264 REPORTS ON THE STATE OP SCIENCE. — ^1916. "* ' ^ ■^ 



Nevertheless, a good deal has been achieved in spite of the absence 

 of universally accepted criteria, and in his ' Manual of Mental and 

 Physical Tests ' Professor G. M. Whipple, of Cornell, has given a 

 useful account of some of the leading methods employed so recently 

 as 1910 with sundry references to fatigue. 



The study of these methods is a good index of the difference between 

 laboratory and industrial work. 



First in importance comes the Ergograph, which records the 

 endurance of a group of muscles, and is also used as an index of the 

 effect of all forms of work. The ergograph, though objections have 

 been raised to it on the ground that it fails properly to isolate a single 

 muscle, is very much more confined in its fatiguing effects than any 

 industrial process. 



The tapping test secures an index of various forms of motor ability, 

 speed, &c., and also of the fatigue effects of rapid movements. It is 

 even further removed from the operations of industry than is the 

 ergograph. 



With the claims of the assthesiometer as a direct index of fatigue 

 we have dealt in connection with school experiments. Of the various 

 methods of producing and testing mental fatigue, which include cancel- 

 lation (the crossing out of assigned letters or words from a printed 

 sheet), completion (Ebbinghaus's test mentioned below under (b)), tests 

 of memory, computation and simultaneous operations, only the two last 

 call for special remarks here. 



Almost all analyses of the work-curve have been based on experi- 

 ments in computation, and the same is true of pauses. Computation in 

 its various forms is assumed to imply perception, movement, attention 

 and retention, as well as associative activity; and Kraepelin and his 

 followers have confined themselves chiefly to addition. In order to 

 produce greater fatigue Thorndike has used four- and five-place numbers 

 both for addition and multiplication. It need hardly be remarked that 

 the kind of fatigue produced by work of this sort is reliable chiefly for 

 certain problems of refined analysis. It is obviously peculiar, and 

 largely temporary in its effects, and is considerably complicated by the 

 elements of boredom and practice, to say nothing of mental types. 



Similarly, the experiments hitherto conducted on simultaneous 

 activities have only a remote connection with the complex operations 

 found in industry. Binet has suggested various methods of testing 

 ability to execute concurrent motor activities, but most of the work 

 has been done on purely intellectual operations. 



One of the most recent and successful pieces of laboratory apparatus 

 is that devised by Dr. W. McDougall ' and described by him in the 

 ' British Journal of Psychology,' 1904-5. The process has more in 



' Dr. McDougall has written as follows (B.A. Report, 1908, p. 487) of the 

 further utility of his apparatus : ' The Kraepelin methods seek to avoid dis- 

 turbances by keeping interest at a minimum. But the human subject is not 

 easily kept in such a state ; he will become interested if only in the approaching 

 end of his task, and hence great irregularities. In view of these difficulties 

 T have suggested a method of estimating fatigue, which follows the opposite 

 principle, and seeks to keep interest at a maximum throughout, the task set 

 being of the nature of a sprint.' 



