40 JOSEPH PETERSON 



correct general orientation by some such means as this. Such 

 habits would then have common factors for all cul de sacs, and 

 in mazes of different kinds. It would seem, too, that on some 

 such basis as this the returns would be eliminated more readily 

 than entrances to the blind alleys, as has already been shown 

 to be the case. This explanation may involve an interaction 

 of sensory and motor impulses in the nerve fibres — each sys- 

 tem, sensor}' and motor, interacting upon and stimulating the 

 other — in such a manner as to make comprehensible how the 

 effect of stimuli may be carried over into later responses and 

 partly condition them as suggested below. 



Possibly the animals also learn with training to utilize better 

 such factors as vague visual stimuli of the closed end of the 

 cul de sac. Certainly the speed of the rat running into the 

 blind alley would make one cautious in assuming that such 

 factors are explicitly reacted to by the animal. That there 

 was a real transfer of some kind is, in any event, a conclusion 

 which also finds support in the results of the A-mazes. For 

 the full length and the shortened cul de sacs, the per cent returns 

 for untrained rats are 42 and 32, respectively, agreeing rather 

 closely with the B-maze results, whereas the corresponding per- 

 centage returns by the trained rats — seven in each A-maze — 

 are 36 and 11, a decrease from that of the untrained animals 

 of 14% for the full length and of 66% for the shortened cul 

 de sacs. In the B-mazes the percentage returns from the full 

 length cul de sacs by trained rats is 24% less than that by un- 

 trained rats; for the shortened blind alleys the percentage re- 

 turns by the trained rats is 21% less than that by untrained 

 rats. 



THE SIGNIFICANCE OF THE RESULTS 



It may be urged by the reader that the more rapid elimination 

 of entrances to the shortened cid de sacs than to the full length 

 ones is due to the fact that the rat, in the case of the short blind 

 alleys at least, sees the closed end and thereby avoids entering 

 so frequently, or so completely. In one sense this begs the 

 whole question. Seeing is not some thing that stimulates or 

 directs the animal; it is only a mode of being stimulated. Its 

 possibility in the present study is not at all denied. The whole 

 question with which we are concerned is: How do all possible 



