170 L. W. COLE 



'The essentials of Cole's apparatus and method were duplicated 

 in our experiment." (P. 244.) Truly, with all these carefully 

 arranged differences, I am quite unable to find that the "essen- 

 tials" of the experiment were even similar to mine, but the 

 reader may judge for himself. Any one who is familiar with 

 my paper will remember that only a small part of the upper 

 portion of the lever projected above the screen board. To be 

 specific, my notes of Dec. 6, 1905, state that the lever "when 

 upright" extended "one inch above the upper edge of the front 

 piece." 



"Controls 1 ' 1 By the charge that I did not employ "adequate 

 controls" is meant chiefly that I did not guard against discrimin- 

 ation by position of cards and levers nor against discrimination 

 by cues given by the experimenter. Let me call attention to 

 two items which my critics have overlooked relative to the first 

 precautions, and quote from notes of the experiments. On 

 page 228, I say, "During one test red would be on the forward 

 lever, one inch in front of the other, during the next test on the 

 rear lever. The animal could not, therefore, react to the position 

 of the cards." I did not re-state this precaution in the portion 

 of my account on which the Chicago laboratory based its experi- 

 ments, but one presumes that a critic reads completely the paper 

 he criticises. To show that this precaution was kept up during* 

 the three-color work I will quote my "daily plan" for one animal 

 for three consecutive days. 



"April 23. Jack. Same as preceding. Blue middle, orange 

 back, white front." 



"April 24. Jack. Three colors. Orange front, white middle, 

 blue back." 



"Jack. April 25. Three colors. Blue front, orange middle, 

 white back." 



It is evident that each card occupied every possible position 

 in each three consecutive tests, and that no card occupied the 

 same position for any two tests. Does this look as if I took no 

 precautions against the animals reacting to the positions of the 

 cards ? I find no such precautions as this, to leave only the 

 colors constant, in the work of Gregg and McPheeters, so it 

 seems that the animal was fed for depending on another cue. 



But the uninformed reader may ask, "But what of level 

 position ?" At the beginning of each days work the levers 



