THE INTERACTIONS OF UNLEARNED BEHAVIOUR 

 PATTERNS AND LEARNING IN MAMMALS 



Irenaus Eibl-Eibesfeldt 



I. INTRODUCTION AND OBJECTIVES 



The term 'innate' as applied to behaviour patterns has become con- 

 troversial. Beach, 1954, Hebb, 1953, Lehrmann, 1953, 1956 and Schneirla, 

 1956 have criticized the ethological approach, which they accuse of 

 performing an artificial dichotomy into innate and acquired patterns. 'I 

 strongly urge that there are not two kinds of factors determining behaviour 

 and that the term "instinct" is completely misleading, as it implies a 

 nervous process or mechanism which is independent of environmental 

 factors and different from the processes into which learning enters '(Hebb, 

 1953). Lehrmann (1953) accuses ethologists in general and Lorenz in 

 particular of misrepresenting unanalysable part-function in such a way as 

 to give them the specious appearance of natural units, caused by the same 

 physiological mechanism. 



The main task of this paper is to show that the two oldest and most 

 important ethological conceptions, that of the fixed motor pattern and 

 that of the Innate Releasing Mechanism (IRM), correspond to very real 

 functional units and that they prove their analytical value in the attempt 

 to analyse the ontogenetic process by which unlearned and learned 

 behaviour becomes integrated into an adaptive functional unit. 



2. EXPERIMENTAL EVIDENCE 



((?) The analysis of nest biiildiw^ and rctricvuK^ yotiin^ in the rat. As is well 

 known, every rat raised in isolation is capable of building a nest. A number 

 of scientists have, therefore, termed this behaviour instinctive. In Mumi's 

 (1950) Handbook oj Psychological Research on the Rat, it is discussed under 

 the heading 'unlearned behaviour', along with retrieving activity; every 

 rat which has given birth retrieves nestlings which were put outside the 

 nest. 



Riess (1947) has investigated the problem of the imiateness of this 

 behaviour. He raised rats under conditions which gave them no oppor- 

 tunity to manipulate solid objects. From the age of 21 days (some even as 



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