240 BRAINS OF RATS AND MEN 



trol — and will be. In the meantime, the record stands 

 as a very illuminating contribution to animal be- 

 havior. 



Domesticated animals and caged wild animals are 

 likely to exhibit their innate and habitual reactions to 

 better advantage than any inventiveness of which 

 they may be capable, for here they lead a routine 

 existence. If the distinctive cortical functions are su- 

 perposed upon these stereotyped activities, the added 

 functions will naturally be invoked only when the 

 mechanized activities prove inadequate, that is, un- 

 der conditions which make unusual demands upon 

 the resourcefulness of the individual and where this 

 resourcefulness is not inhibited by unaccustomed situ- 

 ations. Such conditions are more likely to be realized 

 in the desperate struggle for existence in nature than 

 under laboratory conditions. Yet controlled observa- 

 tions are indispensable, and the problem is to devise 

 experiments that will meet these exacting require- 

 ments. 



Domestication for many generations is sure to 

 alter the whole behavior complex of a species, and 

 probably in the direction of reduction rather than en- 

 hancement of initiative and resourcefulness. The be- 

 havior of tame albino rats is undoubtedly simpler and 

 of more routine character than is that of their wild 

 relatives, the Norway rats, and Donaldson (1924) has 

 found corresponding changes in their brains, the 

 brains of the wild rats being heavier relative to bodily 

 weight. 



