PHYSIOLOGICAL STATES AS DETERMINING FACTORS. 123 



on the basis of such a view that we can understand the changes of 

 reaction which occur when the same stimulus is repeated ; by the facts 

 of the interference of stimuli, even when their direct physical action is 

 by no means opposed ; by the facts of heterogeneous induction, and by 

 the fact that organisms at different times of the day or at different sea- 

 sons show different methods of reaction to the same stimuli. 



(5) This view is also strengthened by the fact that it brings into 

 relation reactions to stimuli and spontaneous movements. On this view 

 both are due directly to the same cause, to changes in physiological 

 condition, produced in one case by internal causes, in the other by 

 external causes. 



(6) This view receives powerful support, it seems to me, in our 

 knowledge of what takes place in the higher animals, including man. 

 This point I shall attempt to develop farther on in the present paper. 



This view, that reactions to stimuli in the lower organisms are pro- 

 duced in general through changes in physiological condition, is not, of 

 course, set forward as anything new or original. Many others have 

 doubtless taken this point of view, and it is implied, perhaps not always 

 consciously, in many attempted explanations of animal behavior. 

 The writer is merely attempting to emphasize that particular interpre- 

 tation, out of many existing ones, towards which the facts seem to 

 point strongly. He is convinced that the factor of physiological con- 

 dition as determining behavior has not oeen so fully and explicitly 

 realized and dealt with in work on the lower organisms as the facts 

 demand, and that many things that seem anomalous fall into their 

 proper places when this factor is taken fully into consideration. 



What is tire nature of physiological conditions, or changes in phys- 

 iological condition? Of course, we are not able to answer this ques- 

 tion. One is tempted to think of these expressions as signifying 

 something like chemical states or changes in chemical states. But the 

 concept of physiological states is, for higher animals at least, one at 

 which we arrive by analysis of complex phenomena in behavior, and 

 this does not give us any direct evidence as to the real nature of the 

 change in the living substance (considered as matter) which takes 

 place when the physiological condition changes. 



The concept " physiological states" is a preliminary collective con- 

 cept, which may later be analyzed into many. Such analysis is certain, 

 however, to be difficult and hypothetical in character in the lowest 

 organisms. In man we have, of course, a basis for analysis in the sub- 

 jective accompaniments of physiological (here called psychological) 

 conditions, in the feelings, emotions, etc. 



