334 BEHAVIOR OF THE LOWER ORGANISMS 



resolved into a succeeding state, this resolution becomes easier, and may 

 take place spontaneously, so that the reaction induced is that due pri- 

 marily to the second physiological state reached. Wherever we find 

 this law in operation, we have the ultimate basis from which habit and 

 memory (objectively considered) are developed. 



From memory in the general sense it is customary to distinguish 

 associative memory. This is characterized objectively by the fact that 

 the response at first given to one stimulus comes, after a time, to be 

 transferred to another one. Examples of associative memory are seen 

 in the experiments of Yerkes and Spaulding on crustaceans, described 

 in Chapter XII. It may be pointed out that the essential basis for 

 associative memory is the same law of the resolution of physiological 

 states which we have set forth in the last paragraph as underlying ordi- 

 nary memory. The physiological condition induced by the first stimu- 

 lus (sight of the screen, in Spaulding's experiments) is regularly re- 

 solved into that due to the second stimulus (food, in the experiments 

 just mentioned). After a time the resolution becomes spontaneous, so 

 that the physiological state primarily due to the food is reached imme- 

 diately after the introduction of the screen, even though no food is given. 

 There seems to be no difference in kind, therefore, between associative 

 memory and other sorts ; they are based on the same fundamental law. 

 The existence of associative memory has often been considered a criterion 

 of the existence of consciousness, but it is clear that the process under- 

 lying it is as readily conceivable in terms of matter and energy as are other 

 physiological processes. Even in inorganic colloids, as we have seen 

 (p. 317), the properties depend on the past history of the colloid, and the 

 way in which it has reached the condition in which it is now found. If 

 this is conceivable in terms of matter and energy, it is difficult to see why 

 the law of the readier resolution of physiological states is not equally so. 



Intelligence is corpmonly held to consist essentially in the modifica- 

 tion of behavior in accordance with experience. If an organism reacts 

 in a certain way under certain conditions, and continues this reaction 

 no matter how disastrous the effects, we say that its behavior is unin- 

 telligent. If on the other hand it modifies its behavior in such a way as 

 to make it more adequate, we consider the behavior as in so far intel- 

 ligent. It is the "correlation of experiences and actions" that consti- 

 tutes, as Hobhouse (1901) has put it, "the precise work of intelligence." 



It appears clear that we find the beginnings of such adaptive changes 

 of behavior even in the Protozoa. They are brought about through the 

 law in accordance with which the resolution of one physiological state 

 into another takes place more readily after repetition, in connection 

 with the other principle that interference with the life processes causes 



