| Author: | Irene Case Sherman. |
|---|
According to the Stanford-Binet intelligence scale, the average individual of adequate intelligence at seven years of age should be able to repeat five digits, and at ten years he should repeat six digits. All subjects of nine years of age or older, then, should be able to repeat at least five digits, provided the intelligence is adequate. From the examination of 391 unselected cases1 in which the chronological age was nine years or more, the following figures were obtained for the various mental classifications: Classification Feebleminded. Borderline. Backward. Adequate. Total. Digits Repeated Number of Cases
3 15 40 43 2 3 20 50 15 16 62 22 1 9 36 54 391
From the table it is seen that all individuals excepting one classified as adequate or backward were able to repeat five digits or more; in every case excepting one in which less than five digits were repeated, a diagnosis of "borderline" or "feebleminded" was made. On the other hand, feebleminded or borderline cases were frequently able to repeat as many as six or seven digits. From this it follows that in case an individual is able to repeat five digits or more, the digit test is of no positive value so far as the ultimate diagnosis is concerned. But when five digits cannot be repeated by a subject nine years or older chronologically, the digit test is a good index test of feeblemindedness.
i Institute for Juvenile Research, Chicago, 111. (124)