The Principles of Psychology, Vols. 1-2

' + F Brentano Psychologic, i. 9, 88 ff.-Uerkel thinks that his results with the method of equal-appearing intervals show that we «>|»Par« ;;«n; siderable intervals with each other by a different law from that by whicl we notice barely perceptible intervals. The stimuli lorn, an arithmetic al series (a pretty wild one according to his tigurcs) in the foiuici geometrical oife in the latter-* least so 1 understand this valiant expert- t This is the formula which Merkel thinks he has verihed (if 1 under-

facts is thus not only seen to be arbitrary and subjective, but in the highest degree improbable as well. The depart ures from Weber's law in regions where it does not obtain, he explains by the compounding with it of other unknown laws which mask its effects. As if any law could not be found in any set of phenomena, provided one have the wit to invent enough other coexisting laws to overlap and neutral ize it! The whole outcome of the discussion, so far as Feclmer's theories are concerned, is indeed nil. Weber's law alone remains true as an empirical generalization of fair extent : What we add to a large stimulus we notice less than what we add to a small one, unless it happen rela tively to the stimulus to be as great.

One can express this state of things otherwise by saying that the whole of the stimulus does not seem to be effective in giving us the perception of ' more,' and the simplest in terpretation of such a state of things would be physical. The loss of effect would take place in the nervous system. If our feelings resulted from a condition of the nervemolecules which it grew ever more difficult for the stimulus to increase, our feelings would naturally grow at a slower rate than the stimulus itself. An ever larger part of the latter's work would go to overcoming the resistances, and an ever smaller part to the realization of the feeling-bring ing state. Weber's law would thus be a sort of latv of friction in the neural machine.* Just how these inner resistances and frictions are to be conceived is a specu lative question. Delboeuf has formulated them as fa tigue ; Bernstein and Ward, as irradiations. The latest, and probably the most ' real/ hypothesis is that of Ebbinghaus, who supposes that the intensity of sensation depends on the number of neural molecules which are disintegrated in the unit of time. There are only a certain number at any time which are capable of disintegrating ; and whilst most of these are in an average condition of instability,

* Elsas : Ueber die Psychophysik (1886), p. 41. When the pans of a balance are already loaded, but in equilibrium, it takes a proportionally larger weight added to one of them to incline the beam. some are almost stable and some already near to decom position. The smallest stimuli affect these latter molecules only ; and as they are but few, the sensational effect from adding a given quantity of stimulus at first is relatively small. Medium stimuli affect the majority o!" the mole cules, but affect fewer and fewer in proportion as they have already diminished their number. The latest additions tc the stimuli find all the medium molecules already disinte grated, and only affect the small relatively indecomposable remainder, thus giving rise to increments of feeling which are correspondingly small. (Pfliiger's Archiv. 45, 113.)

It is surely in some such way as this that Weber's law is to be interpreted, if it ever is. The Feclmerian Maasformel and the conception of it as an ultimate * psychophysic law' will remain an 'idol of the den,' if ever there was one. Feclmer himself indeed was a German Gelehrterol the ideal type, at once simple and shrewd, a mystic and an experi mentalist, homely and daring, and as loyal to facts as to his theories. But it would be terrible if even such a dear old man as this could saddle our Science forever with his patient whimsies, and, in a world so full of more nutritious objects of attention, compel all future students to plough through the difficulties, not only of his own works, but of the still drier ones written in his refutation. Those who desire this dreadful literature can find it ; it has a ' disci plinary value ;' but I will not even enumerate it in a foot note. The only amusing part of it is that Feclmer's critics should always feel bound, after smiting his theories hip and thigh and leaving not a stick of them standing, to wind up by saying that nevertheless to him belongs the imperishable glory, of first formulating them and thereby turning psychology into an exact science,

" And everybody praised the duke Who this great light did win.' ' But what good came of it at last? ' Quoth little Peterkiu. Why, that I cannot tell,' said he, 1 But 'twas a famous victory ! ' " AFTER discrimination, association ! Already in the last chapter I have had to invoke, in order to explain the im provement of certain discriminations by practice, the ' as sociation ' of the objects to be distinguished, with other more widely differing ones. It is obvious that the advance of our knowledge must consist of both operations ; for objects at first appearing as wholes are analyzed into parts, and objects appearing separately are brought together and ap pear as new compound wholes to the mind. Analysis and synthesis are thus the incessantly alternating mental activities, a stroke of the one preparing the way for a stroke of the other, much as, in walking, a man's two legs are alternately brought into use, both being indispensable for any orderly advance.

The manner in which trains of imagery and consideration follow each other through our thinking, the restless flight of one idea before the next, the transitions our minds make between things wide as the poles asunder, transitions which at first sight startle us by their abruptness, but which, when scrutinized closely, often reveal intermediating links of perfect naturalness and propriety — all this magical, im ponderable streaming has from time immemorial excited the admiration of all whose attention happened to be caught by its omnipresent mystery. And it has furthermore challenged the race of philosophers to banish something of the mystery by formulating the process in simpler terniSo The problem which the philosophers have set themselves is that of ascertaining principles of connection between the thoughts which thus appear to sprout one out

*The theory propounded in this chapter, and a good many pages of the text, were originally published in the Popular Science Monthly for March, 1880. of the other, whereby their peculiar succession or coexist ence may be explained. But immediately an ambiguity arises : which sort of connection is meant? connection thought-of, or connection between thoughts ? These are two entirely different things, and only in the case of one of them is there any hope of finding 'principles.' The jungle of connections thought of can never be formulated simply. Every conceivable con nection may be thought of — of coexistence, succession, re semblance, contrast, contradiction, cause and effect, means and end, genus and species, part and whole, substance and property, early and late, large and small, landlord and tenant, master and servant, — Heaven knows what, for the list is literally inexhaustible. The only simplification which could possibly be aimed at would be the reduction of the relations to a smaller number of types, like those which such authors as Kant and Eenouvier call the ' cate gories ' of the understanding.* According as we followed one category or another we should sweep, with our thought, through the world in this way or in that. And all the cate gories would be logical, would be relations of reason. They i would fuse the items into a continuum. Were this the sort v of connection sought between one moment of our thinking and another, our chapter might end here. For the only summary description of these infinite possibilities of transi tion, is that they are all acts of reason, and that the mind proceeds from one object to another by some rational path of connection. The trueness of this formula is only equalled by its sterility, for psychological purposes. Practically it amounts to simply referring the inquirer to the relations between facts or things, and to telling him that his thinking follows them.

But as a matter of fact, his thinking only sometimes follows them, and these so-called 'transitions of reason' are far from being all alike reasonable. If pure thought runs all our trains, why should she run some so fast and some so slow, some through dull flats and some through * Compare Renouvier's criticism of associationism in his Essais de Critique generate, Logique, n. p. 493 foil. gorgeous scenery, some to mountain-heights and jewelled mines, others through dismal swamps and darkness ? — and run some off the track altogether, and into the wilderness of lunacy? Why do we spend years straining after a certain scientific or practical problem, but all in vain — thought refusing to evoke the solution we desire ? And why, some day, walking in the street with our attention miles away from that quest, does the answer saunter into our minds as carelessly as if it had never been called for — suggested, possibly, by the flowers on the bonnet of the lady in front of us, or possibly by nothing that we can dis cover ? If reason can give us relief then, why did she not do so earlier ?

The truth must be admitted that thought works under conditions imposed ab extra. The great law of habit itself —that twenty experiences make us recall a thing better than one, that long indulgence in error makes right thinking \ almost impossible — seems to have no essential foundation in reason. The business of thought is with truth — the number of experiences ought to have nothing to do with her hold of it ; and she ought by right to be able to hug it all the oloser, after years wasted out of its presence. The contrary arrangements seem quite fantastic and arbitrary, but nevertheless are part of the very bone and marrow of our minds. Reason is only one out of a thousand possi bilities in the thinking of each of us. Who can count all the silly fancies, the grotesque suppositions, the utterly irrelevant reflections he makes in the course of a day? Who can swear that his prejudices and irrational beliefs con stitute a less bulky part of his mental furniture than his clarified opinions? It is true that a presiding arbiter seems to sit aloft in the mind, and emphasize the better suggestions into permanence, while it ends by droopping out and leaving unrecorded the confusion. But this is all the difference. The mode of genesis of the worthy and the worthless seems the same. The laws of our actual thinking, of the cogitatum, must account alike for the bad and the good materials on which the arbiter has to decide, for wisdom and for folly. The laws of the arbiter, of the cogitandum, of what we ought to think, are to the former as the

laws of ethics are to those of history. Who but an hegelian historian ever pretended that reason in action was per se a sufficient explanation of the political changes in Europe ? I There are, then, mechanical conditions on which thought depends, and ivhich, to say the least, determine the order in ivhich is presented the content or material for her compari sons, selections, and decisions. It is a suggestive fact that Locke, and many more recent Continental psychologists, have found themselves obliged to invoke a mechanical process to account for the aberrations of thought, the ob structive preprocessions, the frustrations of reason. This they found in the law of habit, or what we now call As sociation by Contiguity. But it never occurred to these writers that a process which could go the length of actually producing some ideas and sequences in the mind might safely be trusted to produce others too ; and that those habitual associations which further thought may also come from the same mechanical source as those which hinder it. Hartley accordingly suggested habit as a sufficient explana tion of all connections of our thoughts, and in so doing planted himself squarely upon the properly psychological aspect of the problem of connection, and sought to treat both rational and irrational connections from a single point of view. The problem which he essayed, however lamely, to answer, was that of the connection between our psychic states considered purely as such, regardless of the objective connections of which they might take cognizance. How does a man come, after thinking of A, to think of B the next moment? or how does he come to think A and B always together ? These were the phenomena which I Hartley undertook to explain by cerebral physiology. I believe that he was, in many essential respects, on the • right track, and I propose simply to revise his conclusions by the aid of distinctions which he did not make.

But the whole historic doctrine of psychological asso ciation is tainted with one huge error — that of the construc tion of our thoughts out of the compounding of themselves together of immutable and incessantly recurring ' simple ideas.' It is the cohesion of these which the ' principles of association ' are considered to account for. In Chapters VI and IX we saw abundant reasons for treating the doctrine of simple ideas or psychic atoms as mythological ; and, in all that follows, our problem will be to keep whatever truths the associationist doctrine has caught sight of without

Association, so far as the word stands for an effect, is *. ^ between THINGS THOUGHT OF — it is THINGS, not ideas, which are associated in the mind. We ought to talk of the association of objects, not of the association of ideas. And so far as association stands for a cause, it is between processes in the brain — it is these which, by being associated in certain ways, determine what successive objects shall be thought. Let us proceed towards our final generalizations by survey ing first a few familiar facts.

I The laws of motor habit in the lower centres of the ner vous system are disputed by no one. A series of move ments repeated in a certain order tend to unroll themselves with peculiar ease in that order for ever afterward. Num ber one awakens number two, and that awakens number three, and so on, till the last is produced. A habit of this kind once become inveterate may go on automatically. And so it is with the objects with which our thinking is con cerned. With some persons each note of a melody, heard but once, will accurately revive in its proper sequence. Small boys at school learn the inflections of many a Greek noun, adjective, or verb, from the reiterated recitations ! of .the upper classes falling on their ear as they sit at their desks. All this happens with no voluntary effort on their part and with no thought of the spelling of the words. The doggerel rhymes which children use in their games, such as the formula

used for ' counting out,' form another familiar example of things heard in sequence cohering in the same order in the memory In touch we have a smaller number of instances, though probably every one who bathes himself in a certain fixed manner is familiar with the fact that each part of his body over which the water is squeezed from the sponge awakens a premonitory tingling consciousness in that portion of skin which is habitually the next to be deluged. Tastes and smells form no very habitual series in our experience. But even if they did, it is doubtful whether habit would fix the order of their reproduction quite so well as it does that of other sensations. In vision, however, we have a sense in which the order of reproduced things is very nearly as much influenced by habit as is the order of remembered sounds. Kooms, landscapes, buildings, pictures, or persons with whose look we are very familiar, surge up before the mind's eye with all the details of their appearance complete, so soon as we think of any one of their component parts. Some persons, in reciting printed matter by heart, will seem to see each successive word, before they utter it, ap pear in its order on an imaginary page. A certain chess player, one of those heroes who train themselves to play several games at once blindfold, is reported to say that in bed at night after a match the games are played all over again before his mental eye, each board being pictured as passing in turn through each of its successive stages. In this case, of course, the intense previous voluntary strain of the power of visual representation is what facilitated the fixed order of revival.

Association occurs as amply between impressions of different senses as between homogeneous sensations. Seen things and heard things cohere with each other, and with odors and tastes, in representation, in the same order in which they cohered as impressions of the outer world. Feelings of contact reproduce similarly the sights, sounds, and tastes with which experience has associated them. In fact, the ' objects ' of our perception, as trees, men, houses, microscopes, of which the real world seems composed, are nothing but clusters of qualities which through simulta neous stimulation have so coalesced that the moment one is excited actually it serves as a sign or cue for the idea oi the others to arise. Let a person enter his room in the

dark and grope among the objects there. The touch of the matches will instantaneously recall their appearance. If his hand comes in contact with an orange on the table, the golden yellow of the fruit, its savor and perfume will forth with shoot through his mind. In passing the hand over the sideboard or in jogging the coal-scuttle with the foot, the large glossy dark shape of the one and the irregular blackness of the other awaken like a flash and constitute I what we call the recognition of the objects. The voice of the violin faintly echoes through the mind as the hand is laid upon it in the dark, and the feeling of the garments or draperies which may hang about the room is not understood till the look correlative to the feeling has in each case been resuscitated. Smells notoriously have the power of recall ing the other experiences in whose company they were wont to be felt, perhaps long years ago ; and the voluminous emotional character assumed by the images which sud denly pour into the mind at such a time forms one of the staple topics of popular psychologic wonder —

" Lost and gone and lost and gone ! A breath, a whisper — some divine farewell — Desolate sweetness — far and far away. " We cannot hear the din of a railroad train or the yell I of its whistle, without thinking of its long, jointed appear ance and its headlong speed, nor catch a familiar voice in a crowd without recalling, with the name of the speaker, also his face. But the most notorious and important case of the mental combination of auditory with optical impres sions originally experienced together is furnished by lan guage. The child is offered a new and delicious fruit and is at the same time told that it is called a 'fig.' Or looking out of the window he exclaims, " What a funny horse ! " and is told that it is a ' piebald ' horse. When learning his let ters, the sound of each is repeated to him whilst its shape is before his eye. Thenceforward, long as he may live, he will never see a fig, a piebald horse, or a letter of the alpha-

Ibet without the name which he first heard in conjunction with each clinging to it in his mind ; and inversely he will never hear the name without the faint arousal of the image of the object.* Beading exemplifies this kind of cohesion even more beautifully. It is an uninterrupted and protracted recall of sounds by sights which have always been coupled with them in the past. I find that I can name six hundred let ters in two minutes on a printed page. Five distinct acts of association between sight and sound (not to speak of all the other processes concerned) must then have occurred in each second in my mind. In reading entire words the speed is much more rapid. Valentin relates in his Physiology that the reading of a single page of the proof, containing 2629 letters, took him 1 minute and 32 seconds. In this experiment each letter was understood in ^ of a second, but owing to the integration of letters into entire words, forming each a single aggregate impression directly associ ated with a single acoustic image, we need not suppose as many as 28 separate associations in a sound. The figures, however, suffice to show with what extreme rapidity an actual sensation recalls its customary associates. Both in fact seem to our ordinary attention to come into the mind

The time-measuring psychologists of recent days have tried their hand at this problem by more elaborate methods. Galton, using a very simple apparatus, found that the sight of an unforeseen word would awaken an associated ' idea ' in about f of a second, t Wundt next made determinations * Unless the name belong to a rapidly uttered sentence, when no sub stantive image may have time to arise. fTn his observations he says that time was lost in mentally taking in the word which was the cue, •• owing to the quiet unobtrusive way in which I found it necessary to bring it into view, so as not to distract the thoughts. Moreover, a substantive standing by itself is usually the cquivalent°of too abstract an idea for us to conceive properly without delay. Thus it is very difficult to get a quick conception of the word 'carnage, because there are so many different kinds-two-wheeled, four-wheeled open and closed, and in so many different possible positions, that the n possibly hesitates amidst an obscure sense of many alternations that cannot blend together. But limit the idea to say a landau, and the mental assc elation declares itself more quickly." (Inquiries, etc. , p. 190.)

in which the ' cue ' was given by single-syllabled Avoids called out by an assistant. The person experimented on had to press a key as soon as the sound of the word awak ened an associated idea. Both word and reaction were chronographically registered, and the total time-interval between the two amounted, in four observers, to 1.009, 0.896, 1.037, and 1.154 seconds respectively. From this the simple physiological reaction-time and the time of merely identifying the word's sound (the 'apperception-time,' as Wundt calls it) must be subtracted, to get the exact time required for the associated idea to arise. These times were separately determined and subtracted. The difference, called by Wundt the association-time, amounted, in the same four persons, to 706, 723, 752, and 874 thousandths of a second respectively.* The length of the last figure is due to the fact that the person reacting (President G. S. Hall) was an American, whose associations with German words would naturally be slower than those of natives. The short est association-time noted was when the word ' Sturm ' sug gested to Prof. Wundt the word ' Wind ' in 0.341 second. t — Finally, Mr. Cattell made some interesting observations upon the association-time between the look of letters and their names. "I pasted letters," he says, "on a revolving drum, and determined at what rate they could be read aloud as they passed by a slit in a screen." He found it to vary according as one, or more than one letter, was visi ble at a time through the slit, and gives half a second as about the time which it takes to see and name a single letter seen alone.

' ' When two or more letters are always in view, not only do the pro cesses of seeing and naming overlap, but while the subject is seeing one letter he begins to see the ones next following, and so can read them more quickly. Of the nine persons experimented on, four could read the letters faster when five were in view at once, but were not helped by a sixth letter ; three were not helped by a fifth, and two not by a fourth letter. This shows that while one idea is in the centre, two,

f For interesting remarks ou the sorts of things associated, in these ex periments, with the prompting word, see Galton, op. ctt. pp. 185-203. and Trautscholdt in Wundt's Psychologische Studien. i. 213. three, or four additional ideas may be in the background of consciou ness The second letter in view shortens the time about -4V, the third sV the fourth ^ the fifth ^ sec. " I find it takes about twice as long to read (aloud, as fast as pos sible) words which have no connection as words which make sentences and letters which have no connection as letters which make words' When the words make sentences and the letters words, not only do the processes of seeing and naming overlap, but by one mental effort the subject can recognize a whole group of words or letters, and by one will-act choose the motions to be made in naming, so that the rate at which the words and letters are read is really only limited by the maximum rapidity at which the speech-organs can be moved. As the result of a large number of experiments, the writer found that he had read words not making sentences at the rate of £ sec., words makin« sentences (a passage from Swift) at the rate of i sec., per word. . . ! The rate at which a person reads a foreign language is proportional to his familiarity with the language. For example, when reading as fast as possible the writer's rate was, English 188, French 167, German 250, Italian 327, Latin 434, and Greek 484 ; the figures giving the thou sandths of a second taken to read each word. Experiments made on others strikingly confirm these results. The subject does not know that he is reading the foreign language more slowly than his own ; this explains why foreigners seem to talk so fast. This simple method of determining a person's familiarity with a language might be used in school examinations.

"The time required to see and name colors and pictures of objects was determined in the same way. The time was found to be about the same (over -J sec.) for colors as for pictures, and about twice as long as for words and letters. Other experiments I have made show that we can recognize a single color or picture in a slightly shorter time than a word or letter, but take longer to name it. This is because, in the case of words and letters, the association between the idea and name has taken place so often that the process has become automatic, whereas in the case of colors and pictures we must by a voluntary effort choose the name.*

In later experiments Mr. Cattell studied the time for various associations to be performed, the termini (i.e., cue and answer) being words. A word in one language was to call up its equivalent in another, the name of an author the tongue in which he wrote, that of a city the country in which it lay, that of a writer one of his works, etc. The mean variation from the average is very great in all these experiments ; and the interesting feature which they show

is the existence of certain constant differences between as sociations of different sorts. Thus : The average time of two observers, experimenting on eight different types of association, was 0.420 and 0.436 sec. respectively.* The very wide range of variation is undoubtedly a consequence of the fact that the words used * This value is much smaller than that got by Wundt as above. No reason for the difference is suggested by Mr. Cattell. Wuudt calls atten tion to the fact that the figures found by him give an average, 0.720", ex actly equal to the time interval which in his experiments (mfo infra, chapter on Time) was reproduced without error either way, and to that required, according to the Webers, for the legs to swing in rapid locomotion. " It is not improbable," he adds, " that this psychic constant, of the mean asso ciation-time and of the most correct appreciation of a time-interval, may have been developed under the influence of the most usual bodily move ments, which also have determined the manner in which we tend to sub divide rhythmically longer periods of time." (Physiol. Psch., IT. 286). The r approvement is of that tentative sort which it is no harm for psy chologists to make, provided they recollect how very fictitious and incom parable mutually all these averages derived from different observers, work ing under different conditions, are. Mr. Cattell's figure throws Wundt's ingenious parallel entirely out of line — The only measurements of asso ciation-time which so far seem likely to have much theoretic importance are a few made on insane patients by Von Tschisch (Mendel's Neurolo gisches Centralblatt, 15 Mai, 1885,3 Jhrg., p. 217). The simple reaction time was found about normal in three patients, one with progressive paralysis, one with inveterate mania of persecution, one recovering from ordinary mania. In the convalescent maniac and the paralytic, however, the association-time was hardly half as much as Wundt's normal figure (0.28" and 0.23" instead of 0.7' —smaller also than Cattell's), whilst in the sufferer from delusions of persecution and hallucinations it was twice as great as normal (1.39" instead of 0.7").

This latter patient's time was six fold that of the paralytic. Herr von Tschisch remarks on the connection of the short times with diminished power for clear and consistent processes of thought, and on that of the long times with the persistent fixation of the attention upon monotonous objects (delusions). Miss Marie Walitzky (Revue Philosophique, xxvm. 583) has carried Von Tschisch's observations still farther, making 18,000 measurements in all. She found associationtime increased in paralytic dementia and diminished iu mania. Choice time, on the contrary, is increased in mania.

as cues, and the different types of association studied, differ mucli in their degree of familiarity. "For example, B is a teacher of mathematics ; C has busied him self more with literature. C knows quite as well as B that 7 + 5 = 12, yet he needs Vo of a second longer to call it to mind ; B knows quite as well as C that Dante was a poet, but needs ^V of a second longer to think of it. Such experiments lay bare the mental life in a way that is startling and not always gratifying." *

Time-determinations apart, the facts we have run over can all be summed up in the simple statement that objects once experienced together tend to become associated in the imagi nation, so that when any one of them is thought of, the others are likely to be thought of also, in the same order of sequence or coexistence as before. This statement we may name the law of mental association by contiguity.^ I preserve this name in order to depart as little as pos sible from tradition, although Mr. Ward's designation of the process as that of association by continuity $ or Wundt's as that of external association (to distinguish it from the internal association which we shall presently learn to know under the name of association by similarity) § are perhaps better terms. Whatever we name the law, since it ex presses merely a phenomenon of mental habit, the most natural way of accounting for it is to conceive it as a result

f Compare Bum's law of Association by Contiguity : " Actions, bensations, and States of Feeling, occurring together or in close succession, tend to grow together, or cohere, in such a way that, when any one of them is afterwards presented to the mind, the others are apt to be brought up in idea" (Senses and Intellect, p. 327). Compare also Hartley's formula tion • " Any sensations A, B. C, etc., by being associated with one another a sufficient Number of Times, get such a power over the corresponding Ideas a b, c, etc., that anyone of the sensations A, when impressed alone, shall be able to excite in the Mind b, c, etc., the ideas of the rest."^ (Ob servations on Man. parti, chap. i. §2, Prop, x.) The statement in the text differs from these in holding fast to the objective point of view. J thing*, and objective properties in things, which are associatec