As a test of intelligence this test is better than that of repeating digits in the direct order. It is less mechanical and makes a much heavier demand on attention. The digits must be so firmly fixated in memory that they can be held there long enough to be told off, one by one, backwards. Feeble-minded children find this test especially difficult, perhaps mainly because of its element of novelty. School children are often asked to write numbers dictated by the teacher, and even the very dull acquire a certain proficiency in doing so; but the test of repeating digits backwards requires a certain facility in adjusting to a new task, exactly the sort of thing in which the feeble-minded are so markedly deficient. As a rule the response consumes much more time than in the other digits test. This is particularly true when the series to be repeated backwards contains four or more digits. The chance of success is greatly increased if the subject first thinks the series through two or three times in the direct order before attempting the reverse order. The subject who responds immediately is likely to begin correctly, but to give the first part of the original series in the direct order. For example, 6-5-2-8 is given 8-2-6-5. Sometimes the child gives one or two numbers and then stops, having completely lost the rest of the series in the stress of adjusting to the novel and relatively difficult task of beginning with the final digit. In such cases the feeble-minded are prone to fill in with any numbers they may happen to think of. A good method for the subject is to break the series up into groups and to give each group separately. Thus, 6-5-2-8 is given 8-2 (pause) 5-6. As a rule only the more intelligent subjects adopt this method. One 12-year-old girl attending high school was able to repeat eight digits backwards by the aid of this device. It would be well worth while to investigate the relation of this test to imagery type. Such a study would have to make use of adult subjects trained in introspection. It would seem that success might be favored by the ability to translate the auditory impression into visual imagery, so that the remembered numbers could be read off as from a book; but this may or may not be the case. At any rate, success seems to depend largely upon the ability to manipulate mental imagery. The degree of certainty as to the correctness of the response is usually much less than in repeating digits forwards. CHAPTER XIV INSTRUCTIONS FOR YEAR VIII VIII, 1. THE BALL-AND-FIELD TEST (SCORE 2, INFERIOR PLAN)