HABIT FORMATION IN ALBINO RATS 5 



Hicks, 4 in summing up the experimental results of several in- 

 vestigators, concludes that " time is the best single criterion, 

 inasmuch as it represents all phases of the process of learning, 

 and since it will yield the most comparable results at the hands 

 of different investigators." In timing the rats a very accurate 

 Swiss split-second stopwatch was used. Under ideal conditions, 

 perhaps, the animal should be presented to the problem by one 

 person, timed by another, while the experimenter himself should 

 merely record the results. But timing very soon becomes auto- 

 matic; when the rat is crossing the line it is almost impossible 

 to inhibit the impulse to press the stem of the watch. 



At the conclusion of the experiments all the rats were shipped 

 to the Wistar Institute where Dr. Shinkishi Hatai ascertained 

 the anatomical data necessary for the formulation of the com- 

 parison between relative brain weight and the ability to form 

 habits. 



III. EXPERIMENT 1: THE MAZE 



The apparatus used in this experiment was the Watson Maze 

 (see Plate I) . This maze is circular in form, five feet in diameter, 

 with entrances from outer runways to the next inner at alternate 

 ends of a quadrant arc. The runways are each four inches wide, 

 and the centre, F, eight inches in diameter. The partitions are 

 of aluminum and rise to a height of five inches above the floor 

 of the maze. A heavy wire screen resting on the top serves 

 the purpose of preventing the rats from climbing over the par- 

 titions, and also allows the experimenter to observe all move- 

 ments within. The perfect course of the animal running is, 

 from the entrance, E, through runway entrances 1, 2, 3, 4, 5, 

 6, and 7 to F (food). Each side of runway entrances 2 to 6 

 inclusive lead into cul-de-sacs. 



The object of the experiment was to have each rat learn to 

 reach the centre, F, in the least possible time, the starting time 

 being taken when the animal crossed runway entrance 1, and 

 the finishing time when he crossed entrance 7. 



In preparation, each animal, beginning at the age of sixty- 

 five days, was fed alone in the centre, F, ten minutes daily for 



4 Hicks, The Relative Values of the Different Curves of Learning. Jour. 

 Animal Behavior., Vol. I, pp. 138 ff. 



