CHANGING CONCEPTS OF THE LEARNING 

 MECHANISM 



Robert Galambos 



general considerations 



Animals almost invariably learn when placed m a situation where an 

 opportunity to do so is provided, and yet they can learn no more than 

 their capacities permit or make possible. It is, in other words, as unprofit- 

 able to try to teach an animal a task beyond his capabilities as it is to try to 

 prevent his learning it when he has been prepared by nature to do so. 

 Such essential facts as the inevitability but limited scope of learned responses 

 were well known to Darwin (e.g. Descent of Man, Chapter 3) and to other 

 astute observers before and since. Herrick, taking this broad biological 

 view, has comprehensively summarized the more recent work (1956)- 



In the analysis of how animals come to learn, scientists from several 

 disciplines generally agree now that they {a) sense environmental events, 

 (/)) react 'reflexly' to them, and (c) modify their subsequent behaviour in 

 the light of those experiences. Much study and an enormous literature 

 have developed around these phenomena and current work on the brain 

 events occurring during learning seems to be directed towards answers for 

 the following three major questions: 



1. What IS the nature oi the neural organization that enables, permits 

 and indeed requires the organism to make contact with the environment 

 through its senses for the purpose of analysing it? Much ei^ort has been 

 spent on defining the physical nature of the energy exchange that occurs at 

 the sensory end organ — e.g. the transmutation into nerve impulses of 

 mechanical motion in the inner ear and of electromagnetic radiation in the 

 eye. Beyond this many investigators have been trying to specify the 

 analysis performed within the sensory afferent pathways; much of this 

 work has been done in anaesthetized or otherwise reduced preparations. 

 Besides this, effort in increasing amount is being devoted to uncovering 

 the basis for the evident ability of normal, intact organisms to respond 

 preferentially to input from one rather than another of its sensory inputs 

 — the problem of 'attention' and its converse 'habituation' if you will. 



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