Although he refers once to Natural Selection as "the principal agency re- 

 sponsible for the hominid evolutionary progression," yet a moment before 

 he had been saying: 



The process of hominization . . . soon acquired a relatively high degree of inde- 

 pendence of the stresses exerted by the external environment, since it was not the 

 external environment but cultural behaviour which provided the main source of 

 selective pressures on the population's genotype. [Bielicki 1969, p. 59; italics mine] 



There is an apparent contradiction between these statements; Doctor 

 Bielicki cannot have his cake and eat it! Apart from this passing reference, 

 the normal Natural Selective mechanism plays no part in the deviation- 

 amplifying system elaborated in Bielicki's paper. The antinomy, I believe, 

 can be resolved by bringing Natural Selection back into the picture. The 

 positive feedback system could well have acquired a momentum of its own, 

 whether or not the environmental stresses were changing; but if the posi- 

 tive feedback system in any way harmed the organism's survival chances, 

 clearly Natural Selection would have acted subtly but definitely against the 

 whole deviation-amplifying system— perhaps in favor of some homeostatic or 

 alternative system that might have facilitated survival. In other words, I 

 am suggesting that. the whole operation of the deviation-reinforcing system 

 was itself subject to Natural Selection. We are saying, in more cybernetic 

 language, what I attempted to say in i960, namely that all will be well as 

 long as the culture-controlled mechanism and the natural selective mecha- 

 nism are not at odds with each other. 



A concrete example comes to mind: a positive feedback system between 

 brain size (and what goes with it) and implemental behavior could have 

 led to a substantial enhancement of brain size. If, however, such increased 

 brain growth were spread more or less evenly over the entire period of im- 

 maturity, prenatal as well as postnatal (and not just postnatal, as Krantz, 

 1961, illustrated), a situation might have been reached where an increasing 

 number of individuals would have had difficulty in giving birth to 

 their large-headed babies. Increasing brain size, under these circumstances, 

 would have been decidedly detrimental to survival. The deviation-amplify- 

 ing system would have been powerless to overcome the hard fact that fewer 

 babies were being born alive after protracted labors! In fact, this particular 

 problem was overcome, not by an interruption of the positive feedback 

 system but by a change in the pattern of brain growth. Instead of babies 

 being born with 60 or 65 per cent of adult brain size, the percentage 



& 148 



