I i02 



II VNDIlooK OF PHYSIOLOGY 



NEUROPHYSIOLOGY III 



tion and did ii become possible to think of human 

 motivation in terms of the simple paradigm provided 

 by the growing study of instinct in animals. Interest- 

 ingly enough, it was through the efforts of students of 

 personality and social processes, in the work of 

 Freud (58) and McDougall (9(1), that the concept of 

 motivation re-entered psychology. Freud's concep- 

 tions of the 'id,' 'libido,' 'pleasure principle,' 'anxiety 1 

 and McDougall's 'propensities' and 'hormic forces' 

 all focused attention on the arousal and direction of 

 behavior, and rooted the notions of instinct and 

 motivation deeply in modern psychological thought. 



But even when laid in the foundations of biology 

 by Darwin and pushed into psychology by Freud and 

 McDougall, the concept of instinct still brought 

 objections, lor it was all too often used as an explana- 

 tory force, and once behavior was labeled instinctive, 

 little was done to investigate it. It was sufficient to 

 s.iv that animals made adaptive responses like build- 

 ing nests and mating because of nest-building in- 

 stincts and mating instincts, and that man fought 

 and banded together in societies because of instincts 

 of aggressiveness and gregariousness. 



In their revolt against the mentalism of the earlier 

 philosophers, the first behaviorists, under Watson 

 (5 I, ''^ ;. 165), rejected the instinct doctrine and with 

 it a large part of the concept of motivation. First, 

 they objected to the use of instinct as an imaginary 

 explanatory force. Second, they rejected instinct 

 because the doctrine implied physiological processes 

 inside the organism, while the behaviorists were 

 trying to account lor behavior solely in terms of 

 environmental stimuli and responses and considered 

 instinctive acts merer) complex chains of reflexes 

 Third, the instind doctrine definitely assumed, con- 

 trary to behavioristic theory, that some behavior was 

 not derived from experience but rather stemmed 

 from the organisms' inherited biological charac- 

 teristics. 



I In- contribution of the behaviorists to psychology 

 is undeniable, fur they firmlv established objective 

 experimental methods in the stud) of behavior, But 

 the) proceeded in the tradition of their mentalistic 

 predeo sors 10 build a psychology withoul motiva- 

 tion, without hcredit) and with nothing more than 

 liji service to the physiological basis ol behavior. As 



I till "l" put il, the behaviorists 'threw the babv 



cjiii with the bath' when the) quite rightly rejected 

 instil i in m force and quite w rongl) 



ignored the biological foundations of important kinds 



of tivated behavior, simplv because they had 



on< >■ been called instinctive. 



I wo important contributions emerge from this 

 controversy over instincts, a) The behaviorists devel- 

 oped an objective operational analysis of motivated 

 behavior without resort to imaginary explanatory 

 forces. /)) The students of instinct called attention to 

 the fact that motivated behavior is more than a 

 complex response to external stimulation by empha- 

 sizing the role of internal physiological states which 

 could determine whether or not external stimuli would 

 be effective. 



( VNXON S LOCAL THEORIES 



The first really scientific stride in our understanding 

 of the physiology of motivation came with the efforts 

 ol ( .iiiiKin 1 |n 1 .mil his co-workers in the investigation 

 of hunger and thirst. Theirs was an approach from 

 the strict experimental and analytic view point with 

 the definite aim of elucidating physiological mecha- 

 nisms. 



On the behavioral side, Cannon was concerned 

 with only two facets of motivated behavior. One was 

 the initiation of the behavior, and the other was the 

 accompanying sensation that could be reported In- 

 human beings. Since he found a correlation between 

 gastric contractions and reports of hunger in his 

 stomach-balloon experiments on man, he coin hided 

 that eating was aroused by local gastric contractions 

 which, moreover, provided the physiological basis 

 for the sensation. Similarly, he concluded that local 

 dryness of the throat and mouth was at the basis of 

 thirst sensation. Neurophysiologically, of course, these 

 local theories must mean that receptors are stimu- 

 lated in the stomach and throat, providing a basis 

 lor .liferent impulses from these peripheral structures. 

 Other workers, following Cannon's lead, proposed 

 local theories for other kinds of motivation, for 

 example local irritation or pressure arising from the 

 genitals in sexual behavior and local changes in 



taste-receptor sensitivity in salt hunger. 

 These local theories were attractive because they 



seemed to lii human personal experience and because 

 the) were so simple in pulling their main emphasis 

 on peripheral structures which could be dealt with 

 experimentally. Furthermore, they provided a verv 

 e.isilv understandable model for the behaviorists who 

 were Irving lo understand all behavior in simple 



stimulus-response terms. When motivation began to 

 enter behavioristic thinking, the theories went some- 

 thing like this: llie hungT) animal works lor food or 

 learns on the basis ol food reward because lood 



