116 



THE ACQUISITION OF SKILL IN ARCHERY. 



and second halves of practice in judging the improvement rather than the 

 records of the first and last few shots (see p. 110). The amount of improve- 

 ment measured in this way is shown in table 37. 



In so far as the improvement in rifle shooting may be considered an index 

 of the relative ability of the groups, the 5- and 40-shot groups seem to be 

 almost equal, the 20-shot group somewhat inferior in rate of improvement. 

 When the percentage of improvement over initial accuracy is considered, as 

 seems justifiable by the data given on page 111, the inferiority of the 20-shot 

 group is less marked. 



TABLE 37. Relative improvement of subjects shooting 20 shots daily with the rifle. 

 [The figures represent centimeters from the bulls-eye.] 



CONDITIONS AFFECTING IMPROVEMENT. 



Before comparing the relative abilities of the groups a few words are neces- 

 sary concerning the complexity of the habits formed and the general character 

 of the learning curve. Very delicate adjustments, both of the eye-hand 

 coordinations at the moment of aiming and particular^ in the quick changes 

 in muscular tension at the moment of loosing, are necessary. The movements 

 involved in loosing the arrow are the most difficult to control exactly. At the 

 moment of aim the extensor muscles of the bow arm are resisting a pull of 

 about 40 pounds; the flexors are under no strain. When the bowstring is 

 released the extensors are suddenly freed from strain and tend to throw the 

 arm outward. The tonus of the flexors must be increased immediately to 

 counteract this tendency. The bow-arm of a beginner frequently swings 

 4 inches out of position before the arrow leaves the string and the delayed 

 tensing of the flexors then draws it a still greater distance in the opposite 

 direction. This movement must be almost wholly overcome before accurate 

 shooting is possible. Equally accurate and difficult movements of the loosing 

 hand must be acquired. An average variation of 2 of arc in the relative posi- 

 tion of the hands results in an average of 25 inches from the center of the 

 bulls-eye. Some of the championship records given below require an average 

 variation of less than 30' of arc in the alignment of the arrows. 



The record of a subject whose practice extended to more than 1,300 shots 

 is given in figure 17. This is the subject mentioned on page 122 as having 

 had opportunity for practice of implicit habits before the beginning of the 

 experiment. This accounts for the high initial skill and for the resulting 

 flatness of the first half of the learning curve. With the exception of the high 

 initial accuracy the curve seems to be typical for this amount of practice. 



