INTEGRATION OF MOVEMENTS IN LEARNING IN THE RAT 477 



consecutive perfect records are made during 60 trials. These 

 are indicated in the table by an asterisk. 



The record of another rat with fairly well developed reflex 

 mechanistic parts is presented in table 12. Fluctuations in 

 the reflex thrust occur rather more frequently than is shown 

 in the record of the previous rat. Reflex excitability is hyper- 

 normal in the first two trials. Timidity is generally manifest 

 for several trials. Directive integration does not appear until 

 the seventh trial. The first perfect record occurs in the eleventh 

 trial. The extensor thrust is used throughout the 60 trials 

 given. Of all the rats used with the inclined-plane problem, 

 more consecutive perfect records were obtained from this rat 

 than all other rats, even exceeding the preceding rat's record. 

 The functional condition of the preceding rat is, however, 

 better than this one, for perfect records appeared sooner, in 

 the second trial with the first rat, and not until the eleventh 

 trial with the second rat. 



The results obtained from these 2 rats point to a rather excep- 

 tional physiological efficiency for learning the inclined-plane prob- 

 lem. The extensor thrust was used throughout learning, and 

 now it will be seen that the occurrence of many consecutive 

 perfect records is dependent upon the attainment of posture 

 before the plane and the production of the extensor thrust. 

 Because of the inability to attain posture, other methods to 

 plunge the plane became compulsory. Tables 13, 14, and 15 

 show a great difference in the effective performance of all re- 

 sponses and the number of trials, as well as the number of con- 

 secutive perfect records made. The rats whose records are 

 presented in these tables possessed functionally undeveloped 

 reflex extensor thrusts, and reflex excitability was hyponormal. 

 Accordingly, that part of directive integration, progression to 

 the door after the plane is plunged, occurred first before direct 

 progression to the plane. Table 13 shows that direct progres- 

 sion to the door appeared in the second trial, to the plane in 

 the sixth and directive integration was established in the eighth 

 trial; in table 14 to the door in the fourth trial, to the plane in 

 the fifth, and directive integration was facilitated in the seventh 



