124 THE BEHAVIOR OF LOWER ORGANISMS. 



PHYSIOLOGICAL STATES IN BEHAVIOR OF HIGHER ANIMALS, 

 AS COMPARED WITH THOSE IN LOWER ORGANISMS. 



Realization of the fact that the behavior, even in the lowest organisms, 

 is determined to a large degree by physiological states must be of great 

 service in welding into one connected whole the study of behavior in 

 all animals, from the lowest up to man. The attempt to divorce the 

 study of the behavior of man from that of the lower animals, which 

 has been evident in late years, seems unfortunate and unnecessary. It 

 is true that we are not justified in reading the subjective states of man 

 directly into the lower organisms. But we are not confronted with the 

 alternative of doing this or of separating the two subjects completely. 

 The behavior of man can be studied from the same objective standpoint 

 which we employ in investigating the behavior of animals. When this 

 is done, there is no reason for holding the results on man aloof from 

 those obtained elsewhere ; if it is proper to compare different organ- 

 isms of any kind from this point of view, in order to obtain general 

 results, as all investigators do, it is certainly proper to draw man also 

 into the circle of comparison. The fact that in man we can know also 

 the subjective accompaniments of the different physiological states and 

 reactions is by no means a disadvantage in this comparison ; it is merely 

 an additional feature, of the highest possible interest. We can even, 

 it seems to me, justifiably call attention to the relation between the 

 subjective states as found in man to certain general phenomena common 

 to man and other organisms. It is only when we proceed directly to 

 attribute to the lower animals the subjective states which we know only 

 in man (and, indeed, only in our own individual minds) that we pass 

 the boundary of scientific procedure. 



In the higher animals, and especially in man, the essential features 

 in behavior depend very largely on the history of the individual ; in 

 other words, upon the present physiological condition of the individual, 

 as determined by the stimuli it has received and the reactions it has 

 performed. But in this respect the higher animals do not differ in 

 principle, but only in degree, from the lower organisms, as we have seen 

 in our analysis of the behavior of Stentor. In this unicellular form 

 we were forced to distinguish at least six different physiological condi- 

 tions, determining in the same individual different reactions to the same 

 stimuli. In the higher animals, and especially in man, we can distin- 

 guish, as might be expected, an immensely greater number of such 

 conditions which induce different reactions, but there is no evident differ- 

 ence in principle in the two cases. Can we go farther and make a more 

 direct comparison of individual physiological states in the higher and 

 lower organisms? We find in Stentor, and again in the flatworm, 

 that after the organism has been repeatedly stimulated by an agent 



