THE ACQUISITION OF SKILL IN ARCHERY. 



123 



As in all other methods of treating the data, practice with few shots per day 

 seems to be more economical than that with many. In the first half of prac- 

 tice there is no close correspondence between the amount of improvement and 

 the distribution of practice, but in the second half, where the effects of varia- 

 tions in the initial stage of learning are omitted, the correspondence is quite 

 striking, the 60-shot group alone being out of order. The position of the 12- 

 shot group, as inferior to the 5-shot group, is very probably correct, since in 

 this case the error due to the overestimate oi failures (p. 121) is no longer sig- 

 nificant. The order of improvement per unit of practice is, then, 5, 12, 20, 

 60, and 40, with um-elated evidence to show that the 60-shot group was some- 

 what superior to the others. 



To what extent do these results express the effect of the distribution of 

 practice, and to what extent may they be due to chance? As has been stated, 

 the 5-, 20-, and 40-shot groups seem very closely comparable in their make-up. 

 The rifle practice, though not verj' dependable as an index to the abilities of 

 the individuals, does give some indication that the relative rate of learning 

 of the groups practicing under similar conditions is not the same as that 



Table 41. — Improvement duing the first and second halves of practice. 



obtained in the archery practice, which differed from the practice with the 

 rifle only in its distribution, antl thus that the differences in the rate of learn- 

 ing to shoot the bow are due primarily to differences in the distribution of 

 practice. If the rifle records are to be trusted as an index to ability, it 

 appears that the improvement of the 20-shot group should be counted as rela- 

 tivel}' somewhat greater than that of the 40-shot group, since the latter .seems 

 to show superiority in rate of learning under like conditions of practice. 



From the results of this experiment it is certain that practice distributed 

 over many days is more economical than when concentrated to a few days. 

 From the improvement shown in the later part of practice and general consid- 

 erations of the relative abilities of the groups, it seems probable that there is 

 a very close relation between the distribution of practice and the amount of 

 improvement. 



