Note 1 — PREFACE

‘Animal Intelligence: An Experimental Study of the Associative Processes 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’ (’01). 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.