146 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



been worked out by Seashore, and was used in the present case.^ 

 Suitable wooden resonators were provided. The tuning-forks were all 

 originally A435 vd. in pitch .^ 



The pitch differences were produced by fiUng between the prongs, 

 hence all of the steps were lower than the standard, i. e., the one fork 

 which had not been filed and which was A435 vd. The pitch intervals 

 between the standard and the other nine forks were 1, 2, 3, 5, 8, 12, 17, 

 23, and 30 double vibrations (vd.), respectively. The experimenter 

 who sounded the forks was completely out of view of the subjects, and 

 the usual precautions were taken concerning noises and such things as 

 could serve as secondary criteria. Care was also taken to make the 

 intensity of the tones equal and of similar duration. A chance order 

 for the presentation of the tones was worked out previous to the tests 

 and followed. Preliminary trials were given and explanations made to 

 arouse interest in pitch discrimination. By numerous trials it was 

 explained to all the subjects that the judgment was to be made in 

 reference to the last of a pair of tones, i. e., he was to judge if the latter 

 of any two tones was higher or lower than the former of the pair. A 

 blank, ruled in centimeter squares, was provided, upon which these 

 judgments could be recorded conveniently, the columns being lettered 

 across the top and numbered down the side at the left. The upper 

 left-hand corner of this blank is shown about full size in figure 21 . The 

 judgment for the first pair of tones is recorded in square A-1. This 

 is given in the illustration as H, meaning that the second tone was 

 judged higher than the first of the pair. The judgment for the second 

 pair of tones is recorded in square B-1. In figure 21 it is given as L, 

 meaning that the second tone was judged to be lower than the first. 

 The particular square in which the judgment was to be recorded was 

 called out in the first experiment and at the first of each experiment just 

 before the pair of tones was given, so that the subject might have no 

 doubt as to where to write his judgment. He was required to make a 

 judgment of either higher or lower, that is, to fill in the appropriate 

 square with either H or L, according as it sounded to him. There were 

 no judgments of equality. 



At the first session with each squad all the pairs of forks were used. 

 This would give 9 pairs of tones for discrimination purposes. It was 

 then discovered that in the case of both squads the pairs of tones, S-30, 

 S-23, S-17, and S-12, were quite uniformly judged correctly. There- 

 fore, it was necessary to use only the remaining pairs in succeeding 

 sessions, that is, S-8, S-5, S-3, S-2, and S-1, or 5 pairs of tones. Really, 

 the pair S-8 might also have been omitted, as the subjects were almost 

 always correct with this judgment. However, some easy judgment is 



'Seashore, Report of the Committee of the American Psychological Association on the Stand- 

 ardizing of Procedure in Experimental Tests, Psychological Monograph, 1910, 13, p. 21. 

 ' The tuning-forks were those listed as No. 1730 in the catalogue of C. H. Stoelting Co., Chicago. 



