Modification by Experience 223 



descending plane. They soon began to make the turn before 

 they got to the bottom, and finally to throw themselves over 

 the edge as soon as they reached the top (450). 



Some of Thorndike's experiments on chicks involve the 

 labyrinth method, others what we shall call the puzzle-box 

 method. The chicks were confined in small pens, with food 

 outside. In some cases they could get out by running to a 

 particular spot, or up an inclined plane; in other cases by 

 pecking or pulling at something. Both sorts of action were 

 learned; obviously the former, involving simple locomotion 

 on the animal's part, are the ones which concern us at pres- 

 ent (393). Porter found that the English sparrow quickly 

 learned the Hampton Court maze (344), and that the vesper 

 sparrow and cowbird learned a simpler form in twenty or 

 thirty trials (345). Pigeons tested by Rouse acquired the 

 ability to traverse four different labyrinths, and it was noted 

 that their experience with the earlier ones seemed to help 

 them in the later ones (371). 



White rats observed by Small learned the Hampton Court 

 maze, in nine experiments made at intervals of two days, 

 so well that they committed only two errors in the ninth 

 test, but the significance of this time is obscured by the 

 fact that the rats were allowed to run freely about the laby- 

 rinth every night (385). Watson's earlier work with the 

 white rat was designed to compare the learning processes of 

 the young with those of the adult animal. The rat is born 

 unable to care for itself, and before those observed by Wat- 

 son had reached the age of twelve days, they were unable to 

 find their way by a simple labyrinth path back to the 

 mother. At twenty-three days of age they learned a 

 labyrinth more quickly than adults, probably because of 

 their greater activity, although for the same reason they 

 made more useless movements. The object of the research 



