Habit Formation : The Labyrinth Habit 211 



the common mouse. This proved impracticable because the 

 same labyrinth is not suited to the motor tendencies of both 

 kinds of mice. 



The first of the four labyrinths, A, appears in ground plan 

 in Figure 25. It was constructed of wood, as were the other 

 labyrinths also, 

 and measured 

 60 cm. in length 

 and width, and 

 10 cm. in depth. 

 The outside 

 alleys were 5 

 cm. wide. In 

 the figure, I 

 marks the start- 

 ing point or en- 

 trance to the 

 maze, and O 

 the exit through 

 which the 

 mouse was per- 

 mitted to pass into its nest-box. Any turn in the wrong direc- 

 tion which the animal made in its progress from entrance to 

 exit was recorded as an error. The four errors, exclusive of the 

 mistake of turning back, which were possible in this labyrinth, 

 are indicated in the figure by the numerals i, 2, 3, and 4. 

 By retracing its steps a mouse might repeat any one or all of 

 these errors, and add to them the error of turning back. 



In the experiments a mouse was permitted to enter the 

 maze from a small box which had been placed by the experi- 

 menter at /, and an accurate record was kept of the number 

 of errors which it made in finding its way from entrance to 

 exit, and of the time occupied. Each of five dancers was given 



FIGURE 25. Labyrinth A. 7, entrance; O, exit; i, 2, 

 3, 4, blind alleys. 



