\ 



150 



48 H 



X 



115 



2345678 



9 10 11 L2 13 14 15 16 17 18 19 20 



FIG. 2. CURVES OF LEARNING AND .RELEARNING 



Abscissae represent series of ten tests given every third day; ordinates the 

 average number of errors. Solid line in each case is the learning and the broken 

 line the relearning curve. The first point on ordinates is an average of the pref- 

 erence tests in case of learning curve and of the retention test in case of the re- 

 learning curve. 



250 



