INTEGRATION OF MOVEMENTS IN LEARNING IN THE RAT 397 



of the neck reflex and the raising of the latch. As a rule, longer 

 or shorter intervals between the first and the second touch and 

 the production of the neck reflex occurred. The very first touch 

 of the rat's muzzle usually appeared soon after the rat was ad- 

 mitted to the problem. When the problem remained unsolved, 

 the under surface of the latch was either not touched, or it was 

 touched several times and usually at long intervals. More often 

 repeated touches occurred on the first 2 or 3 days, but not on the 

 remaining 4 or 5 days. In some rats, inactivity followed short 

 periods of activity on each of the 30-minute trials of the first 

 days, and in other rats no evidence of activity was manifest at 

 any time. With rat I, litter 2, the latch was not touched for 2 

 days, but on the third day, two touches resulted in the solution of 

 the problem. In litter 6 solving the problem did not take place 

 on any of the 6 days, yet touches were recorded. 



The frequent failures to produce the neck reflex movement 

 when the rat's muzzle touched the latch, are evidently due to the 

 functional condition of the entire organism, and not to a depend- 

 ency upon an adequate sensory excitation. For when the under 

 surface of the latch is repeatedly touched and no adequate re- 

 sponse is forthcoming, it appears that the neck reflex movement 

 and associated reflex movements are undeveloped. Later it will 

 be seen that certain fundamental, integrated, reflex movements 

 are undeveloped and fluctuate. The important question is what 

 is required to produce the neck reflex movement rather than the 

 one of the reception of adequate stimuli to produce sensory ex- 

 citations and the " successful" movement. What seems to be 

 required is the initiation of an interaction of many body parts for 

 posturing under the latch to produce the neck reflex movement. 

 This interaction for posturing is less evident when reflex excita- 

 bility is not manifest. Apparently an absence of these mani- 

 festations would indicate that some mechanisms are undevel- 

 oped, and consequently that interaction of body parts for the 

 production of the neck reflex movement is dependent upon the 

 functional development of many parts. If this is so, the inter- 

 esting thing in the observation of an organism during learning, 

 is the functional condition of the rat, and not what the rat does, 



