ACTION PATTERNS 301 



nism coordinating the organism for running in other 

 words, a brain. The difference between Venus' fly- 

 trap and man is the difference between the number of 

 mechanisms possessed by each. A multiplication of 

 the single action pattern of Venus' fly-trap equals the 

 mechanism of man. 



Pawlow has shown , in a recent work, that new re- 

 flexes may be created in an animal by superimposing 

 new stimuli upon older ones, simultaneously with the 

 occurrence of old reflexes. Thus, when a dog is being 

 fed, if he be frequently subjected to a painful electri- 

 cal stimulus applied to a given area of skin, a reflex 

 to this electrical stimulus will soon develop which is 

 precisely like that shown in response to the exhibition 

 of food. This reflex, which corresponds to an action 

 pattern, is termed a "conditioned" reflex, in contrast 

 to the normal or "unconditioned" reflex. 



As an explanation of the creation of the new reflex, 

 Pawlow 1 states that the "nervous impulse resulting 

 from the stimulus, which formerly went to a particular 

 region of the nervous system, is now directed to a dif- 

 ferent one." He says: "In this way we have been 

 able to direct the impulse from one path to another, 

 according to the conditions ; and we cannot avoid the 

 conclusion that this represents one of the most impor- 

 tant functions of the highest parts of the central nerv- 

 ous system." 



In some such manner, doubtless by a slow and con- 

 tinuous process, the changing conditions of environ- 

 ment have superimposed new stimuli upon the old 

 until by the infinitely varying stimuli which simul- 



1 Pawlow : The Investigation of the Higher Nervous Function. 



