326 LINUS WARD KLINE 



7. The higher rates of skill were achieved through the capacity 

 (1) to graduate the service of attention to the changing stages 

 of skill, (2) to control the body as a whole in the interest of the 

 hands, (3) to coordinate the movements of both hands, and (4) 

 to use the thumb and fingers dextrously. 



8. The slight use and aid of visual imagery in learning the loca- 

 tion of the boxes and in distributing the cards was doubtless due 

 to the stacked order. This gradually developed a system of 

 movements that supplanted the service of the eye. At the close 

 of the practice a special period was devoted to distributing the 

 cards unstacked. This reduced considerably the use of the 

 automatic system of movements and in endeavoring to recall a 

 box, its visual image would sometimes appear, particularly of 

 those boxes on the periphery or adjacent thereto. This condi- 

 tion for the appearance of visual imagery is somewhat similar 

 to the task of spelling rather long words backwards, as employed 

 by Dr. Fernald (16) in the " Diagnosis of Mental Imagery," 

 where the necessity for conscious control forced up imaginal 

 processes. 



9. The practical bearing of this study was found in the fact 

 that it determined the more salient traits necessary to become 

 a competent railway mail clerk and a distributing clerk in cen- 

 tral post offices. This aspect of the study will be reported later, 

 in connection with a partial analysis of the processes involved in 

 mail distribution. 



REFERENCES 



(1) ANGIER, R. P.: Die schatzung von Bewegungsgrossen bei Vorderarm- 



beweg-ungen. Zeitschrift f. Psychol. d. Sinnes. Bd. 39, 1905, S. 429. 



(2) BEARD, G. M.: Physiology of mind reading. Pop. Sci. Mo., 1877, x. 



(3) BERGSTROM, J. A.: Experiments upon physiological memory by means of 



the interference of associations. Amer. Jour. Psych., 1893, v, 356-359. 



(4) BILLINGS, M. L.: The duration of attention. Psych. Rev., 1914, xxi, 



121-31. 



(5) BINET, A.: Qu'est-Ce Qu'ene Emotion. L'Annee Psychologique. 1911, 



xvii, 23-28. 



(6) BRYAN, W. L., Development of voluntary Motor Ability, Amer. Sowr. 



psychol. 1892, vol. v, 125-204. 



(7) BRYAN, W. L., AND HARTER, N.: Studies in the physiology and psychology 



of the telegraphic language. Psych. Rev., 1897, iv, 27-53. 



