PAPERS ON PSYCHOLOGY AND PHYSIOLOGY 129 



TABLE HI 



The figures indicate the actual numher of revolutions given to 

 each subject as the number of revolutions per trial increased up to 

 ten. In the column of averages, the small number for 10 revolutions 

 per trial is due to the fact that subjects C and F were not rotated long 

 enough to enable them to pass to eleven revolutions per trial. 



No. of Subjects 



the end. In other ^vords, it takes a greater amount of 

 practice to be able to stand nine turns ai^^r having stood 

 eight than it does to stand three turns after having be- 

 come accustomed to two. Or, again, it took 640 turns 

 for subject C to become accustomed to five turns a trial 

 but it took 3,040 turns to stand the increase up to ten 

 turns per trial. In a similar way it took 680 rotations for 

 subject F to become accustomed to 5 turns a trial wliile 

 3,140 were recpiired to go to ten turns per trial. These 

 facts illustrate a common characteristic of the change 

 that takes place in the organic and mental effects of rota- 

 tion during practice. That is, a curve showing the in- 

 creasing ability of a subject to stand rotation without 

 presenting any organic or mental effects possesses some 

 of the characteristic of the typical learning curve. 



That this is true can be seen bv recalling the general 

 form of the learning curve and by comparing it ^\-ith the 

 curve of Chart I. Chart I is based upon the results ob- 

 tained from the experiments we are now discussing. 

 (See Table III) If becoming accustomed to rotation can 

 be spoken of as a *' performance" then it will be seen 

 that the degree of performance is much greater during 

 the early part of a series than later.^ 



' Compare the curve in chart I with those obtained from subjects who be- 

 gan with ten revolutions per trial or approximately 25 revolutions of after- 

 nystagmus. See J. of Exper. Psychol., 1920, 3. p. 30. 



