The Mental Life of Monkeys and Apes: A Study of Ideational Behavior

The author reports systematic experiments and observations designed to test ideational and problem-solving behavior in monkeys and apes, presenting methods and multiple-choice trial results. Supplementary tests — box stacking, box-and-pole, draw-in, lock-and-key, and hammer-and-nail tasks — probe tool use, planning, and insight in individual animals. Miscellaneous observations address handedness and instinctive reactions such as maternal behavior, fear, and sympathy. The study situates findings in a historical and critical discussion of prior evidence, offers practical recommendations for dedicated primate research provision, and provides a bibliography. Results are given as quantitative tables, case descriptions, and interpretive commentary.