322 LINUS WARD KLINE 



first 13 was thrown, according to plan, to 7 D. The errors of 

 "sensory attraction," socalled, more numerous than those of 

 the motor, were made. by throwing a diamond to a diamond box 

 of like number. Errors of omission were seldom made. They 

 occurred in the higher rates of speed and especially with those 

 movements that threw cards to boxes occupying the vertices of 

 a triangular form of integrated movements and, in the effort to 

 speed up, the box at the vertex was often omitted. 



But since a majority of the errors were mechanical, and there- 

 fore simply inaccuracies of movement and due to the lack of 

 adequate control, a study of the relations between the lengths 

 of the movements and the errors was made. It showed that of 

 two movements in the same direction, the shorter generally re- 

 sulted in the larger number of errors. For example, right up, 

 distance 11.2 inches, gave 9 errors, while right up, 29.7 inches, 

 gave 4 errors; or again, left up, distance 36.1 inches, gave 8 er- 

 rors, while left up, 10.4 inches, gave 12 errors. This principle 

 applies only to mechanical errors. Woodworth (43) found that 

 the accuracy of a movement is determined by " current control" 

 governing the finer adjustments rather than by initial impulse. 

 It is evident that the length of a short movement prevents the 

 exercise of " current control/' while in a long movement its oper- 

 ation is unhampered. 



The marked correlation between the direction of movements 

 and inhibitions (check on rapidity) suggested a similar com- 

 parison between direction of movements and errors (lack of 

 accuracy) and dropped cards or lack of control. For this pur- 

 pose the absolute number of errors and dropped cards as recorded 

 in table 5 are arranged in a reduced form in table 9 according 

 as they occurred with right or left movements and involving 

 substitution or non-substitution of suit. 



The number of movements to the right and left are equal, but 

 those to the right sustain a handicap in that 25 per cent more 

 of them distribute substitution cards. Despite this handicap 

 the rightward movements show 45.9 per cent of the errors and 

 42.9 per cent of the dropped cards, while the leftward movements 

 made 54.1 per cent errors and 57.1 per cent of the dropped cards. 



