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

This early‑century study offers a meticulous look at how monkeys and apes solve problems and display what the author calls “ideational behavior.” Set against the backdrop of a budding effort to create a permanent research station for primates, the work blends personal field experience with a clear scientific agenda, showing how the author secured animals, equipment, and a laboratory in California during a time of global upheaval.

The core of the book presents a series of carefully designed experiments. Readers are guided through multiple‑choice tests with individual specimens—such as a rhesus macaque, a gibbon, and a chimpanzee—followed by hands‑on challenges like box‑stacking, lock‑and‑key puzzles, and tool‑use tasks. Alongside these trials, the author records observations on handedness, maternal instinct, fear, and even signs of sympathy, painting a nuanced picture of primate cognition.

Beyond the data, the author reflects on what these behaviors reveal about the mental lives of our closest animal relatives and argues strongly for the establishment of a dedicated, long‑term primate research facility. The book stands as both a valuable scientific record and a historical snapshot of early comparative psychology.