A STUDY OF COLOR VISION IN THE RING-DOVE 



35 



TABLE 4 



Reactions in Light-dark Training Grouped in Fifties to Show Slowness 

 of Improvement and Irregularities 



to react properly. Between the three hundredth and the four 

 hundredth trials, all of them, however, showed marked im- 

 provement. Were it not that two experimenters were involved 

 and the conditions of observation thoroughly controlled, it might 

 fairly be suspected that the doves finally discovered some other 

 basis for reaction than the difference in the intensity of illumi- 

 nation. We are convinced, however, that this was not the 

 case and that the results satisfactorily prove that the ring-dove 

 is extremely slow, under the conditions described, in learning to 

 react appropriately to achromatic stimuli, even though they 

 differ very markedly. It must be admitted, however, that there 

 are certain features in table 3 which are puzzling. Number 1 

 discriminated perfectly on April 23rd, and number 2 on April 

 24th, whereas on both the preceding and the following days they 

 did poorly. This suggests to the writer that they had happened 

 upon some means of choosing other than that intended by the 

 experimenter. 



From a careful comparison of the data of tables 2, 3, and 4, 

 it is clear that by the use of the electric stimulus, it is possible 

 to develop a visual discrimination habit in the dove much more 

 quickly, and consequently with less labor, than by the employ- 

 ment of the food getting desire alone. 



All of the foregoing observations are merely preparatory to 

 the work with chromatic stimuli. It therefore seems unneces- 



