A CIRCULAR MAZE WITH CAMERA LUCIDA 



ATTACHMENT 1 



JOHN B. WATSON 



The circular maze shown in Fig. 1 is made with wooden base 

 and aluminium walls. The base is 150 cm. in diameter and 4 

 cm. in thickness, and is constructed as follows: Two wooden 

 discs 150 cm. in diameter and 2 cm. in thickness are first sawed 

 out. These two discs are finally glued together. Before glueing, 

 however, the upper disc is marked off into a series of concentric 

 circles. The diameter of each of the circles is as follows, be- 

 ginning with the outermost one: 140 cm., 120 cm., 100 cm., 

 80 cm., 60 cm., 40 cm., and 20 cm. These circles are then sawed 

 out upon a band saw. The width of the saw is so chosen that it 

 is just equal to or slightly larger than the thickness of the alu- 

 minium sheets used for the walls. After sawing, the disc as a 

 whole is converted naturally into a series of concentric rings. 

 These are fastened down to the lower disc with hot glue and screws. 

 The lower surface of the base is thus solid, while the upper surface 

 shows a series of grooves into which the aluminium walls may be 

 slid. Soft aluminium bought in rolls is used for the latter. 

 The height of the aluminium is 18.5 cm., the thickness, .8 mm. 

 The aluminium is unrolled and cut into the proper lengths. 

 Each strip is cut just 10 cm. shorter than the length of the cir- 

 cular groove into which it is to be fitted. This gives an opening 

 into the alley. By means of this arrangement it is possible to 

 slide the aluminium around in its groove and thus to place the 

 entrance in any desired position. Fig. 1 shows clearly the 

 construction of the maze, the number of alleys, the placing of 

 the entrances, and the radial stops. 2 



This maze offers several desirable things in work of this 

 character: in the first place it can be used on the unit plan, in 

 that only the home box and the surrounding segments need be 



■ From the Psychological Laboratory of The Johns Hopkins University. 



' The base as a whole may then be sawed into half or quarter sections for con- 

 venience in shipping or storing. Indeed, it is easier to build the base in half sec- 

 tions. When set up the sections are locked together and placed horizontally upon 

 a wooden framework. The material should be well seasoned. A thorough coat- 

 ing of boiled linseed oil should be applied. 



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