INTEGRATION OF MOVEMENTS IN LEARNING IN THE RAT 437 



TABLE 6 Continued 



* Three pushes. 



t Two pushes. 



t Directive integration. 



Missed latch. 

 1f To side of latch. 



The variations in the reaction time of the neck reflex move- 

 ment and in directive integration is due to the difficulty at times 

 to produce posture, and in the production of which the extension 

 of the rat's limbs is important. For effective posturing of the 

 body under the latch, the extensor thrusts must to a degree be 

 developed, and fluctuations of them must not occur. The 

 significance of posturing can be understood from what takes 

 place in relaxation from posture to produce the neck reflex 

 movement. After posturing and the neck reflex is produced, 

 the fore quarters are raised and the hind quarters slightly low- 

 ered. The forelimbs are extended and the hind flexed. In 

 some cases, before progression to enter the problem box occurs, 

 the body of the rat is momentarily maintained in a posture 

 with the fore quarters raised and the hind lowered. As pre- 

 viously stated, great variation is shown in the extent of posturing 

 and of relaxation of the body to produce the neck reflex move- 

 ment, and this variation results from the different degrees of 

 the development of the unequal antagonistic action of extension 

 and flexion of the rat's limbs. 



This last statement. would indicate that all perfect responses 

 are made before the latch when posturing is difficult to produce, 



