TACTUAL SENSATION IN THE RAT 137 



a while in that vicinity, and then run back and forth between 

 this point and the entrance, stopping here and there to inves- 

 tigate. The chances of discovering the open door at 2 seem to 

 be minimized in proportion to the speed of running at this 

 point. At least, stopping to investigate in this region is more 

 likely to lead to successful results than will high speed. In 

 maze III the rats tended to run rapidly by the opened door and 

 it thus escaped their notice. If the path had been so blocked 

 that the rats were forced to stop in the immediate vicinity the 

 chances for the detection of the opened door would have been 

 increased. 



Since all of the mazes were identical except for the critical 

 portion in the middle, it is surprising that this one act of adjust- 

 ment should be so difficult in comparison to maze I which was 

 learned de novo. The first maze presents a whole series of critical 

 positions while each succeeding maze presents but one. Viewed 

 in this light, it seems that the disadvantages of the old habits 

 rather overshadow their advantages. 



The difficulty of short circuiting even under the most favor- 

 able conditions as in maze II is rather surprising. In all prob- 

 ability much poorer records w^ould have been made if the short 

 circuiting had been optional rather than compulsory. It would 

 seem that the animals are guided but little by the smell of their 

 own path. 



The fact that the removal of doors 2 and 5 at the end of a 

 runway failed to attract the rats' attention indicates that these 

 animals do not rely to any great extent upon stimuli coming 

 from impending walls in order to negotiate a turn. This fact 

 harmonizes with Watson's contention that these turns are nego- 

 tiated mainly upon a kinaesthetic and organic basis. In this 

 connection, however, it was noted that the blind animals ran 

 into the doors used to block the old path with more strength 

 and persistence than did the normal rats. 



