250 The Animal Mind 



narians. The first influence of such increase from 23 de- 

 grees to 26 degrees C. is to produce heightened activity 

 and positive reactions. Then, from 26 degrees to 38 de- 

 grees, the reactions are negative. From 38 degrees to 39 

 degrees, violent crawling movements set in, and then, 

 curiously enough, the righting reaction is given, perfectly 

 irrelevant, of course, to the conditions. Finally, the an- 

 terior and posterior ends are turned under, the central 

 part is arched upward, and the animal falls over forward 

 on its back (462). 



In all these cases where repetition of the same stimulus 

 produces successively different forms of the negative re- 

 action increasing in violence, it is most natural to think 

 of the psychic accompaniment as an increasing degree of 

 unpleasantness. In our own experience, repeating a stimu- 

 lus does not alter the quality of the resulting sensation, 

 except where the structure of a special sense organ is a 

 modifying factor, as in the case of visual after-images. 

 A decidedly disagreeable stimulus acting repeatedly on a 

 human being may produce unpleasantness that grows more 

 and more intense until it is unbearable ; the behavior of a 

 human being under such circumstances is much like the 

 animal behavior we have just been describing. Various 

 movements calculated to get rid of the stimulus are tried, 

 each more energetic than the last. Hence, if the lower 

 animals behaving thus are conscious, we may plausibly 

 assert that their consciousness under these circumstances 

 is increasingly unpleasant. But the human experience in 

 such a case would be, or might be, further characterized 

 by the presence of ideas. That is, the human being 

 would think of the different ways to get rid of the stimulus 

 one after another. This many, at least, of the animals 

 that try different negative reactions are apparently in- 



