Modification by Experience 253 



one also up. Since the cards were shown successively, Cole 

 concludes that "remembrance of the card just shown was 

 required for a successful response." "Why," he asks, 

 "should the animal put the red card down if it did not fail 

 to correspond with some image he had in mind, and why 

 when he put the green up should he leave it up and go up on 

 the high box for food if the green did not correspond with 

 some image he had in mind?" (82). It seems to the writer 

 that the supposition of an image is unnecessary, except 

 possibly in the experiments requiring discrimination of 

 sizes. It is perfectly possible, as we know from our own 

 experience, to react to one stimulus and not to another with- 

 out going through a comparison of the two, unless the differ- 

 ence between them is merely one of degree. It might have 

 been possible for a human being to discriminate between 

 the larger and the smaller cards only by calling up a memory 

 image of the card not shown and comparing it with the one 

 before him ; it surely would not have been necessary for him 

 \ to use images in the reactions to colors, forms, and tones. 

 I And if a human being, accustomed to much dependence on 

 \ memory ideas, could get on without them here, surely a 

 \ raccoon could. Even in judgments of degree, all laboratory 

 \psychologists know that human beings have a strong tendency 

 \to make absolute rather than comparative judgments, and 

 use memory ideas but little. Better evidence of the use of 

 images is furnished by the following method: "Three 

 levers were placed on the displayer. 'One, on being raised, 

 displayed white, another orange, another blue. The plan 

 was to display white, orange, and blue consecutively, then 

 to display the same blue three times. I fed the animal if 

 he climbed upon the high box on being shown the series 

 white, orange, blue, and did not feed him after the series 

 blue, blue, blue." That is, the stimulus immediately pre- 



