38 

 IV and V of the maze and latch-box and Plates I and 



III of the same problems, when given alone. When these 

 problems were undertaken in succession with the inclined 

 plane box, more trials and days were usually necessary 

 than when one problem was offered. However, in making 

 this statement, the records of the abnormal rats, when the 

 maze was used alone, have not been taken into considera- 

 tion. The time and days, there fore, which it takes to 

 learn the three problems is greater than when one problem 

 is given. learning is more difficult when problems are 

 given concurrently than when one is given at a time. This 

 can be seen better, perhaps, on the curves which show the 

 growth of organized movements. Curves VII, VIII and IX 

 are the same in general contour. The individual curves 

 for one and three and five trials show differences in 

 length and regularity. Again, curves representing three 

 and five trials are more irregular than those of one 

 trial. This is true especially of the early trials 



