GENERAL DISCUSSION 



INTRODUCTION OF THE FIRST TOPIC: INBORN AND REFLEX BEHAVIOUR 



Hebb. I should like to make two comments on your first group ot topics. 



The hrst is that, to the best of my understanding, our agreement on the question 

 of the congenital or the instinctive is very good. There are difficulties of termino- 

 logy and probably still imperfect communication but so far as I can understand, 

 wc have not been saying different things. There is not a head-on conflict. 



The second poiiit concerns the distinction that Lashley made in 1938 between 

 reflex and instinct. I think it is most important to recognize that instinctive be- 

 haviour is not a complication of reflexes only. Reflexive behaviour depends on 

 specific receptors and effectors, whereas instinctive behaviour is something which 

 is not definable in such terms. It is not itself to be described as a series of reflexes 

 alone. 



Thorpe. May I say that I entirely agree with what Dr Hebb has just said. I 

 think that this meeting has not revealed any major disagreement about concepts so 

 I don't think much would be gained by attempting a general discussion of innate 

 behaviour now. But there are aspects oi innate patterns which arc relevant to our 

 present meeting, and one that interests me very much is the origin of patterns of 

 nervous discharge, i.e. the ncurophysiological aspect of innate behaviour. 



But first I would like to refer again to a general point which I made earlier in 

 this meeting, and that is that the best way to decide whether we are concerned with 

 instinctive patterns of behaviour or with learned ones is to consider the origin of 

 complexity. Where does the complexity of the behaviour come from? If we can 

 see the necessary complexity of the input from the environment then we are 

 provisionally justified in assuming that it has been learned. If there is complexity 

 in the behaviour pattern which is not seen in the immediate, or indeed the whole, 

 previous experience of the individual animal — then we have to assume that this 

 complexity comes from somewhere else, and it can only have come from the 

 inborn organization of the animal. That seems to me to be a valuable method of 

 deciding whether we are talking about something which has been learned, or 

 something that is instinctive. 



Fessard. I also think this an essential distinction but not an easy one to be made 

 in practice. A reflex is an operation in which we can clearly define a stimulus S and 

 a response R, the response thus appearing as a function of the stimulus. But of 

 course, it is also a function of some unknown internal factors which we could call 

 X for instance, and the question of what is a reflex and what is not depends on the 

 importance of X. 



Even in the simplest reflex there are determining factors which come from the 

 organism and which are inborn or instinctive. On the other hand, in what we call 



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