14/10 REPETITIVE STIMULI AND HABITUATION 



to change the field than if applied to C. A field like C, therefore, 

 with its state of equilibrium near the centre of the region, tends 

 to have a higher immunity to displacement than fields whose 

 states of equilibrium or cycles go near the edge of the region. 



14/10. How would this tendency show itself in the behaviour of 

 the living organism ? 



The processes of S. 7/23 allow a field to be terminal and yet 

 to show all sorts of bizarre features : cycles, states of equilibrium 

 near the edge of the region, stable and unstable lines mixed, 

 multiple states of equilibrium, multiple cycles, and so on. These 

 possibilities obscured the relation between a field's being terminal 

 and its being suitable for keeping essential variables within normal 

 limits. But a detailed study was not necessary; for we have 

 just seen that all such bizarre fields tend selectively to be destroyed 

 when the system is subjected to small, occasional, and random dis- 

 turbances. Since such disturbances are inseparable from practical 

 existence, the process of ' roughing it ' tends to cause their replace- 

 ment by fields that look like C of Figure 14/9/1 and act simply 

 to keep the representative point well away from the critical states. 



191 



