ULTRASTABILITY IN THE LIVING ORGANISM 9/7 



be discussed in S. 9/8.) Ultrastability will then automatically 

 lead to the emergence of behaviour which produces binocular 

 vision or normal progression. For this to be produced, the step- 

 function values must make appropriate allowance for the par- 

 ticular characteristics of the environment, whether ' crossed ' or 

 4 uncrossed '. S. 8/10 and Figure 9/3/1 showed that an ultra- 

 stable system will make such allowance. The adaptation shown 

 by Marina's monkey is therefore homologous with that shown 

 by Mowrer's rat, for the same principle is responsible for both. 



9/7. ' Learning ' and ' memory ' are vast subjects, and any 

 theory of their mechanisms cannot be accepted until it has been 

 tested against all the facts. It is not my intention to propose 

 any such theory, since this work confines itself to the problem 

 of adaptation. Nevertheless I must indicate briefly the relation 

 of this work to the two concepts. 



4 Learning ' and ' memory ' have been given almost as many 

 definitions as there are authors to write of them. The concepts 

 involve a number of aspects whose interrelations are by no means 

 clear ; but the theme is that a past experience has caused some 

 change in the organism's behaviour, so that this behaviour is 

 different from what it would have been if the experience had not 

 occurred. But such a change of behaviour is also shown by a 

 motor-car after an accident ; so most psychologists have insisted 

 that the two concepts should be restricted to those cases in 

 which the later behaviour is better adapted than the earlier. 



The ultrastable system shows in its behaviour something of 

 these elementary features of ' learning '. In Figure 9/3/1, for 

 instance, the pattern of behaviour produced at S 2 is different 

 from the pattern at S v The change has occurred after the 

 1 experience ' of the instability at R. And the new field pro- 

 duced by the step-function change is better adapted than the 

 previous field, for an unstable field has been replaced by a stable. 



An elementary feature of ' memory ' is also shown ; for further 

 responses, S 3 , S^ etc. would repeat S%s pattern of behaviour, 

 and thereby might be said to show a ' memory ' of the reversal 

 at R ; for the later pattern is adapted to the reversal at R, and 

 not adapted to the original setting. 



The ultrastable system, then, shows rudimentary ' learning ' 

 and ' memory '. The subject is resumed in S. 11/3. 



119 



