JOURNAL OF ANIMAL BEHAVIOR 



Vol. 1. JANUARY-FEBRUARY, 1911. No. 1. 



THE DISCRIMINATIVE ABILITY OF THE PAINTED 



TURTLE 



D. B. CASTEEL 

 Contributions from the Zoological Laboratory of the University of Texas, No. io6 



FOUR FIGURES 



INTRODUCTION 



In the experiments herein recounted an endeavor has been 

 made to obtain an accurate measure of the ability of turtles 

 of the species Chrysemys marginata to discriminate between 

 lines of different width and direction and patterns of different 

 form. The evidence for or against such discrimination has 

 been obtained by establishing in the minds of the turtles asso- 

 ciations -between certain kinds of lines and patterns and certain 

 pleasant or unpleasant experiences. The reward for successful 

 choice was food; as punishment for failure the electric shock 

 was used. 



Experiments by various investigators upon a fairly large 

 number of animals have shown that associations between light 

 and darkness, black and white and intermediate shades may 

 be established in a number of cases. In relatively few instances 

 have 'such discriminative associations been established for pat- 

 terns of different form. 



To the systematic zoologist no phenomena in nature are more 

 evident than the occurrence of those slight differences in shape 

 and markings which separate species of the same genus and 

 closely related genera. For the comparative psychologist the 

 question must often arise, Are the higher animals capable of 



