CEREBKAL FUNCTION IN LEARNING 65 



by Franz that habits of long standing persisted after operations 

 which abolished more recently acquired ones. His experiments 

 do not seem to have precluded the possibility that the older 

 habits involved reactions to different stimuli (auditory and vis- 

 ual) from those which called out the more recently formed ones 

 (kinaesthetic). The opinion of other writers seems to be based 

 chiefly on the desire to hustle unconscious reactions out of the_ 

 cerebrum and there is no conclusive evidence that any habit""/ 

 which may be performed at subcortical levels was not acquired / 

 there in the first place. 



These problems are perhaps the most fundamental ones for 

 an understanding of nervous function in learning which will 

 serve as a foundation for investigation of the basic process of 

 reintegration. Many others of a somewhat more limited char- 

 acter are raised by the facts of cerebral localization in man but 

 the facts in that field are too complex and too poorly under- 

 stood to make a discussion of them in this limited space profitable. 

 Still other problems are raised by the results of the present 

 investigation and will be considered after the data have been 

 presented. 



Program of experiments 



The experiments reported in the present paper bear upon many 

 of the questions raised in the foregoing discussion but they were 

 devised especially to test the following points : 



1. Does cerebral injury give rise to disturbances in the general 

 reactions, of the rat such as would interfere seriously with learn- 

 ing, even though the essential structures for learning were still 

 intact (section II)? 



2. Is any part of the cerebrum especially efficient in learning 

 irrespective of the type of sensory-motor coordination involved 

 in the habit (section III)? 



3. Is there any relation between the mass of cerebral material 

 functioning and the rate of learning (section IV)? 



4. Is the frontal region, which is utilized in the formation of 

 the inclined-plane box habit, functional in all learning, or is it 

 utilized in this habit simply because of the particular sensory- 

 motor coordinations involved (section V)? 



PSYCHOBIOLOGT, VOL. II, NO. 1 



