48 THOMAS WILLIAM BROCKBANK 



habit is less difficult; second, there are fewer " errors " 

 in the learning, and integrations are more readily estab- 

 lished. As a consequence, redintegration must neces- 

 sarily be improved. In other words, when a rat has passed 

 through a relatively long period, acquiring integrations, 

 and then is set to learn a standard problem, the process 

 of learnng the integrations necessary for this problem will 

 proceed with much more rapidity than with the rat that 

 has had no previous training, and the redintegration as a 

 consequence will be better than with the untrained rat, 

 not because of better retention — for retention is probably, 

 not bettered by learning — but because of the fact that 

 the learning is better than ordinary. 



(5) Inclined Plane 



The standard norm and methods which were described 

 in the foregoing experiments on the maze were adopted 

 for the present experiment. These comprise the feeding 

 of the respective groups in the problem for a half hour 

 on each of four days preceding the first day of learning, 

 the exercise in the runway each day during the retention 

 period, and the requirement of the fifteen-trial norm, the 

 first six trials of which must be perfect. Three seconds 

 is the usual time set for the exercise of the habit in the 

 present problem, but this time norm was not rigidly 

 adhered to, the same flexibility being allowed as in the 

 maze, providing that perfect integration of movement was 

 exhibited. 



The inclined plane (Fig. Ill) was a problem made up 

 essentially of a box to which access was gained through a 

 small door that opened on the pressing down of an inclined 

 plane located at the rear of the box. The inclined-plane 

 box was 25 cm. square. In the lower center of one side of 

 the box was a door, 11.2 cm. square. The box and also 

 the door was covered with wire netting of 1 cm. mesh. 

 A solenoid coil was so placed above the door that its arma- 

 ture projected approximately 0.3 cm. over the edge of the 

 door, holding the door shut against the force of a small 

 spiral spring. The plane itself was 7.5 cm. long, 4.5 cm. 

 wide, and was hinged to the plate beneath, which was in 



