Classical Texts in Psychology
York University, Toronto, Ontario
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History of Psychology: A Sketch and an Interpretation
James Mark Baldwin (1913)
Scientific Psychology in the Nineteenth Century. II. Special Lines of Work.
Physiological and Experimental Psychology. -- The idea that lies at the basis of physiological psychology, properly so called, is that of a regular and uniform connection between the internal functional conditions of the body, especially the brain, and states of consciousness. The method consists in observing or modifying the physiological, with a view to noting, altering, or producing mental conditions -- sensational, emotional, active, etc. Lotze's book on Medical Psychology was a pioneer work in this direction, as we have already said. The method has been productive in researches on sensation, emotion, and movement; and also notably in the domain of medical diagnosis and surgical treatment. The theory of "localisation of brain functions" rests upon facts observed and experiments made in the pursuit of this method. The development of knowledge and of medicine in the [p. 73] [figure -- Helmholtz] [p. 74] domain of "aphasia," since the discovery of the speech centre by Broca, illustrates its enormous possibilities.
In the domain of sensation, the work of Helmholtz on vision and hearing was epoch-making. It illustrates the extension of the method by means of external stimulation of the senses and experiments upon them, whereby "experimental psychology" came in to enlarge the scope of physiological psychology, understood in the narrower sense.
Researches in physiological psychology go back to the Arabian physicians, to Alhacen especially, and its body of results includes observations and discoveries made by many; but its establishment as a well-defined and well-controlled method of research is one of the notable achievements of the late nineteenth century.
Experimental psychology, as distinguished from physiological, resorts to the external stimulation of the normal senses and to the direct experimental observation of the mind, the physiological conditions within the organisation remaining constant and normal.
In psycho-physics, the psycho-physical relation was experimentally investigated. It was founded by G. T. Fechner (1801-1887), who was led by his pan-psychic theory of the relation of mind and body to the attempt to discover the law of their mutual influence. The outcome of his experiments, in which he utilised results [p. 75] reached by the physiologist E. H. Weber, were stated in a quantitative formula known as "Fechner's psycho-physical law." The quantity or intensity of sensation varies with the quantity or intensity of the stimulation; but not in the same direct ratio. An increase in stimulation does not result in a proportionate increase in sensation; but in order that the latter may increase arithmetically, the former must increase geometrically. Put mathematically, this is equivalent to saying that the sensation increases as the logarithm of the stimulation. This bears out the observation of daily life that two candles do not illuminate a page twice as much as one; that two violins, pitched in the same key, do not double the sound of one. It is a matter of ordinary observation that as the intensity of the excitation increases by well-marked variations, very slight changes are produced in the corresponding sensation.
Fechner's title to recognition as the founder of psycho-physics -- as this special line of quantitative research has been designated -- rests as much, however, upon his careful working out of the "psycho-physical measurement methods." These methods, which provided the code of experimental procedure upon which, with modifications, later investigation has proceeded, are expounded in the special works on psycho-physics.
The Weber-Fechner law, although found applicable [p. 76] in a variety of cases, and employed with considerable license of speculation in others -- as in the theory of supply and demand in political economy -- has not proved of great value. The interpretation of the psycho-physical formula is uncertain. On Fechner's view, the "inner" psycho-physical bond -- that between the intrinsic brain process and the "soul" -- was one of direct proportion or cause and effect. Others think that the facts of psychological relativity and physical inertia account for the apparent discrepancy between the stimulation, considered as cause, and the sensation, considered as effect. It does, however, go far to confirm the postulates upon which the experimental treatment of the mind proceeds: it proves that the mind-body connection is constant and uniform.
Mental Chronometry. -- Another relatively distinct line of experimental research is that which inquires into the time taken up by psycho-physical and mental processes.
Underlying mental chronometry is the idea that since brain processes and mental processes occur together, and brain processes take time, the time of the central occurrence as a whole may be separated off from that of the other parts of a reaction. The time of the entire reaction from sense to muscle -- as when I press a key as soon as I see a light -- may be divided into three parts: that of the sensory transmission by the optic nerve, that of the central or brain process, and that [p. 77] of the motor transmission to the muscles of the hand. Subtracting from the entire time that required for the first and third parts -- quantities known through the researches of Helmholtz and others, on the velocity of the nervous impulse -- or keeping them constant and negligible, the time taken up by the psycho-physical and mental processes may be reached by simple calculation.
A vast amount of detailed research has been carried out in refinements on this experiment. "Times" have been determined for perception, discrimination, memory, association, etc. Broadly considered, however, the results are disappointing. As is the case with psycho-physics, besides plotting in a curve and listing in figures, extending to several decimal points, the results already reached by rough daily observation, there has been little gain.
An important difference, however, has been established between "sensory" and "motor" times -- cases in which the attention is fixed beforehand, respectively, in the direction of the stimulus or of the muscle used. The "motor" reaction is quicker. It has also been held that pronounced differences shown by individuals in their mental type, as beings visual, auditory, muscular, etc., in their preferred mental imagery, show themselves in differences of reaction time. Characteristic variations in reaction-time, occurring in abnormal cases and in nervous diseases, are useful adjuncts to diagnosis.
[p. 78] More important than these special researches in intensity and duration are the results obtained through experiments planned with reference to special problems. Here physiology and psychology go hand in hand. In the fields of sensation, memory, imaging, movement, emotion, attention, association, æsthetic judgment, thought, a mass of valuable facts and inferences have been accumulated: the variety and detail can only be understood by a reference to such handbooks as those of Helmholtz and Wundt already cited, and to the original papers in which the results are reported.
Genetic Psychology. -- With the coming of the evolution theory, especially in the form of the "natural selection" hypothesis of Darwin, considerations of origin, development, and growth came systematically into the natural sciences. Psychology in time felt the impulse; and gradually the genetic concept and method became current. The progress of Darwinism in the mental and moral sciences shows itself in certain of the departments of psychology in which specialisation has recently taken place: normal genetic psychology, child-psychology, animal or comparative psychology, race-psychology.
Jean Baptiste Lamarck (1774-1829), Charles Robert Darwin (1809-1882), and Alfred Russel Wallace. -- Both Darwin and Wallace, the English co-discoverers of natural selection, the latter still living, were in spirit psychologists, so generously did their instinct for nature in all its aspects extend itself. Lamarck, their French predecessor, had recognised as one of the factors of [p. 79] evolution the "efforts," psychological in their character, made by animals in accommodating themselves to their environment. The effects of these efforts, no less than the direct effects of the environment itself upon the animal, were inherited and accumulated from generation to generation, according to the well-known "Lamarckian" theory. In this Lamarck showed that he breathed the atmosphere of the new voluntarism of Maine de Biran and Jouffroy, founded upon the sense of effort.
Charles Darwin recognised this principle of Lamarck, as well as the latter's view of inheritance. But Darwin showed the broadest interest in the facts of the mind itself; and his theories and observations warrant our classing him among the naturalistic psychologists. The problems that exercised him were originally those of the animal kind -- instinct, sexual preference, recognition markings, emotional expression, adaptation, etc. -- all of which he discussed in the light of the theory of natural selection. But in his later work, The Descent of Man, he developed the full bearings of his views in their application to human faculty.
In it all we must recognise the founding of a new and thorough-going naturalistic psychology. The new and permanent element was the suggestion of a genetic morphology of the human faculties whose working out is one of the great tasks of the future. The mind in all its functions is a growth, its natural stages are those of the animal tree of life, its innate powers and a priori forms are inherited accretions which have been [p. 80] selected and accumulated from indeterminate variations. The formal or morphological factor in our equipment, no less than the content or filling given to it by experience, is the outcome of racial adaptation and selection in the physical and social conditions of man's pre-historical life.
In this we see a radical racial empiricism and naturalism, not only in point of view, but in the actual mechanism as disclosed in the principle of natural selection. Darwin not only proposed for the race what the associationists had suggested for the individual, the natural derivation of mental form; but his proposal took the problem of "matter and form" altogether out of the hands of the psychologist who treats of the individual, and made it again the genetic and historical problem that it had been to Aristotle and his Greek predecessors. The Kantian critique of experience asks: "How is the individual endowed to have the experience he has?" The Darwinian genetic naturalist asks: "What are the stages of racial history through which the individual has acquired his endowment?" It was the ring of mechanism and accidentalism in a theory founded upon "fortuitous variations" that made Darwin's views seem ultra-naturalistic in contrast with Lamarck's. But Darwin held also to the principle of the "inheritance of acquired characters" of Lamarck, although giving it a subordinate place.
Alfred Russel Wallace discarded, from the first, the Lamarckian view. In all his subsequent writings he has affirmed the sufficiency of natural selection. Like Darwin, he has an open mind for mental facts and sees their bearings on evolution. He has made many [p. 81] observations of psychological value -- on imitation courtship and mating habits, play, recognition of fellows, etc., among the animals. In one important respect, however, Wallace restricts the Darwinian principle outright. He holds that the rational and spiritual faculties of man could not have had a natural origin; and in his further view he seems to go over to a form of spiritualism understood in the narrower sense of the reality and separateness of spirits, sometimes called "spiritism."
Herbert Spencer (1820 - 1903). -- The psychologist's debt to Spencer has been grudgingly paid. The reason [p. 82] is, perhaps, this, that with an unexampled programme for the science, and an equally unexampled wealth of plausible and research-exciting hypotheses, in this as in other sciences, Spencer combined a semi-deductive method, a speculative and ultra-logical manner, and a dry unattractive style.
Spencer applied consciously and directly the principles of psychological morphology, which were also implicit in Darwin. The native, a priori, forms of the mind are looked upon as solidified social experience -- acquired, stiffened, transmitted by heredity. To the individual they are native; but by the race they have been acquired. Innate ideas are the petrified deposits of race experience. Here is a reconciliation in principle of the empiricist and the rationalist: the principle is that of racial experience; it is substituted for individual experience.
Spencer made Lamarckian inheritance an intrinsic link in the chain; but that is not necessary. Substitute for it the Darwinian conception of the continued selection of variations -- especially as guided in its course by "coincident" individual experience and social custom and habit -- and the result remains the same. To the psychologist, Spencer is an advance upon Darwin, however, in that he discusses the alternatives [p. 83] [figure -- Spencer] [p. 84] ad hoc, and brings out their bearings fully. The transfer of emphasis to racial experience introduced once for all the social way of looking at mental states. No doubt in this Spencer was influenced by Comte.
The genetic point of view, thus placed on a racial basis, remained somewhat formal with Spencer; in this he is in contrast with the extreme concreteness and empiricism of Darwin. In interpreting the actual mental life, Spencer retained the purely structural and associationist point of view. He extended the structural and analytic conceptions -- the theory of mental "elements" -- to a general "composition theory of mind," replacing Condillac's individual human statue by a racial animal colossus, so to speak. Beginnings with a primitive sensation or "feeling," accompanied by an elementary nervous process or "shock," a series of compositions takes place, resulting in more and more compound states. All concrete mental states are compounds resolvable by analysis. The first departure from simple feeling is a feeling of the relation of feelings; the presentative passes into the representative, the representative into the re-representative, etc. Thus the process goes on.
The additional principle invoked is that of association. Here again Spencer simply transfers the recognised pattern of individual psychology to the larger canvas of race history. Association is the cement of the mind; it binds the elements into wholes, and makes of the compositions permanent complexes and com-[p. 85] pounds. In thus rendering the mechanics of ideas in terms of association, Spencer remained true to the British tradition.
Spencer differed from the structural psychologist of to-day principally in being more thoroughgoing: he needed only one primitive element, they require generally two or three. With them he, too, used the analysis of chemical and biological synthesis to replace the looser union suggested by the laws of mechanics. But in this there is no real gain. In what we may call "the H²O theory" -- the chemical analogy -- there is no recognition of a functional reaction of consciousness or of the self upon the mental content; no real progression or genesis is reached in the growing complexity of the compounds produced. The mental process, like its mechanical and chemical analogues, might as well move backwards. The modern choice of phrasing -- "so much intellection, so much conation, and so much affection" -- does not help the case. In their criticisms, the functional psychologists have shown the inadequacy of association, workings on "elements," to accomplish mental synthesis. It is a poor sort of cement. Even those who eulogise it are prone to smuggle in, after the example of Hume, some disguised functional principle like habit.
[p. 86] It should be noted, however, that Spencer, a confessed Positivist, essentially revised the programme of Comte in respect to psychology. The independence and scientific integrity of psychology are recognised. The science is freed front the leading-strings of biology on the one hand, and from its service to sociology on the other; and stands in its true place between the sciences of life and those of society. This step the later history has fully justified; for psychology has since made more real and noteworthy scientific progress than sociology.
Animal and Comparative Psychology. -- It was natural to suppose that under the inspiration of the theory of evolution, various lines of observation would take on new interest; that the leading afforded by genuinely organising genetic principles, like those of Lamarck and Darwin, would result in directed scientific effort. This has been the case in animal psychology. The study of animals passed first from the "anecdotal stage" to that of close observation, that is, from mere story to "natural hsitory [sic]"; it then passed from observation to actual experiment.
The literature of the observation of animal habits and characters is rich and varied. The great naturalists, Buffon, Darwin, Wallace, lead off, following the lead of Aristotle. The works of Brehm, Romanes, Fabre, Hudson, are among the best on the general habits of animals, considered from the psychological [p. 87] side; those of Espinas, Groos, Lloyd Morgan, on special functions, interpreted by theories of psychological and social value. The new experimental method, pursued especially in the United States, raises the problems of comparative psychology, understood in the broadest sense. It attempts to apply actual experimentation to animals, from the lowest to the highest organisms -- from the micro-organism to the monkey. Its results are, of course, of enhanced interest when the comparative point of view is extended from the animals to man.
Leaving to the text-books the recital of the details of methods and results, we may point out the progress made toward the solution of certain of the older and more important problems.
Instinct. -- The problem of instinct gave to the new genetic theories a bone to exercise their teeth upon. Instinct had been looked upon as conclusive evidence of the "special creation," each after its own kind, of the different species of animals; the instincts are common to species, and diverse from one species to another. Further, instinct was taken to prove "design" in nature. Nowhere else were devices to be found so cunning in their construction, and so apt for their [p. 88] purpose, as those brought into play by the animal instincts.
With the rise of the Lamarckian view of evolution the first "natural" and genetic account of instinct came forward. It was held that with the passing down of acquired habits from generation to generation, these became fixed in the nervous structure; that is, they became instinctive. The bird builds its nest as it does because its ancestors learned consciously how to do so in the first instance. This function, acquired by experience, has been inherited and improved upon by countless generations, and has thus become native or innate. Finally, it has become a purely nervous function, requiring no antecedent experience on the part of the individual bird.
In this way all sorts of ancestral experiences were made available to later generations by the simple bridge of heredity, thrown across the chasm between parent and child. Reflex acts, the adaptations due to the "efforts" pointed out by Lamarck, the actual accommodations acquired by the intelligence and preserved by the experience of the forbears -- all these are preserved in solid nervous connections, in the organisms of the individuals of the species. In this way, the individuals are endowed with instincts.
This is the psychological or Lamarckian account of instinct, called by Spencer, to whom its fullest statement is due, the "lapsed intelligence" theory. The instincts seem so intelligent because they once were intelligent; they were acquired by the aid of intelligence. It is only their nervous apparatus that has instinct passing [p. 89] been conserved in the form of instinct; the intelligence, at first required, has lapsed, disappeared.
To this, the strict Darwinian theory, based on natural selection and denying the inheritance of acquired functions, opposes the theory of accumulated "variations." It is evident that if Lamarckian inheritance be disproved, or if it even remain unproved, the lapsed intelligence theory collapses completely. Apart from all questions of plausibility, this has been the result: recent biologists have almost unanimously discarded the inheritance of acquired actions, or so curtailed its scope that it is highly unsafe to give it any important place. Accordingly, except for vitalistic theories, such as that recently formulated by Bergson -- theories supposing in some form an intrinsic internal directive force in the life-process, by which functions are determined wholly or largely in independence of the action of the environment -- the Darwinian theory is the only resource.
Recent advances due to fuller observation and experiment make an essentially Darwinian view less difficult to accept. The principle of social heredity or tradition, recently formulated, rests upon observations which show the union of inherited and social activities in many functions formerly considered purely instinctive. By imitative or other processes of learning, the young of the various kinds acquire what has become a "social [p. 90] tradition" in the species, thus supplementing the rudiments which are inborn. In many of the cries of animals, their special activities of feeding, play, nesting, etc., an inherited but incomplete impulse or tendency is perfected and made effective by acquired tradition, which is handed down from generation to generation, not as a physical but as a social heritage.
It results from this -- and it is confirmed by independent observations -- that animal instincts are in many instances not perfect and invariable functions, as the older observers supposed. There are many partial instincts -- functions partially inborn -- which owe their effective exercise to the supplementing and perfecting due to teaching, exercise, and experience. The influence of the presence of parents, family, and companions on the growing young of animals extends to some of the most vital functions of their life; and few instincts are entirely free from it.
These considerations relieve considerably the strain upon natural selection in the Darwinian theory of instinct; since it is no longer called upon in such instances to account for the perfect, invariable, and precisely adapted instincts described by the older naturalists. Instead, its operation need extend only to that factor or part of the instinct which is actually inherited. Tradition, the social factor, does the rest.
A further selectionist theory of instinct is made [p. 91] possible -- though it has not yet to my knowledge been suggested -- by the new view of the nature and role of variations due to de Vries. Instead of the minute variations supposed by Darwin, "fluctuating" in every direction, upon which natural selection was held to act, de Vries discovers in plants occasional marked variations or "mutations," which breed true, and seem to establish stable departures from type analogous to new varieties. If this should prove to be true in the animal world generally, it would be possible to suppose that instincts, or some of them, arose as mutations or wide variations -- adaptive in character, and permanent in inheritance -- kept alive by selection.
The late definitions of instinct hold to its distinguishing character as being an actual performance or act, not a mere innate impulse or disposition. Impulses or dispositions may be "instinctive," in the broad sense of inborn; but an instinct, properly speaking, is an action, partly at least inherited, relatively complex, adaptive in character, and common to the members of a species. Or, defined negatively, it is a function which is not entirely learned from experience, not a simple reflex, not accidental or inadaptive, and not an individual performance.
Special Functions: Imitation. -- Among the functions closely investigated of late is that of imitation. The older and vague view was that certain animals, such as the monkey and the mocking-bird, were given to capricious imitation; and that the child was notoriously imitative. Recent investigations have treated the func-[p. 92] tion by observation, as it appears in the social life, and by experiment, as it is found in animals and children. In the result, the range of imitative activities has been both extended and restricted, as a clearer definition of the function itself has emerged.
If imitation be defined from the point of view of the mechanism of the imitative reaction, it takes on a very wide range. It may then be considered as a "circular" or self-repeating function; as when the young child repeats endlessly the "Ma-ma" sound that he hears himself make. This conception of imitation has an important place in pathology under the heading of "mimetism"; it appears in many pathological conditions, such as "echolalia," or mimetism of speech. The distinguishing point in this definition is that the stimulation which the act of imitation reproduces need not come from another individual. So far as the act is concerned, the result is the same if the stimulus is due to the action, or arises in the imagination, of the imitator himself. This opens the way for the inclusion of all sorts of auto-mimetic or self-imitative functions. Thus the notion of imitation is broadened. It extends to actions in low organisms which are circular or self-repeating, and also to conscious volitions, in which the imitation is directed toward an end set up in one sown mind. It thus becomes a unifying genetic principle of importance.
The other extreme definition of imitation makes it essentially social, a "copying" of one individual by another. In this form, the function is emphasised in theories of social organisation and inter-psychology.
[p. 93] But this cannot be called either a psychological or a biological conception; since neither the point of view of consciousness nor that of organic behaviour discriminates the character of the source whence a stimulation proceeds. It is rather a sociological conception, and a concession to the popular idea of imitation as an act of personal copying.
The two conceptions may, of course, be held together, one marking a special case under the other. It is necessary, however, to indicate clearly the usage one adopts. In experiments on animals the second or sociological conception is usually adopted, such experiments turning upon the behaviour of one animal in the presence of another. Many experiments have been made on animal imitation as thus defined. The result has been to establish the fact that imitation varies remarkably with the species; also that whether it enters essentially into the animal's learning process -- one animal profiting by what he sees or hears another do -- varies with the grade of the animal's intelligence and with the complexity of the act. In many cases it is so obscured by gregarious habits and social instincts that its signs are very ambiguous. In the higher forms it is especially marked in functions peculiar to the species, in which a rudiment of native impulse in the direction of the function in question may well be supposed. An animal imitates another of his own species, where he would not imitate one of a different kind.
[p. 94] As to its origin, the "instinct" theory of imitation accounts for it, as the instincts generally are accounted for, Larmarck-wise or Darwin-wise. It is opposed by those, among them Bain,  who consider the function acquired. The social or copying mode of imitation is considered by Wundt and others as a case of kinæsthesis -- the prompting of a movement by the idea of that movement -- since the copy may be looked upon as an idea which stirs up a kinæsthetic equivalent of the actual movement. The imitative type of reaction, however, psychologically and biologically considered as one that repeats itself through the reproduction of its own stimulation, is rooted more profoundly in organic conditions. It is seen in organic reaction to pleasurable and painful stimulation; the former being self-repeating, and the latter self-suppressing. On this view, as developed in the "circular reaction" theory, imitation has arisen from pleasure-pain or hedonic reactions which are fundamental to life.
Play. -- Another function, common to animals and man, which has been taken out of the category of mere incidental action and shown to be a function of great utility, is that of play. Principally through the [p. 95] important work of Groos, the topic has become one of interest both to biology and to psychology.
Earlier theories regarded play as a sort of luxury of life, a bit of by-play. The theory of "recreation" gave play a certain utility, that of providing recuperation to exhausted faculties during the game; and the "surplus energy" theory worked out by Spencer, which made play a sort of "escape" or vent for stored-up animal energies, also gave it a certain value. But no theory till that of Groos assigned to it a really important genetic role in the economy of animal growth.
The "practice" theory of Groos considers play a mode of preliminary exercise of the powers of mind and body, which gives them essential practice under conditions free from the storm and stress of their serious exercise. The kitten teasing the ball of yarn is preparing itself to be the cat teasing the mouse. The dog playing at fighting and biting is exercising himself to be the victor in encounters in which dogs really fight and bite. This extends throughout all the playful activities of an animal species; curiously, but on this theory reasonably, they show bungling and tentative imitations of the adult habits of the species. When all reserve as to details and minor qualifications are made, this theory seems likely to remain a permanent contribution to the list of real explanations.
Thus considered, play is a function of high utility. It may have -- and probably does have, as other writers have shown -- other utilities. It is socialising, it is purging of the energies, it is run through with dramatic [p. 96] and æsthetic meaning. Moreover, it serves the purpose of the exhibition and testing of the powers and character of the individual person or self, in a remarkable way. It gives scope to the imagination, allows the free play of fancy. All these psychological utilities go with the biological, as described in the practice theory, and in no way contradict it.
The theory of play which thus describes its role and utility makes of it, along with imitation, a native impulse. The theories of its origin are those of imitation over again; and play and imitation are found together. Most plays are imitative, many consciously so. The connection would seem to have its own utility also; for if play is to have its role in practising adult activities, it must be directed in the line of those activities. This could be done only by the production of an instinct to play each function before using it seriously, or by a more general method of bringing the immature functions, all alike, under the dominion of the play impulse. The latter is nature's method, and imitation seems to be the means adopted. By imitating their adults, their own activities are practised by the young; and by playing naturally as their powers develop, they imitate the strenuous life. Groos sums the matter up in these words: "Instead of saying, the animals play because they are young, we must say, the animals have a youth in order that they may play."
Play has also become the starting-point for new observations and theories in the psychology of æsthetic appreciation and art production. In play the rudiments [p. 97] of self-exhibition, decoration, make-believe or semblance, and imaginative dramatisation appear, which grow up and flower in the æsthetic consciousness. Of this a further word below.
Accommodation and Learning. -- The process by which a new act is learned, a new accommodation effected, has been under very diligent investigation. The older theories were, here as elsewhere, lacking in experimental control; but they hit upon the theoretical alternatives which the newer work is placing in the light.
Apart from the purely "causal" theory -- according to which the mind simply causes the movement of the body as it wishes, without having to learn how to do so -- the "reflex" theory seemed the natural resort: the movement is always a reflex, or a compound of reflexes, brought out by the stimulus. Both in its amount and in its direction and character, the movement is the effect of a definite cause. This is the Cartesian "automaton" theory reinstated in physiological terms.
Opposed to this mechanical view various vitalistic solutions have been proposed. They all assume something in the life processes added to the mechanical response to the environment: certain internal processes which initiate, regulate, or, at the very least, complicate and delay, the responses made by the organism to stimulation.
These three words -- initiate, regulate, and complicate [p. 98] -- are used in this order with the intent to bring out the stages of gradual retreat of vitalistic conceptions, in view of the results of experimental research. Few hold to-day that the will or the soul can initiate a movement of the muscles in an absolute sense. No movement can be made outright, without learning and practice; to be made, it must have been made. Accordingly it is held that a directive control over the energies released by the stimulus is exercised by the mind in its psycho-physical function; voluntary and even semi-automatic movements have a degree of variability and uncertainty that differentiates them, and removes them from the category of direct effects of given mechanical causes.
Not stopping to rehearse again the controversy on the mind-body relation, we may state the results of recent work. Experiments on low organisms have done little more than sharpen the issue and give it a new terminology, in spite of the evident extension of the scope of the mechanical point of view and the accumulation of many facts. The theory of tropisms reduces the higher responses to complications of simple [p. 99] ones, mechanical in character. Except for new evidence, it amounts to a re-statement of the reflex theory, and the utility of the new word is not entirely evident.
The opposition to this theory, made articulate in the work of Jennings, points to the complicated internal processes, chemical and vital, which lie between the stimulus and the response, even in the simplest organisms; and holds that this central network of processes is the seat of the directive and complicating factor, whatever it may be. It is also the seat of consciousness, which seems to vary in degree and positive function with the apparent indeterminism of movement. The natural inference is that, whatever its final meaning may turn out to be, the presence of consciousness makes this link in the chain "psycho-physical," rather than purely "physical"; and this makes a difference. What difference? -- just the difference we see between voluntary and reflex movements, between movements intended and directed as well as caused, and movements merely caused.
While, therefore, a remarkable showing of positive results has been made by experimental research on organisms high and low the outcome for general theory is so far a restatement of the old theoretical alternatives. With this difference, however: it grows more and more difficult to hold to either alternative, mechanical or vitalistic, as being final. Hence it is [p. 100] held by the advocates of a radical genetic point of view that the solution lies in the recognition of "genetic modes'' or stages in the process of nature, which are sui generis, and each of which is a real advance, to be understood only in terms of its own characters or processes, not in terms of a simpler mode or by means of the scientific abstractions made to fit the simpler. The mechanical reading proceeds by the use of physical analogies; the vitalistic, by those drawn from consciousness and volition. Nature, however, achieves a union of the two which is psycho-physical; and our daily observation teaches us that neither the one analogy nor the other is adequate to symbolise it.
In the investigations, however, made on accommodation and learning, in the province of movement, a noteworthy advance has been made. It has been shown that the actual new adjustments which constitute the learning of a movement are, certainly in many cases, subject to the law of "trial and error" or "selection from over-produced movements." The animal tries with more or less success -- actually less and then more -- until he learns. The history of this principle, now probably safely proved, may be briefly indicated.
In principle, as its early proposers recognised, it is an application of Darwin's law of selection. The movements of trial or "try-try again," varying in force and direction, are "cases"; and with the multiplication of cases, the chance of "happy hits" -- a phrase used by Bain in discussing this topic -- is increased. So looked upon, the problem has ably but somewhat abstractly discussed by Spencer, who postulated diffused discharges from the nervous centres, giving an over-[p. 101] production of "random" movements in great variety -- "fortuitous," in the Darwinian phrasing -- of which certain are adaptive. These are subsequently carried out by a wave of "heightened nervous energy," which fixes a path of least resistance in the organism. In order to this, another important factor is necessary, and Spencer recognised it: a feeling of pleasure is connected with such successful and adaptive movements, which, by association with the pleasure, are repeated and made permanent.
Bain brought to the problem the idea of "native spontaneity," a primitive tendency to movement with which, on his view, all life is endowed. Movement precedes sensation. It is from this store of original, restless, overflowing activities that adaptive movements are selected. He adopted the idea that pleasure and pain regulated the selection. In his phrase, pleasure "clinches" the adaptive action and by association makes it permanent through repetition. The order of the factors, in the view of Bain, is as follows: "random movement, pleasure, memory of pleasure with memory of movement, adapted movement." Bain recognised that all the essential factors of his theory had been named by Spencer; but Bain's treatment is more concrete and convincing.
It is upon this background of theory that the law of "trial and error" emerges from experimental research. [p. 102] It re-states, so far as the method of performing and singling out the successful movement is concerned, the law of "functional or excess selection from over-produced movements." It brings the learning process into line with other cases of the production of apparently directed results selected from ill-assorted data. "Trial and error" is a phrase used in the mathematical treatment of chances. Experimental research, however, has not yet answered the other questions involved: what is it that constitutes the act an adaptation? -- and what clinches or preserves such movements rather than those which are suppressed? To these questions, the Spencer-Bain theory in some form still supplies the only answer -- pleasure and pain.
The proof of this law through experiment, however, carries the application of Darwinian selection into a new and unexpected field. Its application is possible and has been made to voluntary no less than to merely responsive movements.
Experiments have been made upon various aspects of learning, understood in the larger pedagogical sense. They extend from the conditions of memorising to those of conscious relating and apperceiving. A much disputed question is as to whether the discipline of one faculty improves others -- the old question of "formal training" -- and more generally as to what are the laws ruling the correlation of the faculties.
Experiments on children have come to supplement observation, in the pursuit of Child Study, another line [p. 103] of genetic work. Biographies, diaries, "questionnaires," experimental studies, theoretical interpretations, have all taken on a more serious and scientific look since the day of the publication of Darwin's and Preyer's careful observations. While not of startling theoretical importance, the results have justified the genetic method and reinforced its data. Serious treatment of certain of the larger questions involved in the psychology and biology of the growing individual are to be found in such works as that of Hall on adolescence.
 On these topics the reader may consult the writer's more detailed but untechnical expositions to be found in the work Fragments of Philosophy and Science, Chaps. VI and VII. The last edition of Wundt's Gründzuge der physiologischen Psychologie, Titchener's Experimental Psychology, and Ladd and Woodworth's Outlines of Physiological Psychology (2nd ed. 1911), are to be recommended for further study. An admirable early English work, written from the medical point of view, is W. B. Carpenter's Principles of Mental Physiology (1876).
 The idea of a "sensational equivalent" -- that there is a definite equivalence between mental manifestations and physical forces, the same as between the physical forces themselves" [sic] -- is stated by Bain, "Correlation of Nervous and Mental Force," in Stewart's Conservation of Energy. Weber had already stated that in order to produce a noticeable increase in sensation, the stimulation must be increased by a constant proportion. Fechner (Elemente der Psychophysik, 1860) called his deduction the "law of quantity or intensity" (Massgesetz).
 This "type theory" of differences in reaction time is presented and discussed in the writer's Fragments in Philosophy and Science, Chaps. XVI-XVIII -- a citation made, however, for the further purpose of adding that the enthusiasm shown in the researches and discussions on this subject in that volume does not appear in the present text. In this dampening of ardour the writer by no means stands alone: cf. James, Principles of Psychology.
 Both Darwin and Wallace recognised the role played by consciousness in animal adaptations; such as the cunning employed in flight, the taste and preference of the female, the warning given by colours and cries, the emotion shown in defence, the consciously social and gregarious actions; as well as imitation, rivalry, maternal and family affection, etc. In certain developments of Darwinian theory, consciousness plays an essential part; note the facts supporting the theory of mimicry, as reported in the writings of E. B. Poulton and others.
 A limitation of the same sort was set upon natural selection by the staunch Darwinian, Huxley, who held (Huxley, Romanes Lecture, on Evolution und Ethics) that the moral sense could not have been produced under conditions involving the "struggle for existence." A criticism of this view is to be found in the present writer's Darwin and the Humanities. See Wallace's Darwinism, for his strictly biological theories, and the Studies, Scientific and Social, for his more general views.
 H, Spencer, Principles of Psychology (1855). It is strange, but it is true, that many British writers find it impossible to do any sort of justice to Spencer. And yet where is there the British writer, save Darwin, whose name and theories are to be found in the whole world's literature of a half-dozen great subjects, since 1850 as Spencer's are? We hear it said that half the world now-a-days thinks in terms of Darwinism: but it is truer to say "in terms of evolutionism"; for half of the half thinks its evolutionism in terms, not of Darwinism, but of Spencerism. Moreover, in the Latin countries and in the United States, it was the leaven of Spencer's evolutionism that first worked its way through the lump. Why not, then, recognise Spencer as what he was, one of the greatest intellectual influences of modern times, a glory to British thought? In psychology this is specially worth insisting upon, since Spencer came just at a time of surprising barrenness in this department in England.
 A term due to C. Lloyd Morgan, one of the discoverers of the supplement to Darwinism, known as "organic selection," indicated in the text between the dashes: Ll. Morgan, Habit and Instinct (1896), pp. 322 ff.; see also H. F. Osborn, Science, Oct. 15 1897, and the present writer's Development and Evolution, Chaps. VIII ff., and Darwin and the Humanities, Chap. I.
 It is a question how far Spencer was influenced by Darwin. The dates of publication would indicate that Spencer's thought was, in the main, independent of Darwin's. Moreover, the theory of natural selection, to which Darwin's Origin of Species was devoted, would hardly have appealed at once to one imbued, as Spencer was, with Lamarckism. This is confirmed, too, by Spencer's subsequent attitude toward natural selection.
 In its result the composition theory and structural views in general, which seek to decompose mental states into elements lead to an analysis based upon the simpler conditions found in other sciences. In Spencer, this procedure was a habit of mind. Through his influence, mechanical analogies plagued biology, and biological analogies plagued sociology. It results everywhere in the "illusion of simplicity." The very flower and fruit of synthesis are lost in the counting of the disjecta membra of "elements.". . . Certain of Spencer's more special theories are noticed in the sections on Comparative and Affective Psychology just below.
 In this and the following sections dealing with special topics, it will be impossible to cite authorities in detail; apart from earlier writers, only works which give summaries will be cited, to guide the reader's further study.
 The need of objectivity and control has led to the emphasis of behaviour as such, and the "science of animal behaviour" tends to replace "animal psychology." Such a science would be in principle natural history over again -- made experimental -- much as Aristotle conceived it. If such a method is to yield psychological results, it must be made a means, a method of securing data for a true comparative psychology. For example, the object of experiments on the colour vision of animals is sensation, not behaviour.
 H. Bergson, Évolution créatrice (1907); Bergson holds that instinct is a sort of direct or "sympathetic" knowledge on the pare of the animal, being in contrast with the "logical" form of knowledge seen in the intelligence.
 Spoken of again below in the section on Social Psychology; its recognition in animal activities was made by Wallace (Darwinism), Ll. Morgan (Habit and Instinct), and Weismann (Studies in Heredity).
 This is made the more evident, if it be true, as the theory of "organic selection" mentioned above maintains, that the accommodations resulting from learning, exercise, tradition, etc., screen and keep alive variations coincident in direction with themselves. In this case, the course of natural selection would be directly in the lines first marked out by intelligent, social, and other adaptations; and any stage of development of the innate factor would be effective if supplemented by acquired modifications, as the circumstances of the case might require.
 A term used by Tarde, Les Lois de l'imitation and Les Lois sociales (1898), both translated into English, for a restricted social psychology. Tarde upholds an extreme imitation theory of social organisation: see below, section on Social Psychology in Chapter VI.
 The literature of imitation gives many distinctions, such as "conscious," "unconscious," "subconscious," "plastic,' "persistent" imitation, etc. A curious phenomenon is that of "deferred" imitation, an example of which I may note here from a body of unpublished observations on West African gray parrots. The parrot seems to make no response whatever to a word repeated in his hearing, for his learning, for days or weeks; when suddenly he is heard uttering the word aloud, or mumbling it over to himself, when there is no copy given him. The stimulus, repeated so often, has a sort of cumulative effect, and after a period of incubation, so to speak, the imitation appears. This may well be called "deferred imitation." A peculiarity of it is that the fairly successful imitation is not preceded by grossly bungling attempts, although there may be a sort of internal practice before the articulate sound is made.
 It is on such correlations as this, and the truths they are based upon, that a new and "natural" pedagogy must be based. Educational theory and practice are already profiting by the recent advances in genetic psychology.
 According to the principle of "kinæsthetic equivalents" established in brain-physiology and pathology, no movement can be made unless and until there is in the mind a memory, image, thought or other symbol equivalent to the movement, due to earlier experience of making it. Cf. the writer's Dictionary of Philosophy and Psychology, sub verbo. The term "kinæsthesis" ("feeling of movement") was first used by C. Bastian, Brain as an Organ of Mind (1880).
 Summaries of researches are to be found in Washburn's The Animal Mind, and Bohn's La Naissance de l'Intelligence. See also the reviews given annually in the "Comparative Psychology" issue of the Psychological Bulletin.
 Quoted from the writer's summing up of a more detailed exposition in another place (Mental Development in the Child and the Race), Chap. II, 3rd ed., p. 173, where it is pointed out that it is the pleasure that is the original term -- if not the first in time -- since it is not a repetition of the movement as such, but of the pleasure and its conditions, that gives utility to the reaction and furnishes evidence of the adaptation.