66 BRAIN MECHANISMS AND LEARNING 



integrated into one functional pattern. According to Kuo, this is due to 

 learning. The first arousal of the animal by visual stimuli is explained by 

 a diffusion of impulses from the optical region in the midbrain centres 

 which previously released the discussed behaviour to tactile stimulation 

 (Maier and Schneirla, 1935). 



Lorenz (195X) objects that this hypothesis completely leaves out of 

 consideration one fact ot the greatest importance: 'All these structures of 

 behaviour, whether they function on the receptor or on the motor side, 

 are adapted to innumerable environmental data. Unless one assumes a 

 mystical "prcstabilizcd harmony" between the organism and its environ- 

 ment — which would be "preformationism" indeed, information con- 

 cerning all these environmental data must, at some time, have been "fed 

 into" the organism to make this adaptation possible. This acquisition of 

 information can have occurred only in the interaction between the 

 organism and its environment, either during the evolution of the species 

 or during the ontogeny of the individual.' 



To uphold the hypothesis that pecking is learned in the egg in the way 

 suggested by Kuo one would have to make at least one of three assump- 

 tions: 



'The tirst ot these is that the heartbeat and the primarily independent 

 swallowing movements just happen, by pure chance, to teach the chick 

 motor co-ordinations that can later on be used in pecking up food. The 

 second, equally impossible assumption is that there is a preformed harmony 

 between what the chick learns inside the egg and the environment with 

 which it is to be confronted later on. The third, improbable but not 

 impossible, is that the heartbeat and the other conditions inside the egg, 

 have, in the evolutionary interaction between the species and its environ- 

 ment, been developed into a highly specialized apparatus whose function 

 it is to teach the chick just those well adapted motor co-ordinations. In 

 other words, the attempt to avoid the assumption of genetically fixed 

 movements saddles us with that of an equally genetically fixated teacher!' 

 (Lorenz, 195S). 



Once we have realized the adaptive character of a behaviour pattern, 

 we can deprive the animal experimentally of the specific information 

 concerning the data to which the behaviour is adapted. If the animal 

 nevertheless shows the adaptive behaviour pattern in the test situation, 

 then we call it innate, despite the fact that learning in the widest sense, e.g. 

 exercise of single muscle units, might have played a role during the 

 ontogeny of the individual. This does not explain why the behaviour 

 pattern as a whole later fits the environment. 



