i6o 



NATURE 



[October io, 1912 



wn.vv IS ixsrixcT? 



Tlie Evolulion of Aiiinial IiiteUigcinc. H>- Prof. 

 S. J. Holmes. Pp. v + 296. (New York: 

 Mciiiy Molt and Co., 1911.) 



Till-; study of animal behaviour ha.s two prob- 

 lems, description and interpretation. Both 

 yive opportunities for error. Thus on the one 

 hand Binet's discussion of the mental life of Proto- 

 zoa is larg-elv based on a mistaken \ lew ol the 

 facts. Didinium does not "hunt" its prey or 

 "cast darts" at it. On the other hand Thorn- 

 dike, on the Isasis of his well-known experiments, 

 arg-ued that his animals showed no hijjh degree 

 of intelligence because there was no sudden drop 

 in their Icarningf curves; Hobhouse opposed this 

 conclusion on the ground that the curves did 

 show a sharp drop. But in a recent article com- 

 paring- human adults, children, and rats in learn- 

 ing- a maze, Prof. Hicks finds that "the relation 

 between the abruptness of slope and the degree 

 of rational ability is just the inverse of that as- 

 sumed by Thorndike and Hobhouse." 



.\s this example sug-gests, problems of inter- 

 pretation lead inevitably to questions of human 

 psycholog:y. Now we know considerably less 

 about human methods than the old naive anthropo- 

 morphism assumed. Nevertheless, the work 

 already done by general psychology upon many of 

 the problems of interpretation occurring- in anim.-al 

 psycholog-y cannot profitably be ignored. The 

 failure to recognise this fully somewhat detracts 

 from the value of Mr. Holmes's discussion of that 

 central problem, the nature of instinct. His treat- 

 n-ient seems to imply that the distinction between 

 reflex action and instinct is merely one ol degree 

 or complexity. 



Spencer's \iew is, of coiu-se, one for which many 

 arguments iiiav be found, but, in any attempt to 

 discuss the matter at all fully, it should surely 

 be made clear that a very different opinion has been 

 taken by most of those approaching the question 

 from the psychological, rather than the biological, 

 viewpoint — the opinion, namelv, that instinct is 

 essentially conscious, in\ol\'ing elements of striv- 

 ing, feeling and cognition. Curiousl)-, Mr. 

 Holmes (|uotes with approx al a well-known 

 passage from James which insists on tlie essential 

 ]<inship (il animal instincts with human impulses, 

 witlioiit a|-]iarently seeing how incninpatible this 

 concc|3licin i-, with anv attempt to define instinct 

 in terms i^l mere mi)\ement. Certainly, unless 

 all interpretation is delusixe, it seems clear that 

 in niany cases consciousness is necessarilv in- 

 volved. .\ bird building a nest or feeding its 

 young is not merely executing a series of move- 

 ments which happen to produce a given result. 

 x«'). 2241, vol.. ()o] 



On different occasions this result reniains the same 

 while the exact movements and their order are 

 continually varying ; that is, the result is not merely 

 an effect but also a cause : we have not nierely 

 movement but action. 



In discussing puzzle-box tests of intelligence Mr. 

 Holmes rightly agrees with Prof. Hobhouse that 

 the frequent xariation of method in lifting the 

 latch, &-C. (i'-g-. using either paw), is conclusive 

 against attributing everything to sensori-motor 

 association. But the same argument seems decis- 

 ive against regarding instinct as a complex of 

 reflexes. Its fran-ieworls; is fixed; the gaps, how- 

 ever small, have to be \aryingly filled in by con- 

 ative and intellectual processes of at least the 

 perceptual level. 



Into the relati;:n of instinct to intelligence it 

 is impossiljle to enter. The use of intelligence 

 as equivalent to the power to form associations 

 may be justified if one means merely that which 

 is opposed to instinct, but it fails to find any place 

 for that perception of relations which is to be 

 found selecting means to ends whether given by- 

 congenital or experiential orientaticjn. 



If Mr. Holmes's discussion of central theoretical 

 questions is not altogether satisfjing, his book is 

 extremely interesting if only because of the amount 

 of concrete illustration. It is unfortunate that 

 a number of slipshod phrases has been allowed 

 to pass. 



OUR BOOKSHELF. 

 Their JVinged Destiny, being a Tale of Two 



Planets. By Donald W. Horner. Pp. 240. 



(London : Sinipkin, Marshall and Co., Ltd.) 



Price 2s. net. 

 There are about one hundred million suns in 

 space; and it is reasonable to suppose that many 

 of them have planets revolving round them similar 

 to those which form our own solar system. 

 Whether life exists upon any of these bodies is 

 a matter of legitimate speculation. It is, perhaps, 

 possible that among so many bodies there is one 

 which has gone through precisely the same stages 

 of development as the earth, and upon which the 

 same forms of life are in being-. This hypothesis 

 pro\-ides Mr. Horner with the basis of his fan- 

 tastic romance. 



As in Mr. Wells's impressive story of "The 

 Star," a new star appears and threatens to destroy 

 the earth. To avoid the calamity, a party leaves 

 the earth in an " Klectronship," which can travef 

 with the velocity of light, and after four years 

 arrives at the svstcm of a Centauri, where black 

 and white giants were at war on one planet, while 

 another was found to be exactly like the earth, not 

 only as regards the distribution of land and water, 

 but also in its inhabitants, who spoke the same 

 languages as the peoples of our globe. Slight 

 differences of tni-chanical and social development 



