CHAPTER VI 



LAWS AND HYPOTHESES FOR BEHAVIOR 



LAWS OF BEHAVIOR IN GENERAL 



Behavior is predictable. The first law of behavior, one 

 fraction of the general law of the uniformity of nature, is 

 that with life and mind, as with mass and motion, the same 

 cause will produce the same effect, - - that the same situa- 

 tion will, in the same animal, produce the same response, - 

 and that if the same situation produces on two occasions two 

 different responses, the animal must have changed. 



Scientific students of behavior will, with few exceptions, 

 accept this law in theory, but in practice we have not fully 

 used it. We have too often been content to say that a man 

 may respond in any one of several ways to the same situa- 

 tion, or may attend to one rather than another feature of 

 the same object, without insisting that the man must in each 

 case be different, and without searching for the differences 

 in him which cause the different reactions. 



The changes in an organism which make it respond differ- 

 ently on different occasions to the same situation range from 

 temporary to permanent changes. Hunger, fatigue, sleep, 

 and certain diseases on the one hand, and learning, immu- 

 nity, growth and senility on the other, illustrate this range. 



Behavior is predictable without recourse to magical agen- 

 cies. It is, of course, the case that any given difference 

 between the responses of an animal to the same situation 

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