Modification by Experience 275 



that the chicks, which were confined in small pens, could 

 escape by running to a particular spot, or up an inclined 

 plane. Porter (610) found that the English sparrow quickly 

 learned the Hampton Court maze, and that the vesper spar- 

 row and cowbird learned a simpler form in twenty or thirty 

 trials (611). 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 (647). Hunter's (349) experiments on the 

 pigeon with the use of the maze will be mentioned later. 



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 

 labyrinth every night (684). 



In Yerkes's (820) study of the Japanese dancing mouse, 

 the reactions to irregular and to regular labyrinths were 

 compared, and it was found that a maze of the latter type, 

 that is, one where left and right turns alternated, was 

 more quickly learned and more perfectly mastered than an 

 irregular one. Kinnaman (401) taught two Macacus 

 monkeys the Hampton Court maze. 



The feature of maze learning which interests us at this 

 point is the dropping off of useless movements. This 

 probably occurs partly through the general tendency of 

 useless movements to be omitted, and partly through the 

 tendency of the successful movements to survive. It has 

 been argued that if the shortening of the maze running is 

 due to the fortunate consequences of the successful move- 

 ments, then the errors which should be earliest dropped 

 off are those at the latter part of the course, which come 

 nearest in point of time to the final success, usually the 



