Fact and Fable in Psychology

by Joseph Jastrow

II

With regard to the blind, much of what has been said above is entirely irrelevant. However intimately we appreciate the function of sight in our own mental development, it is almost impossible to imagine how different our life would have been had we never seen. But here, at the outset, a fundamental distinction must be drawn between those blind from birth or early infancy, and those who lose their sight in youth or adult life.[13] "It is better to have seen and lost one's sight than never to have seen at all," is quite as true as the sentiment which this form of statement parodies. Expressed physiologically, this means, that to have begun the general brain-building process with the aid of the eye insures some further self-development of the visual centre, and thus makes possible a kind of mental possession of which those born blind are inevitably deprived.[14]

A fact of prime importance regarding the development of the sight-centre is the age at which its education is sufficiently completed to enable it to continue its function without further object-lessons on the part of the retina. If we accept as the test of the independent existence of the sight-centre its automatic excitation in dreams, the question can be answered by determining the age of the onset of blindness, which divides those who do not from those who still retain in their dream-life the images derived from the world of sight. The data that enable me to answer this question were gathered at the Institutions for the Blind in Philadelphia and Baltimore. Nearly 200 persons of both sexes were personally examined, and their answers to quite a long series of questions recorded. All dates and ages were verified by the register of the institution, and the degree of sight was tested.

Beginning with cases of total blindness (including under this head those upon whom light has simply a general subjective "heat-effect," enabling them to distinguish between night and day, between shade and sunshine, but inducing little or no tendency to project the cause of the sensation into the external world), I find on my list fifty-eight such cases. Of these, thirty-two became blind before the completion of their fifth year, and not one of this group of thirty-two sees in dreams. Six became blind between the fifth and the seventh year: of these, four have dreams of seeing, but two of them do so seldom and with some vagueness; while two never dream of seeing at all. Of twenty persons who became blind after their seventh year all have "dream-vision"—as I shall term the faculty of seeing in dreams. The period from the fifth to the seventh year is thus indicated as the critical one. Before this age the visual centre is undergoing its elementary education; its life is closely dependent upon the constant food-supply of sensations; and when these are cut off by blindness, it degenerates and decays. If blindness occurs between the fifth and the seventh years, the preservation of the visualizing power depends on the degree of development of the individual. If the faculty is retained, it is neither stable nor pronounced. If sight is lost after the seventh year, the sight-centre can, in spite of the loss, maintain its function; and the dreams of such an individual may be hardly distinguishable from those of a seeing person.

It was a very unexpected discovery, to find, after I had planned and partly completed this investigation, that I had a predecessor. So long ago as 1838, Dr. G. Heermann studied the dreams of the blind with the view of determining this same question, the physiological significance of which, however, was not then clearly understood. He records the answers of fourteen totally blind persons who lost their sight previous to their fifth year, and none of these has dream-vision. Of four who lost their sight between the fifth and the seventh year, one has dream-vision; one has it dimly and occasionally; and two do not definitely know. Of thirty-five who became blind after their seventh year all have dream-vision. The two independent researches thus yield the very same conclusion. Dr. Heermann includes in his list many aged persons, and from their answers is able to conclude that, generally speaking, those who become blind in mature life retain the power of dream-vision longer than those who become blind nearer the critical age of five to seven years. He records twelve cases where dream-vision still continues after a blindness of from ten to fifteen years, four of from fifteen to twenty years, four of from twenty to twenty-five years, and one of thirty-five years. In one case dream-vision was maintained for fifty-two, and in another for fifty-four years, but then faded out.[15]

With regard to the partially blind, the question most analogous to the persistence of dream-vision after total blindness, is whether or not the dream-vision is brighter and clearer than that of waking life; whether the sight-centre maintains the full normal power to which it was educated, or whether the partial loss of sight has essentially altered and replaced it. To this rather difficult question I have fewer and less satisfactory answers than to the former inquiry; but the evidence is perfectly in accord with the previous conclusions. Of twenty-three who describe their dream-vision as only as clear as waking sight, all became blind not later than the close of their fifth year; while of twenty-four whose dream-vision is more or less markedly clearer than their partial sight, all lost their full sight not earlier than their sixth year.[16] The age that marks off those to whom total blindness carries with it the loss of dream-vision from those whose dream-vision continues, is thus the age at which the sight-centre has reached a sufficient stage of development to enable it to maintain its full function, when partially or totally deprived of retinal stimulation. The same age is also assigned by some authorities as the limiting age at which deafness will cause muteness (unless special pains be taken to prevent it); while later the vocal organs, though trained to action by the ear, can perform their duties without the teacher's aid. This, too, is assigned as the earliest age at which we have a remembrance of ourselves. This last statement I am able to test by one hundred answers, collected among these blind persons, to the question, "What is your earliest remembrance of yourself?" The average age to which these memories go back is 5.2 years; seventy-nine instances being included between the third and the sixth years. At this period of child development—the centre of which is at about the close of the fifth year—there seems to be a general declaration of independence of the sense-centres from their food-supply of sensations. Mr. Sully finds sense, imagination, and abstraction to be the order in which the precocity of great men reveals itself; and the critical period which we are now considering seems to mark the point at which imagination and abstraction as permanent mental powers ordinarily come into play. M. Perez likewise recognizes the distinctive character of this era of childhood by making the second part of his "Child Psychology" embrace the period from the third to the seventh year.

III

The general fact thus brought to light—that the mode in which a brain-centre will function depends so largely upon its initial education, but that, this education once completed, the centre can maintain its function, though deprived of sense-stimulation—is sufficiently important to merit further illustration.[17] This fact, though very clear and evident when stated from a modern point of view, has not always been recognized. So ingenious a thinker as Erasmus Darwin inferred from two cases (the one of a blind man, the other of a deaf-mute) in which the wanting senses were also absent in dreams, that the peripheral sense-organ was necessary for all perception, subjective as well as objective; and entirely neglected the age at which the sense was lost. Such noted physiologists as Reil, Rudolphi, Hartman, Wardrop (who says, "when an organ of sense is totally destroyed, the ideas which were received by that organ seem to perish along with it as well as the power of perception"), more or less distinctly favored this view; while some teachers of the blind and the physiologists Nasse and Autentreith rightly drew the distinction between those born, and those who became, blind. An experimental demonstration of the original dependence of the perceptive and emotional powers upon sense-impressions was furnished by Boffi and Schiff, who found that young dogs whose olfactory bulbs had been removed failed to develop any affection for man.

What is true of the visual, is doubtless equally true of the other perceptive centres. The dreams of the deaf-mute offer an attractive and untouched field for such study.[18] The few accounts of such dreams that I have met with, fail to give the age at which deafness set in; in one case, however, in which deafness occurred at thirty years, the pantomimic had replaced the spoken language in the dreams of thirty years later. Similarly, cripples dream of their lost limbs for many years after their loss; in such cases, however, stimulation of the cut nerves may be the suggestive cause of such dreams. A man of forty, who lost his right arm seventeen years before, still dreams of having the arm. The earliest age of losing and dreaming about a lost limb, of which I find a record, is of a boy of thirteen years who lost a leg at the age of ten; this boy still dreams of walking on his feet. Those who are born cripples must necessarily have their defects represented in their dream consciousness. Heermann cites the case of a man born without hands, forearms, feet, or lower legs. He always dreamt of walking on his knees; and all the peculiarities of his movements were present in his dream-life.