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Vol. Xlil 
 No. 3 
 
 PSYCHOLOGICAL REVIEW PUBLICATIONS 
 
 MAY, 1911 
 Whole No. 55 
 
 THE 
 
 Psychological Monographs 
 
 EDITED BY 
 
 JAMES R. ANGELL, University of Chicago 
 HOWARD C. WARREN, Princeton University {Index) 
 
 JOHN B. WATSON, Johns Hopkins University (Review) and 
 ARTHUR H. PIERCE, Smith College (Bulletin) 
 
 Some Types of Attention 
 
 BY 
 
 / 
 
 H. C. McComas, Jr., Ph.D. (Harvard) 
 Princeton University 
 
 An Investigation Conducted in the Harvard and Princeton Psychological 
 
 Laboratories 
 
 THE REVIEW PUBLISHING COMPANY 
 41 NORTH QUEEN ST., LANCASTER, PA. 
 
 AND BALTIMORE, MD. 
 
COMPOSED AND PRINTED AT THE 
 
 WAVERLY PRESS 
 Bt The Wilxjams & Wilkins Company 
 Baltimore, U. S. A. 
 
CONTENTS 
 
 Part I. Introductory 
 
 Plan and Scope of the Experiments. i 
 
 Historical Setting. 3 
 
 Apparatus and Subjects. 7 
 
 Part II. Experiments 
 
 Span of the Attention. 9 
 
 Concentration and Inhibition. 16 
 
 Mobility of Attention. 25 
 
 Celerity of Attention. 27 
 
 Some Memory Factors in Attention. 31 
 
 Ideational Types. 33 
 
 Visual Perception and Attention. 37 
 
 Motor Factors and Perceptual Attention. 40 
 
 Auditory Factors in Perceptual Attention. 44 
 
 Part III. Correlations 
 
 Correlation Formula. 47 
 
 Correlation Results. 50 
 
 Tables of Correlations. 56 
 
Part I. Introduction 
 
 THE PLAN AND SCOPE OF THE EXPERIMENTS 
 
 The experiments described in the following pages were 
 designed to discover whether the differences which appear 
 among individuals, in certain simple acts of the attention, 
 are indicative of typical traits of the attention, or whether 
 they are fortuitous and unrelated. Individual differences in 
 attention are easily found and have been frequently described, 
 but few efforts have been made to determine what traits go 
 together. Popular judgments on such questions are very 
 common. The unconscious sorting out of the bright and 
 the dull, the absent-minded and the alert and many other 
 contrasts, which everyone is constantly making in his daily 
 relations with other people, is a recognition of differences 
 in attention and possible groupings of them for practical 
 purposes. Teachers are very prone to generalize in the 
 estimates of their students, and undoubtedly many of their 
 shrewd discriminations would be borne out by laboratory 
 tests. Though it is exceedingly probable that a great many 
 convictions which have grown up in the classrooms are not 
 based on a sufficient or accurate induction. Thus, the 
 common ‘rules’ that a fast reader remembers less than a 
 slow one, or that the student who learns quickly forgets 
 more easily than the plodder are specimens of the popular 
 correlating which would quickly lose their force under care¬ 
 ful observation or experiment. 
 
 In endeavoring to detect typical traits of the attention the 
 series of experiments to be described were planned to con¬ 
 sider several characteristic attentional acts and to ascertain 
 the individual differences which appeared in each. These 
 differences were then studied and correlations sought by a 
 mathematical formula. Throughout the entire work each 
 
 I 
 
2 
 
 H. C. McCOMAS. 
 
 experiment has been reduced to as simple terms as possible, 
 and every effort was made to make the measurements accurate. 
 
 Of course, in all such work the larger the number of indi¬ 
 viduals studied the better. It is not practicable, however, in 
 a psychological laboratory to examine great numbers and it 
 is impossible in work of the kind in hand to go outside for 
 material, as the apparatus is not easily transported. In all 
 about twenty-five people participated in the experiments. 
 From these it should be evident whether some traits of atten¬ 
 tion are indicative of types or not; though a larger number 
 must be examined before any far reaching conclusions are 
 attempted. This further study is the more desirable as the 
 subjects were university students and had had from four to 
 seven years of college work behind them; which, of course, 
 would tend to give them similar habits of mind. Far greater 
 diversities in concentration, for example, would probably be 
 found among an equal number of men chosen at random in 
 the street. This uniformity of training is a disadvantage 
 in studies of natural differences, but the advantage of having 
 college-bred subjects In some measure compensates for it. 
 For much of the work calls for introspection, which could 
 hardly be obtained from those who had no such training. 
 
 The number, and therefore, the character of the experi¬ 
 ments were limited by the conditions of the experimentation. 
 For example; no work on the influence of fatigue upon atten¬ 
 tion was attempted, when it became apparent that the one 
 hour allotted each experiment would not suffice to induce 
 fatigue in all the subjects; nor was it practicable to find how 
 the personal interests and habits of thought of the various 
 observers affected attention. Questions of involuntary atten¬ 
 tion and of fluctuations were not studied; not because they are 
 not of importance in finding Types, but because the diffi¬ 
 culties to be overcome in preparing conditions were too time- 
 consuming to admit them. To obtain material which would 
 permit accurate comparison of one subject’s results with 
 those of each of the others it was thought advisable to limit 
 the field to tachlstoscopic work as far as possible. Differ¬ 
 ences which creep in when the apparatus Is frequently 
 
SOME TYPES OF ATTENTION. 
 
 3 
 
 changed, were thus obviated. This restricted the field to 
 visual work, in large measure, but allowed ample scope for 
 individual differences to show themselves. In the tests for 
 ‘span’ different classes of objects were exposed, which called 
 for different attitudes of attention in the subjects and showed 
 individual differences clearly. So in the other tachisto- 
 scopic tests; a comparatively wide variety of experiments 
 was found practical. 
 
 The scope of the work, therefore, is limited to groups of 
 university students, each group studied during one college 
 year in one hour periods. The apparatus largely restricts 
 the work to attention in visual perception. 
 
 The plan of the experiments under such conditions shaped 
 itself into a study, first, of the characteristic span of attention 
 of each subject in observing several classes of objects, then, 
 the ability to concentrate upon certain things and to inhibit 
 others, this led into an examination of the differences in the 
 faculty of turning the attention from one class of interests 
 to another and the quickness with which this could be done. 
 Throughout the work the experimenter noticed differences in 
 the records of subjects due to the memory factor. These 
 were studied with a view to detecting a possible correlation 
 between memory and attention. Finally, the question of 
 the relation of memory types to types of attention concludes 
 the experimentation. The results are given in each chapter 
 in tables which show the relative capacities of the subjects 
 for that experiment. This determines the subject’s rankings 
 which are used in the correlation tables. From the corre¬ 
 lations the conclusions are drawn concerning the possibilities 
 of Types of Attention, in the experiments used. 
 
 HISTORICAL SETTING 
 
 There is very little literature upon Types of Attention. 
 Scattered references may be found in recent studies, but no 
 thoroughgoing effort has been made to find actual typical 
 characteristics in the individual differences in attention. 
 The nearest approach to the experiments in hand are the 
 
4 
 
 H. C. McCOMAS. 
 
 tests made for individual differences in several faculties. 
 Some of these we shall consider later. 
 
 While the great body of psychological literature is silent 
 upon the matter of Types of Attention it nevertheless bears 
 witness to them in a very unique way. For many writers 
 upon philosophical and psychological, or near-psychological, 
 topics since Plato’s time have touched upon the activities 
 of attention, and their opinions give an interesting insight 
 into their own mental processes. We find throughout the 
 history of the theories of attention two general classes of 
 opinion^ The one holds that the attention is more or less 
 subjected to the play of stimuli upon the mind, that the in¬ 
 ward direction of one’s course of thought is to be found in 
 the influence of his surroundings. The other view empha¬ 
 sizes the influence of the mind upon the activity of attention 
 regardless of the external world. It magnifies the domina¬ 
 tion of a will or a self. Of course the general philosophy of 
 a thinker will modify his conception of each chapter in psy¬ 
 chology; but, in spite of that, the disposition of his own 
 thinking will tend to be the criterion by which he will be 
 guided. If he is easily distracted by his surroundings, if he 
 finds it difficult to concentrate upon intellectual problems 
 rather than perceptual, if his attention is of a discursive 
 nature, passing easily from one subject to another, then 
 nothing could be more natural than the conlcusion that the 
 attention is directed by stimuli rather than by will. On the 
 other hand, a mind which readily concentrates upon abstract 
 themes, ignoring the passing appeals of the outer world, 
 feeling its ability to turn now to one phase of the subject 
 considered, now to another, without let or hindrance, is 
 very apt to be a mind which concludes it possesses an inde¬ 
 pendent control over the attention. From such experiences 
 the two divergent types of theory, the involuntary and the 
 voluntary, undoubtedly evolved. They are descriptive of 
 two types of attention, insofar as they are based on intro- 
 
 ^D. Braunschweiger, Die Lehre von der Aufmerksamkeit in der Psychologic des i8. 
 Jahrhunderts; L. L. Uhl, Attention, an Historical Summary of the Discussions Con¬ 
 cerning the Subject. 
 
SOME TYPES OF ATTENTION. 
 
 5 
 
 spection, and few men are so abstract in their treatment of 
 such matters that the evidence of their own mental life does 
 not affect their systems of thought. 
 
 Such differences as those appearing between the positions 
 taken by Condillac, Bonnet and Helvetius on the one hand 
 and by Reid and Stewart on the other bespeak more than 
 philosophic and literary differences. The natural differ¬ 
 ences of race and mental traits come into the writings and 
 account in large measure for their attitudes on the question 
 of attention. 
 
 It is perfectly legitimate to assume that we have the mate¬ 
 rials for two types of attention, at least, in the mental life of 
 psychologists and philosophers. It would be a valuable 
 study if the influence of these fundamental mental traits 
 were traced out in the systems of philosophy which these 
 minds found the most acceptable and congenial. 
 
 Baldwin finds five classes of modern psychologists; those 
 who maintain that the affective element is dominant in 
 attention, namely Horwicz and Ribot; those who find in 
 attention an original activity of the mind; Stumpf, Ladd, 
 Ward and Jodi; those who refer the fundamental factors of 
 attention to intensity of sensation and perception and their 
 psychic reinforcement, such as Bradley and Muller; those who 
 see attention as the outcome of inhibition. Terrier and Ober- 
 steiner; and the champions of the theory that attention is to 
 be understood in the light of the motor factors, Baldwin, 
 Lange, and Stout. In the last group of theories we should 
 consider Munsterberg’s ‘Action theory’ and the theories of 
 McDougall and Sherrington. 
 
 Not until the time of Francis Galton do we find any con¬ 
 sistent study of individual differences.^ His suggestions were 
 carried out experimentally among school children by Gilbert, 
 Boas, Bolton and others. However, the most nearly related 
 to Types of Attention is the work of H. Griffing On the Devel¬ 
 opment of Visual Perception and Attention in which he tries 
 to establish a correlation between the Span of Attention and 
 
 ^Inquiries into the Human Faculty. 1883. 
 
6 
 
 H. C. McCOMAS. 
 
 the mental ability of the subjects. Baldwin’s doctrine that 
 the attention is as subject to ideational differences as memory 
 and imagination, which appeared in his Mental Development 
 was not based on any experimental fact. In the work of 
 Henri et Binet, La Psychologie Individuelle, 1896, we have 
 the recognition of the fact that attention may differ in typical 
 ways among individuals. Later Binet endeavored to dis¬ 
 prove Gilbert’s correlation between mental ability and span. 
 The work was done on auditory span. Binet and Vaschide 
 made many experiments for differences in reaction-time, 
 memory and general mental ability, but none bearing directly 
 on our subject. The article of S. E. Sharp upon Individual 
 Psychology gives a very good resume of what work Binet 
 did on attention.^ He sought to determine the degree of 
 attention by having his subjects cancel certain letters as 
 they read a page. The range of attention was sought by 
 having the subjects read aloud and write the alphabet simul¬ 
 taneously. Both methods are, of course, very faulty and 
 no one should expect clear-cut results from them. In L. W. 
 Stern’s Ueher Psychologie der individuellen Differenzen, 1900, 
 we have a very able treatment of Types in psychology. In 
 attention he finds the concentration (Konzentration) and 
 the expansive (Elastizitat) features of attention indicative 
 of two types. Also, he finds typical differences in constancy 
 of application and the intermittency of concentration. He 
 maintains that the psychic energy used in attention varies. 
 This explains some of the phenomena of differences in morn¬ 
 ing and evening workers and of sleep as well. He does not 
 attempt any large correlations between types. 
 
 Kraepelin and Cron in their work Ueher die Messung der 
 Auffassungsfdhigkeit made tests of the simpler mental fac¬ 
 tors and found the results far from satisfactory. This fail¬ 
 ure of correlation is rather characteristic of experiments in 
 individual differences; witness the paucity of results from 
 the experimentation of this character by Wissler, Thorndike 
 and others upon students. Spearman, nevertheless, believed 
 
 ^Amer. J. of Psychol., x, p. 329. 
 
SOME TYPES OF ATTENTION. 
 
 7 
 
 from his experiments that a correlation could be found between 
 all forms of sensory discrimination and the more complicated 
 intellectual activities of practical life. He sums up his results 
 thus: “All branches of intellectual activities have in com¬ 
 mon one fundamental function (or group of functions), 
 whereas the remaining or specific elements of the activity seem 
 in every case to be wholly different from that of all others.” 
 
 The discussions of the work of Miinsterberg, Cattell, 
 Jastrow, Calkins, and others which deal with the larger 
 problems of Individual Differences need not engage us here. 
 Our retrospect upon the historical feature of Types of Atten¬ 
 tion shows the need of a beginning, at least, in the literature 
 of this subject. 
 
 APPARATUS AND SUBJECTS 
 
 The apparatus used in nearly all of the experiments was a 
 very simple form of tachistoscope. It was fastened to a low 
 table and leaned toward the subject, so that he could conven¬ 
 iently place his eye close to the shutter-opening. It was 
 simply constructed with a base-board 36 x 14 inches which 
 sustained supports holding a similar board above it. This 
 upper board was arranged with an incline toward the sub¬ 
 ject. It was 16 inches above the base-board along the line 
 farthest from the subject and 12 inches along the line next 
 him. A frame about 3 inches high held an automatic camera 
 shutter over an orifice in the center of this inclined upper 
 board. Immediately beneath was a heavy grey card, par¬ 
 allel with this upper board, and 17 inches from the subject’s 
 eye. Upon this card the smaller cards, containing the objects 
 to be observed, were placed. The shutter was controlled by 
 a pneumatic device. A pendulum, regulated to traverse its 
 amplitude twice in a second, hung beside the experimenter’s 
 chair. The experimenter was hidden from the subject by a 
 cloth screen which was suspended by a rack on the upper 
 board. The whole frame was covered with black card-board, 
 except the back which was left open for light and to enable 
 the experimenter to change the exposed objects easily. 
 
8 
 
 H. C. McCOMAS. 
 
 Nothing was visible to the subject but the screen upper, 
 board and shutter. When the shutter sprang open the white 
 card, 7 x 5^ inches, which held the objects to be observed, 
 was clearly in view. The letters used were A inches high and 
 were black. The colored letters were about | inch in height, 
 and the colored figures were from | to i inch in height. Where 
 the squares of color were used, they were about f inch each 
 way. 
 
 Another apparatus was used in the experiments upon visual 
 and auditory attention which might be termed a rotary 
 tachistoscope. It was a wooden disk 24 inches in diameter 
 hung upon an axle, and connected by a rubber belt with a 
 dynamo whose wheel connections admitted of several speeds. 
 Thirty-eight words in white letters were fastened at regular 
 intervals near the circumference. Immediately in front of 
 the wooden disc was a black card-board disc with slits oppo¬ 
 site the words. When these two rotated together, words 
 flashed up before the eye and disappeared without their 
 motion being observable. The eye was kept in position by 
 looking through another slit card-board about i foot from the 
 black card disc. 
 
 In the work at the Laboratory in Princeton a tachisto¬ 
 scope was constructed from two black card-board discs 
 50 c.m. in diameter. Each disc had a quadrant cut out of it, 
 and they were rotated with half of the surface of one disc 
 covering half of the surface of the other. Where the cut por¬ 
 tions coincided the observer had a clear view of the card to be 
 exposed. Attached to the wheel, on which one of the discs 
 was fastened, were several copper fingers. These made and 
 broke electric currents to magnets and bells, at the moment 
 when the card was exposed. 
 
 The subjects participating in the first year’s series of experi¬ 
 ments were four graduate students in Harvard University, a 
 practicing physician and a professor in psychology. In the 
 second year three of the subjects were Instructors, the others 
 being graduate students who had had considerable labora¬ 
 tory experience. Two of these were women. In the third 
 year the nine young men were all undergraduates in Princeton. 
 
SOME TYPES OF ATTENTION. 
 
 9 
 
 Part II. Experiments 
 
 THE SPAN OF ATTENTION 
 
 In measuring attention we feel the need of an exact defi¬ 
 nition of what we are measuring more keenly than in any 
 other treatment of the subject. Our work will be confusion 
 worse confounded if we do not have a clear-cut idea of just 
 what is being measured. Unfortunately we encounter the 
 old difficulties, which are met in every attempt to define con¬ 
 sciousness, those of implying the thing defined in the defini¬ 
 tion. This ‘ circulus in definiendo ’ is a very subtle snare just 
 here. Attention is a characteristic of every mental act, we 
 are always in the center of it, we cannot get away from it and 
 survey its borders from without. Nevertheless, we may make 
 clear what is meant in the present chapter by attention, with 
 illustration and comparison. 
 
 When we look at a printed page there is always some portion of it, 
 perhaps a word, which we see more clearly than the rest; and out beyond 
 the margin of the page we are still conscious of objects which we see 
 only in an imperfect way. The field of consciousness is apparently like 
 this visual field. There is always a central point of which we are momen¬ 
 tarily more vividly conscious than anything else. Fading gradually 
 away from this point into vague and vaguer consciousness, is a margin 
 of ideas, or objects, of which we are aware in some sort of mental indirect 
 vision. This fact that consciousness always has a focal point, which 
 reveals the momentary activity of the mind, is what is meant by the 
 fact of attention.* 
 
 This is expressed graphically by means of five concentric 
 circles. The outermost circle representing unconsciousness; 
 the next inner circle, subconsciousness; the next, diffused 
 consciousness; the circle next to the center is called active 
 consciousness or attention and the center circle represents 
 apperception, which synthesizes all mental data. 
 
 Our problem is the measuring of this focal area in con¬ 
 sciousness. That it is not anything like so simple and static 
 
 lAngell, J. R., Psychology, p. 65. 
 
lO 
 
 H. C. McCOMAS. 
 
 a thing as the series of circles might imply goes without 
 saying. Indeed, the mobility and elasticity of that central 
 area are equalled only by the vagueness and uncertainty 
 of the several grades or degrees of consciousness represented. 
 It would seem at first sight that the problem of determining 
 where this central clearness ends and the peripheral obscur¬ 
 ity begins is as thankless a task as finding the line between 
 candle-light and the darkness enveloping it. There are, 
 fortunately, some features in the process which lend us mate¬ 
 rial aid. As Wundt showed, many years ago, every process of 
 attention has two factors, the one increases the clearness of 
 an idea or perception, the other diminishes, by inhibition, 
 other available impressions or memory-images. So our 
 area of light is heightened in its clearness and our circumfer¬ 
 ence of obscurity is darkened, making the margin of uncer¬ 
 tainty between the two narrower than it first appeared, though 
 all too broad at that. Titchener adds. 
 
 Attention, in other words, means a redistribution of clearness in con¬ 
 sciousness, the rise of some elements and the fall of others, with an accom¬ 
 panying total feeling of a characteristic kind.”^ 
 
 A large number of careful experiments have been made to 
 measure this span of clearness. Usually they have sought 
 to catch the act of attention in an instant of time and to take 
 a sort of psychological snap-shop of its processes. This, of 
 course, applies to attention concerned with spacial percep¬ 
 tions, not with temporal, and it is with the spacial aspect we 
 shall deal. A tachistoscope is usually employed which either 
 illuminates the field observed for a fraction of a second or 
 exposes the field by the opening of a shutter. The observer 
 has a fixation point in the middle of the field which obviates 
 loss of time by eye movement, and makes measurements 
 more exact. Wundt says: 
 
 careful introspection easily succeeds in fixating the state of conscious¬ 
 ness at the moment the impression arrives, and in distinguishing this 
 from the subsequent acts of memory. . . these experiments. 
 
 ^Titchener, E. B., The Psychology of Feeling and Attention, p. 183. 
 
SOME TYPES OF ATTENTION. 
 
 II 
 
 show that the scope of attention, when it is kept at its maximum intens¬ 
 ity, remains constant only when the impressions are held apart as in the 
 case of isolated lines, numbers, letters^ Six such simple impressions 
 can, under favorable conditions, be apperceived in the same instant. 
 As soon as the impressions are bound together in complexes the number 
 included in the scope of attention changes. 
 
 This conclusion is borne out by the experiments of Gold- 
 scheider and Muller at Berlin^. They found that for iso¬ 
 lated lines exposed for only yiv of a second, four or at most 
 five could be recognized. When the lines were grouped in 
 symmetrical forms a larger number could be apperceived. 
 Cattell, Erdmann and Dodge corroborate these findings in 
 their experiments upon the psychology of reading. 
 
 We may be sure, then, that the process of attention when 
 concerned with a few unrelated impressions is unlike the 
 process with which we are familiar in the ordinary activity 
 of attention; where we naturally associate and assimilate 
 the impressions and retain these synthesized groups in our 
 memory. But we may not be sure as to just how far these 
 so-called unrelated objects fail to be apperceived. In a few 
 trial experiments upon this problem I quickly discovered that 
 the ability to apperceive in groups varied in the same indi¬ 
 vidual for different arrangements and varied widely in differ¬ 
 ent individuals. Not only was this confusing situation 
 present, but a more subtle difficulty presented itself in 
 the fact that a certain amount of grouping may occur in an 
 unconscious manner. That is, the lines vaguely suggest a 
 box, a house, or a face, but not clearly enough to make it 
 a matter of comment, or even of notice, unless questioned by 
 the experimenter. In such cases the span of attention will 
 appear large, though the cause is a purely accidental one. 
 This occasional activity, the assimilating of impressions into 
 larger wholes, cannot be entirely excluded from any experi¬ 
 ment upon attention. It is one of the several disconcerting 
 factors which we must seek to minimize. I found, however, 
 
 iwundt, W., Outlines of Psychology, Third English edition, p. 236. 
 ^Zeitschrift Klin. Med., Bd. xxiii, p. 131. 
 
12 
 
 H. C. McCOMAS. 
 
 in many hundreds of experiments that the subject’s intro¬ 
 spection and the report he gave went very well hand in hand. 
 That is, when a series of words suggested a sentence and so 
 gave unusually large returns, or when several colors grouped 
 themselves as shades of a fundamental color, I could detect 
 the ease in which the report was made and so corrections 
 could be made, or the result discarded. I do not believe that 
 this grouping is as prevalent in those experiments where the 
 impressions themselves are a complex such as words, colored 
 figures, or geometrical forms, as in those simpler presenta¬ 
 tions where it is difficult to arrange mere dots and dashes 
 so that they will not suggest some form or figure to the eye. 
 Rather the association will arise from alliteration or rhymes 
 in the words or a serial order in the numbers, etc. But these 
 difficulties are in large measure obviated after a little expe¬ 
 rience and practice in arranging the material to be presented. 
 For this, and other reasons, the experiments which I made 
 to measure the span of attention were uniformly of longer 
 duration in exposure, and of more varied and richer content 
 in impression;—tachistoscopically speaking, they are less of 
 a ‘ snap-shot ’ and more of a ‘ time-exposure ’ than those class¬ 
 ical experiments from which we have been quoting. 
 
 The method best adapted to detect individual differences 
 in the scope of attention must be one which enables the atten- 
 tional processes to act in as normal a way as is possible in 
 laboratory work and which gives the experimenter a compre¬ 
 hensive view of what these processes are. Such a method, 
 I believe, is, at least, approximated in the work now to be 
 described. 
 
 Three series of experiments were made extending over 
 several months and giving each subject a sufficient number of 
 trials to enable him to express in averages his characteris¬ 
 tics. Any one lot of experiments, taking the subject for one 
 hour only, would not in all probability, tell a true story. I 
 recall one subject whose results were fully 20 per cent better 
 at one time than at another. It was a very extreme case; 
 but the condition of the subject, if fatigued, nervous, confused 
 by the experiment or what-not, will affect the results of his 
 
SOME TYPES OF ATTENTION. 
 
 13 
 
 work. This objection is done away with by the number of 
 experiments and the wide variations in time between them. 
 
 As Dearborn found it necessary to vary the style and sub¬ 
 ject matter in his reading tests, so I found it necessary to vary 
 the classes of objects exposed. As we shall see later, the 
 sensory and motor elements entering into attention vary in 
 their proportions for words and colors. With colors a visual 
 memory image usually persists; this seldom occurs for words. 
 Were the tests made for one class of exposures only we should 
 probably have errors creeping in from differences in ideational 
 type. To escape this I have taken one series of experiments 
 with the attention upon words, one with the attention upon 
 colors, one with the attention upon figures and letters, and I 
 have used the sum of these results to represent the Span of 
 Attention for the several subjects. 
 
 It became apparent early in the work that a time exposure 
 of three seconds was too long for many of the subjects. One 
 thing inhibited another and there was always a feeling that 
 much more had been attended to than could be reported. It 
 also became as quickly apparent that a half of a second was 
 too short a period. For in this class of experiments the eye 
 had no fixation point and would usually catch two or three 
 objects, but would fail to survey the entire field. It was 
 merely a matter of where the eye chanced to rest that deter¬ 
 mined the class and number of objects. After trying several 
 fractions of a second it seemed advisable to use exactly one 
 second’s time exposure. This enabled the subject to survey 
 an entire card, and did not permit him to overload his mind 
 with observations which could not be retained. It also 
 seemed to be an opportune time for preventing the grouping of 
 objects, such as occurs with long time exposures. Associa¬ 
 tions would occur occasionally, but not frequently. Indeed, 
 five monosyllabic words were frequently given without the 
 subject forming any idea of their meaning, until they were 
 reported. 
 
 At first the subject was requested to write all that had been 
 observed. This had the effect of driving many things out 
 of mind for several subjects, especially those whose memory 
 
14 
 
 H. C. McCOMAS. 
 
 images did not seem as clear or of as long duration as the 
 majority of subjects. So the plan of giving a verbal report 
 was adopted, which entirely altered the results for several 
 subjects. More in detail the experiments were as follows: 
 
 In series No. i, (see Table i) 50 exposures were made of 
 10 colors, upon the regular cards, with the regular one second 
 exposure. The colors were shown to the subject before the 
 experiment began, in order to familiarize the subject with 
 the kind of color to be exposed and to learn his nomenclature 
 for colors. All that was insisted upon was a sufficiently 
 clear report, to make certain that the colors named had been 
 actually perceived. 
 
 In series no. 2 (see Table II) 20 exposures were made of 
 cards containing 5 three-letter words and five colored letters 
 or numbers. The attention was directed to the words in 
 order to involve the speech-motor factor in attention. If 
 other things than words were perceived they were allowed to 
 count in the total of things spanned by the attention. The 
 proportion of objects perceived which were not in the class 
 attended to is exceedingly small; as we shall see later. The 
 totals are, therefore, a satisfactory index of span for this 
 class of work. 
 
 In series no 3 (see Table III) 20 exposures were made of 
 the same class of cards as in series no. 2; but the attention was 
 directed in this case to the colored letters and numbers. The 
 purpose in this was to submit a class of objects to the subject’s 
 attention which were intermediate between the color-class 
 and the word class. For it had been noted n previous experi¬ 
 ments that the setting of the attention was introspectively 
 different for these two classes of objects. 
 
 In Table IV the totals for these three series were given for 
 each subject; thus, the number of colors ‘A’ perceived in the 
 first series was 215, the number in the second series was 97, 
 and in the third 206. The total number of objects attended to 
 in the n'nety experiments was 518. That is, ‘A’ attended to 
 an average of 5.75 objects for each exposure. This figure 
 or the total itself is the index of 'A' for Span in this class of 
 experiments. 
 
SOME TYPES OF ATTENTION. 
 
 15 
 
 TABLE I TABLE II 
 
 SUBJECTS 
 
 TOTALS 
 
 CR. 
 
 AV. 
 
 MV. 
 
 TOTALS 
 
 CR. 
 
 AV, 
 
 MV. 
 
 A . 
 
 215 
 
 4 
 
 4-30 
 
 0.58 
 
 97 
 
 3 
 
 485 
 
 I . 18 
 
 B. 
 
 205 
 
 7 
 
 4.10 
 
 0.62 
 
 86 
 
 6 
 
 430 
 
 0.80 
 
 C. 
 
 223 
 
 
 4.46 
 
 0.62 
 
 70 
 
 10 
 
 3 so 
 
 0.90 
 
 I). 
 
 i6r 
 
 9 
 
 3.22 
 
 o-SS 
 
 96 
 
 4 
 
 4.80 
 
 1.02 
 
 li . 
 
 222 
 
 3 
 
 4 44 
 
 0.44 
 
 106 
 
 2 
 
 5-30 
 
 I 13 
 
 F . 
 
 141 
 
 10 
 
 2.82 
 
 0.40 
 
 72 
 
 9 
 
 3.60 
 
 0-55 
 
 G. 
 
 213 
 
 sl 
 
 4.26 
 
 0-57 
 
 74 
 
 8 
 
 3-70 
 
 0.93 
 
 H. 
 
 199 
 
 8 
 
 398 
 
 0.46 
 
 88 
 
 5 
 
 4.40 
 
 0.88 
 
 J . 
 
 213 
 
 si 
 
 4.26 
 
 0.62 
 
 84 
 
 7 
 
 4.20 
 
 0.90 
 
 K. 
 
 223 
 
 15 
 
 4.46 
 
 0.69 
 
 125 
 
 I 
 
 6.25 
 
 1.14 
 
 
 TABLE III 
 
 
 
 TABLE IV 
 
 
 SUBJECTS 
 
 TOTALS 
 
 CR. 
 
 AV. 
 
 MV. 
 
 TOTALS 
 
 CR. 
 
 AV. 
 
 
 A . 
 
 206 
 
 I 
 
 10.30 
 
 2.04 
 
 S18 
 
 2 
 
 5-75 
 
 
 B. 
 
 137 
 
 8 
 
 6.8s 
 
 1.44 
 
 428 
 
 7 i 
 
 4-75 
 
 
 C. 
 
 169 
 
 5 
 
 8.45 
 
 1-74 
 
 462 
 
 5 
 
 S13 
 
 
 D . 
 
 122 
 
 10 
 
 6.10 
 
 1.04 
 
 379 
 
 9 
 
 4.21 
 
 
 E. 
 
 i8s 
 
 2 
 
 9-25 
 
 1.64 
 
 513 
 
 3 
 
 5 70 
 
 
 F. 
 
 123 
 
 9 
 
 6.15 
 
 I -25 
 
 336 
 
 10 
 
 3-73 
 
 
 G. 
 
 141 
 
 7 
 
 7 05 
 
 1.12 
 
 428 
 
 7 i 
 
 4-75 
 
 
 H. 
 
 166 
 
 6 
 
 8.30 
 
 1.60 
 
 453 
 
 6 
 
 S03 
 
 
 J . 
 
 172 
 
 4 
 
 8.60 
 
 1.30 
 
 469 
 
 4 
 
 5.20 
 
 
 K. 
 
 182 
 
 3 
 
 9.10 
 
 1.62 
 
 53 ° 
 
 I 
 
 5-88 
 
 
 C.R. = Correlation Rank. 
 Av. = Average. 
 
 M. V. = Mean Variation. 
 
 From these tables it appears that there are large individual 
 differences between subjects in their span of attention. Thus, 
 ‘K’ has half again as large a span as 'F'; though several 
 have span results quite close together ‘ B ’ and ‘ G ’ having 
 the same totals. 
 
 In the table of correlations it will be seen that Table III 
 correlates with Tables I and II, but that Tables I and II do 
 not correlate. This shows there is a sufficient difference 
 between the word-class and the color-class to affect the atten¬ 
 tion quite differently. It also shows that the experiments are 
 successful In measuring a characteristic spanning of the atten¬ 
 tion; for the first series and the third, between the perform- 
 
i6 
 
 H. C. McCOMAS. 
 
 ance of which several months elapsed, have the correlational 
 coefficient of 0.48. 
 
 Another evidence of the accuracy of the experiments 
 appears in the tables for averages and mean variations 
 from the averages. It is not possible to find any Probable 
 Error in these measurements for an unusually large or small 
 result does not necessarily indicate an error of any kind. 
 The value of the experiments would be greatly reduced, how¬ 
 ever, if each subject varied very greatly from his average, for 
 no figure would than represent his span accurately enough to 
 permit comparison with the others. When the averages in 
 the tables above are compared with their mean variations it 
 will be seen that the variation is but a small part of the aver¬ 
 age (usually a sixth, occasionally a fourth). So the average 
 is amply representative of the subject for comparison. The 
 average is not given in succeeding experiments as it was found 
 that the actual totals of results give a more accurate ranking 
 for correlations. 
 
 The correlations for the above experiments, as they com¬ 
 pare with each other and as they compare with the other 
 experiments of the thesis, are all given. A separate table is 
 also given of those correlations which are sufficiently above 
 the Probable Error, for this method of correlating, to indi¬ 
 cate significant relations. The method of correlating is 
 discussed in the opening paragraphs of Part III. 
 
 CONCENTRATION AND INHIBITION 
 
 Attention has been regarded as simply the focussing of 
 consciousness, which resulted in a consequent brightening 
 of all it encompassed without directly affecting other por¬ 
 tions of consciousness. It has also been regarded as the proc¬ 
 esses by which all other parts of consciousness are obscured 
 except that which is directly engaged in perception or idea¬ 
 tion. There is surely virtue in the ‘golden mean’ in this 
 case. For that sharpening between the area of clearness and 
 its penumbra of obscurity, which was mentioned in the last 
 chapter, is much better understood if we consider both proc¬ 
 esses as complementary factors in attention. 
 
SOME TYPES OF ATTENTION. 
 
 17 
 
 Probably the sharpness with which the clearness area 
 drops away into the obscurity area differs with different 
 individuals. The introspection of Kiilpe, however, appeals to 
 me as being in close concord with the average type of atten¬ 
 tion. He sums up his views: 
 
 When we ask how the degrees of consciousness are related to one another 
 we find not one unif orm graduation from the highest to the lowest, but 
 in most cases a fairly sharp line of distinction. Certain contents stand 
 at the level of clear apprehension; and from them our consciousness 
 drops away; without transition, to the level of obscure general impression, 
 above which the other contents of time are unable to rise. And the 
 clearer the first group, the more indistinct are all the rest.’^ 
 
 Physiological psychology gives additional weight to this 
 view. 
 
 Striking effects of concentration upon any object are frequent in the ex¬ 
 perience of everyone. There can be no doubt that we must find a physio¬ 
 logical expression for this singleness of the object of attention and for the 
 power of one object to banish all others from the focus of consciousness. 
 Translated into physiological terms it means that only one of the percept¬ 
 ual systems of the cortical paths, consisting of one or more sub-systems of 
 sensory areas united by higher-level paths, can be active at any one mom¬ 
 ent, that the spread of the nervous excitement through one such system 
 somehow brings about the cessation of activity in the system active at 
 the previous moment and prevents the activity of the other systems. 
 Hence we need not seek for inhibitory centers in the cerebrum. Each 
 perceptual system of arcs is an inhibitory center for every other, the 
 activity of each system brings about as a collateral effect the inhibition 
 of all others. . . Though we do not know how this inhibition is 
 
 brought about, it may be conceived as a drainage of the free nervous 
 energy from the inhibited to the inhibiting system, owing to the latter 
 becoming for the moment the path of least resistance. There is evi¬ 
 dence that similar inhibitory effects are excited by the activity of any 
 one group of arcs of sensory area of the cortex upon other arcs of the 
 same area, especially in the case of the visual area.^ 
 
 Such a line of demarcation between the fields of attention 
 and non-attention enables us to determine with considerable 
 
 ^Titchener, E. B., The Psychology of Feeling and Attention, p. 222. 
 
 ’McDougall, W., Physiological Psychology, pp. 102, 103. 
 
i8 
 
 H. C. McCOMAS. 
 
 accuracy the ability of the individual to concentrate his atten¬ 
 tion, From the testimony of those whose introspection 
 resembles that of Kiilpe, the more intense the application of 
 the attention, the plainer appears the inverse proportion in 
 clearness between the attended and the non-attended. From 
 the results of such work as McDougall’s and Sherrington’s, 
 it appears that the more alive the one perceptual system of 
 a sensory area the less alert is its neighbor. The concentra¬ 
 tion value, therefore, appears in the relation between the 
 included and the excluded. In order to bring out individual 
 differences fairly the cards containing five words and five 
 colored letters or figures were exposed for one second in sev¬ 
 eral series of experiments extending over five weeks. In the 
 first series the subject was directed to concentrate upon the 
 colored objects and to ignore the words The success with 
 which this was accomplished was astonishing. The intro¬ 
 spection was quite uniform. After the subjects had become 
 accustomed to the work (and not till then were any of their 
 results recorded) the ability to select one class or the other 
 was very marked. For all subjects I have exposed the same 
 card directing his attention now to the words and now to the 
 colored figures. In not one instance did the subject know he 
 had observed the same card—so completely were the objects, 
 of the group not attended to, inhibited. When itis remembered 
 that there were only ten objects before the subject and that 
 they were exposed for an entire second the phenomenon of 
 the inhibition of half of them becomes impressively significant. 
 There was, however, less ability to get clean-cut results when 
 the attention was directed to the words. The reason for this 
 is the greater difficulty in attending words (compare Tables 
 I and II for Span). It is far easier to catch a color when the 
 attention is upon the word-class than it is to catch a word 
 when the attention is directed to the colors. 
 
 The table below-represents the subjects by the capital 
 letters. The first row of figures represents the number of 
 words which entered attention when the concentration was 
 upon the colored figures, in a series of 25 exposures of the 
 usual cards containing five words and five colored figures. 
 
SOME TYPES OF ATTENTION. 
 
 19 
 
 The second row of figures represents the colors, figures and 
 letters which entered the attention when the concentration 
 was upon the words. Twenty exposures were made for this 
 latter series. In both series the exposure was one second. 
 The totals give the correlation ranking. 
 
 TABLE V 
 
 Cor. R. 
 
 (4) 
 
 (6) 
 
 (9) 
 
 (4) 
 
 (7) 
 
 (4) 
 
 (2) 
 
 (8) 
 
 (l) 
 
 (ro) 
 
 
 
 
 
 
 
 Subjects.. .. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 1st Series.... 
 
 2 
 
 I 
 
 I 
 
 0 
 
 0 
 
 I 
 
 2 
 
 S 
 
 2 
 
 0 
 
 2nd Series... 
 
 5 
 
 8 
 
 23 
 
 7 
 
 13 
 
 6 
 
 I 
 
 10 
 
 0 
 
 28 
 
 Totals. 
 
 7 
 
 9 
 
 24 
 
 7 
 
 13 
 
 7 
 
 3 
 
 IS 
 
 2 
 
 28 
 
 I cannot believe that these totals tell us very much about 
 the ability to concentrate and inhibit as the processes norm¬ 
 ally operate. For it would appear that D is four times 
 as apt as ‘K’ in concentration, whereas ‘D’ was suffering 
 from a nervous depression and could hardly keep his atten¬ 
 tion on his work for fifteen minutes, when the second series was 
 taken. While ‘K’ was in excellent condition, a scientist 
 with powers of concentration trained by many years of 
 exacting work. 
 
 The figures may not be without significance for a study of 
 differences which relate not to general conditions of mental 
 energy, in concentrating, but to the more minute cooperation 
 of the ‘perceptual arcs,’ which need not be a series of acts pro¬ 
 tracted over a considerable period. So that an attention 
 which could not maintain its application for any length of 
 time could still do a very clear-cut piece of work for a few 
 seconds. Thus the above figures tell nothing of those great 
 types of attention which Stern described.^ 
 
 The effort to elaborate these experiments by introducing 
 distractions was also rather abortive of results along the line 
 of individual differences. In fact the work with distractions 
 is rather misleading.^ 
 
 'Stern, L. W., Ueber Psychologie der individnellen Diferenzen, Kap. viii. 
 
 ^Hamlin, A. J., Attention and Distraction, Amer. J. of Psychol., viii, p. 3. 
 
20 
 
 H. C. McCOMAS. 
 
 With one subject the so-called distraction may act as a 
 stimulus, with another it may be very disconcerting when he 
 is tired and nervous, but practically ineffective when he is 
 at his best. 
 
 In one set of tests the room was lighted by electricity and 
 for the cards upon which the usual five words and five colored 
 objects were displayed, I substituted brilliantly colored 
 papers of just the same proportion as the cards to serve as 
 backgrounds. There was sufficient strangeness in the change 
 from daylight to electric light to make the exposure seem a 
 little different from usual, and so to discredit any shock which 
 the first colored background might cause. There was noth¬ 
 ing, however, to prevent the subject from detecting the 
 change in background as the successive exposures were made, 
 for even in the electric light the difference between the 
 colored backgrounds was startling, when they were placed 
 together. The eye, of course, had to traverse the colored 
 papers in passing from one word to another. The concen¬ 
 tration was upon words. Table VI, below, shows the total 
 number of words observed in the seven exposures for each 
 subject and the number of colored squares, letters and figures 
 which were not inhibited. The lowest row of figures shows 
 which background was first detected by the observer. It will 
 be noticed that the first four backgrounds, which consisted 
 of yellow, a pea-green, a light brown and a light blue, were 
 inhibited by all subjects. 
 
 Seven exposures were given with the usual time, one 
 second; the usual signal of one and one-half seconds; the 
 usual objects were presented, in fact everything was care¬ 
 fully arranged to give the experiments the same setting as the 
 many series which preceded them. 
 
 TABLE VI 
 
SOME TYPES OF ATTENTION. 
 
 21 
 
 It would not be safe to draw any far reaching conclusions 
 from seven experiments. It must, however, be obvious from 
 the capacity of two of the eleven subjects to inhibit the 
 change in background entirely that McDougall’s surmise as 
 to the inhibitory capacity of certain perceptual systems in 
 the same sensory area is well grounded. 
 
 A comparison of the number of words attended in these 
 seven experiments and seven similar experiments under 
 usual conditions shows that distraction did retard many of 
 the subjects. This a number of them felt during the experi¬ 
 ment, but none of them assigned the influence to the right 
 cause. Table VII shows in the upper row of figures the 
 number of words attended to in seven experiments with no dis¬ 
 traction, the lower row of figures shows the totals for the 
 seven distraction experiments. 
 
 TABLE VII 
 
 
 
 B 
 
 c 
 
 D 
 
 £ 
 
 F 
 
 G 
 
 H 
 
 j 
 
 K 
 
 L 
 
 Cor. R. 
 
 (s) 
 
 ( 7 l) 
 
 (l) 
 
 (9) 
 
 ( 7 i) 
 
 ( 2 |) 
 
 (10) 
 
 (6) 
 
 (4) 
 
 (2^) 
 
 Not 
 
 used 
 
 
 
 33 
 
 29 
 
 31 
 
 25 
 
 23 
 
 26 
 
 33 
 
 26 
 
 35 
 
 29 
 
 25 
 
 24 
 
 31 
 
 23 
 
 30 
 
 25 
 
 27 
 
 25 
 
 25 
 
 24 
 
 28 
 
 32 
 
 That the distraction affected the several subjects dif¬ 
 ferently is obvious. (Rank for correlations is found by sub¬ 
 tracting the lower from the upper row.) 
 
 The auditory distraction did little better service than the 
 visual. This is to be expected. However, they seemed pref¬ 
 erable to such distractions as require a distribution of interest: 
 for in such work it is hard to distinguish between distraction 
 and an actual division of attention.^ 
 
 In the following experiments a fire-alarm bell was placed on 
 a tin box within eighteen inches of the subject’s ear. An 
 electric attachment rang a bell the instant the shutter of 
 
 ^Darlington, T. and Talbot, E. B. Methods of Distracting the Attention. Amer. 
 J. of Psychol., ix, pp. 332-345. Also, Moyer, F. E., op. cit. viii, p. 405. 
 
22 
 
 H. C. McCOMAS. 
 
 the tachistoscope opened, and broke the circuit the instant it 
 closed. The noise was violent, almost intolerable to the 
 experimenter; but in many cases it was not found objection¬ 
 able to the subject engrossed in seeing the exposure. Ten 
 experiments were made under the usual conditions of time- 
 exposure, signal, number and character of objects exposed. 
 The following table shows how many words were attended 
 under the distraction conditions and how many were obtained 
 in a series of experiments without distraction, which were 
 chosen at random from another series. (Correlation-rank 
 is found by subtracting the Distraction from the Non-dis¬ 
 traction row.) 
 
 TABLE VIII 
 
 Cor. R. 
 
 (lo) 
 
 (5) 
 
 (4) 
 
 (2) 
 
 (9) 
 
 (i) 
 
 ( 8 ) 
 
 (3) 
 
 ( 6 ^) 
 
 ( 6 |) 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G, 
 
 H 
 
 J 
 
 K 
 
 With distraction. 
 
 23 
 
 39 
 
 32 
 
 33 
 
 29 
 
 38 
 
 29 
 
 39 
 
 36 
 
 30 
 
 Without distraction. 
 
 33 
 
 40 
 
 32 
 
 31 
 
 37 
 
 32 
 
 36 
 
 38 
 
 41 
 
 35 
 
 It appears that three subjects ‘D’, ‘F’ and ‘H’ did better 
 with the fire-alarm than without it, and that ‘C’ found its 
 presence indifferent. 
 
 If such an experiment could be varied to prevent accommo¬ 
 dation on the part of the subjects, and could be tried a great 
 many times on many subjects it might bring out an interest¬ 
 ing typical trait in some subjects; namely, that the reinforce¬ 
 ment of those sensori-motor arcs engaged in perception is 
 conditioned by such a general agitation. Physiologically it 
 seems to point to typical differences in the ability to adjust 
 the great afferent currents to their appropriate motor dis¬ 
 charges, and so brightening the vividness and the clearness of 
 the attention. 
 
 A rather difficult experiment was made to discover, if 
 possible, what differences of attention might appear if not 
 perceptual matter, but conceptual matter, were material for 
 concentration and inhibition. As Professor James says: 
 
SOME TYPES OF ATTENTION. 
 
 23 
 
 The immediate effects of attention are to make us perceive, conceive, 
 distinguish, remember better than otherwise we could—both more 
 successive things and each thing more clearly d 
 
 So the facility in discriminating and retaining may be con¬ 
 sidered an indication of the ability to concentrate. Upon 
 this principle a series of fifteen experiments were made. Each 
 card was exposed three seconds, displaying ten words. Five 
 of these words were related to each other. Thus, some were 
 names of parts of the body, or parts of a house, articles of 
 furniture, kinds of animals, of colors, of fruits, etc. All 
 words on any one card were of the same length. Nothing in 
 the appearance of a word would indicate whether it were of 
 the class to be attended or rejected. They were also thor¬ 
 oughly mixed together so that the eye had to traverse the 
 card to observe all those of a certain class. Each subject 
 was carefully instructed about the work and was told a few 
 seconds before the shutter opened what class of words to seek. 
 
 The introspection was of a very similar character in all 
 cases in which it could be given. Two subjects found that 
 they could not recall how certain words were retained and 
 others inhibited. It would seem that the unsought words 
 are perceived, but scarcely recognized as of the unsought 
 class, and instantly dropped. Probably they were not thrust 
 from attention, but their memory is erased by the incoming 
 correct word. This obliteration, or lack of assimilation, when 
 one thing follows closely upon another is a familiar phe¬ 
 nomenon in consciousness. Enough unanimity appeared in 
 the introspection to make it evident that the eye tarried 
 longer upon the desired classes than upon the others. This, 
 too, would add to the process of inhibiting. In a very large 
 number of cases the words of the unsought class would not 
 be recognized by the subject when read to him. Indeed many 
 cards were shown to the subjects when they had made un¬ 
 usually good records, and they declared that they could not 
 have seen the words of the unsought class for not a vestige of 
 them remained in consciousness. 
 
 'James, W., Psychology, vol. i, p. 424. 
 
24 
 
 H. C. McCOMAS. 
 
 The following table gives the total number of words at¬ 
 tended to in the sought classes and the total number of those 
 attended to in the unsought groups: 
 
 TABLE IX 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Words correctly attended. 
 
 56 
 
 61 
 
 47 
 
 59 
 
 63 
 
 56 
 
 61 
 
 64 
 
 62 
 
 55 
 
 Words which should have been inhibited. 
 
 29 
 
 16 
 
 14 
 
 12 
 
 16 
 
 18 
 
 14 
 
 21 
 
 II 
 
 9 
 
 If the figures for the words which were correctly attended 
 to by each subject are used as numerators and those which 
 should have been inhibited, as denominators, then the quo¬ 
 tients will serve for correlation ranking: 
 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Cor. R. 
 
 (10) 
 
 ( 6 ) 
 
 (7) 
 
 (3) 
 
 (5) 
 
 ( 8 ) 
 
 (4) 
 
 (9) 
 
 (2) 
 
 (i) 
 
 
 1-93 
 
 3-8i 
 
 ■ 3-35 
 
 4.91 
 
 3-93 
 
 3 -II 
 
 4-35 
 
 3-05 
 
 5-63 
 
 6. II 
 
 The above tables do not correlate with each other in a 
 single instance. (See Correlation Tables). That is, each 
 series of experiments tells a different story from the others. 
 So no conclusions can be drawn concerning Concentration 
 and Inhibition as a typical mental trait. The experiments 
 show, only, marked individual differences in the subjects 
 under the special conditions of each experiment. 
 
 The Mean Variations in the experiments on Span show 
 individual differences in the constancy of attention. It 
 varies in its efficiency so that one Mean Variation is occasion¬ 
 ally half again as large as another. But here, again, there is 
 absolutely no correlation between the series. The fact of 
 variation in constancy of attention must be recognized along 
 with the facts of variation in concentration, though they may 
 not be shown in their relation to other mental traits. 
 
SOME TYPES OF ATTENTION. 
 
 25 
 
 MOBILITY OF ATTENTION 
 
 From the preceding experiments it seems clear that one 
 class of exposures is easier for certain subjects to attend than 
 others, from which it might be assumed that each subject 
 would quickly choose his best class. But a series of twenty- 
 six experiments, which were performed when the subjects 
 had been working with the tachistoscope a few times, reveals 
 a different situation. For in this instance the subjects were 
 told to get all of the objects presented, if possible. They 
 immediately tried to attend to all the words first and then the 
 colored figures. This continued throughout the series. Sub¬ 
 jects, who later proved that colored figures were more easily 
 obtainable for them, in this early experiment stuck to the 
 word list all through. The explanation is not far to seek. 
 No matter what class of objects the attention is considering 
 it is more natural to continue in that class than to shift to 
 any other. The subjects were disposed to think that words 
 were the easiest to attend to and that bias started them on the 
 words lists. Once started upon that course they staid in 
 it through many experiments. 
 
 Introspectively, it seems obvious that the attention stays 
 upon one class of perceptions in preference to changing. 
 Fechner noted this many years ago. It has often been corro¬ 
 borated. Every day’s experience bears witness. The turn¬ 
 ing from the newspaper to composing a letter, the changing 
 of attitude in passing from social to business affairs, the 
 shifting of thought in passing from one picture to another in 
 a gallery; these and a host of experiences give evidence of 
 the ‘inertia of attention.’^ 
 
 The explanation of this lack of agility in attention is to be 
 sought in that setting of consciousness which results in ad¬ 
 justment of end organs, nervous system and brain paths, to 
 receive the sensation expected. Organic adjustment, then, 
 and ideational preparation, or perception are concerned in 
 all attentive acts. As Wundt says: 
 
 ^Titchener, E. B., Psychology of Feeling and AUention, p. 246. 
 
26 
 
 H. C. McCOMAS. 
 
 Every idea takes a certain time to penetrate to the focus of conscious¬ 
 ness. And during this time we always find in ourselves the peculiar 
 feeling of attention. The phenomena show that an adaptation of at¬ 
 tention to the impression takes place. 
 
 Of course this has been apparent since Wundt’s experi¬ 
 ments upon reaction-time and attention; and especially since 
 Miinsterberg’s more complicated reaction experiments which 
 showed that a portion of consciousness could hold itself in 
 readiness to do certain work at a certain time. This was also 
 evident in those experiments in which the attention was pre¬ 
 pared to get a certain class of words exclusive of others, 
 (described in the last chapter.) 
 
 Such preparation of the perceptual and conceptual systems 
 argues that certain percepts and concepts have certain 
 courses through consciousness, that there are definite adjust¬ 
 ments in the complexes of sensori-motor paths. So several 
 of my subjects would say, “Now I am going to attend to this 
 exposure with motor attention,” or sometimes “with purely 
 visual attention. ” They were conscious of a different setting 
 in each case. For the colored objects the attention was 
 largely visual, for the words it was largely motor,—in many 
 cases the subjects repeated the words sotto voce. The figures 
 and letters were sometimes attended in one way sometimes 
 in another. The point is, however, that for the different 
 classes of objects, different kinds of acts of attention were 
 required. The change from one class to another demanded 
 a change of attentional attitude. This we shall discuss more 
 fully in a later chapter. It is sufficient to state the mere 
 facts in the matter. 
 
 The ability of the attention to change from one to another 
 class shows an interesting trait in the control of the attention. 
 I'o bring this out clearly I arranged fifteen cards with colored 
 geometrical forms, colored figures and letters, and mono¬ 
 syllabic words. These were placed on the cards in miscel¬ 
 laneous positions and in widely varying proportions. It was 
 impossible to set the attention for any one class. It was nec¬ 
 essary to change swiftly from class to class in order to obtain 
 several objects in the one second exposure allowed. 
 
SOME TYPES OF ATTENTION. 
 
 27 
 
 The table shows the per cent of objects attended to the 
 total number of objects displayed in each series. 
 
 TABLE X 
 
 Cor. R. 
 
 (d 
 
 (3) 
 
 (i) 
 
 ( 8 ) 
 
 (10) 
 
 ( 7 ) 
 
 (5) 
 
 (6) 
 
 (9) 
 
 (4) 
 
 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 I 
 
 K 
 
 Percentage... 
 
 56.4 
 
 53-5 
 
 S 9-9 
 
 42.4 
 
 40.8 
 
 44-5 
 
 52.0 
 
 48.5 
 
 42.0 
 
 52.1 
 
 So it appears that between ‘C’, and ‘E’ there is the greatest 
 difference in mobility of attention. ‘C’ is nearly half again 
 as apt as ‘E’ in switching the attention from one class to 
 another. 
 
 Here, as in Concentration, we must remember that these pro¬ 
 cesses which occur in the fraction of a second may not he descrip¬ 
 tive of all those activities which take a longer time and are more 
 natural. 
 
 CELERITY OF ATTENTION 
 
 That there are differences in the rapidity with which the 
 central processes prepare to attend certain stimuli is amply 
 demonstrated by those experiments in reaction-time where a 
 signal is given at varying intervals before the stimulus is 
 offered. Some individuals react better to a two-second 
 warning, some to one second; the average preferring one and 
 one-half seconds. So, too, we have seen that the rates of 
 rapidity of attentional acts vary greatly in different readers. 
 This difference was thought by Dearborn to correlate with 
 breadth of span in attention, ‘‘The slow readers have a nar¬ 
 rower span or working extent of attention.”^ 
 
 It seems well worth comparing some experiments which 
 bring out the subject’s attitude in attending to a number of 
 objects in quick succession and a series which indicates a 
 span of attention. 
 
 The following experiments were performed in the spring 
 of 1908 with different subjects from those whose results are 
 
 ‘Huey, E. B., The Psychology of Reading, p. 178. 
 
28 
 
 H. C. McCOMAS. 
 
 given in the other experiments. Let us call the six subjects 
 ‘X/ ‘Y/ ‘Z,’ ‘W,’ ‘A/ ‘A’ and ‘D’ are the same subjects 
 
 represented by these letters in the other experiments. 
 
 To bring out the rapidity with which the attention could 
 pass from one subject to another, about thirty monosyllabic 
 words, thirty black geometrical forms and thirty small 
 colored squares were arranged in parallel columns. (A dif¬ 
 ferent form of tachistoscope was used from that described 
 above. It allowed a very large field of exposure.) The sub¬ 
 ject was told to count the objects present as rapidly as possible. 
 Three-second exposures were given. Then he was directed to 
 write down as many objects as he could remember. The re¬ 
 called objects were remarkably few in view of the fact that 
 the subjects had seen these same words, forms and colors 
 in other experiments many times. This phenomenon of in¬ 
 hibition does not interest us here, except that it shows the 
 rapidity with which the counting was done. The remembred 
 objects were totalled and presented in the lower row of figures 
 in table A. 
 
 TABLE A 
 
 Cor. R. 
 
 (i) 
 
 (6) 
 
 ( 3 ) 
 
 (s) 
 
 (2) 
 
 ( 4 ) 
 
 Subjects. 
 
 X 
 
 Y 
 
 Z 
 
 W 
 
 A 
 
 D 
 
 Total Objects seen. 
 
 77 
 
 49 
 
 54 
 
 SI 
 
 57 
 
 52 
 
 Total objects remembered. 
 
 II 
 
 9 
 
 8 
 
 14 
 
 II 
 
 7 
 
 In this series it appears that X is half again as quick as Y 
 in control of his attention. 
 
 This experiment was supplemented by one in which the 
 subjects counted eighty objects and their time of observation 
 was carefully taken. The following table shows the time 
 required. 
 
 TABLE B 
 
 COR. R 
 
 (i) 
 
 ( 4 ) 
 
 ( 3 ) 
 
 ( 5 ) 
 
 (2) 
 
 (6) 
 
 Subjects. 
 
 X 
 
 Y 
 
 Z 
 
 W 
 
 A 
 
 D 
 
 Number Seconds. 
 
 i8 
 
 25.6 
 
 20 
 
 26.8 
 
 19.6 
 
 27 
 
SOME TYPES OF ATTENTION. 
 
 29 
 
 When these two experiments are compared they both tell 
 the same story as we shall see later. 
 
 To get the span of attention a photograph was exposed for 
 ten seconds and the subjects wrote down all the details they 
 had attended to. This was done with a colored picture also. 
 Then a series of exposures of three seconds was made for ten 
 cards containing eight to ten colored letters and geometrical 
 forms. The following table gives the number of objects 
 attended to by each subject and the totals. 
 
 TABLE C 
 
 COR. R 
 
 (1) 
 
 (s) 
 
 0 ) 
 
 (4) 
 
 (3) 
 
 (6) 
 
 Snhjert.s. 
 
 X 
 
 Y 
 
 Z 
 
 W 
 
 A 
 
 D 
 
 Picture. 
 
 54 
 
 54 
 
 87 
 
 II 
 
 29 
 
 23 
 
 66 
 
 22 
 
 18 
 
 18 
 
 Pnlnrerl Picture. 
 
 12 
 
 19 
 
 22 
 
 18 
 
 . 
 
 55 
 
 63 
 
 76 
 
 31 
 
 
 
 Totals. 
 
 195 
 
 78 
 
 118 
 
 104 
 
 116 
 
 67 
 
 
 
 
 In addition to the experiments which sought to determine 
 the span of attention for visual perception a large number 
 of trials was given each subject for auditory span (‘umfang’). 
 An instrument clicked uniformly for several minutes. The 
 subject was instructed to group the clicks, without counting 
 them, in the largest numbers possible. This was indicated 
 by the subjects raising the hand or tapping with a pencil when 
 a group was completed. 
 
 The following table shows the groups to represent the 
 subject’s average 'span’. The figures represent the number 
 of clicks to a group. 
 
 TABLE D 
 
 COR. R 
 
 (2) 
 
 (6) 
 
 (i) 
 
 ( 4 i) 
 
 (3) 
 
 ( 4 i) 
 
 Subjects. 
 
 X 
 
 Y 
 
 Z 
 
 W 
 
 A 
 
 D 
 
 Groups. 
 
 14 
 
 4 
 
 16 
 
 8 
 
 12 
 
 8 
 
 
 
 
 
 
 
 If these four tables are correlated according to Spearman’s 
 'Footrule’ for correlating, which is explained later,^ the 
 following correlations appear. 
 
 ^See page 47 for explanation of the ‘Footrule. 
 
3° 
 
 H. C. McCOMAS. 
 
 TABLES 
 
 A 
 
 B 
 
 C 
 
 D 
 
 B. 
 
 0.67 
 
 
 0.67 
 
 0.69 
 
 C. 
 
 0.48 
 
 0.67 
 
 
 0.56 
 
 D. 
 
 0.56 
 
 0.69 
 
 0.56 
 
 
 The probable error is . 176 . 
 
 From these figures it is very evident that, under the condi¬ 
 tions of our experimentation, there is an intimate relation 
 between the ability to shift the attention from one object to 
 another and the ability to grasp a large number of the objects. 
 That this celerity and spanning of the attention are not 
 merely a peculiarity of attention in visual perception is 
 proved by the high correlation between the auditory ‘um- 
 fang’ and the results for celerity. 
 
 The results of some experiments designed to detect the 
 relation between span and association time, performed at the 
 Princeton Laboratory, should be noted here. The span of 
 attention was obtained as follows. Cards with five mono¬ 
 syllabic words upon them were exposed for two seconds, in 
 Series A , of twenty tests. While the subject was attending to 
 the words a series of sounds (four on an average per experi¬ 
 ment) were made by striking iron on wood, on tin, on a gong, 
 on a steel rod, by a buzz, a series of tones on steel bars, etc. 
 The subject sought to attend to all of the words and all of the 
 different sounds. The scheme was reversed in Series B, of 
 twenty experiments. Here the subject put his attention pri¬ 
 marily upon the five words which the experimenter read aloud 
 while six colors or colored forms passed before the eyes in the 
 second during the reading. Obviously, the attention was 
 strained to its uttermost. The total number of different 
 sounds heard and of words seen in the first series for the two 
 second exposures served as an index of span of attention. 
 The second series, with the attention primarily upon the 
 words spoken, but seeking to grasp all the colors and figures 
 seen, supplements the first series and gives a further value in 
 its totals for span. 
 
 Each of these series was compared with the subjects’ 
 
SOME TYPES OF ATTENTION. 
 
 31 
 
 association time for one word and for four words. The follow¬ 
 ing correlations resulted. 
 
 EXPERIMENTS COMPARED 
 
 COR. COEF. 
 
 PROB. ERROR 
 
 Span in Series A and Ass. Time i word. 
 
 •334 
 
 . 16 
 
 Span in Series A and Ass. Time 4 words. 
 
 •334 
 
 . 16 
 
 Span in Series B and Ass. Time i word. 
 
 .429 
 
 . 16 
 
 Span in Series B and Ass. Time 4 words. 
 
 no correlation 
 
 These results show that there is probably a connection be¬ 
 tween the ability to span many things in a short period and 
 the ability to associate quickly. However, such a correlation 
 as that which appears between the span of attention for 
 spoken words, colored objects, etc., and association time for 
 one word is very suggestive, when considered in the light of 
 the results for span and quick shifting of the attention in per¬ 
 ception. Here the connection lies between span and the 
 quick shifting of the attention in conceptions. 
 
 SOME MEMORY FACTORS IN ATTENTION 
 
 A very noticeable difference appeared among the subjects, 
 throughout the entire work, in the way in which the objects 
 attended to in one experiment would lie dormant in the mind 
 and would be reported as seen in a later exposure. By what 
 unconscious or co-conscious process this was done no intro¬ 
 spection could discover. In order to throw some light upon 
 the phenomenon four sets of experiments were made. In the 
 four sets the same cards were used. These contained 5 three- 
 letter words and five colored letters or figures. The exposure 
 was one second. In each set the subject was instructed to 
 attend to the word-class in a first series, and later to attend to the 
 color-class. In both cases he was to perceive as many objects 
 of the class attended to as possible, but was to report everything 
 he observed. In each set a number of cards were repeated, after 
 the lapse of a certain period, to discover whether any details 
 would appear in the second exposure which were not reported 
 
32 
 
 H. C. McCOMAS. 
 
 in the first. If the influence of an exposure lingered in the 
 memory, it should, of course, make itself evident in some 
 difference between the repeated cards and those which were 
 presented for the first time. 
 
 Proceeding upon this hypothesis, about twenty cards were 
 repeated after the lapse of a week. There was nothing what¬ 
 ever in the results of any subject to indicate the influence of 
 previous experiments. The results for cards never seen before 
 were quite as large as for the repeated cards. There were no 
 introspective results to indicate a continuance of the previous 
 objects exposed in memory. 
 
 It was impracticable to vary the number of days between 
 the experiments, so the next set of trials was made within 
 an hour’s experimentation. In order to repeat a sufficient 
 number of cards in the hour a period of five minutes was al¬ 
 lowed to elapse between the original exposure of a card 
 and its repetition. In Table I five minutes elapsed between 
 the first and the second exposures of the cards. In Table 
 II there was a two minute Intermission, and in Table III 
 the card repeated followed immediately upon its first ex¬ 
 posure. The figures in the tables are found by subtract¬ 
 ing the results for the first exposures from those of the 
 repeated exposures, then dividing by the number of experi- 
 
 
 TABLE E 
 
 TABLE F 
 
 TABLE G 
 
 
 
 
 w 
 
 L 
 
 w 
 
 L 
 
 w 
 
 L 
 
 TOTALS 
 
 FOR 
 
 SUBJECTS 
 
 COR. 
 
 RANKS 
 
 A . 
 
 o. go 
 
 0. II 
 
 -6.80 
 
 I . 22 
 
 0-7S 
 
 2.50 
 
 4.68 
 
 (6) 
 
 B . 
 
 0-75 
 
 0.83 
 
 0.80 
 
 -0.25 
 
 0.00 
 
 1-50 
 
 3 63 
 
 (10) 
 
 C . 
 
 0.07 
 
 0 
 
 H 
 
 1-33 
 
 1.80 
 
 0.60 
 
 2.00 
 
 7-30 
 
 (2) 
 
 D . 
 
 O.S4 
 
 1.44 
 
 -0.16 
 
 0.50 
 
 0.40 
 
 1.80 
 
 4-S2 
 
 (7) 
 
 E . 
 
 0.44 
 
 2.00 
 
 0.40 
 
 0.20 
 
 2.00 
 
 1.80 
 
 6.84 
 
 (3) 
 
 F . 
 
 0.27 
 
 1.00 
 
 0-33 
 
 1-25 
 
 0.25 
 
 1.80 
 
 4.90 
 
 (s) 
 
 G . 
 
 0.60 
 
 0.62 
 
 0.60 
 
 1-33 
 
 1.00 
 
 0.20 
 
 4-35 
 
 (8) 
 
 H . 
 
 0-45 
 
 0.33 
 
 0.40 
 
 0.00 
 
 I-25 
 
 I-75 
 
 4.18 
 
 (9) 
 
 J. 
 
 0.10 
 
 0.83 
 
 0.00 
 
 2.00 
 
 0.7s 
 
 1.30 
 
 4.98 
 
 (4) 
 
 K . 
 
 1.00 
 
 0,87 
 
 -0.16 
 
 2.16 
 
 1.70 
 
 2.30 
 
 7.87 
 
 (i) 
 
 
 0.512 
 
 0-953 
 
 0.274 
 
 1.021 
 
 0.870 
 
 j 
 
 1.69S1 Averages (for experi- 
 j ments) 
 
SOME TYPES OF ATTENTION. 
 
 33 
 
 merits per subject. Where the subject averaged less per 
 experiment in the repeated than in the original exposures 
 the loss is indicated by the minus sign. (‘W’ = word-class, 
 ‘L’= letter-class). 
 
 The difference between the subjects is very evident from 
 the tables; there is, however, no correlation between the sub¬ 
 jects’ averages. 
 
 In noting the greater increment in repetitions for the word- 
 class than for the letter-class it must be remembered that 
 the Span itself is greater for the letter-class. 
 
 The most instructive feature in the Tables is the increase 
 in the averages for the repeated exposures. This clearly 
 proves that something of the first perceptions of the cards 
 lingered in memory and assisted in later observations. This 
 influence became more marked as the time between the 
 original and its repetition was shortened. In the repetitions 
 which followed immediately upon the originals the cards were 
 frequently recognized after the subject had seen two or three 
 objects, but in the series of repetitions following two and five 
 minutes after the originals, recognition was comparatively 
 infrequent. 
 
 IDEATIONAL TYPES 
 
 The terms ‘Memory Types,’ ‘Speech Types’, ‘Types of 
 Imagery’,have been used very frequently to point out charac¬ 
 teristic differences in the way in which different classes of 
 individuals imagine, remember, and speak. 
 
 In both physiological and theoretical psychology the 
 ‘division of labor’ in the mental economy is constantly em¬ 
 phasized. Experiments are often performed to show that 
 memory is not a faculty dealing with all matter in the same 
 way, but that it divided its labor among visual, motor, 
 auditory and other functions of the mind. The work upon 
 aphasia has been especially enlightening. 
 
 Internal speech is a revival of auditory, visual and articulatory 
 memories, its integrity depends upon the united action of these three 
 centers; but the one which is the most highly cultivated is revived most 
 vividly.^ 
 
 ^Collins, J., The Genesis and Dissolution of the Faculty of Speech, p. 62. 
 
34 
 
 H. C. McCOMAS. 
 
 Charcot and his school referred to those who were the 
 most proficient in any one faculty as Visuels,’ ‘auditifs,’ and 
 ‘moteurs.’ Such proficiency comes from either a natural 
 bent or an adaptation of certain faculties to certain work. 
 So Baldwin states: 
 
 The brain is a series of centers of relatively stable dynamic tension, the 
 various associative connections among these centers are paths of less 
 and more rather than least and most resistance; the range of alternative 
 judgment is occasionally wide, and consequently any individual has his 
 ‘personal equation in all functions as complex as those of speech. One 
 man is a ‘motor’, a second a ‘visual’, a third an ‘auditive’, according 
 as one or another of the extrinsic causes of stimulation suffices to release 
 the necessary energy into his motor-speech center.”^ 
 
 Not only are the activities of these complexes, that give 
 rise to expression, conditioned by the brain paths which nature 
 designed as the highways for her nervous currents; but, also, 
 by those byways which much traffic has developed into high¬ 
 ways. Could we make blue prints of these courses our charts 
 would show some strikingly characteristic differences. And 
 we should be thoroughly prepared to believe that the conduct 
 of consciousness in general is obliged to adapt itself to the 
 conditions of its thoroughfares. Certainly it would seem 
 most probable that the “area of greatest clearness” in con¬ 
 sciousness would correlate with the broader and more evident 
 mental types. We find, on examining consciousness, that 
 attention is not a fixed thing, a faculty, any more than are 
 memory and imagination. 
 
 Yet in much of the literature of late years, in which the faculties have 
 been scouted, I know of no author who has applied his own criticisms 
 consistently to the attention. Memory on the other hand is now known 
 to be a function of the content remembered, and not a faculty which 
 takes up the content and remembers it. So we have no longer one 
 memory, but many, visual, auditory, motor memories. Yet the very 
 same thing is true of attention. We have not one attention but many. 
 Attention is a function of content; and it is only as different contents 
 
 ^Baldwin, J. M., Philos. Rev., July, 1893, p. 389. 
 
SOME TYPES OF ATTENTION. 
 
 35 
 
 attended overlap and repeat one another that they have somewhat the 
 same function in attention.^ 
 
 The problem before us is to discover whether these idea¬ 
 tional differences actually do affect the attention. Does a 
 strongly visual type naturally select a different class of 
 objects to attend to from those that appeal to the motor type? 
 Is it easier for those perceptions which call out motor activi¬ 
 ties to be attended to by the motor type than by the visual? 
 Do such differences stand out clearly, or are individuals now 
 of one and now of another type? These and similar problems 
 are now before us. 
 
 It will, perhaps, make the work appear clearer if the experi¬ 
 ments upon types of imagery are given first. It will enable 
 us to detect those subjects who are of a pronounced type and 
 we may follow their results through the other experiments 
 readily. 
 
 Galton, who with Titchener, is one of the pathfinders in 
 mental types, prepared a table of questions whose answers 
 indicated the subject’s type.^ These answers were graded 
 according to the degree of the subject’s realization of the 
 imagery. If it was very clear, bright and distinct it headed 
 the series; if no image at all was realized, it was graded zero. 
 Between these extremes were seven intermediary grades. In 
 general, I followed Gallon’s scheme. With this difference, 
 however, that each subject graded himself according to the 
 clearness and vividness of his imagery upon a scale of ten; 
 zero being the lowest and ten the highest. The questions 
 were read to the subjects and any misunderstandings were 
 made clear. Ample time was allowed for deliberation. The 
 subject considered a visual image first, then auditory, then 
 motor. This enabled him to make frequent comparisons of 
 the three orders and allowed for a separate effort and judg¬ 
 ment for each question. The experiments continued through 
 several weeks. This tended to eliminate minor differences. 
 
 ^Baldwin, J. M., Mental Development, p. 468. 
 
 ^Gallon, F., Inquiries in Human Faculty. 
 
 Titchener, E. B., Experimental Psychology, vol. i, chap, xii; 
 
36 
 
 H. C. McCOMAS. 
 
 Subjects varied in their abilities from time to time. Thus 
 'K' who was very good in introspection found that certain 
 kinaesthetic images would vary perceptibly. ‘D’ was un¬ 
 usually poor in his introspection; so inefficient, in fact, that 
 all images seemed equally distinct whether visual or gusta¬ 
 tory, auditory or olfactory. I have inserted his results for a 
 similar series of experiments performed in the spring of 1908, 
 when he was in better physical and mental condition. I 
 found that the memory images of nearly all of the sub¬ 
 jects were conditioned by the memory of the particular per¬ 
 son or the particular thing remembered. To acquire a greater 
 uniformity I selected purely imagery matter for considera¬ 
 tion. 
 
 The questions were for the auditory imagery: “How clearly 
 can you hear a harp and flute playing together; a trio, of two 
 males and a female voice; the wind blowing through trees and 
 sound of waves; the wind blowing a tune; the songs of the 
 Bedouin Arabs; a conversation in Arabic; the cry of camels; 
 the scraping of a file on a violin; the sharpening of a saw; an 
 artillery bombardment.” For the visual were asked: “Can 
 you represent to your mind an image of a pyramid; can you 
 see the stones clearly; the cracks between the stones; the sand 
 wastes around the pyramid; the skies above it; can you 
 imagine a cobweb colored red; a battlefield; a printed page 
 with every other line in colored ink; a giraffe reaching for the 
 leaves of a tree. ” For the motor imagery the following were 
 asked: “Can you represent to yourself how it feels to write 
 with the left hand; to wind the watch with left hand; to throw 
 a stone with the hand not usually used in throwing; to walk 
 backward; to lift the hat with the left hand; to walk through 
 sand shod in sandals; to do an oriental dance; to waltz and 
 stoop at the same time; to gesticulate like the deaf and dumb; 
 to ride upon a camel.” 
 
 When a subject was left-handed or ambi-dextrous a ques¬ 
 tion was substituted for those implying a normal right- 
 handed practice. 
 
 The following tables represent the totals of the grades for 
 the three orders. Questions were not asked concerning gus- 
 
SOME TYPES OF ATTENTION. 
 
 37 
 
 tatory or olfactory images after the lists for strictly memory 
 images were discarded 
 
 SUBJECTS 
 
 TABLE XI 
 
 TABLE XII 
 
 TABLE XIII 
 
 VISUAL 
 
 C. R. 
 
 (auditory) 
 
 C. R. 
 
 (motor) 
 
 C. R. 
 
 A. 
 
 47 
 
 ( 2 ) 
 
 16 
 
 ( 10 ) 
 
 48 
 
 (i) 
 
 B. 
 
 39 
 
 ( 5 ) 
 
 22 
 
 ( 7 ) 
 
 31 
 
 (6) 
 
 C. 
 
 SO 
 
 (i) 
 
 41 
 
 ( 2 ) 
 
 37 
 
 ( 3 ) 
 
 D. 
 
 27 
 
 ( 9 ) 
 
 49 
 
 (i) 
 
 33 
 
 (5) 
 
 E. 
 
 41 
 
 ( 4 ) 
 
 37 
 
 ( 3 ) 
 
 25 
 
 ( 10 ) 
 
 F. 
 
 23 
 
 ( 10 ) 
 
 25 
 
 (5) 
 
 27 
 
 ( 8 ) 
 
 G. 
 
 30 
 
 (8) 
 
 18 
 
 (8) 
 
 34 
 
 (4) 
 
 H. 
 
 38 
 
 (6) 
 
 33 
 
 ( 4 ) 
 
 30 
 
 (7) 
 
 J. 
 
 45 
 
 ( 3 ) 
 
 17 
 
 ( 9 ) 
 
 41 
 
 (2) 
 
 K. 
 
 36 
 
 ( 7 ) 
 
 23 
 
 (6) 
 
 26 
 
 (9) 
 
 These tables were supplemented by a series of experiments 
 upon associations, to discover whether the visualizer differed 
 from the others in the class of associations or in his association¬ 
 time. The subjects were also given problems, from time to 
 time, and sought to introspect upon their habits of mind in 
 solving the different kinds of problems. The result of this 
 work is not given as it did not prove satisfactory. The above 
 table, which is based upon Titchener’s method gave the 
 clearest results obtained. 
 
 VISUAL PERCEPTION AND ATTENTION 
 
 Our perceptions are directed by the heritage of brain traits 
 and experiences. When these mark us as visualizers, our 
 perceptions will be different from those of the motor types. 
 In the perception of simple color there is very little motor 
 activity. Usually there is no disposition to pronounce the 
 name of the color or shade and the effort to recall it is dis¬ 
 tinctly visual. This is not so of words. Though they, too, 
 are sometimes recalled usually and perceived as visual 
 objects without an introspectively perceptible reaction, when 
 they occur, as a usual experience they are pronounced. 
 Frequently this is merely an internal expression; very often 
 
38 
 
 H. C. McCOMAS. 
 
 it results in lip-movement, and frequently in an audible 
 though unconscious articulation. When the distractions ac¬ 
 companied the effort to perceive the largest number of words 
 possible, there was a very marked increase in motor activity 
 which in several instances resulted in the subjects speaking 
 aloud though they were not aware of it at the time. 
 
 In the following experiment there were exposed fifteen 
 cards containing colored objects, figures, letters and three- 
 lettered words. The subject was told to select as many ob¬ 
 jects as possible regardless of class. The exposures were one 
 second. Each subject had had a long and varied experience 
 in perceiving the classes of objects presented and instinctively 
 sought that which was easiest. This had to be instinctive, as 
 each card varied so in the number of the several classes of 
 objects and the time was so short, there was no opportunity 
 for deliberation. 
 
 In the following table the per cent of colors obtained, to 
 total number of colors, is given: 
 
 TABLE XIV 
 
 Cor. R. 
 
 (4) 
 
 (2) 
 
 (i) 
 
 
 (s) 
 
 (10) 
 
 (6) 
 
 ( 81 ) 
 
 (7) 
 
 (3) 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Percents. 
 
 42 
 
 54 
 
 S 8 
 
 30 
 
 39 
 
 26 
 
 38 
 
 30 
 
 31 
 
 
 The high figures for several subjects whom we saw classed 
 as visualizers in the ideational type experiments is practically 
 explainable by the fact that they have a very wide span of 
 attention for the color classes, as may be seen by comparing 
 their results for ‘span,’ and they would get large results in 
 such cases. We shall speak of this later. 
 
 Another experiment involving color, and used in another 
 connection, will assist in the present problem. Twenty-six 
 one-second exposures were made for cards containing five 
 words and five colored figures. The attention was upon the 
 colored figures primarily and the subject was to perceive both 
 figure and color and associate them together in his report. 
 This involves motor as well as visual factors. The total num- 
 
SOME TYPES OF ATTENTION. 
 
 39 
 
 bers of associated colors and figures are given for each 
 subject in the table below: 
 
 TABLE XV 
 
 Cor. R. 
 
 (i) 
 
 (6) 
 
 (3) 
 
 (d 
 
 (7) 
 
 (8) 
 
 (10) 
 
 (5) 
 
 
 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 Totals. 
 
 67 
 
 28 
 
 38 
 
 39 
 
 22 
 
 21 
 
 6 
 
 30 
 
 35 
 
 
 
 The totals of all the colors perceived out of a possible hun¬ 
 dred and thirty for this same series are given in Table XVI 
 
 TABLE XVI 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 T 
 
 K 
 
 Cor. R. 
 
 (i) 
 
 (7) 
 
 (2) 
 
 (10) 
 
 (3) 
 
 ( 8 ) 
 
 (9) 
 
 (5I) 
 
 ( 5 i) 
 
 (4) 
 
 Total Colors. 
 
 92 
 
 S 3 
 
 73 
 
 35 
 
 69 
 
 42 
 
 37 
 
 54 
 
 54 
 
 67 
 
 Another experiment was made in which five colors and five 
 geometrical forms were presented in one second exposures. 
 In all there were fourteen exposures with the attention directed 
 to the colors which were simple and easily perceived and re¬ 
 called. The totals for the colors attended are as follows: 
 
 TABLE XVII 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Cor. R. 
 
 (5) 
 
 (7) 
 
 ( 3 i) 
 
 (9) 
 
 (6) 
 
 (8) 
 
 (10) 
 
 (2) 
 
 (i) 
 
 ( 3 i) 
 
 
 Totals. 
 
 62 
 
 54 
 
 63 
 
 42 
 
 55 
 
 43 
 
 27 
 
 64 
 
 66 
 
 63 
 
 
 One of the most interesting of these experiments was per¬ 
 formed as follows: ten brightly colored squares were exposed 
 for one second, the subject was to perceive as many as 
 possible and report. After fifty such exposures were made five 
 words were substituted for five of the colored squares. The 
 change in the character of the cards was not announced until 
 subjects discovered it themselves. All through the series the 
 the instructions were to get all that it is possible to perceive 
 
40 
 
 H. C. Me COM AS. 
 
 no matter what it is. The result was that some subjects con¬ 
 tinued to get colors and some switched over to the words. 
 There was probably no fatigue, certainly not enough to count 
 for any changes in the direction of attention. The choice of 
 the word class after the mometum of fifty experiments in 
 the color class is indicative of a natural preference for the 
 word class. 
 
 In Table XVIII the totals for the colors In the first fifty 
 experiments are given. And in Table XIX the per cent of 
 colors in relation to total perceptions are given. (The former 
 is Table I for Span.) 
 
 TABLE XVIII 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Cor. R. 
 
 ( 4 ) 
 
 ( 7 ) 
 
 (i|) 
 
 (9) 
 
 (3) 
 
 (10) 
 
 (5I) 
 
 (8) 
 
 (5^) 
 
 (T) 
 
 Total Colors. 
 
 215 
 
 205 
 
 223 
 
 161 
 
 222 
 
 141 
 
 213 
 
 199 
 
 213 
 
 223 
 
 TABLE XIX 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 
 H 
 
 J 
 
 K 
 
 Cor. R. 
 
 Percent of 
 
 (i) 
 
 ( 6 ) 
 
 (4) 
 
 (7) 
 
 (5) 
 
 (9) 
 
 (10) 
 
 (3) 
 
 ( 8 ) 
 
 (2) 
 
 Colors. 
 
 100 
 
 57 
 
 64 
 
 44 
 
 60 
 
 30 
 
 21 
 
 69 
 
 41 
 
 85 
 
 In the Table of Correlations a number of significant corre¬ 
 lations appear between these experiments on the visual 
 factors in attention. Thus, this last table correlates with 
 tables XV, XVI and XVII. The meaning of this will be 
 discussed In the Conclusion; here It Is sufficient to call 
 attention to the fact that this class of experiments do not 
 correlate with a single one of the experiments in the next 
 chapter designed to bring out motor factors in attention. 
 
 MOTOR FACTORS IN PERCEPTUAL ATTENTION 
 
 The common experience was that the words called forth 
 the ‘inner speech.’ Each one was pronounced. At times the 
 subject would pronounce the word ‘Bug’ as ‘Rug,’ and when 
 
SOME TYPES OF ATTENTION. 
 
 41 
 
 giving his report would repeat it as he pronounced it to him¬ 
 self, but it would seem wrong and after a little thought he 
 would correct it by visual memory. This was not at all 
 common. The motor-auditory process usually predominated, 
 especially in memory. For it was a universal experience that 
 the words meant nothing. They were as so many nonsense 
 syllables until reported, and within two minutes after the 
 report, they were forgotten. Without the co-operation of the 
 'inner expression.’ the mere visual perception of the words 
 would have been retained very poorly. From the experi¬ 
 ments in reading it would seem that this inner speech is an 
 incipient movement. It does not effect the larger or chest 
 muscles perceptibly, nor does it produce lip-movements neces¬ 
 sarily. It is a motor activity which apparently varies as the 
 effort to make the perception clear and strong varies. It is 
 marked in children learning to read. I have found it very 
 pronounced when learning a strange language, but it is 
 diminished as the language was acquired. Quantz thought: 
 
 It is a specific manifestation of the general psycho-physical law of dyna- 
 mogenesis by which every mental state tends to express itself in muscu¬ 
 lar movement.* 
 
 Our interest is to discover whether those who appear, ac¬ 
 cording to their own introspection, to be clearly motor types 
 are influenced in the direction their attention instinctively 
 takes, in the effort to grasp as many objects as their span will 
 allow, when these objects call out more or less of the motor 
 activity. 
 
 To bring this out a series of fifteen exposures was given the 
 subjects, of cards containing five words and five colored letters, 
 numbers or figures. The subjects were told to make their 
 own selection of class of objects, but that they must attend to 
 the largest number possible in every case. In Table XX the 
 per cent of words to the total number of objects attended to is 
 given. 
 
 iQuantz, J. O., Psychol. Rev., Mon. Supp., vol. ii, No. I. See also, Philos. Rev., ii., 
 pp. 385-407; Psychol. Rev., 1894, pp. 441-453; Yale Studies, Psychol. Laboratory, ii. p. 122. 
 
42 
 
 H. C. McCOMAS. 
 
 TABLE XX 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Cor. R. 
 
 Percent of 
 
 (4) 
 
 (i|) 
 
 (8) 
 
 (7) 
 
 (9) 
 
 (3) 
 
 (i|) 
 
 (5) 
 
 (10) 
 
 (6) 
 
 Words. 
 
 73 
 
 8i 
 
 6o 
 
 62 
 
 38 
 
 74 
 
 81 
 
 72 
 
 37 
 
 65 
 
 The differences in the results for the subjects are sufficiently 
 large to show individual preferences which may be taken as 
 indicative of mental traits as affected by this kind of experi¬ 
 ment. What these traits are does not appear, for this series 
 does not correlate with any other in the whole Table of 
 Correlations. 
 
 After the lapse of several weeks another series of ex¬ 
 posures was made in which the subjects were again directed 
 to seek that class which is the easier to attend to. In this case 
 there were five words and five colored figures. Twenty one- 
 second exposures were made. The totals for word are given 
 in Table XXL 
 
 TABLE XXI 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Cor. R. 
 
 (8) 
 
 (10) 
 
 (s§) 
 
 (sl) 
 
 (7) 
 
 (3) 
 
 (4) 
 
 (9) 
 
 (2) 
 
 (i) 
 
 Total Words. 
 
 60 
 
 42 
 
 72 
 
 72 
 
 69 
 
 77 
 
 76 
 
 48 
 
 8S 
 
 86 
 
 This table not only does not correlate with the precediny 
 experiment of like character; but it also fails to correlate with 
 any of the others except those represented by Table IX in 
 Concentration and Inhibition. From this correlation it would 
 appear that the disposition to turn the attention to words in 
 preference to colored objects and the ability to set the atten¬ 
 tion for a certain class of words and to inhibit others, are 
 faculties which go together. 
 
 In the next experiment the subjects concentrated upon the 
 words only. They sought to inhibit all else. The purpose 
 in this was to discover whether there were any correlations 
 between the ability to attend to the word class and the other 
 
SOME TYPES OF ATTENTION. 
 
 43 
 
 acts of attention involving motor factors. There were six 
 three-letter words and six colored figures on each card. 
 Twenty exposures of one second each were made. The total 
 number of words attended to are given for several subjects in 
 Table XXII. 
 
 TABLE XXII 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Cor. R. 
 
 ( 8 ) 
 
 (2) 
 
 (9) 
 
 (7) 
 
 (3) 
 
 (10) 
 
 (s) 
 
 (4) 
 
 (i) 
 
 (6) 
 
 
 Totals. 
 
 66 
 
 79 
 
 64 
 
 70 
 
 78 
 
 63 
 
 75 
 
 76 
 
 82 
 
 71 
 
 
 Here, the only correlation is with the experiments for 
 auditory factors. In this case the high correlational coefficient 
 of .51 indicates a relation between the ability to concentrate 
 upon the word-class and the ability to attend to the reading of 
 poetry while viewing the presentation of a succession of 
 words. (See Table XXVIII in chapter on Auditory Factors.) 
 
 Table XVIII of the last chapter may be used to find the 
 per cents of those who, having observed colors for fifty experi¬ 
 ments detected the wordsand attended to them when they were 
 added to the color-cards. The per cent of words to total 
 number of objects seen,—when the words were added, is given 
 in Table XXIII; which is Table XVIII of the last chapter 
 reversed. 
 
 TABLE XXIII 
 
 Subjects. 
 
 A 
 
 B 
 
 C 
 
 D 
 
 E 
 
 F 
 
 G 
 
 H 
 
 J 
 
 K 
 
 Cor. R. 
 
 Percent of 
 
 (10) 
 
 ( 5 ) 
 
 (7) 
 
 (4) 
 
 (6) 
 
 (2) 
 
 (i) 
 
 (8) 
 
 (3) 
 
 (9) 
 
 Words. 
 
 0 
 
 43 
 
 36 
 
 56 
 
 40 
 
 70 
 
 79 
 
 31 
 
 59 
 
 15 
 
 This series makes two interesting and important correla¬ 
 tions with the experiments on Concentration. The first cor¬ 
 relation is with the experiments which were designed to show 
 the subjects’ ability to concentrate upon words or colored 
 objects to the exclusion of other classes of objects. The corre¬ 
 lation here points to a relation between an aptitude for the 
 word-class and the ability to expend the attention upon one 
 
44 
 
 H. C. McCOMAS. 
 
 class exclusively. This hints at what has already been noted, 
 that the greater activity of attention required by the word- 
 class demands a greater effort; and, further, appeals to those 
 to whom this kind of effort is natural and congenial. The 
 second correlation is with the series of experiments in which 
 the subject set his attention for a certain class of words before 
 the exposure, and inhibited all of the other classes. Here the 
 faculty of turning instinctively to the word-class and the 
 ability to set the attention to perceive a certain class of 
 objects appear related. This may mean that the motor 
 factors which make it easier for certain subjects to attend to the 
 word-class also make it easier for them to react to a word for 
 which they are seeking. The efficiency then, in both cases 
 would be attributable to a characteristic readiness of motor 
 response. 
 
 AUDITORY FACTORS IN PERCEPTUAL ATTENTION ' 
 
 In the experiments upon aphasia it has been shown that the 
 motor-auditory complexes play as important a role, in the 
 processes of attention which accompany speaking and reading, 
 as any other. The inner speech, of which we spoke in the 
 last chapter is, according to Huey, a combination of motor 
 and auditory elements, with one or the other predominating 
 according to the subject’s habitual mode of imagining.’^ Huey 
 and Dodge both agree that the motor element is present with 
 those who auditize in reading and that the auditory element 
 is present with those who motorize. Huey believes that these 
 factors may not be so prominently present with visualizers. 
 
 Now, our interest is to learn what differences characterize 
 this motor-auditory type in their attentional processes. They 
 should find those perceptions which can be the more readily 
 dealt with by the habits and traits of their motor-auditive 
 systems easier to bring into the ‘area of greatest clearness’ 
 than perceptions which do not call out such reactions. We 
 should be justified, in the light of experiments previously 
 described, in performing a series of experiments in which the 
 
 ^Huey, E. B., The Psychology and Pedagogy of Reading, p. 120. 
 
SOME TYPES OF ATTENTION. 
 
 45 
 
 competition between the visual-motor and the auditory-motor 
 would indicate which was the more characteristic of the 
 subject’s type. 
 
 Such a series of experiments was undertaken as follows; 
 the subject sat before a rotary tachistoscope in which several 
 words were exposed clearly to view during each exposure. 
 While the subjects saw and read these words two lines of a 
 poem were read to them. The attention in the first series 
 of experiments was directed to the words, but the subject 
 was also told to retain as much of the poetry as possible. 
 When the report was given, the words were recited first, then 
 the poetry. The purpose in having the attention thus 
 divided, rather than free to choose either class of perceptions, 
 was this; it is impossible to present auditory and visual stimuli 
 with such equality that the one does not obtain some advan¬ 
 tage over the other. It is better therefore, to give an advan¬ 
 tage first to one and then to the other by distributing the 
 attention consciously, and placing its emphasis on one or the 
 other. This would give the advantage first to one type and 
 then to the other. This is what was done. After a series of 
 twenty-three experiments (Tables XXVII and XXVIII) in 
 which the attention was primarily upon the visual impres¬ 
 sions, another series (Tables XXV and XXVI) of twenty-two 
 experiments was made with the attention directed to the 
 auditory impressions. The per cent of words to the total 
 presented is given in the left-hand columns of both tables. 
 The accuracy with which the poetry was attended to was graded 
 with one hundred as the highest count. The results for poetry 
 appear in the right-hand columns. Care was taken that the 
 poetry should be simple and the lines of sufficient brevity 
 to enable each subject to grasp it no matter how inefficient 
 he might be in memorizing lines read aloud. 
 
 In Table XXV are given the words perceived when the 
 attention was on poetry, and in Table XXVI the grades for 
 the amount of poetry attended in the same series are given. 
 In Table XXVII appear the word totals when the attention 
 was directed primarily to words, and in Table XXVIII are 
 the grades for the poetry in this series. Table XXIV gives 
 
46 
 
 H. C. McCOMAS. 
 
 the sums of the grades for the poetry, and the totals for the 
 words together, for each subject. These indicate the span 
 of attention for visual and auditory perceptions combined. 
 
 TABLES. 
 
 XXV 
 
 XXVI 
 
 XXVII 
 
 XXVIII 
 
 XXIV 
 
 
 WORDS 
 
 C.R. 
 
 POETRY 
 
 C.R. 
 
 WORDS 
 
 C.R. 
 
 POETRY 
 
 C.R. 
 
 TOTALS 
 
 C.R. 
 
 A. 
 
 78.8 
 
 (2) 
 
 93-4 
 
 (4) 
 
 96.7 
 
 (i) 
 
 57-9 
 
 (5) 
 
 326.8 
 
 (2) 
 
 B. 
 
 82.3 
 
 (i) 
 
 81.3 
 
 (6) 
 
 93-3 
 
 (2) 
 
 80.8 
 
 (i) 
 
 337-7 
 
 (i) 
 
 C. 
 
 45-8 
 
 (7) 
 
 80.6 
 
 (8) 
 
 76.4 
 
 (8) 
 
 32.6 
 
 (7) 
 
 235-4 
 
 ( 7 §) 
 
 D. 
 
 65-3 
 
 (3) 
 
 48.0 
 
 (9) 
 
 7 I-S 
 
 (9) 
 
 31 I 
 
 (8) 
 
 215-9 
 
 (9) 
 
 E. 
 
 56.6 
 
 (4) 
 
 92.6 
 
 (s) 
 
 76.8 
 
 (7) 
 
 65.6 
 
 (3) 
 
 291.6 
 
 (4) 
 
 F. 
 
 34-2 
 
 ( 9 §) 
 
 94-4 
 
 (2I) 
 
 82.4 
 
 (5) 
 
 24.4 
 
 (10) 
 
 235-4 
 
 ( 7 i) 
 
 G. 
 
 44-4 
 
 (8) 
 
 43-2 
 
 (10) 
 
 85-7 
 
 (4) 
 
 26.8 
 
 (9) 
 
 200.1 
 
 (10) 
 
 H. 
 
 541 
 
 ( 5 ) 
 
 95-4 
 
 (i) 
 
 80.5 
 
 (6) 
 
 50.0 
 
 (6) 
 
 280.0 
 
 ( 5 ) 
 
 J . 
 
 47-7 
 
 (6) 
 
 81.0 
 
 (7) 
 
 89.2 
 
 (3) 
 
 76.7 
 
 (2) 
 
 294.6 
 
 (3) 
 
 K. 
 
 34-2 
 
 ( 9 §) 
 
 94-4 
 
 ( 2 i) 
 
 7^-4 
 
 (10) 
 
 58.0 
 
 (4) 
 
 258.0 
 
 ( 6 ) 
 
 The most obvious result of these tests is that there are very 
 wide differences in the abilities of the several subjects to 
 attend to what is being heard and what is being seen at the 
 same time. The order of ability to ‘span’ both visual and 
 auditory presentations clearly corresponds with the order 
 found for span when the perceptions were visual and visual- 
 motor. This appears in several correlations between the 
 Tables for Span and those above, (see Table of Significant 
 Correlations). This correlating of the visual, motor and 
 auditory factors in attention confirms what was said in the 
 chapter on Celerity, that the experiments measure actual 
 differences in the attentional processes, and not mere eccen¬ 
 tricities of perception. 
 
 The primary question in this chapter is; do those who have 
 the clearer auditory imagination give any evidence of this 
 trait when the attention is directed to auditory perceptions. 
 The answer is in the high correlation coefficient for Table 
 XXIV above, and Table XII, Ideational Types, (Auditory 
 Type.) This correlation is the highest the Auditory Type 
 yields. Indeed there is but one other correlation with 
 auditory type in the entire work. There is, however, no 
 
SOME TYPES OF ATTENTION. 
 
 47 
 
 correlation between Auditory Type and any of the other 
 Tables for Auditory Factors. 
 
 The Visual Type has as high a correlation with the Table 
 XXIII, above, as does the Auditory. But it must be remem¬ 
 bered that the visualizer has a broad span, as numerous 
 correlations throughout have shown, and it is to be expected 
 that his results in these experiments would total high. The 
 Visual Type, also, shows a correlation with the ability to per¬ 
 ceive words when the attention is engaged in hearing words. 
 Both of these aptitudes may be due to the facility with which 
 the visualizer catches the objects of visual perception leaving 
 other energies of the attention free to engage with other 
 things. This the Motor Type could not do, for his sole corre¬ 
 lation with these tables is in the ability to attend the word 
 series when the attention was upon the words, primarily; 
 which bears out what has been observed before, that when 
 the words are attended with a motor reaction, as they usually 
 are by the Motor Type, there is little attentional energy left 
 to be occupied with aught else. 
 
 Part III. Correlations 
 
 In the present chapter we shall compare the entire list of 
 experiments to discover what traits of attention are related. 
 The most satisfactory way to accomplish this is by pre¬ 
 senting the results in one great correlation table. The sig¬ 
 nificant correlations in this table are presented in a smaller 
 table in order that they may be more readily seen and studied. 
 (See tables at end of monograph.) After considering a num¬ 
 ber of methods for the comparing the results of the experi¬ 
 ments, Spearman’s ‘Footrule’ for measuring correlations was 
 adopted. The method is explained in full in the article en¬ 
 titled Footrule for Measuring Correlation, by C. Spear¬ 
 man, in the British Journal of Psychology, vol. ii, pp. 89-108. 
 Briefly, the method is this: the subjects are arranged in the 
 order of their ability for two sets of experiments; for example, 
 the two experiments recorded with their results in Table XXI 
 in the chapter on Motor Factors and Table IX in the chapter 
 
48 
 
 H. C. McCOMAS. 
 
 on Concentration. The second series of results is compared 
 with the first and the sum of the gains in rank for the several 
 subjects carefully noted. Thus: 
 
 SUBJECTS 
 
 MOTOR FACTORS 
 
 CONCENTRATION 
 
 SUM OF GAINS 
 
 Table XXI 
 
 Table IX 
 
 A. 
 
 8 
 
 10 
 
 2 
 
 B. 
 
 10 
 
 6 
 
 
 C. 
 
 sl 
 
 7 
 
 15 
 
 D. 
 
 5 i 
 
 3 
 
 
 E. 
 
 7 
 
 5 
 
 
 F. 
 
 3 
 
 8 
 
 5 
 
 G. 
 
 4 
 
 4 
 
 
 H. 
 
 9 
 
 9 
 
 
 J. 
 
 2 
 
 2 
 
 
 K. 
 
 I 
 
 I 
 
 
 Total. 
 
 00 
 
 The sum of gains in rank is denoted by Sg in the follow¬ 
 ing formula. 
 
 Let the 2g to be expected on an average, for mere chance 
 
 *■” I 
 
 be denoted by M; this amounts to - when n is the num- 
 
 6 
 
 ber of cases in each series. (For proof see page 105 of Spear- 
 
 man’s article). Then the coefficient, say R= i-. 
 
 M 
 
 10^ —I 
 
 In the present experiments n = 10. So that M = —g— = 
 
 — = 16. s. Then the correlation for the above tables will be 
 6 ^ 
 
 i? = i—— = 1— = 0.4849. 
 
 M 16.5 ^ 
 
 It must be remembered that in this (and in almost every) probability 
 formula, any experimental result such as R has no scientific significance 
 —except negatively—unless it be at least twice as great as its probable 
 error; for otherwise it is almost as likely as not to be a chance coincidence. 
 To be fairly good evidence, the R must be over three times greater than 
 its probable error {Ibid., p. 96). 
 
SOME TYPES OF ATTENTION. 
 
 49 
 
 In the following tables the decimal is carried only to the 
 second place as the numbers are sufficiently far apart to make 
 decimals of the second and third places unnecessary. 
 
 The Probable Error may be taken with sufficient nearness 
 
 as being (For proof see p. The Probable Error 
 
 V n 
 
 in the following Table is: 
 
 243 = 0 . 136 . 
 
 V 10 3- i 62 
 
 In this way we learn that our correlation in the above 
 tables is just about large enough to be beyond reasonable 
 suspicion of chance coincidence. 
 
 Positive correlations point out relationships which actually 
 exist between two mental traits. The negative correlations 
 show that the traits compared do not exist in conjunction, 
 but that where we find one the other will be absent. Nega¬ 
 tive correlations are of value in corroborating, or contradict¬ 
 ing the positive. 
 
 In the correlation formula used a large negative correla¬ 
 tion may be changed to a positive if one of the two series 
 being compared is inverted. Thus, if the sum of the gains 
 in the second of the two series totals 11.5 the correlational 
 coefficient will be 0.30. If the order of this second series were 
 reversed the sum of the gains will be 19.55 and its R is .18. 
 
 The table of significant correlations contains all those posi¬ 
 tive correlations which are above twice the probable error. 
 In the groups discussed below only those correlations which 
 are above three times this probable error are considered; for, 
 as Spearman points out, a low correlation is not trustworthy. 
 It is important, however, if it occurs frequently. For that 
 reason the smaller figures appear in the positive correlation 
 table. In arranging the correlation results, below, each 
 experiment is given and its correlations with the others. 
 The correlational coefficient is given in parentheses and the 
 experiment is briefly described with an abbreviated reference 
 to the chapter and table where it is described in detail. 
 
50 
 
 H. C. McCOMAS. 
 
 Span 
 
 Totals for all experiments in Span (Span IV): 
 
 Correlate (0.54) with Visual Imagination (Ideat. Types XI). 
 Correlate (0.57) with Ability in Attending color-class (Vis. Per. XVI). 
 Correlate (0.42) with Adherence to color-class (Vis. Per. XIX). 
 Span of Attention for Colored Objects (Span I): 
 
 Correlate (0.63) with Instinctive Selection of color-class (Vis. 
 Per. XIV). 
 
 Correlate (0.54) with Ability in Attending color-class (Vis. Per. 
 XVI). 
 
 Correlate (0.45) with Retention in Fringe of Attention of former 
 objects seen (Mem. Factors). 
 
 Correlate (0.45) with Visual Imagination (Ideat. Types XI). 
 
 Span of attention for Colored Letters And Numbers (Span III): 
 
 Correlate (0.66) with Ability in Attending color-class (Vis. Per. 
 XVI). 
 
 Correlates (0.45) with Visual Imagination (Ideat. Types XI). 
 Correlations between the several Experiments upon Span. 
 
 Span for colored objects (Span I) correlates with span for colored 
 letters and figures, (Span III) and the Totals for all Span 
 Experiments (Span IV), Correlate (63) with Span I, (42) with 
 Span II and (0.78) with Span III; 
 
 Concentration and Inhibition 
 
 Ability to concentrate upon one class of Objects (Concent., etc. V). 
 
 Correlate (0.51) Preference for word-class (Motor Fac. XXIII). 
 Ability to concentrate when objects are upon Colored Backgrounds 
 (Concent. VII). 
 
 Correlate (0.45) Ability in color-class (Vis. Per. XVII). 
 
 Ability to concentrate upon words of a certain Class (Concent, etc. IX). 
 Correlate (0.48) Instinctive Selection of the word-class (Motor 
 Fac. XXI). 
 
 Ideational Types 
 
 Visual Imagination (Ideat. Types XI); 
 
 Correlate (0.57) with Ability in Attending color-class (Vis. Per. 
 XVI). 
 
 Correlate (0.51) with Ability to Associate colors with their objects 
 (Vis. Per. XV). 
 
SOME TYPES OF ATTENTION. 
 
 51 
 
 Correlate (0.42) with Instinctive Selection of the color-class (Vis. 
 Per. XIV). 
 
 Correlate (0.48) with Span of Auditory Attention (Aud. Factors 
 XXIV). 
 
 Auditory Imagination (Ideat. Types XII). 
 
 Correlate (0.48) with Span of Auditory Attention (Aud. Factors 
 XXIV). 
 
 Correlate (0.42) Concentration of Attention during Fire-alarm 
 distraction (Concent, etc. VIII). 
 
 Motor Imagination (Ideat. Types III). 
 
 Correlate (0.45) with Ability to associate colors with their objects 
 (Vis. Per. XV). 
 
 Motor Factors, etc. 
 
 Ability in Attending the word-class (Motor Fac. XXII). 
 
 Correlate (0.51) with ability to attend Poetry read while concen¬ 
 trating primarily on words seen (Aud. XXVIII). 
 
 Ability in attending the word-class (Motor Fac. XXI). 
 
 Correlate (0.42) with memory experiments. 
 
 Visual Perception, etc. 
 
 Instinctive selection of color-class (Vis. Per. XIV). 
 
 Correlate (0.45) with the ability to shift the attention from one 
 class to another (Mob. X). 
 
 Ability in Attending the color-class (Vis. Per. XVI) correlates. 
 
 (0.42) Totals for Auditory work (Aud. XXIV). 
 
 The Adherence to the color-class when the word is introduced (Vis. Per. 
 XIX). 
 
 Correlate (0.42) with Auditory spanning of attention. (Aud. XXVI) 
 
 The Experiments upon Visual Perception and Attention 
 correlate among themselves as follows. The ability to attend 
 the color-class correlates (0.48) with the adherence to the 
 color-class when the word-class is also introduced. The two 
 similar experiments upon ability to attend the color-class 
 correlate (0.42) with each other. 
 
52 
 
 H. C. McCOMAS. 
 
 Auditory Factors in Perceptual Attention 
 
 The majority of correlations between the auditory experi¬ 
 ments and the other experiments appear in the above groups. 
 It remains for this group to note simply the correlations of 
 these experiments with each other. The totals for Span in 
 all the auditory work (Aud. XXIV) correlate (o.6o) with 
 the ability to attend to poetry read when the attention is pri¬ 
 marily upon words seen (Aud. XXVIII), and the totals, also 
 correlate(o.48) with the ability to attend the words seen in 
 the same tests (Aud. XXV). It is also noteworthy that the 
 totals for these experiments give a ranking which correlates 
 with three out of the four of the constituent experiments. 
 
 From the above correlations it may be inferred that the 
 observer who is broad-spanned for all classes of objects seen 
 is of the visual type of imagination. Further, he shows a 
 preference and an unique ability in attending to the color- 
 class of objects. The ability to attend to a large number of 
 colored objects is coupled with an instinctive preference for 
 that class and is related to the faculty of carrying the im¬ 
 pression of former observations in the fringe of attention. 
 
 The results for concentration are rather scattering. The 
 knack of inhibiting the distraction of a colored background is 
 related to special ability in attending to the color-class. Why 
 this should be so is hard to understand. The ability to con¬ 
 centrate upon the word-class and to ‘set the attention’ for a 
 certain class of words both seem to be connected with a 
 fondness for the word-class. This may be due to a motor 
 setting of the attention. 
 
 The Ideational Types are most instructive in the relation 
 the Visual Imagination sustains to visual perception. There 
 can be little doubt that the visualizer is more successful in at¬ 
 tending to the color class than to the words. It is curious that 
 the visualizer also does well in the auditory work. The very 
 few correlations that the Auditory Type of Imagination makes 
 renders its correlation with span for auditory work significant. 
 This correlational value with auditory span is the same for 
 the visualizer, and it must be remembered that the attention 
 
SOME TYPES OF ATTENTION. 
 
 53 
 
 was directed to visual as well as auditory perceptions in the 
 auditory work. An unusual correlation is that between the 
 ability to span visual and auditory perceptions synchron¬ 
 ously and the ability to inhibit auditory distractions. The 
 connection between the motor type of imagery and the 
 ability to connect a color with the object upon which the 
 color appeared would seem to imply a relation between visual 
 and motor retention of objects observed. 
 
 The connection between the faculty for attending to the 
 word-class and for attending to poetry while viewing words 
 may point to a motor repetition of the verses which would be 
 easier for the moteur than the visualizer. Ability in the 
 word-class correlates with the holding of objects previously 
 observed in the fringe of attention. 
 
 In the experiments upon Visual Perception and Attention 
 the most significant fact is the correlation between the dif¬ 
 ferent experiments in this same class. It is evident that 
 there -is some underlying trait of attention which appears in 
 these tests. It is probably an ability to attend, remember and 
 imagine in visual terms better than in others. 
 
 The auditory-visual experiments show rather scattering 
 correlations. Their correlations among themselves show they 
 point in one general direction. The lower correlations show 
 an interesting relation to span for visual work. 
 
 A comparison of the Tables of Significant Correlations and 
 Negative Correlations is one of the best indications that the 
 experiments actually point out typical traits in Attention and 
 that the results are not accidental. 
 
 If the Significant Correlations were in about the same pro¬ 
 portion as the Negative for each set of experiments, it would 
 be apparent that the whole work is unreliable, and the results 
 fortuituous. This is not the case. Following the correlations 
 for Span across the Table it appears that the Positive and 
 Negative correlations, which are significant, occur in the fol¬ 
 lowing proportions; 3 : o; 2 : 6; o : o; 3 : o; 10 : i; o : 7; 
 
 5 •' I; 2 : o. Those for Visual Perception are much more 
 striking; 8:o;o:i3;7:o;i;i. The negative correlations 
 support the positive in nearly every case. The results for 
 
54 
 
 H. C. McCOMAS. 
 
 Concentration and Inhibition are, as might be expected, 
 the least reliable. 
 
 The negative correlation between concentration experi¬ 
 ments and Span is a further support to what has been found 
 before, that span and concentration do not seem to be related. 
 
 The many negative correlations between Span and Motor 
 Factors show conclusively that the motor element in attend¬ 
 ing to the word-class is a feature of attention which does 
 not go with Span. 
 
 It is interesting to note that the only positive correlation 
 Mobility makes is with Instinctive preference for color-class 
 and the only high negative is with Preference for the word- 
 class. 
 
 The five negative correlations between Visual and Audi¬ 
 tory Types and the three experiments on Motor Factors are 
 not high enough to carry much weight but they are suggestive 
 in showing a negative relation between Motor Factors and 
 the Visual and the Auditory Types but not the Motor Type. 
 
 The many negative correlations between the experiments 
 with Motor Factors and in Visual Perception show again, 
 that the series of experiments affected attention in charac¬ 
 teristically different ways. 
 
 In summing up the results of the Negative Correlations it 
 may be said that they corroborate the findings of the Posi¬ 
 tive Correlations, but do not add to our information materi¬ 
 ally. A casual comparison of the two Tables shows this 
 clearly. A more exact study brings to light the fact, noted 
 earlier in the text, that those experiments whose results were 
 not entirely clear (such as the work in Concentration) have a 
 more even proportion of positive and negative correlations 
 than do the experiments upon Span, Types, Motor and Visual 
 Factors, etc. In the latter the proportions for the two classes 
 of correlation are thoroughly consistent and convincing. 
 
 CONCLUSION 
 
 From the foregoing correlations and discussions the follow¬ 
 ing conclusions are deduced, concerning Types of Attention, 
 
SOME TYPES OF ATTENTION. 
 
 55 
 
 under the conditions of experimentation described in the pre¬ 
 ceding chapters. 
 
 1. There are broad and narrow spanned types of atten- 
 tional activity. The broad spanned type for visual per¬ 
 ceptions is also broad spanned for auditory perceptions (um- 
 fang). 
 
 2. There is also a type of attention which is alert, active, 
 under quick control; and there is a type which moves slug¬ 
 gishly. The former is broad spanned. 
 
 3. The ability to concentrate and inhibit does not appear 
 in close relation with any other marked traits of attention. 
 This ability varies in individuals but not in a manner which 
 gives evidence of type. 
 
 4. The dexterity or suppleness in control of attention is 
 another feature which cannot be classed as a Type. 
 
 5. The impressions which catch in the ‘Fringe’ of atten¬ 
 tion and later enter the ‘Clearness Area,’ vary characteris¬ 
 tically with individuals. The type most susceptible to this 
 experience is also broad spanned. 
 
 6. The Visualizer is broad spanned for both visual and 
 auditory perceptions. 
 
 7. The ‘Auditif’ shows his attentional type in the ability 
 to inhibit sound and in the breadth of span for visual and 
 auditory impressions presented synchronously. 
 
 8. The Motor Type of ideation makes so few correlations 
 that its evidence is largely negative. It is not broad spanned 
 for the work given in these experiments. It is probably more 
 efficient in concentration than the Visual. 
 
 In view of these resuls it must be acknowledged that the 
 Attention is a function of the co-operation of many factors 
 of the mind and it takes its character from them. The activi¬ 
 ties of the Attention will not be understood until the relation 
 to these component and controlling factors is understood. 
 As Goethe has well said: 
 
 “Das Besondere unterliegt ewig dem Allgemeinen 
 Das Allgemeine hat ewig sich dem Besonderen zu fiigen.” 
 
Span. 
 
 Span. 
 
 Span. 
 
 Span. 
 
 Concentration and Inhibition . 
 
 Mobility. 
 
 Ideational Types. 
 
 Visual Perception and Attention. 
 
 Motor Factors and Perceptual Attention. 
 
 Auditory Factors and Perceptual Attention. 
 
 0.24 
 
 0.48 
 
 0-33 
 
 0.63 
 
 0.42 
 
 0.78 
 
 TABLE OF ALL CORRELATIONS 
 
 Concentration, Etc. 
 
 0.30 
 —o. 12 
 0.24 
 0.30 
 -0.15 
 
 0-39 
 o. 18 
 0-39 
 -0.36 
 — o. i8 
 
 03 
 
 o. 12 
 
 o-iS 
 
 0.03 
 
 0.09 
 
 o-iS 
 
 18 
 
 09 
 
 Ideational Type 
 
 0.03 
 0.03 
 0.15 
 o. 12 
 0-33 
 0.03 
 0.42 
 0.03 
 —0.09 
 —0.03 
 
 0.03 
 o.is 
 0.09 
 0.03 
 0-33 
 —0.06 
 — o. 12 
 0.09 
 o. 27 
 0.27 
 —0.27 
 
 Visual Perception, Etc. 
 
 I 0-63 
 I 0'09 
 I 0.24 
 
 ' 0.30 
 —o. 27 
 0.18 
 —0.30 
 0.00 
 0-45 
 0.42 
 -0.15 
 -0.03 
 
 -0.06 
 0.09 
 0.09 
 o. 12 
 
 0.09 
 
 O.IS 
 
 0.12 
 
 -0.06 
 
 0.03 
 
 0.51 
 
 0.09 
 
 0-45 
 
 —0.09 
 
 0-54 
 0.24 
 0.66 
 0-57 
 0.30 
 0.36 
 0.30 
 — o. 18 
 o. 27 
 0-57 
 o. 12 
 0.12 
 0.30 
 0-33 
 
 o. 24 
 0.00 
 0.30 
 0-33 
 
 -0.15 
 
 0-45 
 
 — 0.09 
 0.00 
 o. 12 
 0-33 
 
 — 0.06 
 0.06 
 0.12 
 0.24 
 0.42 
 
 1.00 
 0.24 
 0.48 
 0.63 
 -0.21 
 0.30 
 -0.39 
 0.12 
 
 O.IS 
 
 0.45 
 
 -0.03 
 
 0.03 
 
 0.63 
 
 -0.06 
 
 0-54 
 
 0.21 
 
 — o. 27 
 
 0.39 
 
 0-39 
 0.42 
 -0.39 
 18 
 —0.06 
 —0.12 
 o. 21 
 0.03 
 0.03 
 0.03 
 o. 27 
 O 33 
 0.48 
 0.42 
 o. 27 
 
 Motor Factors, Etc. 
 
 -0.30 
 
 -O.IS 
 
 -0.27 
 “ 0-33 
 0.1s 
 -0.12 
 0.00 
 ‘ 0-33 
 0.27 
 -0.27 
 -0,21 
 -0.09 
 —0.03 
 —0.27 
 -0.36 
 -0-33 
 -0.30 
 -O.IS 
 
 0.06 
 ■o. 18 
 0.06 
 0.03 
 0.18 
 o. 18 
 0.09 
 0.48 
 O. 24 
 0.30 
 — 0.21 
 0.03 
 -O.IS 
 —0.27 
 — 0.27 
 —0.03 
 0.06 
 —o. 24 
 -O.IS 
 
 Auditory Factors, Etc. 
 
 5oav XXV XXVI xxvn xxvnr 
 
 0.03 
 
 0.09 
 
 0.03 
 
 0.09 
 
 0.03 
 
 -0.33 
 
 -0.21 
 
 -O.IS 
 o. 
 
 —0.09 
 
 0.09 
 
 0.09 
 
 — O. 21 
 
 — 0.09 
 0.09 
 0.03 
 
 — 0.09 
 0.03 
 
 — 0.09 
 
 -0-33 
 
 -0.33 
 
 -0.39 
 
 -0.39 
 
 51 
 — 0.18 
 o. 18 
 0-33 
 -0.39 
 -o. 2 
 -0.09 
 0.09 
 -0-33 
 -O.IS 
 —0.48 
 -0-33 
 -0-33 
 -0.51 
 0.06 
 0.24 
 0.03 
 
 0.00 
 oiS 
 0.30 
 0-33 
 o. 12 
 0.09 
 -0.27 
 -o. 12 
 0.09 
 0.48 
 0.48 
 - 0.00 
 O.IS 
 
 0.24 
 
 0.42 
 
 0.30 
 
 0.00 
 
 0.24 
 
 •0.06 
 
 ■0-33 
 
 ■0.33 
 
 -o. 21 
 
 -O.O 9 
 
 0-33 
 
 0.09 
 
 CIS 
 
 0.00 
 
 - 0-33 
 
 -0.06 
 
 -0.09 
 
 -0.03 
 
 0.30 
 
 -0.03 
 
 0.09 
 
 0.12 
 
 0-39 
 
 0.12 
 
 -O.IS 
 
 •0.09 
 
 015 
 
 0.00 
 ■0.48 
 o. 18 
 0.09 
 0.48 
 
 0.03 
 o. 18 
 0.09 
 
 O. 21 
 
 -0.15 
 0-39 
 0.03 
 -0.18 
 -0.09 
 -0.03 
 -0.09 
 -0.39 
 •0.06 
 -0.09 
 o. 18 
 0.36 
 0.03 
 0.42 
 0.09 
 •o. 12 
 -0.15 
 ■0.24 
 0.24 
 •0.09 
 
 —o. 18 
 - 0.21 
 0.09 
 0.03 
 0-39 
 0.03 
 -0.30 
 
 -O.IS 
 
 015 
 
 O. 21 
 
 ■0.45 
 
 0-33 
 
 0.00 
 
 O.IS 
 
 0.09 
 
 0.09 
 
 0.18 
 
 O.IS 
 
 0.30 
 
 0.09 
 
 O.IS 
 
 015 
 
 0.42 
 
 0.24 
 
 0.03 
 
 0.21 
 
 O. 21 
 
 0-33 
 
 0.36 
 
 -O.IS 
 
 0.09 
 
 -0.33 
 
 0.09 
 0.03 
 0-39 
 -o. 21 
 -0.09 
 O 33 
 -0.03 
 -0.09 
 
 - 0.33 
 
 o. 21 
 0-39 
 -0.06 
 
 -O.IS 
 
 0.51 
 
 -o. 21 
 0.60 
 0.36 
 0.09 
 O IS 
 
 0.45 
 
 0.09 
 
 0.15 
 
 0-39 
 
 -0.21 
 
 0-33 
 
 -0.21 
 
 O.IS 
 
 -0.09 
 
 O.IS 
 
 O.IS 
 
 -O.IS 
 
 0.09 
 
 -0.1s 
 
 0.30 
 
 0.09 
 
 0-45 
 
 0.09 
 
 ■0.39 
 
 0,42 
 
 ■O.IS 
 
 •0.21 
 
 •0.09 
 
 •0.27 
 
 0.00 
 
 •0.27 
 
 0.09 
 
 X !J 
 
 I 
 
 II 
 
 in 
 
 IV 
 
 V 
 
 VII 
 
 VIII 
 
 IX 
 
 X 
 
 XI 
 
 XII 
 
 xni 
 
 XIV 
 
 XV 
 
 XVI 
 
 XVII 
 
 XVIII 
 
 XLX 
 
 XX 
 
 XXI 
 
 XXII 
 
 XXIII 
 
 xxrv 
 
 XXV 
 
 XXVI 
 
 xxvn 
 
 xxvin 
 
 Span of attention 
 
 Span 
 
 Span 
 
 Span 
 
 Concentration and inhibition 
 Mobility 
 
 Ideational types of attention 
 
 Visual perception and attention 
 
 Motor factors and perceptual attention 
 
 Auditory factors and perceptual attention 
 
 Colored squares 
 Words 
 
 Colored letters, numbers and figures 
 Totals 
 
 ( Concentration upon one class of objects 
 With colored background distraction 
 With fire-alarm distraction 
 Concentration upon a certain class of words 
 Shifting the attention from class to class 
 The visual type 
 The auditory type 
 The motor type 
 Preference for the color-class 
 Associating colors with their objects 
 Ability in attending the color-class 
 Selecting colored objects 
 Span for colors 
 Concentration for colors 
 Choice of the word-class 
 Choice of word-class 
 Ability in attending word-class 
 Preference for word-class 
 Totals for auditory factor experiments; span 
 Words seen, attention on poetry read 
 Poetry, attention on poetry read 
 Words, attention on words 
 Poetry, attention on words.