GENERAL DISCUSSION 645 



determines particular responses ot that system to given stimuli at any time. From 

 that point of view, it seems useful to consider whether instinct is or is not a reflex. 

 1 don't recall the criteria Lashley used, but let me suggest an operational approach 

 to this. 



If we hnd that the behaviour ot essentially all normal members of an adequate 

 sample of some species is the same to the same external situation, then we can say 

 tliat the experience of individuals has been sufficiently unitorm to insure a constant 

 response, for all individuals. I have not been specific about this experience tor it 

 includes everything that happened from the time the egg was fertilized. Normally, 

 the experience of the 2-cell and the S-cell and the 32-cell stages ot the embryo are 

 enormouslv constant from one individual to another, so the behaviour that develops 

 is constant, and we can sately call all this, inborn constancy. 



On this kind oi criterion, is instinct or instinctive behaviour less determined, less 

 reflex, if depending on inborn patterns than is what we call a spinal reflex; If it is as 

 constant, then it might be perfectly valid to think ot it as a reflex. My picture is 

 that the emotional patterns elicited from hypothalamic animals, and the like, are 

 just about as stereotyped and universal as the flexor or other reflexes elicited from 

 the spinal cord. 



Magoun. I was happy to hear Dr Fessard introduce an acknowledgement to 

 philosophy in this discussion and would suggest that we could go back to John 

 Locke who proposed that the mind, as this field was called in the eighteenth 

 century, was a total blank, and that its concept were derived entirely trom sensa- 

 tion. But he differentiated the content and responsiveness derived directly trom 

 sensation trom that derived indirectly from reflection which, I think, is to say that 

 sensation and reflection can be equated with \our 5 and A', since reflection to 

 Locke was the reactivation ot previous sensation. In elaborating those arguments, it 

 is of some relevance to consider the attempt to detine the problem in philosophical 

 terms at least a century betore it began to be studied with pliysiological 

 techniques. 



Fessard. I am surprised to see that in the course ot our debate no mention has 

 been made ot 'trial and error' learning. 



Thorpe. I like to think ot 'trial and error' learning as comprising both classical 

 and operant (or instrumental or action) conditioning, whichever term you preter 

 to use. It is the two together that \ou almost always see co-operating in the natural 

 learning process of a normal animal. For convenience they are isolated in laboratory 

 experiments but they are hardl\- ever tound isolated in nature. I think 'trial and 

 error learning' is an invaluable term to include the two combined and I have 

 indicated elsewhere (Thorpe, 1956, Table II, page So) how I think this combination 

 should be understood. 



Anokhin. I should like to sa\- that when we compare inborn to learned be- 

 haviour, we should bear in mind a universal rule ot behaviour, which connects 

 both inborn and learned behaviour: the rule of evaluation oi the results of an act 

 done with the help ot the reverse afferent impulses received by the brain at the end 



