LITERATURE FOR 1910 ON THE BEHAVIOR OF 



VERTEBRATES * 



JOHN B. WATSON 



Johns Hopkins University 

 VISION 



Fish. In his paper, published in 1909, on light and color- 

 vision in fishes, Hessf maintained that all the results of his 

 experiments were in harmony with the assumption that the 

 fishes under observation were totally color-blind. He admitted 

 that the brightness-distribution in the spectrum is different 

 from that of the human eye. Victor Bauer '-* has obtained 

 certain results upon several different species of fish, which 

 apparently are not in accord with the above conclusions of Hess. 

 Young Charax were allowed to live for several days in a long, 

 slender 'phototactic trough.' The trough was blackened upon 

 the inner surface, with the exception of one end. This end 

 admitted the stimulus light. Either one or two ray filters could 

 be set up in front of this end, or any given region of the spectrum 

 could be projected upon it. ' Diffuse white light was admitted 

 from above in all experiments conducted in the dark room. 

 The introduction of this diffuse light was necessitated by the 

 fact that the fish were restless if the stimulus lights alone were 

 used. Bauer tells us nothing about the intensity of this light. 

 It has rather important bearings upon his conclusions. 



Fish with light adapted eyes, when tested in the phototactic 

 trough, showed no tendency to collect at the lighter of the 

 two ends. They were neither negatively nor positively photo- 

 tactic, and swam from the light end to the dark end and vice 

 versa in a calm and restful manner. If suddenly frightened 

 by a shadow, they attempted to hide themselves by pressing 

 closely to the angles and edges of the glass vessel and remaining 

 there for a time. If one brought a white paper to the un- 

 blackened end of the trough, in which the fish had dwelt for 



* I have been greatly assisted in the preparation of this review by Mr. H. M. 

 Johnson, Fellow in Psychology, Johns Hopkins University. 



t C. Hess, Untersuchungen uber den Lichtsinn bei Fischen. Arch. f. Augen- 

 heilk. Bd. 64, Erganzungsheft, S. 1-38, 1909. 



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