ANIMAL INTELLIGENCE, AND HOW TO STUDY IT 9 



make a special study of mind the psychologists 

 and perhaps the biologists might be added, there is 

 considerable diversity of opinion as to the exact nature 

 of animal intelligence. One very distinguished writer 

 would deny the power of thought proper to any creature 

 that did not use language articulate words. He 

 would even go so far as to affirm that man himself can 

 only think in words. But plainly his definition of 

 " thinking " must be very restricted ; it must be con- 

 fined to a very few mental processes, and leave out a 

 vast amount of what enters into the daily mental being 

 of every man. There are others that would not go 

 so far as this writer, who, nevertheless, deny to animals 

 the power to perceive relations and to reason. When 

 a dog appears to act as if he had reasoned, those who 

 hold such views would explain by admitting that the 

 animal had profited by experience ; they would concede 

 that he was intelligent, but claim that his apparently 

 rational action was merely the outcome of mental 

 association, or a use of " sense-experience." When, for 

 example, a dog or a cat opens a door by manipulating 

 the latch, writers of this school deny reasoning or any 

 analogous processes, but explain the action by utilisa- 

 tion of sense-experience under the law of association. 

 The dog somehow on one occasion, more or less accident- 

 ally, opened the door by using his paws or teeth on the 

 latch, and this at once established an association in 

 sense-experience ; hence any future repetitions have 

 nothing to do with any process of reasoning to the 

 effect that if the paw be used on the latch the door 

 will open. On the contrary, such writers deny the 

 power to the animal to perceive any such relations. 



This theory reduces the mental life of the animal 

 very considerably, and restricts the dog's thoughts 

 within a narrow compass. But is there not a danger 

 of cutting down the possibilities of animal intelligence 



