INTERACTION BETWEEN ADAPTATIONS 18/6 



Not only could the list be extended almost indefinitely, but 

 each item is itself representative of a great number of incidents, 

 carried out on a variety of occasions in a variety of ways. The 

 total number of incidents contributing to the adult's skill may thus 

 be very large. 



So by the time a human being has developed an adult's skill 

 and knowledge, he has been subjected to the action of ultrastability 

 repetitively to a degree which may be comparable with that to 

 which an established species has been subjected to natural selec- 

 tion. If this is so, it is not impossible that ultrastability can 

 account fully for the development of adaptive behaviour, even 

 when the adaptation is as complex as that of Man. 



References 



Ashby, W. Ross. Statistical machinery. Thales, 7, 1 ; 1951. 



Lashley, K. S. Nervous mechanisms in learning. The foundations of 

 experimental psychology, edited C. Murchison. Worcester, 1929. 



Muller, G. E., and Pilzecker, A. Experimentelle Beitrage zur Lehre 

 vom Gedachtniss. Zeitschrift fur Psychologie und Physiologie der Sinnes- 

 organe, Erganzungsband No. 1 ; 1900. 



Robinson, E. S. Some factors determining the degree of retroactive inhibi- 

 tion. Psychological Monographs, 28, No. 128 ; 1920. 



Skaggs, E. B. Further studies in retroactive inhibition. Psychological 

 Monographs, 34, No. 161 ; 1925. 



Skinner, B. F. Are theories of learning necessary ? Psychological Review, 

 57, 193 : 1950. 



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