, a vast amount of 
 preliminary prospecting has been done by physicians, and 
 the ground prepared for more rigorous observation and 
 experiment, which has indeed been begun, particularly 
 with neurotic patients, hysterical neurasthenic and epi- 
 leptic. 
 
 Abnormal psychology is in large measure an application 
 of the science for the practical ends of diagnosis, of sug- 
 gesting modes of treatment and of testing their success. 
 It is hoped, not only that the results of psychology may 
 help towards the understanding of mental abnormalities, 
 but that the methods of psychology may prove capable of 
 
 23
 
 adaptation to the needs of those who require quantitative 
 tests of mental condition. 
 
 The principal application of psychology is, at present, 
 to education. Such work as that above mentioned on 
 practise and learning has an obvious bearing on the prob- 
 lems of the schoolroom, while some of the broader results 
 of genetic psychology are germane to the task of those 
 who arrange the courses of study. But, as with the appli- 
 cations to medicine, it is not simply the results of psy- 
 chology that should prove fruitful in education; it is still 
 more to be hoped that the empirical and experimental 
 method may spread over from the one to the other. Edu- 
 cation must become a science on its own account an ex- 
 perimental science related to psychology somewhat as 
 engineering is related to physics, or agriculture to botany. 
 With so much experience as he gets of the great differ- 
 ences in result that sometimes follow from slight changes 
 in the conditions, the psychologist would be the first to 
 admit that the conclusions reached in his laboratory ought 
 not to be carried over without discrimination into the 
 schoolroom. The problems of education must finally be 
 solved by experimentation within the educational field. 
 
 With much the same reserve the psychologist ap- 
 proaches the possibility of applying his science to other 
 fields, such as business in which, for example, the con- 
 ditions of successful advertising form clearly a psycho- 
 logical problem and such as the practise of law. The 
 courtroom teems with problems which are not simply 
 psychological in the vague sense that they are concerned 
 with mental processes, but are such as can be attacked by 
 methods that have been worked out in psychology. The 
 reliability of testimony, the influence of leading questions 
 on the reliability of the answers, the relative merits of judge 
 and jury as devices for establishing questions of fact, are 
 fit subjects for an experiment, the main point of which 
 
 24
 
 would be to insure that the facts regarding which the testi- 
 mony is to be given be certainly known in advance to the 
 experimenter. Some work has already been done by 
 psychologists in collaboration with professors of law on 
 the reliability of the testimony of eye-witnesses ; and rather 
 a surprising degree of unreliability has been disclosed. 
 Not only is there a large percentage of omissions, but there 
 is a smaller but still considerable percentage of positive 
 assertions of what did not take place. It is almost impos- 
 sible for anyone to witness an event without forming to 
 himself some conception of its inner meaning and reading 
 this meaning into the event as he sees and as he remembers 
 it; and as a false meaning may very readily be read into 
 events, the testimony will be correspondingly vitiated. 
 Such general criticism as is implied in this result is perhaps 
 of no great practical value; and in fact the legal profes- 
 sion has not received this incipient irruption of psychology 
 into law with any great show of enthusiasm. But when 
 the experiment is carried into details, and the varying re- 
 liability of testimony to different classes of facts and by 
 different classes of persons is assigned when, for ex- 
 ample, it is found that the time occupied by an event is 
 judged very poorly, that inherently probable and com- 
 monplace events are less reliably reported than inherently 
 improbable, or that the reliability of a person's testimony 
 bears no very close relation to the confidence with which 
 he gives it it would seem that the results were capable of 
 application. Here again, however, the conclusions ob- 
 tained in the laboratory need to be retested in the sphere 
 where they are applied. 
 
 It is the hope of psychology that her results may prove 
 capable of application in the work of her sister sciences, 
 especially zoology, anthropology, sociology and every 
 science that has to do with human or animal behavior. She 
 comes in contact with still other sciences, especially with 
 
 25
 
 physics, from which she derives much of her technical 
 equipment; with mathematics, from which she derives the 
 statistical methods that are necessary in much of her work ; 
 and even with astronomy, which gave the impetus to one 
 of her earliest problems, that of reaction time and the per- 
 sonal equation. But it is to philosophy and physiology 
 that the relations of psychology are particularly interest- 
 ing. Psychology has sprung from each of them, though not 
 exactly from their union. Both philosophy and medicine ' 
 have been called mothers of the sciences, and psychology 
 filially owns the relationship in each case. The philo- 
 sophical parentage is of long standing, the medical or 
 physiological for in this instance it is fair to identify the 
 two dates from the last century. In spite of these his- 
 torical dependences, psychology has the right to an 
 independent standing as a science. The close relation of 
 philosophical and psychological interests can easily be 
 over-emphasized. Philosophy is not specially dependent on 
 psychology; it needs the data of psychology, but it needs 
 equally the data of the other sciences. Nor is the depend- 
 ence of psychology on philosophy peculiarly close. Every 
 science has its metaphysics, its presuppositions and ulti- 
 mate questions the proof or solution of which is not ap- 
 proached by the methods appropriate to that science. The 
 fact that students of psychology seem particularly prone 
 to become worried over such questions is probably to be 
 explained by the historical association of the two sciences, 
 and is' a tendency rather to be deprecated than encouraged. 
 In the actual, immediate, concrete work of his science, the 
 psychologist is no more concerned with metaphysical ques- 
 tions than is the chemist or the zoologist. 
 
 The relation of psychology to physiology is of a differ- 
 ent kind. Physiology is not only occupied with applying 
 physics and chemistry to the living organism which is no 
 doubt its main business but also, finding certain organs 
 
 26
 
 the function of which can not as yet be stated in physical 
 and chemical terms, namely, the sense organs and the brain, 
 and yet wishing, for the sake of completeness, to state the 
 functions of these organs as well as may be, it has had 
 recourse to methods which do not differ appreciably from 
 those of psychology, depending as they do on the reactions 
 and self -observation of the conscious subject. Thus the 
 provinces of the two sciences overlap to quite an extent; 
 and there are those who will have it that psychology, in 
 so far as it amounts to anything, is but a part of physi- 
 ology. The practical answer to this is that physiologists 
 will not usually investigate such things as the peculiarities 
 of memory and imagination. Were it not for the psychol- 
 ogist, the problems of mental action would remain un- 
 studied. He comes in to fill the gap left by physiology 
 because of the high development of its physical and chemi- 
 cal technique and the engrossing success which that tech- 
 nique is meeting. 
 
 But is this gap more than temporary? If the goal of 
 the physiologist were attained, and all organic functions 
 were dissected and accurately stated in physical and chemi- 
 cal terms, would there be anything left for the psychol- 
 ogist to say? Would not his cruder statements become 
 obsolete, as the vague outlines of a landscape seen in the 
 morning twilight lose their significance in the full, clear 
 view of day? 
 
 Socrates, one of the founders of psychology, as he sat 
 in prison with his disciples, waiting for the jailer to bring 
 him the fatal draught of hemlock, alluded to the difference 
 between the physiological and the psychological points of 
 view in some such terms as these : "What should we think 
 of a person who, when he endeavored to explain the causes 
 of my actions, should proceed to explain that I sit here 
 because my body is made up of bones and muscles: . . . 
 and as the bones are lifted at their joints by the contrac- 
 
 27
 
 tion or relaxation of the muscles, I am able to bend my 
 limbs, and that is why I am sitting here in a curved pos- 
 ture; . . . and should give a similar explanation of my 
 talking with you, which he would attribute to sound, and 
 air, and hearing, and ten thousand other causes of the same 
 sort; forgetting to mention the true cause, which is, that 
 the Athenians have thought fit to condemn me, and accord- 
 ingly I have thought it better and more right to remain 
 here and undergo my sentence?" 
 
 The modern psychologist would not think so lightly of 
 the physiological explanation; he recognizes in it one of 
 the worthiest goals of scientific endeavor. But he would 
 still maintain that the psychological interpretation of con- 
 duct has its proper place. The distinction is not properly 
 that between mechanism and teleology ; for a motive, to the 
 psychologist, is a cause among causes. The difference is 
 essentially one of minuteness; physiology being the more 
 minute in its analysis of cause and effect. It is related to 
 psychology much as microscopic is related to gross anat- 
 omy. Now the invention of the microscope has not made 
 the sight of the naked eye valueless, even for scientific pur- 
 poses. Microscopic anatomy has not supplanted gross 
 anatomy but has simply been added to it. In much the same 
 way, the conception of the geological ages is not made 
 trivial by reflecting that the actual succession was one of 
 seconds and not of ages. Detailed maps of every quad- 
 rangle in the country do not enable us to dispense with a 
 condensed map of the whole country. The relations which 
 are visible in the condensed map can not be grasped from 
 the detailed maps. The relations brought out by geology 
 would be lost sight of in following second by second, if that 
 were possible, the physical and chemical history of the 
 earth. In a word, the relations that appear in the gross 
 disappear, give place to others, on a minuter view. A de- 
 tailed view must always be a limited view, for no greater 
 
 28
 
 assemblage of facts can be grasped in one act of compre- 
 hension when the facts are minute than when they are 
 broad and inclusive. And as time and space are apparently 
 divisible without limit, as to omniscience "a thousand years 
 are as a day and a day as a thousand years," neither the 
 broad nor the minute view can boast itself against the other. 
 Examine every tissue of the body under the microscope, take 
 cognizance of every cell, its form and relations; and you 
 still know nothing of the facts taught by gross anatomy. 
 Trace out each reaction of an animal, noting every trans- 
 formation and transmission of energy from the point of 
 stimulation to the point of response, and you still know 
 nothing of animal behavior. 
 
 Quite akin to the science of behavior, psychology seeks 
 to trace the relations of those rather gross fragments of the 
 universal process which we call contents of consciousness 
 and mental activities. Its dissection is less minute than 
 that of physiology, but the relations which it reveals are 
 none the less real, and may be none the less illuminating. 
 Motives, conduct, training, efficiency, stages in the devel- 
 opment and dissolution of the mind, will still retain their 
 significance however minutely their inner mechanism shall 
 be analyzed by physiology ; and the relations between them 
 which psychology discovers and is to discover will always 
 retain both scientific and practical value. 
 
 29
 
 COLUMBIA UNIVERSITY PRESS 
 
 A SERIES of twenty-two lectures descriptive in untechnical language of 
 the achievements in Science, Philosophy and Art, and indicating the 
 present status of these subjects as concepts of human knowledge, are being 
 delivered at Columbia University, during the academic year 1907-1908, by 
 various professors chosen to represent the several departments of instruction. 
 
 MATHEMATICS, by Cassius Jackson Keyser, Adrain Professor of Mathe- 
 matics. 
 
 PHYSICS, by Ernest Fox Nichols, Professor of Experimental Physics. 
 
 CHEMISTRY, by Charles F. Chandler, Professor of Chemistry. 
 
 ASTRONOMY, by Harold Jacoby, Rutherfurd Professor of Astronomy. 
 
 GEOLOGY, by James Furman Kemp, Professor of Geology. 
 
 BIOLOGY, by Edmund B. Wilson, Professor of Zoology. 
 
 PHYSIOLOGY, by Frederic S. Lee, Professor of Physiology. 
 
 BOTANY, by Herbert Maule Richards, Professor of Botany. 
 
 ZOOLOGY, by Henry E. Crampton, Professor of Zoology. 
 
 ANTHROPOLOGY, by Franz Boas, Professor of Anthropology. 
 
 ARCHAEOLOGY, by James Rignall Wheeler, Professor of Greek Archae- 
 ology and Art. 
 
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 POLITICS, by Charles A. Beard, Adjunct Professor of Politics. 
 
 JURISPRUDENCE, by Munroe Smith, Professor of Roman Law and 
 Comparative Jurisprudence. 
 
 SOCIOLOGY, by Franklin Henry Giddings, Professor of Sociology. 
 
 PHILOSOPHY, by Nicholas Murray Butler, President of the University. 
 
 PSYCHOLOGY, by Robert S. Woodworth, Adjunct Professor of Psy- 
 chology. 
 
 METAPHYSICS, by Frederick J. E. Woodbridge, Johnsonian Professor of 
 Philosophy. 
 
 ETHICS, by John Dewey, Professor of Philosophy. 
 
 PHILOLOGY, by A. V. W. Jackson, Professor of Indo-Iranian Lan- 
 guages. 
 
 LITERATURE, by Harry Thurston Peck, Anthon Professor of the Latin 
 Language and Literature. 
 
 These lectures are published by the Columbia University Press separately in 
 pamphlet form, at the uniform price of twenty-five cents, by mail twenty-eight 
 cents. Orders will be taken for the separate pamphlets, or for the whole series. 
 
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