Researchers identify new form of superior memory syndrome

Mar 15 2006

Researchers at UC Irvine have identified the first known case of a new memory syndrome -- a woman with the ability to perfectly and instantly recall details of her past. Her case is the first of its kind to be recorded and chronicled in scientific literature and could open new avenues of research in the study of learning and memory.

Researchers Elizabeth Parker, Larry Cahill and James L. McGaugh spent more than five years studying the case of "AJ," a 40-year-old woman with incredibly strong memories of her personal past. Given a date, AJ can recall with astonishing accuracy what she was doing on that date and what day of the week it fell on. Because her case is the first one of its kind, the researchers have proposed a name for her syndrome -- hyperthymestic syndrome, based on the Greek word thymesis for "remembering" and hyper, meaning "more than normal."

Their findings are published in the current issue of the journal Neurocase.

AJ first wrote McGaugh with the details of her extraordinary ability in 2000. She wrote that she "can take a date, between 1974 and today, and tell you what day it falls on, what I was doing that day and if anything of importance occurred on that day." She had been called "the human calendar" for years by her friends and acquaintances.

According to McGaugh, her case is different from others who have been studied in the past with superior memory. Nearly all recorded cases involve people who use mnemonic devices, memory aids such as rhymes or visual imagery to create associations among facts. By using mnemonics, they are able to memorize great amounts of meaningless information. In the most famous case, a man known as "S" started his career in the 1920s as a journalist but eventually became a professional mnemonist and earned his living using his memory to entertain.

"What makes this young woman so remarkable is that she uses no mnemonic devices to help her remember things," said McGaugh, a National Academy of Sciences member and a pioneer in the field of memory research. "Her recall is instant and deeply personal, related to her own life or to other events that were of interest to her."

AJ's powers of recollection can be astonishing. In 2003, she was asked to write down all the Easter dates from 1980 onward. In 10 minutes, and with no advance warning, she wrote all 24 dates and included what she was doing on each of those days. All the dates except for one were accurate. The incorrect one was only two days off. Two years later when she was asked, again without warning, the same question, she quickly responded with all the correct dates and similar information about personal events on those dates.

There are limits to AJ's memory. While she has nearly perfect recall of what she was doing on any given date and instantly can identify the date and day of the week when an important historical event in her lifetime occurred, she has difficulty with rote memorization and did not always do well in school. She scored perfectly on a formal neuropsychological test to measure her autobiographical memory, but during the testing had difficulty organizing and categorizing information. She refers to her ongoing remembering of her life's experiences as "a movie in her mind that never stops".

"AJ is both a warden and a prisoner of her memories," said Parker, a clinical professor of psychiatry and neurology and lead author of the paper. "They can at times be a burden because they cannot be controlled, but she told us that if she had a choice, she would not want to give them up."

Researchers do not yet know how many other cases of hyperthymesia may exist. They plan on continuing to work with AJ to better understand the underlying cause of her unusual abilities. Their hope, according to Cahill, is that AJ's case will open new doors in research involving superior memory, an avenue that has been largely neglected to date.

"To date, the field of memory research has primarily moved forward on two legs -- studying subjects with normal memories, or those with memory deficits," said Cahill, an associate professor of neurobiology and behavior. "This presents the opportunity for a new leg of research, the study of individuals who have exceptionally strong abilities related to memory that do not rely on mnemonic devices, but presumably have more of a genetic basis."