A Note on the Psychology of Fishes 171 
his only act is to go ‘to the right-hand side,. rise up, and 
swim out. In correspondence with this change in behavior 
you will find a very marked decrease in the time he takes to 
escape. The fish has clearly profited by his experience and 
modified his conduct to suit a situation for which his innate 
nervous equipment did not definitely provide. He has, in 
common language, learned to get out. 
This particular experiment was repeated with a number of 
individuals. Another experiment was made, using three 
slides, ZZ, III, and another, requiring the fish to find his way 
from A to B, BtoC, andfromC to D. The results of these 
and still others show exactly the same general mental 
process as does the one described — a process which I have 
discussed at length elsewhere. 
Whatever interest there is in the demonstration in the case 
of the bony fishes of the same process which accounts for so 
much of the behavior of the higher vertebrates may be left to 
the neurologists. The value of the experiment, if any, to 
most students will perhaps be the extreme simplicity of the 
method, the ease of administering it, and its possibilities. 
By using long aquaria, one can study the formation of very 
complex series of acts and see to what extent any fish can 
carry the formation of such series. By proper arrange- 
ments the delicacy of discrimination of the fish in any re- 
spect may be tested. The artificiality of the surroundings 
may, of course, be avoided when desirable. 
