62 Animal Intelligence 



placed at A and left to find its way out. The walls were 

 made of books stuck up on end. 



Q was a similar pen arranged so that the real exit was 

 harder to find. (See Fig. 16.) 



R was still another pen similarly constructed, with four 

 possible avenues to be taken. (See Fig. 17.) 



S was a pen with walls n inches high. On the right side 

 an inclined plane of wire screening led from the floor of the 

 pen to the top of its front wall. Thence the chick could 

 jump down to where its fellows and the food and drink 

 were. S was 17X14 in size. 



T was a pen of the same size as S, with a block of wood 3 

 inches by 3 and 2 inches high in the right back corner. 

 From this an inclined plane led to the top of the front wall 

 (on the right side of the box). But a partition was placed 

 along the left edge of this plane, so that a chick could reach 

 it only via the wooden block, not by a direct jump. 



U was a pen 16X14X10 inches. Along the back 

 toward the right corner were placed a series of steps ij 

 inches wide, the first i, the second 2, and the third 3 inches 

 high. In the corner was a platform 4X4, and 4 high, from 

 which access to the top of the front wall of the pen could 

 be gained by scrambling up inside a stovepipe n inches 

 long, inclined upward at an angle of about 30. From 

 the edge of the wall the chick could, of course, jump down to 

 food and society. The top of the pen was covered so that 

 the chick could not from the platform jump onto the edge 

 of the stovepipe or the top of the pen wall. The only 

 means of exit was to go up the steps to the platform, up 

 through the stovepipe to the front wall, and then jump 

 down. 



The time-curves for chicks 90, 91, 92, 93, 94 and 95, all 

 2-8 days old when experimented on, follow on page 65. 



