DOCKERAY I PHYSICAL FATIGUE AND MENTAL EFFICIENCY. 235 



Four of the subjects have shown decreased learning power 

 after the physical work. Of these, three not only have made 

 lower scores but have required longer times for the recall. 

 The fourth, Do., has a slightly shorter average time of recall 

 after physical work, which seems to be due to the elimination 

 of a few of the extremely long times. The average times after 

 work for the other three subjects is due to a general increase 

 in the time of recall. On the other hand, H. has a better score 

 after work, but his average time is much greater, due in part 

 to more extremely long times, but also due to a more general 

 lengthening of the time. The results of E. are very doubtful. 

 Two of the days following rest he has a higher per cent cor- 

 rect than on the corresponding work days, but the association 

 time has been longer for these days. His average time is 

 longer on work days in spite of a much greater number of 

 extremely short times. Were it not for the fact that his aver- 

 ages here are very similar to results of his work in other ex- 

 periments, to be reported in another paper, we might consider 

 these results as of little value. The indications of these later 

 experiments are that in a longer series of association experi- 

 ments with physical fatigue the average result would have been 

 approximately the same as it is here. Furthermore, we can 

 not consider him as thoroughly fatigued after running two 

 miles across country as most of the subjects were after their 

 form of physical work, as E. was a regular track man in train- 

 ing at the time. H., who presents a consistently higher average 

 after the long walks, was accustomed to long walks every day, 

 and usually reported only slight feelings of fatigue. It is sig- 

 nificant, also, that there is a general tendency with most sub- 

 jects to make a greater effort to recall when learning followed 

 fatigue. At least this is suggested by the generally longer as- 

 sociation times and more extremely long times. 



The results of R. deserve separate consideration, as they do 

 not involve purely rote learning as the others do. Whereas all 

 cases involving sensible associations were discarded in the 

 other series, R. was allowed to form all the associations he de- 

 sired. Nevertheless, his results were quite as consistent as 

 those of the other subjects. In only one case has he made a 

 better score after physical work than on the corresponding 

 rest day, and then the association time is unusually long. Only 

 two work days produced higher scores than the poorest rest 



6 — Univ. Sci. Bull., Vol. IX. No. 17. 



