64 K. S. LASHLEY 



by this standard, the progress of reeducation is not surprisingly 

 r" slow. Results indicating slower learning after cerebral lesion are 

 significant for this question only when the rate of learning is 

 idependent of preexisting habits. Experimental work where 

 this condition has been met covers only the frontal region of the 

 cerebrum and must be extended to other parts as well. 



C. A number of observations establish the fact that learned 

 reactions are mediated by certain regions of the cerebrum, the 



"""""frontal and parietal association areas in higher mammals, the 

 frontal pole in the rat. Is the function of these areas truly 

 associational, that is, do they function in the reintegration of 

 habits as such, or do they take part in the performance of the 

 habit simply because they lie, anatomically, between the neces- 

 sary afferent and efferent projection areas? In other words, do 

 the association areas have a directive function in learning or are 

 they masses of conductive tissue through which nerve impulses 



^penetrate at random from afferent to efferent projection areas 

 in the formation of new functional connections? There is no 

 evidence which answers this question. Franz ('07) found that 

 destruction of the frontal region of the brain of cat and monkey 

 abolished recently formed habits, but the habits studied all had 

 a kinaesthetic-motor foundation and it is not clear that all 

 habits would be abolished by this operation provided that they 

 had a different sensory basis. The problem can be attacked 

 effectively only by the study of the acquirement of a variety of 

 habits after the destruction of each and all of the association 

 areas. 



D. The suggestion of complete vicarious functioning of the 

 parts of the cerebrum in learning, raised by Lashley and Franz 

 and extended in this paper, raises the further question of the 



C relation of the absolute quantity of cerebral material to the 

 f rate* of learning. There seems to be no evidence bearing upon 



this point. 



r~ E. It has been suggested by many writers that habits which 

 are practiced until they become automatic are thereby reduced 

 to subcortical levels. The only experimental evidence bearing 

 upon the point that I have been able to find is the statement 



