Allen, Association in tlie Giiinca Pig. 299 



(i) What processes are characteristic of the adult guinea 



pig- 



(2) How these processes develop from birth to maturity. 



More specifically, it was undertaken to show what prob- 

 lems could be learned, at what age the most complex problems 

 were first learned (thus affording an indication of psychical ma- 

 turity), and what elements contributed to tKe learning of the 

 problem. As far as possible, the purpose was to gain an in- 

 sight into the psychical processes of the guinea pig. 



The problem and method of work were suggested to me by 

 Professor Angell and Professor Donaldson. They have con- 

 stantly defined the inquiry, and indicated the general bearing of 

 particular observations. 



The investigation is a complement to that made by Dr. 

 Watson in this laboratory, and to his work ^ there will be con- 

 stant reference ; before the close there will be a comparison of 

 our results with deductions from them. I am under obligation 

 to Dr. Watson for constant suggestions and help, as well as for 

 the method of work." 



However, ic is quite essential, both from a psychological 

 and a neurological point of view, that this work should be un- 

 dertaken. The white rat is born very immature, its eyes are 

 not yet open, it is naked, its nervous system is entirely unme- 

 duUated. The guinea pig, a rodent closel}' related to the white 

 rat is, on the other hand, born very mature. It is quite able 

 to take care of itself at birth, has full possession of all its senses, 

 is well covered with hair, and, as will be seen, its nervous sys- 

 tem is almost completely medullated. The psychical imma- 

 turity of the white rat is such as would be expected from its 

 physical immaturity ; whereas the guinea pig has a compara- 

 tively complete mental equipment at birth. 



' John B. Watson. Animal Education, Chicago^ 1903- 

 ' Loc. cit., pp. v6- 



[ 7] ...!(LIBRARYl:;:t, 



