The Foundations of Normal and Abnormal Psychology/Part 1/VII
The popular scientific literature of today often asserts dogmatically the belief that the investigation of the normal precedes that of the abnormal. This belief is erroneous and is only given credence to by people who had not thought much on the subject, and especially by those who belong to the so-called "new psychology" school. As a matter of fact the abnormal in scientific research precedes that, of the normal. The investigation of the abnormal is one of the most potent instruments for new discoveries. The method of experimentation, the most powerful tool of modern science, is in fact the creation of artificial conditions, in other words, the effecting of abnormal states. Where the compound is highly complex, where the constituent factors and their relations are imperfectly or all but unknown and are not therefore under control, the spontaneous occurrence of some anomaly ought to be greeted enthusiastically, as it discloses the role played by the modified or excluded factor. This is specially true in the case of mental life, where the phenomena under investigation are the most complex in the whole domain of science, where a direct modification of the functioning mental activity is as a rule impossible without the production of some anomaly.
In the case of psychic life experimentation may be conducted on two different lines of research. The one is the modification of the objective content by means of changing the objective stimulus. The other method, and by far the most efficient and fruitful, is the modification of the very function on which the psychic content depends.
Memory, for instance, may be studied by giving the subject a series of auditory or visual impressions at given intervals, and then seeing how many of the series the subject can remember after a given interval. We can thus determine the role played by such factors as time, number of impressions, number of repetitions, etc. The function of memory remains the same, and only the stimuli of the psychic content are modified. We may, however, study memory from a totally different standpoint, and that is by the disturbance of its function. Disturbance of function may be studied in artificial states produced by drugs, or induced by hypnosis; or by investigating cases in which the function is accidentally disturbed, such, for instance, as are to be found in different forms of amnesia and aphasia.
The second method is by far the more important of the two, and is extremely valuable. For it is only by disturbances in the function of thought that we can learn something about the factors and nature of mental life. We cannot possibly learn about the nature of a process, unless we disturb it artificially, or unless we try to study cases in which we can find the process in different stages or degrees of perturbation; here one factor is missing, there another is exaggerated, and so on. From such cases it is easy to analyze the constituent factors and their interrelations. In mechanics, for instance, the law of inertia would have never been discovered, if not for the imagining of such a case as the absence of all friction, or its approximate removal. The ancients who looked to the ordinary phenomena of common life, that is to the normal, considered that bodies are bound to stop. The ancient physicists, relying on their observations of the normal, believed that bodies in falling traverse space in proportion to their weight; it required a Galileo to detect the fallacy and show that bodies, no matter what their size and weight be, falling from a high place or in a vacuum, fall to the ground at the same time. The same holds true in the case of chemistry; no observer of water in its "normal" state would have detected the presence of hydrogen and oxygen. Only under highly artificial or abnormal conditions was it possible to discover the constituents that go to make up the compound water.
If we turn to the sciences dealing with more complex phenomena, we find illustrated the same truth. We know how highly instructive Darwin found it to follow closely for a period of many years experiments of breeds in artificial selection, and to what capital account he turned his highly valuable observations of all forms of curiosities and monstrosities. We all know how valuable the observation and study of all forms of anomalies or variations from the normal type or species proved to the final establishment of the theory of evolution. The pre-Darwinian zoologist ignored variation regarding it simply as an exception to the normal, as a mere abnormality, as a pathological manifestation which is of little value to the scientist, who is only occupied with the discovery of general laws, laws of the normal. As a matter of fact, it was just these neglected variations, deviations from the normal that turned out to be at the very foundation of biology, revealing the nature and mechanism of the evolution of species.
The same truth we find illustrated in the investigations of the functions of the different parts of the organism. Experiments on animals such as vivisection, injecting of toxin matter, etc., experiments that actually mean the putting of animals in pathological states, as well as the investigation of pathological cases in man, have given physiology its most valuable treasures. Knowledge of the normal arises out of knowledge of the abnormal. In fact we may even say that the normal itself originates in the abnormal. It is in variation, in anomalies, that the normal species takes its origin.
Strictly speaking the normal is not at all a scientific concept, it is purely provisional in its nature, and holds only good from a restricted point of view in transitional stages of science. The normal is that which is common; the normal is the usual; and it is not the usual, but the unusual that gives birth to new life in science. The unusual attracts our attention and reveals to us the function and role played by the particular affected product in the total compound. Taking all this into consideration, I think that they are wrong who insist that the abnormal can be known only from the normal. We can realize now how superficial are those who tell us "we learn but little from the abnormal, for first of all comes the normal." We realize now how detrimental to scientific investigation such a contention is. As a matter of fact the progress of science is not from the normal to the abnormal, but the very reverse, from the abnormal to the normal; the normal is but an arbitrary temporary concept, modified, and determined by the abnormal or unusual.
The supreme importance of pathological research holds especially true in the case of psychology, where the phenomena and the conditions on which these depend are so highly complex and so intricate, appearing at the same time so simple and taken as a matter of course in ordinary life.
As we have pointed out in the investigation of mental life we may either change the psychic or objective content, or effect changes in the mental function itself. In the study of vision, for instance, we may effect changes in the conditions of external objects, leaving the eye itself undisturbed. We may keep the object at different distances and study its appearances, put the object in water and have it refracted at different angles; we may look at it through different prisms, colored glasses or contrast its color when appearing in combination with other colors, whether it be successive or simultaneously. Instead, however, of effecting changes in the objects taken in by the eye, we may study the mechanism of vision by investigating the disturbances of the function of sight itself under the influence of drugs injected into the eye, or in different ocular diseases. The latter method is by far the more valuable for revealing the real mechanism of the visual apparatus.
Similarly in the study of memory we may follow the method of the German school, such for instance as that of Ebbinghaus and others, and investigate the laws of memory by analyzing the changes effected in its contents; or we may study the mechanism of memory by studying its disturbances in different forms of amnesia and mental diseases. Since psychology primarily deals with the laws of psycho-physiological functions, it will be admitted that the more important and valuable method is the one that has for its subject matter the changes going on directly in the material under investigation. The investigations, however, of changes or disturbances of mental function itself are really a study of the abnormal, researches into the domain of mental pathology. In psychology, as in many other sciences, especially those of the biological order to which psychology naturally belongs, the pathological method is by far the most important. We can realize now the reason why it would be well for psychology to follow closely not the methods of physical sciences, but those of the biological sciences. The material with which physics deals lacks the pathological element, it can be introduced only figuratively, not so is it in the order of phenomena with which biology deals. In biology variations, abnormalities, pathological elements stand out in the foreground, and no step can be made without taking them into consideration. The psychologist in order to succeed and obtain more efficient and valuable results must keep in mind clearly the fact that the psychic process is a form of life in general, its phenomena are naturally related to the province of biology, and that of the highest part of it. The methods of psychological investigation must follow the line not of the physical, but of the biological sciences.