PSYCHOLOGICAL MEASUREMENTS. 577 



The factor of accuracy entered into the second set of curves, showing 

 the number of columns correctly added. There is a reversal in the 

 first three sessions in this case, Squad B showing the better score. 

 The two squads are very nearly equal at their fourth session. At 

 the fifth session. Squad B was handicapped by the absence of Tho. 

 In the sixth and seventh sessions they again show a poorer performance 

 than would have been expected on the basis of their previous experience 

 and records. On the last date they rallied, with a performance on 

 the average two columns better than anything they had previously 

 done. The curve for Squad A is fairly regular; there is a very slight 

 decline in the fifth and sixth sessions as compared to the fourth, and 

 in the eighth session as compared with the seventh, but these do not 

 seem large enough to be of much significance. The curve is below that 

 for Squad B during the first three sessions, including the normal of 

 September 29. 



In the percentage of errors the two squads differ widely. Although 

 they began fairly near the same point, Squad A at 21.5 per cent and 

 Squad B at 19.7 per cent, the distance between them becomes prominent 

 in the next two experiments. It is also large in the fourth and fifth 

 sessions. In the sixth for Squad B, which was their first during the 

 low-diet period, they show a definite decline. There is some recovery 

 in the seventh session, i. e., the second low-diet session, but the level 

 reached is not what would be expected on the basis of their previous 

 records. On the last date, even though there was some tendency to a 

 spurt of unusual effort, they did not reach a level exceeding that which 

 had previously been reached. The fact that the two squads began at 

 almost the same level of errors, and that in the second, third, fourth, 

 and fifth sessions Squad A did not make nearly so much improvement 

 as Squad B, coupled with the fact that Squad B at the beginning of the 

 reduced diet showed an increase in the percentage of error,^ makes it 

 appear that the reduction in diet was not favorable to the highest 

 possible performance in accurate work in intensive adding during a 

 period of 10 minutes of continuous test. 



(5) MEMORY SPAN FOR 4-LETTER ENGLISH WORDS. 



When the subjects tried to recall and record as many as possible 

 of the 25 monosyllable English words which were read for the memory- 

 span test, nothing was said about what would be done in the case of 

 words entered which were not pronounced. In a few instances, several 

 words having nearly the same sound were entered, showing that the 

 subject evidently remembered the general sound complex of the word, 

 but was not absolutely sure as to its identity. In these special cases 

 the extra words entered were not counted as errors. In tables 157 



^It should be noted that this increase in the percentage of error does not occur on January 5, 

 ■when there is a drop in the curve above, and is not due to the absence of any one man, since 

 the whole personnel of the squad was present on this and on the other low-diet dates. 



