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NA TURE 



[October 7, 1922 



diseases at Guy's Hospital, laying special stress on their 

 psychological aspect. Meanwhile, at Cambridge, 

 Michael Foster was seeking some one who would give 

 instruction there in the physiology of the sense organs, 

 McKendrick having, as examiner in physiology, recently 

 complained of the inadequate training of the Cambridge 

 students in this branch of the subject. Foster's choice 

 fell on Rivers, and in 1893 he invited him to the 

 University for this purpose. Rivers went to Germany 

 for a short period of study under Professor Krapelin, 

 then of Heidelberg, whose brilliant analysis of the work 

 curve and careful investigations into the effects of 

 drugs on bodily and mental work had aroused his 

 intense interest. At Cambridge he set himself to 

 plan one of the earliest systematic practical courses in 

 experimental psychology in the world, certainly the 

 first in this country. In 1897 he was officially recog- 

 nised by the University, being elected to the newly 

 established lectureship in physiological and experi- 

 mental psychology. But the welcome and encourage- 

 ment he received from cognate branches of study at 

 Cambridge could scarcely be called embarrassing. 

 Even to-dav practical work is not deemed essential 

 for Cambridge honours candidates in elementary 

 psychology ; psychology is not admitted among the 

 subjects of the Natural Sciences Tripos ; and no pro- 

 vision is made for teaching the subject at Cambridge 

 to medical students. Rivers first turned his attention 

 principally to the study of colour vision and visual 

 space perception. Between 1893 and 1901 he pub- 

 lished experimental papers " On Binocular Colour- 

 mixture " (Proc. Cambs. Philosoph. Soc, vol. viii., 

 pp. 273-77), on " The Photometry of Coloured Papers " 

 (Jour, of Physiol., vol. xxii., pp. 137-45), and " On 

 Erythropsia " (Trans. Ophthal. Soc, London, vol. xxi., 

 pp. 296-305), and until 1908 he was immersed in the 

 task of mastering the entire literature of past experi- 

 mental work on vision, the outcome of which was 

 published in 1900 as an article in the second volume of 

 the important " Text-book of Physiology," edited by 

 Sir Edward Sharpey Schafer. This exhaustive article 

 of 123 pages on vision by Rivers is still regarded as the 

 most accurate and careful account of the whole subject 

 in the English language. 



In 1896 Rivers published an important paper " On 

 the Apparent Size of Objects " (Mind, N.S., vol. v., 

 pp. 71-80). in which he described his investigations 

 into the effects of atropin and eserin on the size of seen 

 objects. He distinguished two kinds of micropsia 

 which had hitherto been confused — micropsia at the 

 fixation-point due to irradiation, and micropsia beyond 

 the fixation-point, which is of special psychological 

 importance. Rivers came to the interesting conclusion 

 that the mere effort to carry out a movement of 

 accommodation may produce the same micropsia as 

 when that effort is actually followed by movement. 

 In other words, an illusion of size may be dependent 

 solely on central factors. His later work, in conjunc- 

 tion with Prof. Dawes Hicks, on " The Illusion of 

 Compared Horizontal and Vertical Lines," which was 

 published in 1908 (Brit. Jour, of Psychol., vol. ii., pp. 

 241-60), led him to trace this illusion to origins still 

 less motor in nature. Here horizontal and vertical 

 lines were compared under tachistoscopic and under 

 prolonged exposure. The amount of the illusion was 



NO. 2762, VOL. 1 IO] 



found to be approximately the same for tachistoscopic 

 as for prolonged exposure of the lines, but in the former 

 the judgment was more definite and less hesitating — in 

 other words, more na'ive, more purely sensory, more 

 " physiological " — than in prolonged exposure. Al- 

 though this result is not inconsistent with the view that 

 visual space perception depends for its genesis on eye 

 movement, it compels us to admit that visual space 

 perception, once acquired, can occur in the absence of 

 eye movement ; or, in more general language, that 

 changes in consciousness, originally arising in connexion 

 with muscular activity, may occur later in the absence 

 of that activity. The provision of experimental 

 evidence in favour of so fundamental and wide-reaching 

 a view is obviously of the greatest importance. 



In 1898, in which year he was given the degree of 

 Hon. M.A. at Cambridge, Rivers took a fresh path in 

 his varied career by accepting Dr. A. C. Haddon's 

 invitation to join the Cambridge Anthropological 

 Expedition to the Torres Straits. This was the first 

 expedition in which systematic work was carried out 

 in the ethnological application of the methods and 

 apparatus of experimental psychology. His former 

 pupils, Prof. W. McDougall and I, assisted Rivers in 

 this new field. Rivers interested himself especially 

 in investigating the vision of the natives — their visual 

 acuity, their colour vision, their colour nomenclature, 

 and their susceptibility to certain visual geometric 

 illusions. He continued to carry out psychological 

 work of the same comparative ethnological character 

 after his return from the Torres Straits in Scotland 

 (where he and I sought comparative data), during a 

 visit to Egypt in the winter of 1900, and from 1901-2 

 in his expedition to the Todas of Southern India. 

 His psychological investigations among the Torres 

 Straits islanders, Egyptians and Todas (Reports of the 

 Cambridge Anthrop. Exped. to Torres Straits, vol. ii., 

 Pt. I., pp. 1-132 ; Jour, of Anthrop. Inst., vol. xxxi., 

 pp. 229-47 ; Brit. Jour, of Psychol., vol. i., pp. 321-96) 

 will ever stand as models of precise, methodical observa- 

 tions in the field of ethnological psychology. Nowhere 

 does he disclose more clearly the admirably scientific 

 bent of his mind — his insistence on scientific procedure, 

 his delight in scientific analysis, and his facility in 

 adapting scientific methods to novel experimental 

 conditions. He reached the conclusion that no sub- 

 stantial difference exists between the visual acuity of 

 civilised and uncivilised peoples, and that the latter 

 show a very definite diminution in sensibility to blue, 

 which, as he suggested, is perhaps attributable to the 

 higher macular pigmentation among coloured peoples, 

 lie observed a generally defective nomenclature for 

 blue, green, and brown among primitive peoples, both 

 white and coloured, and large differences in the 

 frequency- of colour-blindness among the different 

 uncivilised peoples whom he examined. In his work 

 on visual illusions he found that the vertical-horizontal- 

 line illusion was more marked, while the Miiller-Lyer 

 illusion was less marked, among uncivilised than among 

 civilised communities ; and he concluded that the 

 former illusion was therefore dependent rather on 

 physiological, the latter rather on psychological factors, 

 the former being counteracted, the latter being favoured, 

 by previous experience, e.g. of drawing lines or of 

 apprehending complex figures as wholes. 



