82 EUPHA FOLEY TUGMAN 



lish sparrow and the cowbird learned to distinguish these de- 

 signs, but the sparrow showed some superiority in being able 

 the more quickly to unlearn an old habit and to learn a new 

 one. In discriminating colors all the birds did about equally 

 well, except the sparrow which showed superiority in the case 

 of blue. 



(3) History of the investigation. — (a) Preliminary experiment. 

 This investigation was begun in the Psychological Laboratory 

 of Indiana University on February 8, 1911. Twenty-six house 

 sparrows were obtained but seventeen soon died. The experi- 

 ment was begun with the nine remaining birds. Two birds 

 were tested to see if they could be trained to choose the darker 

 of the two stimulus areas. One was given 38 trials but chose 

 the darker side only six times or 14% of the time. The other 

 bird was given 32 trials and it chose the darker side 5 times, 

 which is 14%. Then both birds died. The other seven birds 

 were allowed to choose the brighter side which seemed to be 

 the natural tendency. But the experiment was not continued 

 very long as these birds also died. However, the few results 

 obtained seemed to show that all the birds were able to discrim- 

 inate the wide differences in intensities used. 



The preliminary experiment was important in that it showed 

 wherein the apparatus and method needed revision. One of the 

 most important changes made in the apparatus was in the 

 method of producing a motive. In the preliminary experiment 

 the floor of the discrimination chamber was covered with par- 

 allel copper wires one centimeter apart. The wires were con- 

 nected so as to form an interrupted circuit in connection with 

 the induction coil and key. This was the plan used by Yerkes 9 

 in his experiments with the dancing mouse. But the sparrows 

 rested with their feet in a sort of arched position with only the 

 claws touching the wires. Consequently it was not easy to 

 shock them. It was necessary to construct perches as described 

 in a later section of this paper, and as used in the final experiment. 



In October, 1911 the writer resumed the experiment with 

 four birds, — two males and two females. The work continued 

 until June, 1912. 



• Yerkes, R. M., 1907. The Dancing Mouse. The Macmillan Co., N. Y. 



