Animal Intelligence

o! ru -D -D =o r-R O O D m CD ANIMAL INTELLIGENCE T Q THE MACMILLAN COMPANY NEW YORK BOSTON CHICAGO SAN FRANCISCO MACMILLAN & LONDON CO., LIMITED BOMBAY CALCUTTA MELBOURNE THE MACMILLAN CO. OF TORONTO CANADA, LTD. f ANIMAL INTELLIGENCE EXPERIMENTAL STUDIES BY EDWARD L. THORNDIKE TEACHERS COLLEGE, COLUMBIA UNIVERSITY THE MACMILLAN COMPANY 1911 Att rights reserved COPYRIGHT, 1911, BY Set THE MACMILLAN COMPANY. up and electrotyped. Published June, 1911. no J. 8. Norfaooft Jinas Berwick & Smith Co. Cushing Co. Norwood, Mass., U.S.A. PREFACE volume is to make accessible and biology the author's experipsychology 1 These mental studies of animal intellect and behavior. THE main purpose of this to students of studies have, I am informed by teachers of comparative Since they represent the psychology, a twofold interest. extended and first deliberate application of the experianimal mental method in 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 detailed and often highly technical experiments interpreted terms of original and acquired connections between and response. Since they represent the point of and the method view of present animal psychology, but in situation 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. An Experimental Study of the Associative ProAnimals' ('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 1 ' Animal Intelligence : cesses in Human Intellect,' and which was a which appeared in the Popular Science Monthly direct outgrowth of the experimental work. I am in 1901, indebted management of the Psychological Review, and that of the American Naturalist and Popular Science Monthly, for permission to reprint the three to the shorter papers. v vi Preface It for has seemed best to leave the texts unaltered except the correction of typographical errors, renumbering In a and figures, and redrawing the latter. few places, where the original text has been found likely It is to be misunderstood, brief notes have been added. of tables hard to of the ' impulse to temper the style, especially Intelligence,' with a certain sobriety and resist the Animal restraint. What one writes at the age of twenty-three as it doubtlikely to irritate oneself a dozen years later, The charitable reader less irritated others at the time. is a degree of allay his irritation by the thought that to exuberance,