MECHANISMS OF LEARNING 189 



er experiments as already explained (p. 186), but the 

 separate movements were simpler and the rat does not 

 need to climb upon the top of the food-box as before. 

 The latch is tripped whenever in the course of or- 



FiG. 47. — The double-platform box. a and h are platforms which 

 must be pushed down in the order a-b so as to open the door, d^ to the 

 food-box. After Lashley. 



dinary running movements the rat steps on both of 

 the platforms in proper sequence. The normal rats 

 readily acquired this habit perfectly, though this re- 

 quired about twice as many trials as did the mastery 

 of the inclined plane box. 



In these experiments a definite part of the cortex 



