DEVELOPMENT OF MODERN COMPARATIVE PSYCHOLOGY 



453 



developmental stages of the human with 

 the mental levels of the various phyla 

 of the animal kingdom as these were sup- 

 posedly revealed by the anecdotal evidence 

 at hand. At birth the human infant has 

 reached the mental level of the echinoder- 

 mata. Some twelve successively higher 

 stages are then recapitulated before the 

 fifteenth month, at which time the mental 

 level of the dog and the anthropoid ape 

 has been reached . Romanes seems to have 

 considered his psychogenetic scale as a 

 scientific application of the principle of 

 mental continuity, and so it was looked 

 upon by many of the foremost thinkers of 

 the time. 



Contemporary scientific contributions 



Fortunately, not all of the interest 

 aroused in comparative psychology was 

 absorbed in fruitless speculation or in col- 

 lecting anecdotes. Original observations 

 of plant and animal behavior were being 

 made constantly during the period and 

 many of these have proven to be of genuine 

 value. The naturalists made a worthy 

 contribution to our knowledge of animal 

 life and behavior under natural environ- 

 mental conditions. There was a marked 

 tendency for field studies to become more 

 and more intensive and precise. In fact 

 sthe observation of the period, at its 

 best, often approached and sometimes 

 attained the experimental level. Impor- 

 tant developments in the related fields of 

 comparative anatomy and comparative 

 physiology made available a wealth of 

 fundamental facts that were necessary 

 before genuine progress in comparative 

 psychology could be made. The structure 

 and function of the sense-organs and 

 nervous system of the lower forms in 

 particular were studied extensively by 

 many of the leading biologists of the day. 

 The findings in these fields usually involve 

 behavior data of a more or less simple 



sort, and no attempt will be made to 

 distinguish between the contributions of 

 anatomist, physiologist, naturalist and 

 psychologist in the following discussion. 



The works of Darwin, Wallace, Hudson, 

 Houzeau, Bates and Belt are examples of 

 the better and more comprehensive general 

 field studies . As will be noted, these deal 

 in large part with the relatively unknown 

 fauna of various countries covered by 

 scientific expeditions. The volume of 

 Hartmann on anthropoid apes, of Espinas 

 on the social life of animals, and of 

 Poulton on animal coloration are impor- 

 tant illustrations of field studies of more 

 limited extent. The classic natural 

 history of the period was Brehm's Thier- 

 leben, which occupied much the same 

 position in the nineteenth century as 

 the Histoire Naturelle of BufFon had in the 

 preceding century. 



Except for anatomical-physiological 

 investigations the vertebrates were rela- 

 tively neglected aside from field studies 

 of the type indicated above. It was 

 decidedly easier to gather anecdotes than 

 to make careful and long continued obser- 

 vations at close range and naturally the 

 birds and higher mammals were especially 

 favored with anecdotal lore. Rarely does 

 one find in the literature of the period 

 covering infra-human vertebrates a study 

 at once as intensive and as comprehensive 

 as that of Kusstnaul (6z) or Darwin (34) 

 on the human infant or that of Preyer 

 (72.) on the human child. The report of 

 Romanes and his sister (74, 483-498) on 

 the cebus monkey and that of Spaulding 

 (83, 84) on birds are among the better class 

 of first hand observations made at close 

 range on higher forms during this period. 



Much more serious work was attempted 

 on various classes of the invertebrates. 

 Binet (2.4) has given us a good account of 

 investigations on the behavior of the 

 protista previous to the epoch making 



