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591.5 
VII 
Animal Intelligence as an Experimental Study 
HE investigation of the problems suggested by the observable 
phenomena of instinct and intelligence in animals is passing — 
we may now say has passed,—into the experimental stage. The col- 
lection of anecdotes, useful enough for preparing the ground and (as 
Time’s irony has shown) for enabling one to perceive the insecurity 
of any such basis for reliable conclusions, has had its day. It is 
realized by serious students that, not only for the interpretation but 
also for the observation of the phenomena, if they are to serve the 
ends of science, some real training and discipline in psychology are 
essential. Dog-stories and cat-stories though often full of subtle 
humour and though not infrequently revealing an affectionate and 
imaginative nature, serve rather to tickle the fancy than to appeal 
to the rational faculties. It is not on such foundations, nor with 
such materials, that a science of comparative psychology can be 
securely built. Observations ad hoc by an investigator trained ad 
hoc, will always carry weight. But the casual jottings of well 
meaning though uninstructed people serve rather to check than to 
forward the diffusion of exact knowledge. 
Mr E. L. Thorndike in a monograph on “ Animal Intelligence ’ 
published as a supplement to the Psychological Review (June 1898) 
has approached his subject in the right way, as one full of difficult 
problems to be grasped, faced, and if possible solved, and has 
furnished an experimental basis, narrow perhaps, but capable of 
further extension for the conclusions that he draws. I have 
briefly noticed his work elsewhere (Nature, July 14th, 1898); but 
I regard it as of sufficient importance to justify a more extended 
presentation and consideration here. 
The subjects (one might, alas! almost say victims) of Mr 
Thorndike’s experiments—or those to which the exigences of space 
compel us to confine our attention—were thirteen kittens or cats 
from three to eighteen months old. His method of investigation 
shall be stated in his own words. 
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“After considerable preliminary observation of animals’ behaviour under 
various conditions, I chose for my general method one which, simple as it is, 
possesses several other marked advantages besides those which accompany experi- 
ment of any sort. It was merely to put animals when hungry in enclosures from 
which they could escape by some simple act, such as pulling at a loop of cord, 
at 
