194 H. M. JOHNSON AND FRANKLIN C. .PASCHAL 



as the variations in speed and accuracy, and in some cases are 

 even more important. Unless they are included in the record, 

 or are at least considered, a mere inspection of the subject's 

 record of performance may give a very misleading impression. 



PURPOSE OF THE PRESENT EXPERIMENT 



In its essential features, the test described below is one of 

 several which were attempted early in 1918 and abandoned. 

 In January, 1919, the original method was materially improved 

 and used for another purpose than the original one: namely, 

 as a part of a somewhat general attempt to ascertain whether 

 the more complex processes of behavior tend to deteriorate 

 before, after, or simultaneously with, the simpler processes. 



A definite impression regarding this question was made on the 

 pioneer investigators, by a mass of observational material yielded 

 by themselves as well as by other subjects. 1 The material as 

 presented hi fragmentary form is not readily susceptible of 

 analysis, and the conclusions drawn from it have not been 

 unanimously accepted. 



The present type of experiment was selected for use in a part 

 of this investigation, since it involved sustentation of the visual 

 function, attention, memory, and muscular coordination during 

 a longer period than can be included in an ordinary voluntary 

 "spurt." Certain of the factors involved are also capable of 

 being isolated for further study by other methods. 



THE METHOD EMPLOYED 



The task assigned the subject is the transliteration of a number 

 of sets of nonsense-material into corresponding codes, one of 

 which is presented with each set of material. The codes are from 

 a group compiled by Capt. Johnson with a view of insuring the 

 closest practicable approximation to equality of difficulty. After 

 a large number of systems for deriving them had been tried and 

 rejected, a method of satisfying this condition was found. The 



1 Cf . Dunlap, Knight: Psychological research in aviation. Science, N. S., 

 vol. 49, 1919, pp. 94-97. 



