500 



THE QUARTERLY REVIEW OF BIOLOGY 





The influence of Morgan on the early 

 thought of the period can hardly be 

 overestimated. His writings show a 

 broad sympathy and a sound scholarship 

 in dealing with the more theoretical prob- 

 lems of comparative psychology that has 

 scarcely been equalled since, except, per- 

 haps, by Hobhouse in his Mind in Evolu- 

 tion. Nor was he a mere theorist — his 

 contribution to early experimental de- 

 velopments, though somewhat limited in 

 scope, was of first rate importance. In 

 the Introduction (1894) he refers repeatedly 

 to his genetic studies of incubated chicks 

 and ducklings and distinguishes the types 

 of instinctive behavior characteristic of 

 each. In Habit and Instinct (1896) he 

 gives a more complete account of this 

 work, which he has extended, in the 

 meantime, to include wild ducklings, 

 moorhen chicks, and partridges. He also 

 investigated various aspects of habit 

 formation in young birds and emphasized 

 the method of trial and error in animal 

 learning. As early as 1891 (175) he 

 speaks of the "trial and practice" element 

 in "incomplete instincts" and of the 

 maturation factor in "deferred instincts." 



These early studies of Morgan on birds 

 are important as marking the beginnings of 

 the application of laboratory methods in 

 any extensive way to the higher verte- 

 brates. The material of Habit and In- 

 stinct was delivered as the Lowell Lectures 

 in the spring of 1896 at Harvard Univer- 

 sity, and parts of it later at Chicago, New 

 York, and other university centers, and 

 doubtless had much to do with the out- 

 burst of experimental work in America 

 that soon followed. Thorndike began his 

 studies on instinct and habit formation in 

 the chick at Harvard in the fall of 1896 

 and Kline independently began somewhat 

 similar work on the chick at Clark the 

 following year. Morgan seems to have 



been the first to make use of the "incu- 

 bator method" in his genetic studies of 

 birds, and his plan of keeping the young 

 in the incubator for varying periods of 

 time after hatching before testing them 

 foreshadowed the more recent work of 

 Breed and Shepard (1911). 



Although the views of these four leaders 

 regarding the nature of animal life and 

 behavior appear to be widely divergent 

 as individually formulated, the differ- 

 ences were much less important than the^ 

 general points of agreement. Lubbock 

 and Morgan, no less than Verworn and- 

 Loeb, were stoutly opposed to the 

 older anthropomorphism. Moreover, the' 

 tropism theory of Loeb was, in a sense, 

 merely the application of the canon of) 

 Morgan- — albeit somewhat strictly — to 

 the lower organisms. Both Lubbock and 

 Morgan believed in adopting physico- 

 chemical explanations of behavior in all 

 cases in which they seemed adequate. 

 Loeb admitted consciousness to such* 

 higher animals as gave conclusive evidence 

 of the ability to form associations. The 

 main point of difference concerned the 

 stage in phylogenetic development at 

 which the psychic factor emerged, and 

 this is clearly a matter of minor impor- 

 tance in the last analysis. Furthermore, 

 each of the leaders rejected the method of 

 anecdote and each was a pioneer experi- 

 mentalist in his own special field. 



It is apparent from all the evidence at 

 hand that a worthy beginning had been 

 made toward the establishing of compara- 

 tive psychology on a reasonably sound 

 theoretical and experimental basis. The: 

 further development during the present 

 century of experimental methods and 

 results will be given in some detail in the 

 following section. The final section will 

 show the gradual emancipation of the 

 subject matter of comparative psychology 



