It has seemed best to leave the texts unaltered except for the correction of typographical errors, renumbering of tables and figures, and redrawing the latter. In a few places, where the original text has been found likely to be misunderstood, brief notes have been added. It is hard to resist the impulse to temper the style, especially of the ‘Animal Intelligence,’ with a certain sobriety and restraint. What one writes at the age of twenty-three is likely to irritate oneself a dozen years later, as it doubtless irritated others at the time. The charitable reader may allay his irritation by the thought that a degree of exuberance, even of arrogance, is proper to youth.

To the reports of experimental studies are added two new essays dealing with the general laws of human and animal learning.

January, 1911.

CONTENTS

PAGE
The Study of Consciousness and the Study of Behavior[1]
Animal Intelligence[20]
Introduction[20]
Description of Apparatus[29]
Experiments with Cats[35]
Experiments with Dogs[56]
Experiments with Chicks[61]
Reasoning or Inference[67]
Imitation[76]
In Chicks[81]
In Cats[85]
In Dogs[92]
The Mental Fact in Association[98]
Association by Similarity and the Formation of Concepts[116]
Criticism of Previous Theories[125]
Delicacy of Association[128]
Complexity of Associations[132]
Number of Associations[135]
Permanence of Associations[138]
Inhibition of Instincts by Habit[142]
Attention[144]
The Social Consciousness of Animals[146]
Interaction[147]
Applications to Pedagogy, Anthropology, etc.[149]
Conclusion[153]
The Instinctive Reactions of Young Chicks[156]
A Note on the Psychology of Fishes[169]
The Mental Life of the Monkeys[172]
Introduction[173]
Apparatus[177]
Learning without Tuition[182]
Tests with Mechanisms[184]
Tests with Signals[195]
Experiments on the Influence of Tuition[209]
Introduction[209]
Imitation of Human Beings[211]
Imitation of Other Monkeys[219]
Learning apart from Motor Impulses[222]
General Mental Development of the Monkeys[236]
Laws and Hypotheses of Behavior[241]
The Evolution of the Human Intellect[282]

ANIMAL INTELLIGENCE

CHAPTER I
The Study of Consciousness and the Study of Behavior