C. A third method has been that of analogy. Some test is devised which bears real or supposed resemblance to the sort of situation met by the worker in the given occupational activity. The material is new, but the attitude and endeavor of the worker seem to be much the same. There is indeed usually a tacit or expressed belief that the same simple or complex mental processes or psychological functions are involved in the two cases, although the precise nature of this function has seldom been clearly stated. Thus girls employed in sorting steel ball-bearings, and also typesetters, have been selected on the basis of their speed of reaction to a sound stimulus. Muensterberg has suggested that marine officers who can quickly perceive a situation and choose an appropriate mode of reaction to it may be selected by letting candidates sort into their appropriate piles a deck of cards bearing different combinations of letters. The same investigator has described a test for motormen which, while being neither a miniature of their required work nor yet a sample of it, is said to produce in them much the same mental attitude. In another case telephone operators were tested for speed in canceling certain letters from a newspaper page, in the belief that this work involved an ability that was also required at the switchboard, although there directed to different material. McComas has described a dot-striking test for measuring accuracy of aim or motor coordination, which forms an essential factor in manipulating a switchboard.