15/10 ADAPTATION IN ITERATED AND SERIAL SYSTEMS 



to be achieved. Thus, the learner can proceed in the order 

 ' Addition, long multiplication, . . .' but not in the order ' Long 

 multiplication, addition, . . .' Our present knowledge of mathe- 

 matics has in fact been reached only because the subject contains 

 such stage-by-stage routes. 



As a clear illustration of such a process, here is Lloyd Morgan 

 on the training of a falcon: 



1 She is trained to the lure — a dead pigeon . . . — at first with 

 the leash. Later a light string is attached to the leash, and 

 the falcon is unhooded by an assistant, while the falconer, 

 standing at a distance of five to ten yards, calls her by shout- 

 ing and casting out the lure. Gradually day after day the 

 distance is increased, till the hawk will come thirty yards or 

 so without hesitation; then she may be trusted to fly to the 

 lure at liberty, and by degrees from any distance, say a 

 thousand yards. This accomplished, she should learn to 

 stoop to the lure. . . . This should be done at first only 

 once, and then progressively until she will stoop backwards 

 and forwards at the lure as often as desired. Next she should 

 be entered at her quarry . . .' 



The same process has also been demonstrated more formally. 

 Wolfe and Cowles, for instance, taught chimpanzees that tokens 

 could be exchanged for fruit: the chimpanzees would then learn 

 to open problem boxes to get tokens; but this way of getting fruit 

 (the ' adaptive ' reaction) was learned only if the procedure for 

 the exchange of tokens had been well learned first. In other 

 words, the environment was beyond their power of adaptation 

 if presented as a complex whole — they could not get the fruit — 

 but if taken as two stages in a particular order, could be adapted to. 



\ . . the growing child fashions day by day, year by year, a 

 complex concatenation of acquired knowledge and skills, adding 

 one unit to another in endless sequence ', said Culler. I need not 

 further emphasise the importance of serial adaptation. 



15/10. To see the process in more detail, consider the following 

 example. A young animal has already learned how to move about 

 the world without colliding with objects. (Though this learning 

 is itself complex, it will serve for illustration, and has the advantage 

 of making the example more vivid.) This learning process was 

 due to ultrastability : it has established a set of values on the 

 step-mechanisms which give a field such that the system composed 



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