50 THOMAS WILLIAM BROCKBANK 



and effort, and concentration of these on the problem itself. 

 The glass sides were firmly fixed in grooved wooden up- 

 rights located at each of the four corners of the base of 

 the problem box. They could easily be slid upw^ard, and 

 access readily gained to the problem box within. The 

 entrance to the problem box was located at a distance 

 of 28 cm. directly in front of the door of the inclined-plane 

 box. This entrance box was constructed of wood with a 

 wire-mesh top. 



In the learning of the inclined plane-problem the be- 

 havior of the rat appeared more complex than in the 

 learning of the maze. This point is well worthy of notice. 

 The present problem is one requiring a habit of manipula- 

 tion to solve it, while the maze evokes a general motor 

 habit. Motor habits are in general the simplest habits 

 in the entire repertoire of the rat's movements, while habits 

 of manipulation require more complex integrations of 

 movement in their process of establishment. The maze 

 evokes a habit requiring the integrating of movements of 

 running in a certain direction and turning the whole body 

 at certain intervals in response to the environment. The 

 inclined plane likewise calls forth the motor movements 

 of running and turning the body at certain stages; but 

 it calls forth the additional integration of certain definitely 

 adjusted movements of the body and particularly the 

 forelimbs in the pressing down of the inclined plane. Sim- 

 pler methods of pressing down the plane may be used, 

 such as stepping on the plane in running over it; but 

 the method of pressing down the plane with the forelimbs 

 is the most satisfactory. Although these movements may 

 be included under motor movements in the widest sense, 

 yet they are movements of manipulation in the strict 

 sense and are much more complex and difficult of adjust- 

 ment than the movements of running, etc. Thus the 

 establishment of integration in the learning of the inclined 

 plane is much more difficult than the establishment of 

 integrations in the learning of the maze. 



As in the first trial on most new problems, the rat usually 

 entered slowly and investigated every accessible place in 

 the problem. If it so occurred that in the first trial the rat 



