How We Experiment on the Mind : Part 5

The Story of the Mind
by James Mark Baldwin

(Page 10 of 15)

The results from all these experiments were combined with those of another series, secured from a large class of Princeton students; and the figure (Fig. 8) shows by curves something of the result. The figure is given in order that the reader may understand by its explanation the "graphic method" of plotting statistical results, which, with various complications, is now employed in psychology as well as in the other positive sciences.

Briefly described in words, it was found that the three methods agreed (the curves are parallel) in showing that during the first ten minutes there was a great falling off in the accuracy of memory (slant in the curves from 0 to 10); that then, between ten and twenty minutes, memory remained relatively faithful (the curves are nearly level from 10 to 20), and that a rapid falling off in accuracy occurred after twenty minutes (shown by the slant in the lines from 20 to 40).

Further, the different positions of the curves show certain things when properly understood. The curve secured by the method of Reproduction (not given in the figure) shows results which are least accurate, because most variable. The reason of this is that in drawing the squares to reproduce the one remembered, the student is influenced by the size of the paper he uses, by the varying accuracy of his control over his hand and arm (the results vary, for example, according as he uses his right or left hand), and by all sorts of associations with square objects which may at the time be in his mind. In short, this method gives his memory of the square a chance to be fully assimilated to his current mental state during the interval, and there is no corrective outside of him to keep him true.

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 recognize 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 recognized 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.

Copyright 1902 by D. Appleton and Company.

About the Author

James Mark Baldwin (1861-1934) was an American philosopher and psychologist who was educated at Princeton under the supervision of Scottish philosopher James McCosh. He made important contributions to early psychology, psychiatry, and to the theory of evolution.