Donald O. Hebb

Donald Olding Hebb was born on 22 July 1904 in Chester, Nova Scotia, to two physician parents. His mother Clara, influenced by Maria Montessori, homeschooled him until age eight. He was bright enough to skip into seventh grade at ten but failed eleventh grade in Chester and graduated twelfth grade at Halifax County Academy at sixteen. He entered Dalhousie University intending to become a novelist and took his BA in 1925. He then taught at his old Chester school, worked on an Alberta farm, and labored in Quebec, all while reading William James, Sigmund Freud, and John B. Watson — reading that turned him toward psychology. In 1928 he entered McGill graduate school while serving as principal of Verdun High School in suburban Montreal, where he tried more imaginative pedagogy: more interesting assignments and turning misbehaving students out of the classroom so that schoolwork became a privilege. He completed his master's thesis on conditioned and unconditioned reflexes in 1932 under the eminent psychologist Boris Babkin, trying to show that skeletal reflexes were due to cellular learning.

1933 was a year of collapse. His first wife died in a car accident on his 29th birthday, and his work in Quebec schools was, in his own words, defeated by the rigidity of the curriculum. He decided to leave Montreal, wrote to Robert Yerkes at Yale, but Babkin convinced him instead to study with Karl Lashley at the University of Chicago. He followed Lashley to Harvard in 1935 and received his PhD in 1936 on the effects of early visual deprivation on size and brightness perception in rats. He spent a year as Lashley's research assistant and as teaching assistant to Edwin G. Boring at Radcliffe. In 1937 he married Elizabeth Nichols Donovan and on a tip from his sister applied to work with Wilder Penfield at the Montreal Neurological Institute. There he observed that a child's brain could regain function after surgery while an adult's could not. From this he argued that adult cognition depends critically on external stimulation and that the frontal lobes matter most early in life. He helped design the Adult Comprehension Test and the Picture Anomaly Test for surgical patients. In 1939 he was appointed to Queen's University, where with Kenneth Williams he designed the Hebb-Williams maze, later a standard for animal intelligence and a building block of the case for Head Start programs.

In 1942 he rejoined Lashley at the Yerkes Laboratories of Primate Biology in Florida and wrote The Organization of Behavior (1949), the work that defines neuroscience to this day. In it he wrote: When an axon of cell A is near enough to excite cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A's efficiency, as one of the cells firing B, is increased. This is Hebbian learning, popularly paraphrased as neurons that fire together wire together, and it remains the foundational principle of modern artificial neural networks. He grouped neurons into cell-assemblies as units of processing and into phase sequences as streams of thought. He returned to McGill as professor in 1947 and chaired the department from 1948. Brenda Milner, Mortimer Mishkin, and Haldor Enger Rosvold came from his line, extending his earlier work with Penfield on the human brain.

His 1953-54 sensory deprivation studies at McGill cast a long shadow over his legacy. Subjects spent hours in cubicles with vision, hearing, and touch blocked and exhibited cognitive disturbance and hallucinations. Recent historical research has documented that the work was funded by the CIA and informed MKULTRA-era interrogation techniques. Hebb himself acknowledged at a 1958 Harvard symposium that the work actually began with the problem of brainwashing — and that the team had not been permitted to say so in the first publishing. He was president of the Canadian Psychological Association in 1953, president of the American Psychological Association in 1960, and received the APA Distinguished Scientific Contribution Award in 1961. He was elected Fellow of the Royal Society of Canada and of the Royal Society of London in 1966, and received honorary doctorates from fifteen universities. He retired in 1972, returned to Nova Scotia in 1977 to complete Essay on Mind (1980), and continued to colloquia at Dalhousie until his death at 81 on 20 August 1985.

Hebb's pedagogy at McGill was distinctive. He believed motivation could not be taught directly, only created by arrangement of conditions: one could train students to write, help them choose problems, and protect them from distraction, but the passion had to come from the student. He thought students should be evaluated on their ability to think and create rather than memorize, and his attitude made McGill a major center of psychological research. He also introduced the A/S ratio as a measure of brain complexity in different species. His 1949 Organization of Behavior brought together biological function and higher mental processes in a way nineteenth-century associationism, twentieth-century Pavlovian behaviorism, and Gestalt theory had each failed to do, and his cell-assemblies remain a working concept in computational neuroscience. The 1980 Donald O. Hebb Award is given annually by the Canadian Psychological Association to distinguished Canadian psychologists, with Hebb himself receiving the inaugural award. He was posthumously inducted into the Halifax Discovery Centre's Hall of Fame in 2011 and into the CSI Pantheon of Skeptics. His archives are held by McGill University. A 2002 Review of General Psychology survey ranked Hebb the 19th most cited psychologist of the 20th century. Modern deep learning still cites Hebb's rule as its most basic learning principle, and the ethical questions raised by his sensory deprivation work are now standard reading in research ethics courses.