STUDIES OF CEREBRAL FUNCTION. IX 11 



generalization. If the animals made such generalizations, 

 mazes of this plan should all be of about equal difficulty, 

 whether they have few or many culs de sac. We believe, 

 however, that this objection is not serious since the forma- 

 tion of the alternation habit seems to require many more 

 trials than are required for complete mastery of our longest 

 maze (Carr, T7; Hunter, '20; Loucks, '31). 



A maze with 16 culs de sac was so constructed that seg- 

 ments could be closed off to give mazes with 4, 8, or 12 culs de 

 sac. The ground plans of the resultant mazes are shown in 

 figure 1. The maze was constructed of f-inch pine with 4-inch 

 partitions between the alleys. The top was covered with fine 

 wire mesh. Electrical contacts on counterbalanced sections 

 in the floor permitted automatic recording of errors. Four 

 separate starting boxes gave access to the segments of the 

 maze and were closed off: by one-way doors of sheet metal. In 

 later discussion the four mazes which can be arranged by 

 blocking or opening the doorways between the culs de sac 

 will be referred to as mazes I, II, III, and IV, as shown in 

 figure 1. 



As a control of the training records with these four mazes, 

 a fifth having 8 culs de sac was used. The ground plan of 

 this maze is also shown in figure 1. Its construction was 

 similar to that of the other, except that the order of alterna- 

 tion of turns was reversed and the relative position of food 

 box and starting box altered. Its orientation in the room 

 during use was also different from that of the other mazes, 

 as indicated in the figure. In later discussion this will be 

 called maze V. 



Training methods 



Before controlled training in the mazes was begun, the 

 animals were given preliminary training in traversing a 

 straight runway, 10 feet in length, until they came through 

 promptly and were not disturbed by handling. They were 

 then fed for 3 days in succession only in the food box of the 

 maze, without access to the alleys. In training a ' trial ' was 



