This is a fact of comparatively recent discovery. The first proponent of the idea was Fechner, but no statistical work was done in this line until Galton entered the field, in 1880. In his “Inquiries into Human Faculties,” he says:
Investigations of Doctor Galton
“To my astonishment, I found that the great majority of the men of science to whom I first applied protested that mental imagery was unknown to them, and they looked on me as fanciful and fantastic in supposing that the words ‘mental imagery’ really expressed what I believed everybody supposed them to mean. They had no more notion of its true nature than a color-blind man, who has not discerned his defect, has of the nature of color. They had a mental deficiency of which they were unaware and naturally enough supposed that those who affirmed they possessed it were romancing.”
Investigations of Professor James
The investigations of Dr. Galton were continued by Professor James, of Harvard University. He collected from hundreds of persons descriptions of their own mental images. The following are extracts from two cases of distinctly different types. The one who is a good visualizer says:
“This morning’s breakfast-table is both dim and bright; it is dim if I try to think of it with my eyes closed. All the objects are clear at once, yet when I confine my attention to any one object it becomes far more distinct. I have more power to recall color than any other one thing; if, for example, I were to recall a plate decorated with flowers I could reproduce in a drawing the exact tone, etc. The color of anything that was on the table is perfectly vivid. There is very little limitation to the extent of my images; I can see all four sides of a room; I can see all four sides of two, three, four, even more rooms with such distinctness that if you should ask me what was in any particular place in any one, or ask me to count the chairs, etc., I could do it without the least hesitation. The more I learn by heart the more clearly do I see images of my pages. Even before I can recite the lines I see them so that I could give them very slowly word for word, but my mind is so occupied in looking at my printed image that I have no idea of what I am saying, of the sense of it, etc. When I first found myself doing this I used to think it was merely because I knew the lines imperfectly; but I have quite convinced myself that I really do see an image. The strongest proof that such is really the fact is, I think, the following:
“I can look down the mentally seen page and see the words that commence all the lines, and from any one of these words I can continue the line. I find this much easier to do if the words begin as in a straight line than if there are breaks. Example:
Etant fait
Tous .............
A des ............
Que fit ..........
Ceres ............
Avec ...........
Un fleur .........
Comme ..........
(La Fontaine S. IV.)”
“My ability to form mental images seems, from what I have studied of other people’s images, to be defective, and somewhat peculiar. The process by which I seem to remember any particular event is not by a series of distinct images, but a sort of panorama, the faintest impressions of which are perceptible through a thick fog—I cannot shut my eyes and get a distinct image of anyone, although I used to be able to a few years ago, and the faculty seems to have gradually slipped away. * * * In my most vivid dreams, where the events appear like the most real facts, I am often troubled with a dimness of sight which causes the images to appear indistinct. * * * To come to the question of the breakfast-table, there is nothing definite about it. Everything is vague. I cannot say what I see. I could not possibly count the chairs, but I happen to know that there are ten. I see nothing in detail. * * * The chief thing is a general impression that I cannot tell exactly what I do see. The coloring is about the same, as far as I can recall it, only very much washed out. Perhaps the only color I can see at all distinctly is that of the tablecloth, and I could probably see the color of the wall paper if I could remember what color it was.”