ULTRASTABILITY IN THE LIVING ORGANISM 9/6 



From Si onwards, T's behaviour is determinate at every instant ; 

 so the system composed of 1, 2, 3, T, and the uniselectors, is 

 absolute. 



Another property of the whole system should be noticed. 

 When the movement-combination 4 1 and 2 moving similarly ' 

 occurs, T is thereby impelled, under the rules of the experiment, 

 to force 3 outside the region bounded by the critical states. Of 

 any inanimate system which behaved in this way we would 



Figure 9/5/1 : Three units interacting. The downstrokes at S are 

 forced by the operator. If 2 responds with a downstroke, the 

 trainer drives 3 past its critical surface. 



say, simply, that the line of behaviour from the state at which 

 1 and 2 started moving was unstable. So, to say in psychological 

 terms that the ' trainer ' has i punished ' the 4 animal ' is equiva- 

 lent to saying in our terms that the system has a set of step- 

 function values that make it unstable. 



In general, then, we may identify the behaviour of the animal 

 in ( training ' with that of the ultrastable system adapting to 

 another system of fixed characteristics. 



9/6. A remarkable property of the nervous system is its ability 

 to adapt itself to surgical alterations of the bodily structure. 

 From the first work of Marina to the recent work of Sperry, such 

 experiments have aroused interest and no little surprise. 



Over thirty years ago, Marina severed the attachments of the 

 internal and external recti muscles of a monkey's eyeball and 

 re-attached them in crossed position so that a contraction of 



117 I 



