Modification by Experience 219 



84. Dropping off Useless Movements: the Labyrinth 

 Method 



The next form of modification of behavior by individual 

 experience which we shall consider occurs when an animal, 

 under the influence of some stimulus which it strives either 

 to get rid of or to get more of, goes through a series of reactions 

 until one proves successful ; on being after an interval of time 

 placed in the same situation, the unsuccessful movements are 

 fewer, and further repetition causes them to be dropped off en- 

 tirely. This is the mode of behavior which was first brought 

 into clear relief by the experiments of Thorndike on chicks, 

 dogs, and cats. Since then an increasing number of inves- 

 tigators have shown its existence in a large number of forms. 

 One of the simplest methods for the testing of this sort of learn- 

 ing is the labyrinth method. In its developed form it was first 

 used, I believe, by Small in his work on white rats, and was 

 suggested by the natural habits of the animal, which is, of 

 course, accustomed to run about through narrow passages. 

 The plan consists in placing food, or something else attractive 

 to the animal, at the end of a series of passages containing 

 a number of false turns. The labyrinth used for the rats 

 was very complicated, being in fact a replica in wire netting 

 of the Hampton Court maze, but much simpler ones have 

 since been employed for other animals. One advantage of 

 the labyrinth method is that it requires nothing of the animal 

 except what is perfectly natural to it, namely, locomotion. 



The lowest forms which have been thus far tested by this 

 means are certain Crustacea. The crab Carcinus granulatus 

 was placed in a very simple labyrinth with only two points 

 where a choice between the right and wrong paths was pos- 

 sible. At the end of the labyrinth was the aquarium, and the 

 crab's discomfort out of the water served as the occasion stir- 



