Watching chimpanzees and thinking about the nervous system: The Yerkes years
I last visited with Donald Hebb in the Fall, 1984, the year before his death, and approximately 26 years after Hebb (and Peter Milner) had signed my dissertation. During that meeting, after noting that he considered himself a Comparative Psychologist, Hebb reminisced about the years he had spent at the Yerkes Laboratories of Primate Biology in Orange Park, Florida. He told me that the 5-year period at Yerkes was the most significant intellectual experience of his life. Hebb added that observing chimpanzee behavior was “like watching human beings with the veneer of culture stripped away.” In an article devoted to the evolution of mind, and comparisons between human and animal minds, Hebb described chimpanzees in captivity: “…as unpredictably explosive as a fireworks display, sometimes viciously aggressive without cause and capable of being angered by trivial things; terrified at the sight of a toy animal or a model of a human head…and in these and other ways reminding us of human fears, hostilities and abhorrences, each of which is familiar by itself but which in their totality make a picture of man that we have not seen clearly.”
Hebb’s publications from the Yerkes period involve a set of 7 papers / abstracts dealing with fear and emotional expression, as well as sex and individual differences, in chimpanzee behavior. The papers are notable for perceptive observation of behavior as well as methodological innovation. The majority of these articles also make little, if any, reference to underlying physiology. However, Hebb was also writing the book that established his reputation in the field: The Organization of Behavior. In one of the chimpanzee papers, there is a highly speculative discussion of central representations of orderly thought processes, (the “phase sequence”). And, in a paper on the behavior of the bottlenose dolphin, which also emerged from Hebb’s stay in Florida, there is a good dose of “neurologizing,” including a discussion of the unique behavioral characteristics that emerge in a large-brained mammal.
Mindful that this presentation is for the ISHN, I will link Hebb’s animal-watching in Florida with a set of persistent themes that drove his neurophysiological theorizing, i.e., construction of a “phyletic” scale ranging from “lower” to “higher” mammals, recognition of the importance of central cognitive processes (e.g., set and attention)--particularly in “higher” mammals, and a focus on ontogeny and the effects of early experience.
Session V -- Donald O. Hebb Seminar
Montreal, Quebec, Canada