THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



VOL. IX, No. 17.] SEPTEMBER, 1915. [vI ho xix s no ib i S 7 



The Effects of Physical Fatigue on Mental 



Efficiency. 



FLOYD CARLTON DOCKERAY. 



OUTLINE. 



page 



Introduction 197 



Historical 198 



Methods 204 



Addition Test 204 



Multiplication Test 205 



Sounder Test , 207 



Association Test 210 



Methods of Tabulating Results 212 



Results 213 



Discussion of Results 224 



Evidences of Physical Fatigue 224 



Addition Test 225 



Multiplication Test 226 



Sounder Test 229 



Association Test 234 



The Curve of Mental Work 236 



Conclusions : 238 



INTRODUCTION. 



THERE are three possible effects of physical fatigue upon 

 mental efficiency: (a) It may produce decreased mental 

 efficiency, either in the speed or accuracy of the work, or in 

 both; (b) it may serve as an incentive to greater effort and 



Received for publication July 1, 1915. 



(197) 



