INTEGRATION OF MOVEMENTS IN LEARNING IN THE RAT 499 



such instances when rapid progression occurs from the entrance 

 box over the plane to the opened door, and in another instance 

 when progression is to the plane, the plane plunged with the 

 extensor thrust and progression continued to the opened door, 

 and all gradations exist between these two extreme methods, 

 it is difficult to believe that definite modifications in the nervous 

 system alone account for the different ways in which the plane 

 is plunged. These various ways exist because of the inherent 

 functional condition of many body parts interacting in learning. 



Because of the dependency of the movements to plunge the 

 plane upon this functional condition of the rat, it can not be 

 supposed that the rat plans its own actions, using alternative 

 methods when the most adequate method to plunge the plane, 

 the extensor thrust, is at all difficult to produce. All rats come 

 to use the method of plunging the plane in accordance with the 

 development of the reflex thrusts. There is no evidence that 

 the rat tries one way then another, until the " successful" move- 

 ments appear, or that the behavior of the rat is ascribable to 

 previous experience; that is, there does not exist a correlation of 

 past experiences with subsequent behavior, unless there is meant 

 by this a progressive development of physiological interaction 

 of body parts to facilitate the production of effective movements 

 which the problem demands. What is observable is compulsory 

 behavior, and probably much of the so-called " intelligent" 

 behavior will eventually be regarded in the same light. Con- 

 sequently, it does not seem to be scientific to say that a rat 

 "does something" when different responses are made to one 

 situation, and when different methods of plunging the plane 

 are dependent upon the development of fundamental reflexes; 

 or when different responses are made to two different situations, 

 the latch-box and the inclined plane problems, which demand 

 different fundamental movements, the neck reflex and the 

 extensor thrust; or when different methods are used in the same 

 situation when fluctuations occur in the extensor thrusts. 



The effective adjustment in one rat to the inclined-plane 

 problem in the second trial and the same adjustment in two 

 rats in the second and third trials to the latch-box problem, 



