The Story of the Mind

by James Mark Baldwin

That this difficulty is a real one no one who has examined students will be disposed to deny. When we ask them to reproduce what the text-book or the professor's lectures have taught, we also ask them to express themselves accurately. Now the science of correct expression is a thing in which the average student has had no training. With his difficulty in remembering is connected his difficulty of expression; and with it all goes a certain embarrassment, due to responsibility, personal fear, and dread of disgrace. So the results finally obtained by this method are really very complex.

One of the curves, that given by the method of Selection (I), also shows memory to be interfered with by a certain influence. We saw in connection with the experiments reported above that, even in the most elementary arrangements of squares in the visual fields, an element of contrast comes in to interfere with our judgment of size. This we find confirmed in these experiments when the method of Selection is used. By this method we show a number of squares side by side, asking the individual to select the one he saw before. All the squares, being shown at once, come into contrast with one another on the background; and so his judgment of the size of the one he remembers is distorted. This, again, is a real influence in our mental lives, leading to actual illusion. An unscrupulous lawyer may gradually modify the story which his client or a witness tells by constantly adding to what is really remembered, other details so expertly contrasted with the facts, or so neatly interposed among them, that the witness gradually incorporates them in his memory and so testifies more nearly as the lawyer desires. In our daily lives another element of contrast is also very strong—that due to social opinion. We constantly modify our memories to agree more closely with the truths of social belief, paring down unconsciously the difference between our own and others' reports of things. If several witnesses of an event be allowed to compare notes from time to time, they will gradually come to tell more nearly the same story.

The other curve (II) in the figure, that secured by the method of Identification, seemed to the investigators to be the most accurate. It is not subject to the errors due to expression and to contrast, and it has the advantage of allowing the subject the right to recognise the square. It is shown to him again, with no information that it is the same, and he decides whether from his remembrance of the earlier one, it is the same or not. The only objection to this method is that it requires a great many experiments in order to get an average result. To be reliable, an average must be secured, seeing that, for one or two or a few trials, the student may guess right without remembering the original square at all. By taking a large number of persons, such as the three hundred students, this objection may be overcome. Comparing the averages, for example, of the results given by the men and women respectively, we found practically no difference between them.

This last point may serve to introduce a distinction which is important in all work in experimental psychology, and one which is recognised also in many other sciences—the distinction between results obtained respectively from one individual and from many. Very often the only way to learn truth about a single individual is to investigate a number together. In all large classes of things, especially living things, there are great individual differences, and in any particular case this personal variation may be so large that it obscures the real nature of the normal. For example, three large sons may be born to two small parents; and from this case alone it might be inferred that all small parents have large sons. Or three girls might have better memories than three boys in the same family or school, and from this it might be argued that girls are better endowed in this direction than boys. In all such cases the proper thing to do is to get a large number of cases and combine them; then the preponderance which the first cases examined may have shown, in one direction or the other, is corrected. This gives rise to what is called the statistical method; it is used in many practical matters, such as life insurance, but its application to the facts of life, mind, variation, evolution, etc., is only begun. Its neglect in psychology is one of the crying defects of much recent work. Its use in complicated problems involves a mathematical training which people generally do not possess; and its misuse through lack of exactness of observation or ignorance of the requirements is worse than its neglect.

Another result came out in connection with these experiments on memory, which, apart from its practical interest, may serve to show an additional resource of experimental psychology. In making up the results of a series of experiments it is very important to observe the way in which the different cases differ from one another. Some cases may be so nearly alike that the most extreme of them are not far from the average of them all; as we find, for example, if we measure a thousand No. 10 shot. But now suppose we mix in with the No. 10 some No. 6 and some No. 14, and then take the average size; we may now get just the same average, and we can tell that this pile is different from the other only by observing the individual measurements of the single shot and setting down the relative frequency of each particular size. Or, again, we may get a different average size in one of two ways: either by taking another lot of uniform No. 14 shot, let us say, or by mixing with the No. 10 a few very large bullets. Which is actually the case would be shown only by the examination of the individual cases. This is usually done by comparing each case with the average of the whole lot, and taking the average of the differences thus secured—a quantity called the "mean variation."

In the case of the experiments with the squares, the errors in the judgments of the students were found to lie always in one direction. The answers all tended to show that they took, for the one originally shown, a square which was really too large. Casting about for the reason of this, it was considered necessary to explain it by the supposition that the square remembered had in the interval become enlarged in memory. The image was larger when called up after ten or twenty minutes than it was before. This might be due to a purely mental process; or possibly to a sort of spreading-out of the brain process in the visual centre, giving the result that whenever, by the revival of the brain process, the mental image is brought back again to mind, this spreading out shows itself by an enlargement of the memory image. However it may be explained, the indications of it were unmistakable—unless, of course, some other reason can be given for the uniform direction of the errors; and it is further seen in other experiments carried out by Messrs. W. and B. and by Dr. K.[9] at a later date.

[9] Dr. F. Kennedy, demonstrator, now professor in the University of Colorado (results not yet published).

If this tendency to the enlargement of our memories with the lapse of time should be found to be a general law of memory, it would have interesting bearings. It would suggest, for instance, an explanation of the familiar fact that the scenes of the past seem to us, when we return to them, altogether too small. Our childhood home, the old flower garden, the height of house and trees, and even that of our hero uncle, all seem to the returning traveller of adult life ridiculously small. That we expect them to be larger may result from the fact that the memory images have undergone change in the direction of enlargement.

V. Suggestion.—Space permits only the mention of another research, which, however, should not be altogether omitted, since it illustrates yet other problems and the principles of their solution. This is an investigation by Messrs. T. and H.,[10] which shows the remarkable influence of mental suggestions upon certain bodily processes which have always been considered purely physiological. These investigators set out to repeat certain experiments of others which showed that if two points, say those of a pair of compasses, be somewhat separated and put upon the skin, two sensations of contact come from the points. But if while the experiment is being performed the points be brought constantly nearer to each other, a time arrives when the two are felt as only one, although they may be still some distance apart. The physiologists argued from this that there were minute nerve endings in the skin at least so far apart as the least distance at which the points were felt as two; and that when the points were so close together that they only touched one of these nerve endings, only one sensation was produced. Mr. T. had already found, working in Germany, that, with practice, the skin gradually became more and more able to discriminate the two points—that is, to feel the two at smaller distances; and, further, that the exercise of the skin in this way on one side of the body not only made that locality more sensitive to minute differences, but had the same effect, singularly, on the corresponding place on the other side of the body. This, our experimenters inferred, could only be due to the continued suggestion in the mind of the subject that he should feel two points, the result being an actual heightening of the sensibility of the skin. When he thought that he was becoming more sensitive on one side—and really was—this sense or belief of his took effect in some way in both hemispheres of his brain, and so both sides of the body were alike affected.

[10] G. A. Tawney, now professor in Beloit College, and C. W. Hodge, now professor in Lafayette College.