OF THE NATIONAL RESEARCH COUNCIL 117 



2. All candidates for examination are selected by their officers. 

 Candidates must have: 



{a) The general training of a seaman, especially military dis- 

 cipline, care of a seaman's belongings and person, and the 

 ability to handle firearms effectively, 



{h) General intelligence sufficient to profit by an intensive 

 course of school work. 



(c) Loyalty to and interest in Naval work. 



{d) Enough self-reliance and initiative to carry the responsi- 

 bility of the Listeners' task. 



(if) Enough team -spirit to make him livable in cramped quarters. 



3. In the absence of other clear indications of the requisite gen- 

 eral intelligence to profit by the intensive course of school training 

 required of Listeners (2^), it is required that candidates have at 

 least two years of high school. Other indications of superior in- 

 telligence would be a record of success at some electrical trade, or 

 some business where the candidate had given evidence of superior 

 mental ability. 



4. The medical examination of candidates emphasizes the integ- 

 rity and normal functioning of the auditory apparatus, with less 

 emphasis on the visual equipment. 



5. The group elimination examination aims to eliminate from 

 the group selected by their officer those men who are least fitted 

 for the special tasks of the listener. 



The ideal examination would probablv be to try out every can- 

 didate with the special apparatus used under the actual conditions 

 of service. Since that seems to be impracticable, a set of tests had 

 to be developed that would correspond to those tasks as closely as 

 possible. After a considerable experience with the men selected 

 by these tests, consequent to which the tests have been checked and 

 corrected, it seems important to give them as uniformly as possible 

 in all Naval Districts, and to make no intentional change either in 

 substance or method until that change has been fully considered by 

 the Bureau of Navigation and checked by correlation with the ac- 

 tual work of the men at the school. 



6. The mental test consists of four parts. 



{a) The memory span for 4-, 5-, and 6-place digits. 



{b) The ability to read a circular scale to an error of one degree. 



(c) The ability to locate the source of sounds from behind a 

 long horizontal screen. 



{d) The ability to discriminate between softly spoken or whis- 

 pered syllables and nonsense words. 



