Edinger, Comparative Psychology. 4C7 



seen when an animal assures itself of safety, a matter which 

 Greppin has especially studied. Every bird before alighting or 

 before taking food looks about on all sides very knowingly. This 

 inspection is not an inherited habit but, as shown by Greppin's 

 observations on young blackbirds, is acquired. Very young birds 

 at every jar, every noise, stretch out the head and open the bill. 

 It is only later that they learn the opposite behavior. Ground 

 birds acquire the habit of assuring themselves much earlier than 

 birds of the air. Visual images and associations surely play an 

 important role in this assurance. Crows, which remain quietly 

 at rest as one approaches, fly away as soon as one of them is shot, 

 and thereafter they can be shot only from ambush. 



Birds very carefully seek out a place for their nest and often 

 reinforce it purposefully with very remarkable supports. It is not 

 conceivable that all these actions should take place without the 

 participation of the cortex, for they involve numerous memories 

 and associations. 



It must also depend upon the presence of the cerebral cortex 

 that birds are particularly easy to tame and that they may be 

 trained to a large number of performances. Thus, they learn to 

 modify the old hereditary behavior; in fact such activity rules in 

 close relation with instinct, as one may see in the feeding of 

 nestlings by the mother, or in the teaching of young storks to fly. 



What the anatomy of the bird brain leads one to expect is in 

 excellent accord, as one may see, with the results of studying the 

 behavior. The differences between reptiles and birds are easily 

 referable to anatomical differences in the brain. To be sure, it 

 must be the task of further observation to elaborate what is here 

 set forth; above all things, to determine what activities of the lower 

 vertebrates are palaeencephalic and what are neencephalic. Ac- 

 cordingly, reptiles and birds must be studied much more thor- 

 oughly than they have been hitherto, because we have demon- 

 strated the first appearance in them of activities which depend 

 upon a cortex and these activities occur in relative simplicity. It 

 is also an important question whether neencephalic reflexes and 

 instincts exist. 



We have come to know fishes as strictly palaeencephalic animals. 

 In reptiles and birds a small neencephalon cooperates. Finally, 

 in the mammals we meet a brain which has so large a neencephalon 

 that we may well expect a subordination of reflexes and instincts 



