PREFACE 



THE main purpose of this volume is to make accessible 

 to students of psychology and biology the author's experi- 

 mental studies of animal intellect and behavior. 1 These 

 studies have, I am informed by teachers of comparative 

 psychology, a twofold interest. Since they represent the 

 first deliberate and extended application of the experi- 

 mental method in animal psychology, they are a useful 

 introduction to the later literature of that subject. They 

 mark the change from books of general argumentation 

 on the basis of common experience interpreted in terms 

 of the faculty psychology, to monographs reporting de- 

 tailed and often highly technical experiments interpreted 

 in terms of original and acquired connections between 

 situation and response. Since they represent the point 

 of view and the method of present animal psychology, but 

 in the case of very general and simple problems, they are 

 useful also as readings for students who need a general 

 acquaintance with some sample of experimental work in 

 this field. 



1 ' Animal Intelligence : An Experimental Study of the Associative Pro- 

 cesses in Animals' ('98), 'The Instinctive Reactions of Young Chicks' ('99), 

 * A Note on the Psychology of Fishes' ('99), and 'The Mental Life of the 

 Monkeys' ('oi). I have added a theoretical paper, 'The Evolution of the 

 Human Intellect,' which appeared in the Popular Science Monthly in 1901, 

 and which was a direct outgrowth of the experimental work. I am indebted 

 to the management of the Psychological Review, and that of the American 

 Naturalist and Popular Science Monthly, for permission to reprint the three 

 shorter papers. 



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