Cognitive psychologist Endel Tulving.Handout
University of Toronto psychologist Endel Tulving came up with numerous paradigm-shifting theories about how memory functions, and backed them up years later using human studies.
“He was one of the very top scientists of memory in the last hundred years,” says his colleague Fergus Craik, a neuropsychologist and University of Toronto professor emeritus. “He got us to understand memory in the way we think of it today.”
In his most-cited work, a chapter from the 1972 book Organization of Memory, which he co-edited, Dr. Tulving wrote about episodic and semantic memory, which he described as “two parallel and partially overlapping information processing systems.”
Episodic memory, a term he coined, relates to how we remember personal experiences tied to specific moments in time. This type of long-term memory is delicate and susceptible to being changed or lost. His explanation of episodic memory is important today in our understanding of the impact of dementia and stroke on memory. For instance, research he did well after his official retirement showed that the loss of episodic memory from a brain injury did not change a person’s ability to understand the feelings and intentions of others.
By contrast, Dr. Tulving described semantic memory, as “a system for receiving, retaining and transmitting information about meaning of words, concepts and classification of concepts.” He observed that semantic memory was somewhat less susceptible to being transformed or lost.
In 1993 he wrote in his paper “What is Episodic Memory,” that episodic and semantic are two of five major memory systems, the others being perceptual representation, short-term memory and procedural memory.
Dr. Tulving tested and ultimately proved many of his theories about the different kinds of memory by working with a man he called K.C. (later identified as Kent Cochrane). K.C. had severe amnesia after a 1981 motorcycle accident, but his semantic memories were intact and he could identify equipment and technical drawings he used in his former job. He could explain how to change a car tire – using his procedural memory – but could not recall if he personally ever did such a thing, because his episodic memories were gone.
Another aspect of episodic memory, Dr. Tulving observed, is that it makes possible something he called “mental time travel,” both into the past and into the future. Consequently, because of his impairment, K.C. could not make plans or imagine what he might do the next day.
“That took people a long time to get their head around,” says Daniel Schacter, a psychology professor at Harvard University who studied under Dr. Tulving, “how memory related to thinking about the future.”
Dr. Tulving was also interested in the retrieval of memories, and in a 1962 study he showed that people recalling a list of unrelated facts create their own ways to organize the information to help themselves remember, something he called subjective organization. In 1966, he showed that people can remember more when they have cues to help them retrieve a memory.
His later research delved into the importance of memory in personal identity, and he was also among the first to use positron emission tomography (PET) to look at the parts of the brain activated by memory. He was using scans as early as the 1980s, for his work with K.C., and later explored things such as which parts of the hippocampus were activated when episodic memories were made and retrieved.
In a 2006 interview with the Toronto Star, Don Stuss, Dr. Tulving’s boss at the Rotman Research Institute said, “He’s won every prize but the Nobel.”
Dr. Tulving, who was 96, died on Sept. 11, likely from complications related to a heart attack, according to his daughters, Elo Tulving-Blais and Linda Tulving. He had been in failing health for some time.
He published about 200 research articles and chapters, plus several books, and is still heavily cited by other academics. In a list of eminent psychologists of the 20th century published by the American Psychological Association in 2002, he was ranked No. 36.
“He was one of the major figures in memory research,” Dr. Schacter says.
According to the Canadian Medical Hall of Fame, into which was inducted in 2007, Dr. Tulving is considered the founder of memory research in Canada.
“He was the kind of guy who had ideas all the time. He would often assign ideas to other people to follow through on because he had so many of them,” his younger daughter, Linda, says. He particularly liked concepts that disrupted existing assumptions.
“He made a lot of discoveries that were counterintuitive. He’d have a theory and a lot of people would think it was outlandish. But he’d turn out to be right,” says friend and frequent collaborator Roddy Roediger, a professor at Washington University in St. Louis, where Dr. Tulving was a visiting professor.
Endel Tulving was born on May 26, 1927, in Petseri, Estonia (now part of Russia) to Juhan, a judge, and Linda Tulving, who owned a furniture store. He attended Hugo Treffner Gymnasium and was top of his class but was bored by academics, preferring track and field.
After the Soviet Union invaded Estonia, Endel and his younger brother, Hannes, were separated from their parents and found themselves in Germany serving in the army. (They were unable to communicate with their parents again for 14 years, during which the parents believed their sons were dead. It was 22 years before the family members were reunited.)
Endel met fellow Estonian Ruth Mikkelsaar at a refugee camp in Germany when he tutored her in math. He moved to Canada in 1949 and the two married in 1950. He immigrated as part of a labour program and was to work on a farm.
“The farmer recognized that this is a guy who should not be doing what he’s doing. He had the opportunity to go to university and [the farmer] let him pursue that route,” Linda says.
He did an undergraduate degree in psychology and then a master’s at the University of Toronto, and completed a PhD in experimental psychology at Harvard in 1957, writing about vision and the brain for his thesis.
U of T hired Dr. Tulving as a lecturer after graduation and he became an associate professor in 1959. By this time he had moved away from vision research and into memory, publishing landmark papers by the 1960s. He worked briefly at Yale then returned to U of T and became chair of its Department of Psychology.
Dr. Tulving retired from the university in 1992, becoming a professor emeritus, and that year took on the inaugural Tanenbaum Chair in Cognitive Neuroscience at the Rotman Research Institute, a position that was created for him. He continued to publish books and articles for more than two decades.
His later work relied heavily on neuroimaging, and he continued to explore how episodic memory is related to the concept of the passing of time and also deeply connected to identity.
Dr. Tulving received numerous honours, including the Gold Medal Award for Life Achievement in Psychological Science from the American Psychological Foundation in 1994, and a Canada Gairdner International Award in 2005. He was named an officer of the Order of Canada in 2006.
His daughters recall him working long hours – starting early, coming home for dinner and then returning to the office at night, plus working weekends. Later, when he got a computer at home, he would retreat to his study outside traditional office hours.
“He was doing what he loved and that’s the reason why he worked a lot,” Linda says.
His late wife, Ruth, was a painter and printmaker who created the cover of his book Mälu (which means “memory” in Estonian) with a piece that depicted the memory concept hemispheric encoding retrieval asymmetry. She loved the performing arts, so the couple frequently attended the symphony, opera and ballet. She died in 2012.
Dr. Tulving played tennis regularly into his 70s. Only in recent years did he stop playing a Sunday bridge game with friends. Dr. Craik, a long-time friend, also recalls Dr. Tulving being an accomplished chess player.
He had a reputation among colleagues for being forthright. Dr. Roediger took one of his classes as a graduate student and, the first week, Dr. Tulving held up his essay and told everyone he was wrong. While others dropped out of the class, “I took it as a challenge and worked harder on those essays,” Dr. Roediger says.
Indeed, some found him formal and opinionated at first. “You had to pass the Tulving test,” Dr. Craik says. Once you showed you were passionate and hard-working, he was generous with his time and support.
That extended to his daughters. “He told me when I was young that there’s nothing I couldn’t do that boys could do, and to not stop any of my aspirations,” Linda recalls.
Once, in the 1980s, Dr. Tulving and his research team needed to put together a grant proposal on a tight deadline. Dr. Schacter recalls his renowned mentor being the one at the typewriter.
“You would not expect him to be there, at Sidney Smith Hall until 2 a.m. with his grad students, getting it done.”
Dr. Tulving leaves his brother, two daughters and five grandchildren.