IRENAUS EIBL-EIBESFELDT 7I 



Hebb. My objection to 'instinct' is that it refers to a mechanism which is ciistinct 

 from what enters into normal learning processes. 



EiBL-EiBESFELDT. But thcrc are differences, for example, m the physiology of 

 these innate patterns. I would like to mention their spontaneity. Furthermore they 

 are often released by certain key stimuli — innately. All this shows that we are 

 justified in distinguishing innate and accjuired behaviour patterns. 



Hebb. The argument against that is exactly the evidence that you have in your 

 paper. You show how closely the two collaborate. The implication of a separate 

 mechanism is that some behaviour is controlled by instinct, some by intelligence 

 and learning. It seems to me that it is all intelligence or all instinct. The higher 

 species has a wider range of situation to which it can adapt, innately. The operation 

 of intelligence and learning is within the scope of the innate aptitude, hi certain 

 cases we see the deviation from the species pattern clearly, and call that learning. 

 But learning also operates in the things which are characteristic of the species. My 

 objection to instinct as a term is the suggestion that we have two different kinds of 

 mechanism controlling behaviour. 



Gerard. There is a continuity from growth, through heredity, prebirth experi- 

 ence, to youth and ageing experience. Only in the fertilized egg have you heredity 

 — from then on, the chromosome pattern interacts with its surroundings. If we 

 find it useful to separate innate reflexes from conditioned reflexes, it is not mean- 

 ingless to try and distinguish other different levels; some higher level reflexes 

 common to the species we may call instinctive. What reallv matters in any given 

 situation is whether the variance normally introduced by the environmental 

 experience of the individual is relatively important compared with the variance 

 introduced by the past experience of the race and put in the genes. 



The most interesting aspect is the adaptive one, for example, the rats building 

 nests to keep their young warm. The pattern seems innate, but the execution of the 

 details of the pattern is clearly learned. 



As an illustration of the innate character, the behaviour pattern should cease if a 

 non-adaptive situation is brought about. For example, it you put the rat in a hot 

 room, where the young might become overheated would it still make a nest? 



EiBL-EiBESFELDT. Kinder (1927) has studied the influence of temperature on the 

 nest-building activity of the rat. If it gets too warm, the animal stops nest-building. 

 But that this behaviour is controlled by temperature and thus variable to a certain 

 extent does not prove that it is not innate in the way pointed out in my paper. 

 Pregnant rats, by the way, are less easily influenced by temperature, because of the 

 secretion of progesterone. 



Gerard. A negative result does not disprove it but if you have an instance when 

 an animal does a complex act despite the harmful effects, it would be a strong case. 



Eibl-Eibesfeldt. May I mention two examples. Turkey cocks have a highly 

 ritualized way of fighting with rivals. They do not jump in the air and hit their 

 opponent with the spurs, as other gallid birds do, but wrestle with their necks, 

 grasping each other at the bill. As soon as one wants to give up it assumes a sub- 

 missive posture, by lying down on the floor. In captivity it can happen that a 

 turkey cock and a peacock get involved in a fight. Both closely related species have 

 a similar display and therefore understand the expression movements of the 

 preliminary display. But their techniques of fighting do not fit together. While the 

 turkey cock expects wrestling the peacock hits him with his spurs. This leads to 



