Human psychology

Contents

lAPTEB PAGE

I. The Science of Psychology 1

Preliminary Definitions, 1. ^^

Appendix

PROBLEM , PAGE

I. The Mind-Body Relation 413

Subjective and Objective Phenomena, 413. Perception of the External World, 416.

Thought-Transference; Psychical Research, 418. Personal Immortality, 422.

References, 423.

II. Mechanism and Purpose 425

Purpose in Organic Growth, 425.

Conscious Purpose, 427.

Free- Will, Determinism, and Responsibility, 431. Personification of Natural Phenomena, 433. References, 434.

III. Neural Activity 435

Nature and Modal Variation of the Nerve Impulse, 435. Retention, Metabolism, and Modification, 437. References, 440.

IV. The Visual Process 441

Principal Facts, 441.

Three-Color Theories, 441.

Metabolic Theories, 443.

Genetic Theory, 445.

References, 446.

Directions for Performing the Exercises . . . 447 Index 451

ILLUSTRATIONS

FIGURE CHAPTER PAGE

1. The Cell and its Parts II 18

2. Types of Cells " 19

3. Neuro-Terminal Circuits Ill 33

4. The Neuron and its Parts " 34

5. Types of Neurons " 36

6. Synapses " 37

7. Synapses " 37

8. Central Cerebrospinal System " 39

9. Cerebrospinal System and Sympathetic Ganglia . . " 40

10. Paths in Cord and Brain " 42

11. Cross-Section of Cord " 44

12. Model of Human Brain facing " 44

13. Base of Brain " " 44

14. Cross-Section of Brain " " 45

15. Cortex, from Above " " 46

16. Cortex, from Left Side " " 47

17. Projection Areas in Cortex " 48

18. Association Fibers in Cortex " 49

19. Autonomic System " 50

20. Muscle, with Nerve Endings " 53

21. Alternative Nerve Paths IV 67

22. Summation of Nerve Impulses " 68

23. Distribution of the Nerve Impulse " 68

24. Simple Reflex VI 96

25. Distributed Reflex . " 97

26. Chain Reflex " 99

27. Mazes for Investigating Habit Formation .... VII 113

28. Changes of Path in Habit Formation . . . . . " 118

29. Curve of Learning " 124

30. Cross-Section of Eye IX 152

31. Layers of the Retina " 153

32. Map of Blind Spot " 155

33. Eyeball and Muscles " 156

34. Focusing of Objects on Retina " 157

35. Course of Optic Nerve " 159

36. Refraction of Light " 162 xvi HUMAN PSYCHOLOGY

FIGURE CHAPTER PAGE

37. Color Mixer IX 164

38. Variations in Color-Shade and Tint " 169

39. Color Spindle and Color Belt " 171

40. Perimeter " 177

41. Color Zones of Retina . " 178

42. Masson Disk " 182

43. Cross-Section of Ear X 184

44. Diagram of Middle Ear ......... " 185

45. Labyrinth and Section through Cochlea .... " 187

46. Organ of Corti " 188

47. Musical Intervals " 193

48. Nasal Cavity and Olfactory Region . . facing " 196

49. Olfactory Cells . " " 196

50. Olfactometer " 198

51. Tongue, showing Papillae facing " 199

52. Taste Bulbs and Taste Cells " 199

53. Pressure and Temperature Spots " 201

54. Types of Cutaneous Receptors " 202

55. Semicircular Canals " 212

56. Space Perception in Touch XII 236

57. Visual Space Perception " 237

58. Curve of Weber's Law " 259

59. A Study in Perspective .....,.." 260

60. Staircase Illusion " 261

61. Illusion of the Cubes " 262

62. Filled-in Perception " 263

63. Double Perception " 263

64. Hidden Perception " 264

65. Miiller-Lyer Illusion " 265

66. Bering Illusion " 265

67. Perception of Mirror Script " 266

68. Hedonic Curve XIII 283

TABLES

TABLE CHAPTER PAGE

I. Classification of Science I 6

II. Vital and Mental Functions II 28

III. Human Reflexes ^ . . VI 101

IV. Human Instincts " 106

V. Instinctive Tendencies of Man " 107

VI. Progress of Learning VII 123

VII. Fundamental Operations of Conscious Experience VIII 144

VIII. Spectral Lines and Color Range IX 165

IX. Complementary Colors ...'.... " 174

X. Classes of Odors X 197

XI. Threshold of Intensity for Taste .... " 201

XII. Classification of the Senses XI 225

XIII. Classes of Mental States " 231

XIV. Values of the Weber Constant XII 258

XV. Secondary 'Mental States . . . . . . XIV 294

XVI. Human Emotions " 299

XVII. Classification of Sentiments " 303

XVIII. Classes of Associations XVI 343

XIX. Human Attitudes XVII 362

XX. Human Dispositions ........ " 367

XXI. Higher Human Attitudes " 370

XXII. Classification of Temperaments XVIII 376

XXIII. Visual Phenomena App. 442

ACKNOWLEDGMENTS

The general standpoint adopted in this book was determined largely by the writings of David Hartley, James Mill, and George Henry Lewes; the influence of these epochal thinkers should be acknowledged equally with that of my fornier teachers, James McCosh, Wilhelm Wundt, and J. Mark Baldwin. The empirical data have been drawn from many sources, for the most part too familiar to need special mention. Many features of the analysis and classification of material may be traced to personal association with William James, George T. Ladd, Hugo Munsterberg, E. B. Titchener, James R. Angell, Raymond Dodge, Edwin B. Holt, John B. Watson, and other workers in the field — even where my treatment differs widely from theirs.

For general suggestions and criticisms I am much indebted to my colleagues, Henry C. McComas and Henry L. Eno, and to Walter T. Marvin of Rutgers College. In the treatment of special topics considerable assistance has been given by Oliver S. Strong (Columbia), C. F. W. McClure (Princeton), and S. P. Hayes (Mount Holyoke).

Thanks are due to Anna Berliner for critical verification of data, references, and collateral reading; and to Ulric Dahlgren (Princeton), Charles P. Elgin, and Martin Petersen, for drafting illustrations. I am also indebted to my successive office assistants, Naomi S. Peterson, Dorothy Fox, Anna A. Weelans, and Grace Meng, for their painstaking aid in preparing the manuscript and proof.

Acknowledgments are due to the following authors and publishers for permission to make use of illustrations from the works mentioned: C. J. Herrick, Introduction to Neurology (W. B. Saunders Co.). E. B. Titchener, Textbook of Psychology, and Experimental Psychology; E. A. Schaefer, Text-

XX HUMAN PSYCHOLOGY

book of Physiology; W. B. Pillsbury, Fundamentals of Psychology; E. B. Wilson, The Cell (Macmillan Co.). E. L. Thorndike, Elements of Psychology (A. G. Seiler). J. D. Lickley, The Nervous System (Longmans, Green & Co.). Joseph Jastrow, Fact and Fable in Psychology (Houghton Mifflin Co.). Bailey and Miller, Textbook of Embryology (W. Wood & Co.). Gelett Burgess, Nonsense Book (F. A. Stokes Co.). C. H. Judd, Laboratory Equipment for Psychological Experiments (C. H. Judd). E. J. Swift, article in Psychological Bulletin (Psychological Review Co.). R. M. Yerkes, in Harvard Psychological Studies (Harvard Psychological Laboratory). Helen B. Hubbert, in Journal of Animal Behavior (Henry Holt & Co.). While the sources from which material has been drawn are generally shown in the references, special acknowledgment should be made to C. S. Sherrington, whose distinction between exteroceptors, interoceptors, and proprioceptors suggested the classification of the senses adapted in this book.

Princeton, New Jerset

Chapter I The Science Of Psychology

Preliminary Definitions. — Psychology is the scientific investigation of mental life. Mental life comprises the events which occm* in the active give-and-take relations between organisms and their environment.

These are not intended as final definitions; they indicate in a preliminary way the general field which psychology covers. First of all we must be sure that we understand the meaning of the principal terms in these statements. What is meant by scientific investigation, or science ? What is an organism, and what are the characteristic features of organization ? These notions must be made clear before we can see just what is included within the field which we are to investigate.

Science. — It may seem unnecessary to explain what is meant by scientific investigation. But while most of us are familiar in a general way with the ' sciences of nature,' we do not always realize that the same facts which form the subject-matter of science may also be treated in other ways and fall outside the province of science. For example, the same material may be used as an instrument for other purposes, or it may be studied historically.

When we take up the study of French, for instance, we may propose to become familiar with the structure of the language and the general principles or laws of inflection, grammar, and the like. This would be a scientific study of the language. On the other hand, we may take no interest in this aspect, but may wish rather to attain a practical mastery of French in order to speak it and to read French literature. In this case we are not concerned with the science of French but with French as an instrument for acquiring information of other sorts. Finally, we may be interested in neither of these aspects of French, but in the historical development of the language. In all three cases the material we deal with is largely the same; but the mode of procedure and the facts brought out are quite different. The same subject-matter may be treated either (1) scientifically, or (2) practically, or (3) historically. These three view-points lead in any branch to Science, Art, and Genetics.

The distinction just noticed is of greater importance in psychology than in most branches^ because psychology deals with phenomena of our intimate personal life, and its processes are used to obtain information of every sort. Mental facts, like the French language used in our illustration, may be studied in at least three different ways:

(1) As a science. We may seek to discover the principles or laws of mental life and activity, such as the modes of habit formation, the laws of association, thinking, etc.

(2) As an instrument^ to obtain information of other sorts. If we wish to understand the nature of the world itself, including matter as well as living creatures, we proceed by means of ' rational thinking '; and rational thinking, or logic, is a mental process. But when we use logical principles in order to miderstand the universe we are not studying mental facts as a science, but only as an instrument for philosophical research. Or again, we may use psychological principles in order to classify human beings on a scale of higher and lower intelligence. Here again we are not studying the science of mental phenomena — we are merely using the principles of mental life as an instrument in investigations of another sort. This study is known as applied psychology.

(3) As an historical growth or development. Mental states and processes are subject to change and growth. They differ in the child and the human adult ; they exhibit various forms

SCIENCE 3

\ in different animal species. This historical study constitutes

a department of study in itself, quite different from the study

of the principles of mental activity in any one of the stages or

species. It is called genetic psychology.

When we speak of the science of psychology it should be made perfectly clear whether we are concerned with the static view of mental operations as they appear in some definite form of being, or with the application of the principles of mental life to some other sphere, or with the genetic development of mental phenomena. In this book our interest centers mainly upon the static view; we are to investigate the phenomena which constitute the mental life of adult human beings.

Classification of Science. — It will help us to understand the field of psychology if we consider its relation to the other branches which are ordinarily grouped under the generic term science. Science means the discovery and systematic formulation of general truths of nature. The division of science into branches is more or less a matter of convenience. Nature is a single interworking system of things and events, and hence in a way all science is one. But for convenience of study we group together those phenomena which are similar in character, and we investigate them apart from the rest. Any such group is called ' a science.' For example, the properties and combinations of elements in a cell are studied in the science of chemistry, the play of forces in the science of physics, the special activities of cells in the science of physiology. These events usually occur at the same time and concern the same objects; but the investigator or student examines one set or class, assuming or passing over the others for the time being.

It should be emphasized also that science as such is not concerned with individual facts or events. Each event is considered as representing any number of similar events, and it is especially the interworking of events that interests the scientist. The observation of nature in all its phases during many centuries has shown us that nature acts uniformly — that given the same conditions, the same results follow. The doctrine of the ' uniformity of nature ' enables us to experiment with individual things and to apply the results of these particular observations to all similar things by means of generalizations, or ' laws.'

The most fundamental division of science is into abstract and concrete. Abstract science investigates the relations which hold equally well for every kind of specific facts. The abstract sciences include mathematics in all its branches and logic. Quantitative and numerical relations apply alike to atoms, masses, forces, and living creatures. What the savage or the child discovers by counting his fingers and by adding, subtracting, and grouping them in various ways, may be applied on a larger scale to the study of the stars and to tables of human mortality — in fact to all phenomena. The intelligent man forms habits of mathematical association and uses them in connection with every event of life. These habitsare modes of reasoning, and when they are developed into an organized system they become a branch of science — or a group of such branches. These branches form the abstract sciences, or, as they are sometimes called, the mathematiccd sciences. They may also be called the general sciences, sincel they hold for all classes of natural phenomena. \

The concrete sciences deal with phenomena which belong f to special phases of nature. They are also often called special' sciences or empirical sciences, which points to the fact that the truths of nature in each specific field are discovered by observing the actual course of events in that field, and not by taking the truths discovered in one sphere and applying them to another without question.

Formerly scientists thought it proper to carry over generalizations from one field to another in this way. It was assumed that the planets revolved in circles on account of the geometrical simplicity of the circle. Even Newton assumed that there must be seven primary colors corresponding to the seven

CLASSIFICATION OF SCIENCE 5

tones of the musical scale. We find many such instances where early science carried over generalizations from one field to another instead of observing the actual course of events. This is called the apriori or rational method of investigation. At present it has been almost wholly abandoned for the empirical method in each of the special fields of science. The laws of abstract science are still carried over to the various concrete sciences; but this is because they have been found by repeated observation to apply universally. ^--^^

The fundamental concrete sciences are chemistry a,nd physic^. Chemistry deals with the relations between specific material units; physics deals with the general relations between bodies in space and time. At present it is not clear which of these two branches is the more fundamental. Probably they are coordinate phases of nature, a fact which is expressed in the phrase " physicochemical relations." j ^.^

"* Biology is another special branch of science, but less fundamental than physics or chemistry. It treats of phenomena which appear only in certain special groups of physicochemical units called organisms. Coordinate ,.#ith biology_areJhebranches known as astronomy and geology. AH three of these branches deal with ' local ' phases of nature which appear on the earth or in the universe about us ; they are less general than physics and chemistry. Biology is divided for convenience into a number of branches, such as zooldgy and bo^tny, which need not be discussed here. A more important subdivisio: of biology is into the three sciences of morphowgy, physiology, and psychology. Morphology deals with the structure and ar-) rangement of the various parts and organs of living creatures; physiology deals with the internal processes of organisms], psychology with their relations to their surroundings. \

A further group of sciences deal with the relations between separate organisms. These are called the social sciencesr They are less fundamental than biology. The science of sociology treats of the general interaction among organisms

6 THE SCIENCE OF PSYgHOLOGY

of the same species. Human sociology is the most highly developed of these branches, because the human species displays far greater mutual interaction among its members than any other kind of organism. But other species, such as ants and bees, may be studied from the same standjf6int. A branch closely related to this is social 'psychology, which examines psychological data so far as they are modified or affected by the social grouping of individuals. Other social branches are econojnics, ethics, jurisprudence, etc. [Table I.]

/ ,/ Table I. — Classification of Science

^ '' Branches Levels

1. Abstract (General) : | « MShematics } ^

2. Concrete (Special) :

j Physics ( Chemistry

|n

! Astronomy ^

Geology ( i Morphology I jjj

Biology < ii Physiology f

( iii Psychology ' J

( i Sociology )

c Social Science < ii Social Psychology >• IV

' iii Ethics, etc. )

Organisms and Organization. — According to this conception of the relation of the sciences, psychology is regarded as a branch of biology, the science which studies certain sorts of units called organisms or living beings.

Plants and animals taken together form one important natural division of the material world. In spite of striking differences in size, shape, and modes of activity, all living things have certain characteristics in common and differ fundamentally from other forms of matter. The words living and lifeless bring out this distinction. Living creatures are called organisms, and lifeless matter is called inorganic. What do these terms mean.?

Life is often called a force; but this does not help the explana-

ORGANISMS AND ORGANIZATION 7

tion unless we can determine how this force acts and what it accomplishes.

Animals and plants are very complex aggregations of matter. They consist of several differentiated organs and usually of many segments or members. These parts cooperate in the activities of the creature. Organization is the term used to denote the peculiar structural and functional ^ relation of parts which exists in all animals and plants; it means (1) that the parts of a living thing are capable of interaction, and (2) that this capacity persists despite growth and changes of substance. Life means that the parts (the organs and members) of an organism act in this cooperative way.

The structure and activities of organisms will be examined later. But it may be stated here that the specific forms of activity called ' organic ' are those concerned with the continuance of the creature's individual existence or with the perpetuation of the species. Now the prolongation of existence involves two different sorts of process: (1) internal maintenance and growth, and (2) preservation from external destroying agencies. Thus the activities of organisms may be divided into two classes, which we shall call respectively growth processes or vitality, and mental processes or mentality.

(1) Vitality in the broadest sense expresses the fact that an organism not only is able to restore its losses and repair its injuries, but that during its earlier life it can become larger and more differentiated and in later life can reproduce. (2) Mentality is a term used to express a certain give-and-take relationship which exists between an organism and the world about. These two characteristics are due to the special make-up of organized living creatures.

Vital Life and Mental Life. — The various activities which

^ The term structure denotes the composition of a thing and the spatial relations between its parts. Function and process denote the manner in which the thing acts and its parts interact.

make up the vital functions of growth and maintenance consti"= tute the creature's biological or vital life. We are only indirectly concerned with them here. The object of study in this book is the relations of give and take between organisms and their environment. The facts which arise from these relations are the data of psychology.

If we examine a number of representative organisms, both plant and animal, we observe a very marked difference between their relations to the world about them and the relations of ' inert ' matter to its surroundings. An organism is not merely affected by external forces, but on account of its systematic organization it is able to control these forces to a greater or lesser extent. It receives impressions from the outer world, and acts accordingly. This characteristic interaction, through stimulation, adjustment, and response, is called mentality, and the various activities involved in the process make up the creature's mental life.^

Among plants interaction with the environment is not often apparent; but sometimes it is unmistakable. The sun-flower, which turns toward the sun and follows its course from east to west, is an instance of stimulation and response. So is the sensitive plant, whose leaves close when they are touched.

Animals exhibit this characteristic to a very marked degree. Their power of locomotion accentuates the response. The lowest species (amoeba and other protozoa) respond to stimulation by light, heat, and chemical action on their external covering, and to mechanical contact or pressure. Sometimes the response is positive — that is, toward the source of stimulation; in other cases it is negative, that is, away from the source.

^ Many terms, such as mentality, impulse, stimulation, sensation, contrast, attitude, are used in a precise, technical way by psychologists. Their meaning is often much narrower or much broader than in popular language. The reader should be careful to 'think' them correctly, according to the definitions given in the text.

VITAL LIFE AND MENTAL LIFE 9

Among higher species of animals we find much more comphcated types of response. When a partridge sees a hunter approaching her nest she trails oflf " in an effort to draw him away from her young." This is a negative response to the visual impression of the man's appearance. When a dog sees a rabbit he sets out in pursuit — a positive response which finds expression in violent movements of all the bodily members. In complex activities like these the response usually involves cooperation of many different muscles.

Self-observation ; Consciousness. — In man, the highest animal species, we find the greatest complexity of activity. This of itself would give special importance to the study of human psychology. But in addition there is a special circumstance which broadens the sphere of study. Scientific observers belong to the human species. The psychologist can not merely observe the responses of human beings and of animals generally, but he can study his own relations to the environment through self-observation.

If we examine our own mental life, we find that the effect of stimulation by outside forces is something different from what we observe in others. When we are affected by a loud sound or a brilliant color, we observe the phenomena in a different way from that in which we observe these forces affecting the ears or eyes of another human being. More than this, we can picture the appearance of a friend when he is miles away; and sometimes we form a tolerably accurate idea of a coming event long before it happens. There is nothing like this in our observations of what animals and other men are doing. Your friend's memories are observed by you only indirectly — you listen to his verbal description of them, or you infer them to be present by the way he acts. Yoiu* own memories are a direct and immediate part of your life.

The experiences which we observe in ourselves either form a new set of occurrences to be examined in connection with the study of mental life; or else they are another way of looking at the same set of facts which we observe in others. The latter hypothesis seems more probable.^ However, the question of interpretation is far less important than the facts themselves. The phenomena of memory, imagination, perception, and the like, which we notice in self-observation, are grouped together under one general term, conscious phenomena.

Consciousness and conscious are terms used to characterize the phenomena which occur in an individual's own experience, so far as these differ from what another individual would note in observing him.^ For instance, when my gaze falls on the old engraving of Lincoln and his Cabinet I see the figures grouped together. I recall certain incidents of Lincoln's life and the Civil War. I have an indistinct feeling of attraction and admiration. Another person watching me (not the picture) would get practically nothing of all this. Possibly if he could examine my brain with some fine instrument yet to be devised, he would be able to trace out certain chemical and molecular changes corresponding to each detail of my conscious experience. Consciousness denotes the fact that the experience is personal tome (' subjective '), and it includes any other distinguishing features of the experience which are apparent to me and not to a second person.

Behavior and Conscious Experience. — The two ways of observing the relation between organism and environment in man bring out quite different sets of facts. When we study the influence of the environment upon some other person than ourselves, the effect of stimulation is observed as a response, which takes the form of some characteristic movement. At a shout, he turns his head and speaks. Seated at a table he picks up his knife and fork and conveys food to his mouth. Passing a shop window he walks up, stops, and casts

^ See Appendix, "Subjective and Objective Phenomena," p. 413.

^ The term conscious, as here defined, is much narrower than the term mental. There are many phenomena in mental life which are not open to self-observation, and are consequently not characterized as conscious phenomena.

BEHAVIOR AND CONSCIOUS EXPERIENCE 11

his eyes over the articles displayed. All these obvious movements, together with many minute muscular adjustments and secretion by the glands, are eflFects of the influence of the environment on the man; they constitute his response to stimulation. These motor phenomena, taken together, are called behavior.

A man's (or any animal's) behavior includes the various ways in which he acts upon the environment as a result of the environment acting upon him. But the word ' act ' is used here in a very specific way. If a violent gust of wind strikes a man suddenly and blows him down, his movement in falling is not behavior, nor is the dent he makes in the ground a response — he is not acting upon the environment in an organic manner. But if he is able to brace himself against the wind and avoids falling, or if he puts out his hands to break the fall, these movements are instances of behavior; the external force in such cases affects him not merely physically but also organically — he responds as an organism to the stimulation. It is this activity that goes under the name of behavior.

In psychology, then, we do not study every effect of the environment upon the creature, nor every effect produced by the creature on the environment, but only the behavior phenomena — those movements and changes in which the creature is acted upon and responds as an organism.^

The second mode of studying mental life is through self-observation (commonly called introspection), which examines the phenomena of conscious experience. Consciousness phenomena are the effects of the environment upon the creature as they appear to the creature himseff.

At first glance it might seem as if the facts of conscious experience were nothing more than the facts which we study in physics and chemistry. When we look at a friend's face, we observe an irregular surface broken up into patches of different

1 The characteristics of the specific type of activity included under behavior are treated in chapters vi and vii.

colors and shading; these configurations are called the eyes, nose, mouth, cheeks, hair, etc. The human features as we see them are particles of matter reflecting light. The molecular composition of the human body, the grouping of the different cells in space, the reflection of light — all such phenomena are data which properly belong to physics and chemistry and concerning which these sciences have formulated general laws and principles.

But when we study them as effects upon ourselves we are dealing with an entirely different set of relations and principles. When we look at a human face certain features stand out prominent, while others are barely noticed or escape observation altogether. The eyes may be the chief object of attention. The color of the hair may be noticed casually as part of the total impression; a mole on the cheek may remain unnoticed; and so of other features. In a word, the face impresses us as a whole, and certain features are vivid items of our experience, while other items form a background or fringe of fainter impressions. That is, the facts of perception (as this type of experience is caUed) stand in quite different relations to one another from the physical facts which stimulate us through the eye and other organs. The prominence of certain features in the human face is not always due to the intensity of illumination, nor in most cases is the obscurity of other features due to their actual lack of physical intensity. The difference depends rather upon the internal organization of the perceiving creature. Still more do our ' memory images ' and our feelings of pleasure, annoyance, hope, and desire differ from the physical characteristics of the objects which incite them.