H. W. MAGOUN 3 



In each of these conceptual systems (Fig. i), the management of pnmi- 

 tive, innate, stereotyped behaviour, having to do with the preservation of 

 the individual and the race, was attributed to older, subcortical, neuraxial 

 portions of the central nervous system, which formed Jackson's lowest 

 level and subserved the Pavlovian unconditioned reflex and the 

 Freudian id. 



Fig. I 

 Chart coinpanng the evolutionary concepts of the organization and function ot the brain 

 whiclr developed after Darwin and Spencer. 



Modified from a chart by Stanley Cobb, Human nature and the understandintj; of disease, 

 in: Faxon, N.W. The Hospilnl in Coiiiciiipordry Lift'. Harvard Univ. Press, Cambridge, Mass., 

 1949- 



Next, the more mutable, adaptive, learned behaviour of Pavlov's 

 conditioned reflex, together with the capacity of the Freudian ego for 

 perception and the initiation of movement were ascribed to higher neural 

 structures, including the sensori-motor cortex of Jackson's middle level, 

 which developed above or upon the older subjacent parts. 



Finally, in the brain of man, hypertrophy of the associational cortices of 

 the frontal and parieto-occipito-temporal lobes, forming Jackson's highest 

 level, was correlated with the capacities of Freud's superego and, in the 



