Peter Marshall Milner
Professor Emeritus of Psychology at McGill University, Peter Marshall Milner died in Montréal on 2 June 2018, 11 days before his 99th birthday. Peter was born in Silkstone Common, Yorkshire, 13 June 1919, and was educated in electrical engineering at Leeds University. Shortly after the start of World War II, he was appointed an experimental officer in the Ministry of Supply, where he worked on the development of radar. Later he was invited to come to Chalk River, Ontario, where Canada was building a nuclear reactor, to work on several problems associated with nuclear energy. His interests eventually led him to McGill University and research on the nervous system, where he made fundamental contributions to biological psychology and neuroscience.
When his first wife Brenda Milner was accepted as a graduate student by Donald Hebb, the eminent Canadian neuropsychologist, Peter had the opportunity to read a draft of Hebb’s seminal theoretical book The Organization of Behavior, and he became excited about the possibility of working with Hebb to study brain-behavior relations. Hebb agreed to supervise his research, and Peter proceeded to develop techniques for focal electrical stimulation of the rat brain that are still in wide use. While Peter was conducting research for his dissertation, Hebb asked him to show the ropes to an enthusiastic postdoctoral fellow from the USA, James Olds, and he and Olds set about to determine whether brainstem stimulation would improve learning in rats. Peter had already been studying the effects of stimulation of the reticular formation, and so they initially aimed their electrodes there. However, their inaccurate surgical techniques resulted in misplacement of the electrodes into the forebrain in several rats, and Olds made the startling observation that the rats seemed to be seeking out the stimulation, as though it was rewarding or pleasurable. Olds and Milner began to study their discovery of Intracranial Self-Stimulation (ICSS) systematically; for example, they quantified the strength of the rats’ motivation to seek the stimulation by measuring the rate of lever-pressing in an operant conditioning chamber. Publication in 1954 of the discovery of ICSS – which quickly came to be called “pleasure centers in the brain” – generated a firestorm of interest and publicity, and for many decades researchers throughout the world have continued to employ it as a means to investigate the reward systems of the brain.
Peter was primarily a theoretician, and early on he worked on updating Hebb’s theory of the cell-assembly. For example, synaptic inhibition had not been discovered when Hebb was formulating his theory. In 1957 Peter published a revised version of the theory that, among other things, incorporated inhibition among competing cell-assemblies. He was also impressed with Roger Sperry’s emphasis on the motor system and preparation for action, and he incorporated that emphasis on motor planning into his subsequent theoretical excursions. Peter argued that planning for action influences sensory perception and hence that Hebb’s emphasis on perceptual mechanisms alone was somewhat misguided. His theoretical work in the 1950s resulted in the invitation for him to participate in early efforts to develop artificial intelligence in the primitive computers then being constructed by IBM. He subsequently published two important books on the brain and behavior, one the textbook Physiological Psychology (1970), which was theory-rich and highly influential, and the other The Autonomous Brain (1999), which updated his theories about the triggers for behavior, which are generated internally in the brain rather than by external stimuli, and explicated his theories of the neural mechanisms for motivation, memory, and perception.
Let me close on a personal note. When I was finishing up my undergraduate studies at Northwestern University in 1967, my research mentor was Aryeh Routtenberg, who had been an undergraduate at McGill University, where he had worked with Peter Milner and Donald Hebb. He urged me to apply to McGill, which he felt had the best available graduate program in behavioral neuroscience, to perform research under the supervision of Peter Milner, who he said knew “more about the brain than almost anybody else on the planet.” I arrived at McGill and discovered several things about Peter: First, he was exceptionally and indeed freakily bright. Second, he really did know an enormous amount about the brain – it was not hyperbole. Third, because by that time he was focused on reading the literature and generating theoretical models of brain function, as well as writing his textbook, Peter himself was no longer involved in laboratory research. Hence almost all the research in his lab was conducted by his graduate students. Oddly enough, he typically had very little idea of what we were doing in the lab, but he had a unique way of informing himself. He would meet with a student, usually at the student’s behest. As the student talked about his or her research and ideas, Peter’s eyelids would start to droop, and if left undisturbed he would gradually fall asleep (he claimed he suffered from narcolepsy). This presented a dilemma for the student: Do I keep talking, or get up and walk out, or stop talking until he awakens and then resume? I found a fourth way: As his eyelids started to droop, I began talking really quickly, with the goal of finishing and leaving before he nodded off. I usually won.
Peter Milner supervised numerous honours students, graduate students, and postdoctoral fellows. Many of them went on to productive and, in some cases, distinguished careers in neuroscience in Canada, the United States, and elsewhere. He was predeceased by his second wife Susan Milner, and is survived by their son David and grandson Marshall, and by his dear friend Brenda Milner.
Read Peter Milner's chapter in The History of Neuroscience in Autobiography Volume 8.
