PSYCHOLOGICAL MEASUREMENTS. 



605 



their first experiment on word reactions. On February 2 the men 

 returned to the level of their December reaction averages. 



The standard deviation was largest for both groups at their first 

 session and fairly uniform beyond that, with the exception of a definite 

 increase for Squad A on January 26. As shown in the lowest pair of 

 curves, the standard deviation is about the same per cent of the 

 average reaction time for both groups. The curves run remarkably 

 close together. As might be expected, the percentage variability 

 was largest at the first, that is, on October 13 and November 3 for 

 Squads A and B. After that it remained between 8 and 10 per cent. 



Fig. 113. — Word-reaction time and its variability. 

 Solid lines represent Squad A, and broken lines Squad B. 



The record for January 26 shows a depression. We conclude that the 

 low-diet condition produced no definite change in the general group 

 averages or in the variability of the latency in the word-reaction 

 measurement. In general the results tended to be somewhat poorer 

 following the Christmas vacation. 



(11) CONTINUOUS DISCRIMINATION AND REACTION IN FINDING SERIAL 



NUMBERS. 



The total time required to find and point out the numbers 1 to 50 

 in proper order and without skipping any is shown for both squads 

 in tables 173 and 174. Each squad began this test at their second 

 experimental session, i. e., the second time they came to Boston. 

 There is thus no normal for Squad A. Many of the individual dif- 

 ferences between the members of Squad A which were found in the other 

 measurements are also observable here. Obviously, the best scores are 



