CHAPTER IV 



A NOTE ON THE PSYCHOLOGY OF FISHES 1 



NUMEROUS facts witness in a vague way to the ability of 

 fishes to profit by experience and fit their behavior to situa- 

 tions unprovided for by their innate nervous equipment. 

 All the phenomena shown by fishes as a result of taming are, 

 of course, of this sort. But such facts have not been exact 

 enough to make clear the mental or nervous processes in- 

 volved in such behavior, or simple enough to be available as 

 demonstrations of such processes. It seemed desirable to 

 obtain evidence which should demonstrate both the fact and 

 the process of learning or intelligent activity in the case of 

 fishes and demonstrate them so readily that any student 

 could possess the evidence first hand. 



Through the kindness of the officials of the United States 

 Fish Commission at Woods Holl, especially of the director, 

 Dr. Bumpus, I was able to test the efficiency of some simple 

 experiments directed toward this end. The common Fun- 

 dulus was chosen as a convenient subject, and also because 

 of the neurological interest attaching to the formation of 

 intelligent habits by a vertebrate whose forebrain lacks a 

 cortex. 



The fishes studied were kept in an aquarium (about 4 feet 

 long by 2 feet wide, with a water depth of about 9 inches) 

 represented by Fig. 24. The space at one end, as repre- 



1 This chapter appeared originally in the American Naturalist, Vol. XXXIII, 

 No. 396. 



169 



