CANADA PORCUPINE 61 



TABLE XII 



Porcupine No. 10. (Memory 105 Days) 



Black- White Records accidentally destroyed. 



Blue-Green food in blue 15, 12, 17, 18, 17, 17, 17, 14, 13. 



Black-White 20. 



Blue-Green food in blue 17, 16, 17, 17, 20. 



B^-G, food in light green 14, 12, 7, 12, 5, 10, 10. 



B2-G2 food in blue 15, 11, 10, 10, 8. 



B,-G2 food in dark blue 10, 7, 13, 16, 13, 20. 



B:-Go food in dark blue 17, 14, 11, 11, 12, 13, 12, 20. 



Blue-Green food in blue 17, 16, 20. 



Tables XI and XII show the memory of these two porcupines 

 on the color and brightness reactions and also add another check 

 on the problem of whether these animals were discriminating by 

 color or brightness in their selection of the food box. Let it 

 be remembered that the index figure indicates the relative 

 brightness of the colors used, i.e., B^ G- representing the light 

 blue and the light green respectively while B, and Gj stand for 

 the darker shades of the blue and green. The black- white 

 records for No. lo were unfortunately lost but they differed 

 in no essential feature from those of No. 3. Again the two 

 animals give practically the same results. Both fail or at least 

 do not progress with the blue-green stimulus after relearning 

 the black- white, but both make 100% in the first series when 

 black-white is restored and move steadily to success with the 

 color boxes afterwards. No. 3 was tested on the original alter-, 

 nating series in which the "food" color was changed from blue 

 to green and vice versa with each experiment, the food always 

 being in the darker box. He made 16 errors in seven series, 

 whereas with chance he should have made 70 wrong choices. 

 In the experiments which follow the alternating series with 

 No. 3, a regular plan was followed in which blue was main- 

 tained as the "food" stimulus while its relative brightness was 

 varied from time to time till brightness had been reversed. 

 Both failed when brightness was nearly equal and both changed 

 color to feed in the darker box when brightness was restored. 

 Both later succeeded with blue-green as they had previously; 

 but both just as completely failed when food was placed in 

 the relatively lighter box and there was no better success in 

 solving the problem when both the light tinted boxes were 

 paired. This would appear to be a color difference sufficiently 

 characteristic if they were reacting to color, whereas the bright- 



