Donald O. Hebb

Donald Olding Hebb (July 22, 1904 – August 20, 1985) was a prominent Canadian psychologist. His book The Organization of Behavior, published in 1949, established Hebb's position in psychology. Donald Hebb has been described as the father of neuropsychology and neural networks. In neuropsychology, Hebb sought to understand how the function of neurons contributed to psychological processes, such as learning.

Life

Donald Olding Hebb was born in Chester, Nova Scotia, Canada, in 1904. Donald was the oldest of four children of Arthur and Clara (Olding) Hebb, both physicians. He lived in Chester until the age of 16, when his parents moved to Dartmouth, also in Nova Scotia.

Donald's mother was heavily influenced by the ideas of Maria Montessori, and she home schooled him until the age of eight. He performed well in elementary school, but his rebellious attitude and disrespect for authority led to problems in high school. However, he was able to graduate.

The older of Donald's younger brothers, Andrew, obtained a law degree but went on to a career in journalism and then insurance. Donald's youngest brother, Peter, became a physician like his parents. And his sister, Catherine, eventually became a prominent physiologist. Donald, early in life, had no aspirations toward psychology or the medical field; rather, he wanted to be a writer.

Donald Hebb entered Dalhousie University aiming to become a novelist. He was not an exceptional student but he graduated with a Bachelor of Arts degree in 1925.

After working for a number of years as a high school teacher and elementary school principal, Hebb turned to graduate study in psychology at McGill University.

In 1931, Hebb became bedridden because of tuberculosis in his hip. He used the time to read Charles Scott Sherrington's The Integrative Action of the Nervous System and Ivan Pavlov's Conditioned Reflexes. His master's thesis, written later that year, titled Conditioned and Unconditioned Reflexes and Inhibition, tried to show that skeletal reflexes were due to cellular learning. This he later dismissed as nonsense. And yet, one of the faculty who later approved the thesis, Boris Babkin, had worked with Pavlov. At the very least, the thesis demonstrated the start of a thought process that would later lead to the Hebb synapse. Hebb passed cum laude and Babkin arranged for Hebb to do research on conditioning with Leonid Andreyev, another former member of Pavlov's laboratory.

Hebb received his M.A. in psychology from McGill University, in 1932. Between 1933 and 1934, Hebb wrote a booklet titled Scientific Method in Psychology: A Theory of Epistemology Based on Objective Psychology. It was never published, but it contained many ideas that would become part of his later work.

By the beginning of 1934, Hebb's life was in a slump. His wife had died, following a car accident, on his twenty-ninth birthday (July 22, 1933). His work at the Montreal school was going badly. The focus of study at McGill was more in the direction of education and intelligence, and Hebb was now more interested in physiological psychology and became quite critical of the methodology of the experiments conducted there.

In 1934, Hebb decided to leave Montreal and wrote to Robert Yerkes at Yale University where he was offered a position to study for a Ph.D. in psychology. Babkin, however, convinced Hebb to study with Karl Lashley instead. In July 1934, Hebb was accepted to study under Karl Lashley at the University of Chicago. His thesis was titled The problem of spatial orientation and place learning. Hebb, along with two other students, followed Lashley to Harvard University in September, 1935. Here, he had to change his thesis. At Harvard, he did his thesis research on the effects of early visual deprivation upon size and brightness perception in rats. That is, he raised rats in the dark and some in the light and compared their brains. He was awarded his Ph.D. in 1936. The next year, he worked as a research assistant to Lashley and as a teaching assistant in introductory psychology for Edwin G. Boring at Radcliffe College.

In 1937, Hebb married his second wife, Elizabeth Nichols Donovan. That same year, on a tip from his sister Catherine (herself a Ph.D. student with Babkin at McGill University), he applied to work with Wilder Penfield at the Montreal Neurological Institute. There he researched the effect of brain surgery and injury on human brain function. He saw that the brain of a child could regain partial or full function when a portion of it is removed but that similar damage in an adult could be far more damaging, even catastrophic. From this, he deduced the prominent role that external stimulation played in the thought processes of adults. In fact, the lack of this stimulation, he showed, caused diminished function and sometimes hallucinations.

Hebb returned to McGill University to become a professor of psychology in 1947 and was made chairman of the department in 1948. There he once again worked with Penfield, but this time through his students, who included Mortimer Mishkin, Haldor Enger Rosvold, and Brenda Milner, all of whom extended his earlier work with Penfield on the human brain.

Hebb was a member of the American Psychological Association (APA) and served as its president in 1960, the first non-US citizen to hild this position. He won the APA Distinguished Scientific Contribution Award in 1961.

Hebb stayed as professor at McGill until his retirement in 1972. He remained at McGill after retirement as an emeritus professor, conducting a seminar course required of all department graduate students. Finally, in 1980, he returned to Dalhousie University as professor emeritus of psychology.

Donald Hebb died in Nova Scotia on August 20, 1985, two years after his third wife. He was survived by two daughters (both by his second marriage), Mary Ellen Hebb and Jane Hebb Paul. The Donald O. Hebb Award, named in his honor, is awarded to distinguished Canadian scientists.

Work

Hebb also became critical of the Stanford-Binet and Wechsler intelligence tests for use with brain surgery patients. These tests were designed to measure overall intelligence, whereas Hebb believed tests should be designed to measure more specific effects that surgery could have had on the patient. To achieve this, he created the Adult Comprehension Test and the Picture Anomaly Test.

Putting the Picture Anomaly Test to use, he provided the first indication that the right temporal lobe was involved in visual recognition. He also showed that removal of large parts of the frontal lobe had little effect on intelligence. In fact, in one adult patient, who had a large portion of his frontal lobes removed in order to treat his epilepsy, he noted "a striking post-operative improvement in personality and intellectual capacity" (Hebb and Penfield 1940). From these sorts of results, he started to believe that the frontal lobes were instrumental in learning only early in life.

In 1939, he was appointed to a teaching position at Queen's University. In order to test his theory of the changing role of the frontal lobes with age, he designed a variable path maze for rats with Kenneth Williams called the Hebb-Williams maze, a method for testing animal intelligence later used in countless studies. He used the maze to test the intelligence of rats blinded at different developmental stages, showing that "there is a lasting effect of infant experience on the problem-solving ability of the adult rat." This became one of the main principles of developmental psychology, later helping those arguing the importance of the proposed Head Start programs for preschool children in economically poor neighborhoods.

In 1942, he moved to Orange Park, Florida to once again work with Karl Lashley who had replaced Yerkes as the Director of the Yerkes Laboratories of Primate Biology at the Yerkes National Primate Research Center. Here, studying primate behavior, Hebb developed emotional tests for chimpanzees. The experiments were somewhat unsuccessful, however because chimpanzees turned out to be hard to teach. During the course of the work there, Hebb wrote The Organization of Behavior: A Neuropsychological Theory, his ground-breaking book that set forth the theory that the only way to explain behavior was in terms of brain function.

The Organization of Behavior

The Organization of Behavior (1949) is considered Hebb's most important book. A combination of his years of work in brain surgery mixed with his study of human behavior, it finally brought together the two realms of human perception that for a long time could not be connected properly. That is, it connected the biological function of the brain as an organ together with the higher function of the mind.

There were many theories on how the brain and the mind were connected. Pavlovian theories, for example, were based on a theory of stimulus and response, based on the belief that a path existed from sensory organs to the mind, which then made a response. The problem with the theory was that it was assumed that signals travel one way to the brain. It could not explain all the extra processing that adds to the input signals of human senses. Perhaps this was based on the fact that neurons themselves transmit in only one direction, but connections between various neurons are not necessarily one-way.

Another theory, the Gestalt theory, stated that signals to the brain established a sort of field. The form of this field depended only on the pattern of the inputs, but it still could not explain how this field was understood by the mind.

The behaviorist theories at the time did well at explaining how the processing of patterns happened. However, they could not account for how these patterns made it into the mind. Donald Hebb combined up-to-date data about behavior and the mind into a single theory. And, while the understanding of the anatomy of the brain did not advance much since the development of the older theories on the operation of the brain, he was still able to piece together a theory that got a lot of the important functions of the brain right. His theory became known as Hebbian theory and the models which follow this theory are said to exhibit Hebbian learning. This method of learning is best expressed by this quote from the book:

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 often paraphrased as "Neurons that fire together wire together." It is commonly referred to as Hebb's Law. The combination of neurons which could be grouped together as one processing unit, Hebb referred to as "cell-assemblies." And their combination of connections made up the ever-changing algorithm which dictated the brain's response to stimuli.

Let us assume that the persistence or repetition of a reverberatory activity (or "trace") tends to induce lasting cellular changes that add to its stability.… When an axon of cell A is near enough to excite a 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.

The theory is often summarized as "cells that fire together, wire together," although this is an oversimplification of the nervous system not to be taken literally, as well as not accurately representing Hebb's original statement on cell connectivity strength changes. The theory is commonly evoked to explain some types of associative learning in which simultaneous activation of cells leads to pronounced increases in synaptic strength. Such learning is known as Hebbian learning.

Hebbian theory concerns how neurons might connect themselves to become engrams. Hebb's theories on the form and function of cell assemblies can be understood from the following:

"The general idea is an old one, that any two cells or systems of cells that are repeatedly active at the same time will tend to become 'associated', so that activity in one facilitates activity in the other." (Hebb 1949, p. 70)

"When one cell repeatedly assists in firing another, the axon of the first cell develops synaptic knobs (or enlarges them if they already exist) in contact with the soma of the second cell." (Hebb 1949, p. 63)

Not only did Hebb's model for the working of the mind influence how psychologists understood the processing of stimuli within the mind but also it opened up the way for the creation of computational machines that mimicked the biological processes of a living nervous system. And while the dominant form of synaptic transmission in the nervous system was later found to be chemical, modern artificial neural networks are still based on the transmission of signals via electrical impulses that Hebbian theory was first designed around.

Hebb as an educator

Throughout his life, Hebb enjoyed teaching and was very successful as a teacher. Both in his early years as a teacher and a headmaster in a Montreal school and in his later years at McGill University, he proved to be a very effective educator and a great influence on the scientific minds which were then his students. Donald Hebb's most prominent students were Donald Forgays, Stevan Harnad, Woodburn Heron, Bernard Hymovitch, W. Jake Jacobs, Helen Mahut, Ronald Melzack, Brenda Milner, Peter Milner, Mortimer Mishkin, Gordon Mogenson, Aryeh Routtenberg, Seth Sharpless, Case Vanderwolf.

As a professor at McGill, he believed that one could not teach motivation, but rather create the conditions necessary for students under which to do their study and research. One could train them to write, help them choose a problem to study, and even help keep them from being distracted, but the motivation and passion for research and study had to come from the students themselves. He believed that students should be evaluated on their ability to think and create rather than their ability to memorize and reprocess older ideas.

Hebb believed in a very objective study of the human mind, more as a study of a biological science. This attitude toward psychology and the way it is taught made McGill University a prominent center of psychological study. Hebb also came up with the A/S ratio, a value that measures the brain complexity of an organism.

Hebb's name has often been invoked in discussions of the involvement of psychological researchers in interrogation techniques, including the use of sensory deprivation, because of his research into this field. Speaking at a Harvard symposium on sensory deprivation in June, 1958, Dr.Hebb is quoted as remarking:

The work that we have done at McGill University began, actually, with the problem of brainwashing. We were not permitted to say so in the first publishing.... The chief impetus, of course, was the dismay at the kind of “confessions” being produced at the Russian Communist trials. “Brainwashing” was a term that came a little later, applied to Chinese procedures. We did not know what the Russian procedures were, but it seemed that they were producing some peculiar changes of attitude. How?

One possible factor was perceptual isolation and we concentrated on that (Solomon et al 1961).

Legacy

Reception of Hebb's neurological speculation was facilitated by a set of experiments that emerged from the McGill laboratories in the 1950s. Given the necessarily tentative nature of psychological theorizing in the mid-twentieth century, Hebb argued that the best justification for a psychological theory was the production of data that endured long after the details of the theory had falled by the wayside. The frequency of citation to Hebb's work has increased markedly over the years (Martinez & Glickman, 1994). This reflected in part the transition from stimulus-response learning theories to more cognitively oriented positions anticipated in Hebb's writings. The bulk of recent citations refer to Hebb's speculative postulate regarding the conditions surrounding permanent synaptic change in the nervous system. For many contemporary neuroscientists, Hebb's fame roots on a prescient hypothesis that was not testible in his time but now generates a great deal of research.

Major works

• Hebb, D. O. 1949. The Organization of Behavior. New York, NY: Wiley.
• Hebb, D. O. 1958. A Textbook of Psychology. Philadelphia, PA: Saunders.
• Hebb, D. O. 1959. A neurepsychological theory. In S. Koch (Ed.), Psychology: A study of a science. Vol. 1. Sensory, perceptual, and physiological foundations, pgs. 622-643. New York, NY: McGraw-Hill.
• Hebb, D. O. 1980. D. O. Hebb. In G. Lindzey (Ed.), A history of psychology in autobiography, Vol. 7. San Francisco: Freeman.
• Hebb, D. O., and Wilder Penfield. "Human behaviour after extensive bilateral removal from the frontal lobes." Archives of Neurology and Psychiatry 44 (1940): 421–436.

References

ISBN links support NWE through referral fees

• Boring, E. G. 1950. A History of Experimental Psychology, 2nd ed. Englewood Cliffs, NJ: Prentice Hall. ISBN 0133900398
• Brennan, J. F. 1986. History and Systems of Psychology. Englewood Cliffs, NJ: Prentice-Hall, Inc. ISBN 0133922189
• Brown, Richard E., and Peter M. Milner. "The Legacy Of Donald O. Hebb: More Than The Hebb Synapse" Nature 4 (2003): 1013–1019.
• Campbell, D. T., and Watson, R.I. eds. 1963. History, Psychology, and Science: Selected Papers of E. G. Boring. New York, NY: Wiley.
• Firkin, B. G., and J. A. Whitworth. 1987. Dictionary of Medical Eponyms. Parthenon Publishing. ISBN 1850703337
• Harnad, Stevan. 1985. D. O. Hebb Father of Cognitive Psychobiology 1904-1985 Retrieved July 3, 2008.
• Hartlage, L. C., and C. F. Telzrow. 1985. The Neuropsychology of Individual Differences. New York, NY: Plenum Press.
• Kertesz, A., ed. 1994. Localization and Neuroimaging in Neuropsychology. New York, NY: Academic Press.
• Kolb, B., and I. Q. Wishaw. 2003. Fundamentals of Human Neuropsychology 5th edition. Freeman. ISBN 0716753006
• Lashley, K. S. "In search of the engram." Society of Experimental Biology Symposium 4 (1950): 454–482.
• Leahey, T. H. 1991. A History of Modern Psychology. Third edition, 2000. Englewood Cliffs, NJ: Prentice Hall. ISBN 0130175730
• Loring, D. W. (ed.). 1999. INS Dictionary of Neuropsychology. New York, NY: Oxford University Press.
• Luria, A. R. 1973. The Working Brain: An Introduction to Neuropsychology.
• Martinez, J. L., and S. E. Glickman. 1994. "Hebb revisited: Perception, plasticity, and the Hebb synapse." Contemporary Psychology 39: 1018-1020.
• McCarthy, R. A., and E. K. Warrington. 1990. Cognitive Neuropsychology: A Clinical Introduction. New York, NY: Academic Press.
• Milite, George A. 2001. Hebb, Donald O. (1904-1985) Gale Encyclopedia of Psychology, 2nd ed. Gale Group. Retrieved July 3, 2008.
• Orbach, J., ed. 1981. Neuropsychology after Lashley: Fifty Years since the Publication of Brain Mechanisms and Intelligence. Lawrence Erlbaum Associates. ISBN 0898590884
• Rains, G. D. 2002. Principles of Human Neuropsychology. Boston, MA: McGraw-Hill.
• Sheehy, N., ed. 2002. Biographical Dictionary of Psychology. London: Routledge. ISBN 0415285615
• Solomon, P., Philip E. Kubzansky, P. Herbert Leiderman, Jack H. Mendelson, Richard Trumbull, and Donald Wexler (eds.). 1961. Sensory Deprivation: A Symposium Held at Harvard Medical School. Cambridge, MA: Harvard University Press.
• Tarter, R.E., D. H. Van Thiel, and K. L. Edwards. 1988. Medical Neuropsychology: The Impact of Disease on Behavior. New York, NY: Plenum Press.
• Tiner, J. H. 2000. One Hundred Scientists who Shaped World History. Bluewood Books. ISBN 0912517395
• Yerkes, R. M. 1929. Great Apes: A Study of Anthropoid Life. Johnson Reprint. ISBN 0384701507

External links

• Biographies of Donald Olding Hebb
• Biography

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