158 Animal Intelligence 
far is the evidence that from the first the chick reacts to all 
colors. In no case was there any y random pecking at the 
white surface of the cardboard. ane 
On a black peskaroum’ the same chicks reacted to all the 
colors. 
‘II is a table of the results. 
II 
Times Reacrep To | ToTaL NuMBER oF PEcKS 
White 6 19 
Blue 4 II 
Red . 4 8 
Green 4 4 
Orange . 2 7 
Yellow . 2 4 
In other experiments chicks were tried with green spots on 
a red ground, red spots on a green ground, yellow spots on an 
orange ground, green spots on a blue ground, and black spots 
ona white ground. All were reacted to. Thus, what is ap- 
' parently a long and arduous task to the child is heredity’s 
gift to the chick. It is conceivable, though to me incred- 
ible, that what the chick reacts to is not the color, but the 
very minute elevation of the spot. My spots were made so 
that they were only the thickness of thin paper above paste- 
board. Any one who cares to resort to the theory that this 
elevation caused the reaction can settle the case by using 
color-spots absolutely level with the surface.! 
1The crude experiments reported in this and the preceding paragraphs 
were not made to test the presence of color vision proper, that is, of differ- 
entiation of two colors of the same brightness, but only to ascertain how 
chicks reacted to ordinary colored objects. It was, however, almost certain 
from the relative frequency of the reactions that the intensity factor was not 
the cause of the response. For example, if it had been, black on white and 
yellow on black should have been pecked at oftener. 
