ANIMAL PSYCHOLOGY 175 



men are called materialists. Yet another group insisted that as mind 

 and matter are always together, neither may be given the preference. 

 Both are different sides of the same coin. Each thought-wave is always 

 associated with a nerve-wave of some kind, and neither can -exist with- 

 out the other. Such men are called monists. It will be seen that the 

 term "monists" is applied to this group because they do not accept a 

 dualism in life. 



These different groups of contenders attack psychological problems 

 with different prepossessions. The spiritualist is likely to call himself 

 an interactionist in psychology, the materialist a behaviorist, and the 

 monist a parallelist. 



As it makes a profound difference to a patient as to which one of 

 these theories his physician holds, the student must know what each 

 term means or he will be totally unable to pass judgment on the many 

 and conflicting discussions which are ever coming before him. 



The interactionist holds that the state of mind of an individual can 

 and does influence his physical being and vice versa. An example of 

 this is a man worrying over financial losses, whose body becomes run 

 down until disease clutches him. 



The behaviorist insists that only a definite physical reaction, meas- 

 urable in the laboratory, is valid data on which to base a scientific con- 

 clusion, and that until the individual mentioned above shows a definite 

 measurable reaction, there is no change which we as scientists can use 

 or accept. 



The parallelist, insisting as he does that both the mentality and the 

 physical organ which is associated with it are different sides of the same 

 thing, must necessarily consistently claim that the mind is totally un- 

 able to influence the body and the body totally unable to influence the 

 mind. In fact, one of their prominent writers says that one may as 

 well expect a piece of beefsteak put into a sausage machine to come out 

 a moonlight sonata as to expect either body or mind to influence each 

 other. 



It is therefore only the interactionist who can consistently speak of 

 nervous and mental diseases, and who can consistently use both physical 

 and psychic remedies. 



At this point we may consider what is commonly designated as* 

 structural and functional psychology. 



Structural psychology concerns itself with (1) the general organi- 

 zation of an organism, (2) the general organization of its nervous sys- 

 tem, and (3) the organization of the specialized nerve parts such as the 

 eye, ear, nose, etc. 



Functional psychology is interested in (1) the general way an or- 

 ganism reacts (discrimination), (2) whether the organism can modify 

 its action (docility), and (3) in how many ways and in what way its 

 behavior will vary (initiative). 



