VISUAL DISCRIMINATION IN RACCOONS. 



L. W. COLE AND F. M. LONG. 



With One Figure. 



In a former paper concerning the behavior of raccoons certain dis- 

 criminations which they made between two colored objects which 

 differed both in color and brightness were described.^ These were 

 purely sensory discriminations (i. e., an added motor factor which 

 the animals later spontaneously contributed to the experiment was 

 not an essential feature of it). We wished, if possible, to ascertain, 

 further, whether these animals can discriminate colors of equal bright- 

 ness, and some months after the aboA'e mentioned paper was published 

 we began at the University of Oklahoma the experiments here de- 

 scribed. The work was completed at Harvard University. The 

 method used was that of employing reflected light under conditions 

 of daylight illumination. 



In using this method we at first adopted the procedure which 

 Kinnaman had used in investigating the color vision of monkeys.^ 

 Later this procedure was modified in order to adapt it for use with 

 the raccoon. The method has been used, with varying details, in 



^CoLE, L. W. Concerning the intelligence of raccoons. Jour, of Comp. 

 Neur. and Psych., vol. 17, pp. 211-261. 1907. 



^Kinnaman, A. J. Mental life of two Macacns rhesns monkeys in captivity. 

 Amer. Jour, of Psych., vol. 13, pp. 98-148 and 173-216. 1902. 



The Journal of Compakative Nedrology and Psychology. — Vol. XIX, No. 6. 



