Spatially Determined Reactions 197 



previously found honey on a blue circle, even though the two 

 had been made to exchange places. They flew first to the 

 place where the blue circle had been, but did not alight upon 

 the strip. Wasps, also, according to Forel, distinguished 

 among a disk, a cross, and a band of white paper, going first 

 to the form on which they had last found honey (130). 

 Various species of birds were experimented on by the method 

 of placing cards carrying simple designs over glasses covered 

 with gray paper, food being placed always under the same 

 card. The English sparrow and the cowbird both learned to 

 distinguish a card bearing three horizontal bars and one 

 bearing a black diamond from each other and from plain 

 gray cards. On the other hand, the sparrow, curiously 

 enough, did not succeed in discriminating vessels of different 

 form ; the cowbird was not fully tested with these, but gave 

 some evidence that it was learning (344, 345) . Pigeons were 

 only moderately successful in a similar test (371). 



Many dogs have been taught to distinguish printed letters 

 on cards; Sir John Lubbock's poodle "Van" is a familiar 

 example. Van learned to pick out cards marked "Food," 

 "Bone," "Out," "Water," and the like, and to present each 

 on its appropriate occasion. It took him ten days to begin to 

 make the first step of distinguishing between a printed card 

 and a plain one ; in a month this was perfected and in twelve 

 more days, when he wanted food or tea, he brought the right 

 card one hundred and eleven times and the wrong one twice. 

 The second mistake consisted in bringing the word "door" 

 instead of "food," indicating that it was really the look of the 

 words that he distinguished (251, p. 277 f.). 



The dancing mouse could not learn to distinguish two equal 

 illuminated areas of different forms (469). Raccoons learned 

 to discriminate a round card from a square one (82). Thorn- 

 dike taught the two Cebus monkeys under his observation to 



