Think of a random date from your childhood onward. Can you remember what day of the week it was, what you were doing that day, and what news events occurred? Somebody with an ordinary memory would probably have trouble, especially if nothing significant transpired. But 34-year-old Joey DeGrandis can almost definitely tell you within seconds.

Believe it or not, DeGrandis is one of fewer than 100 people worldwide who have been identified as having Highly Superior Autobiographical Memory, or HSAM, a rare condition that typically allows them to recall life memories from specific dates with ease. Those who have HSAM have a very strong ability to remember details of past daily experiences—even from decades ago—and do so with great accuracy.

Take February 25, 2010. Your average person probably can’t tell you about what they did on that exact day, especially if nothing eventful transpired. But DeGrandis remembers that it was a Thursday (which is correct) and it was snowing in New York (also correct), where he still lives—“that sort of wet snow,” he says. He knows he went to Katz’s Deli with his friends Jeff and Dan, and it was two days after he had gone on a job interview for a position he really wanted.

hsam memory, snow blanketing a new york home

New York, February 25, 2010.

And what about an early memory—say, the first day of third grade? DeGrandis knows it was Tuesday, August 31, 1993.

“I feel very intimately connected with my own timeline,” says DeGrandis, whose superior memory has been studied by researchers in the field and well documented in the media. “It’s almost like I’m a puppet—think of a puppet with strings. Here’s this side of the string attached to my arm. The other end of the string magnets into a date on the timeline.”

Until the mid-2000s, this condition was unknown to the world (though there was a possible case documented way back in the 1870s). A woman’s search for answers about her memory opened the door to the fascinating topic of research at the University of California, Irvine, where it’s been studied for more than a decade.

HSAM manifests itself differently across those who have it. Some of them view it more as merely an interesting ability. Others say it has caused significant challenges in their daily lives. Some experts say HSAM may open new doors in the study of memory and potentially offer new insights into Alzheimer’s disease and other memory loss issues.

The story of how HSAM first came to be studied begins with Jill Price, a 53-year-old Los Angeles resident who spoke with in a phone interview.

The Woman Who Doesn’t Forget

jill price 1974 HSAM

Credit: Jill Price & Family

It was summer 1974, and eight-and-a-half-year-old Jill Price and her family were moving from New Jersey to California. Price was sad to leave her old life behind. Though she says she always had a very good memory, something changed that summer. When it comes to the second half of 1974, “I can give you exact moments in time and what happened, these really minutia things and what days they fell on,” she says. She knows, for instance, that she went to the doctor’s office for a checkup on Friday, December 13, 1974.

In February 1980, she says, her memory became even stronger when it came to remembering life and world events. Price can literally recall details about every day of her life since then, instantly linking a given date with specific memories. “I see it through my eyes, as if I am watching it happening again,” she says. It’s similar to how people remember where they were yesterday or during major national tragedies—except for Price, it’s like that for every day for the past four decades.

Price’s superior memory was something she recognized and grew to understand gradually over time. The unique abilities that come with it have been studied at length by doctors, detailed in her 2009 book, and covered by various news outlets, as have the struggles HSAM has caused her. She’s totally in the present moment, but there’s also a running movie of her life replaying each day in her mind—from her fondest memories to the most traumatic. “Minute to minute, I describe it sort of like having this split screen in my head,” Price says. It’s as if she can’t “turn off” any memories.

Around the time eight-year-old Price’s family moved to California, she started using a tape recorder to capture audio from TV shows and routine life occurrences—singing and talking with her brother, for instance, or playing with friends. Right before she turned 11, Price also started writing in a journal every day, recording her detailed thoughts on paper. Doing so, she says, relaxed her mind. It was when she was 12 that she realized something. “I had a light bulb go off and say, ‘Oh, my God. I can remember a year ago today or two years ago today, or whatever it was,’” Price says.

Saturday, January 8, 1983. Then a senior in high school, Jill Price says she went horseback riding with her friends. The group went back to one of their houses, pushed each other in the pool, and then sat in towels as their clothes dried. Price has also always been an avid TV watcher. Due to her HSAM, she can often tell you what episode of a popular TV show aired on a specific date. February 28, 1983: she instantly (and correctly) says it was a Monday and remembers (also correctly) that it was the day of the series finale of the TV show M*A*S*H.

Still, Price says, there’s a reason why people forget, why memories fade, and why people typically don’t have the real, full story permanently ingrained in their minds. For her, HSAM is an issue that has greatly impacted her life. So in 2000, Price began searching for somebody who could provide answers, maybe even conduct tests. The first name that appeared was Dr. James McGaugh, then a professor at the University of California, Irvine.

In June of that year—or to be exact, June 5, 2000, as Price recalls—she began drafting an email, explaining that she couldn’t forget, and it was invading her life. It took her three days to put it into the right words. Thinking that Dr. McGaugh must have heard about this type of issue before, Price emailed him on June 8.

The Memory Test

dr. mcaugh

Credit: Dr. James McGaugh

When Dr. McGaugh received Price’s email, he was surprised by what he read. “When somebody says they have a memory problem, it usually means they just have a problem with memory. But she had a special kind of problem with memory,” says Dr. McGaugh, now a distinguished emeritus professor at UCI. “She insisted that she meet with me.” Just a few weeks later, she did.

Before anything else, Dr. McGaugh needed to get a better understanding of Price’s memory and verify that what she was saying was true. Price and Dr. McGaugh met on a Saturday morning, where she underwent psychological testing. In part, that included Dr. McGaugh using a historical reference book—a day-by-day chronology of the 20th century—and opening to random pages, asking Price what happened in the world on different days from her early teenage years onward: On what month, day, and year was this plane crash in San Diego? What was the date of the death of Princess Diana?

Price answered these questions with considerable ease. Dr. McGaugh also tested Price’s recollection of events from throughout her personal life. He used Price’s journals to match up dates with her memories and found that she was “remarkably accurate,” he says. So he studied her memory for the next several years.

Price had more meetings with McGaugh and his colleagues, and in February 2006, details about Price’s memory were published in a report in Neurocase science journal titled “A Case of Unusual Autobiographical Remembering.” At the time, Price was identified only by the pseudonym “AJ.” The paper by Dr. McGaugh, Dr. Larry Cahill, and Dr. Elizabeth S. Parker highlighted Price’s unique abilities, also describing her memory as “nonstop, uncontrollable, and automatic.” At the time, they proposed the name hyperthymestic syndrome, or hyperthymesia, coming from the Greek word thymesis which means “remembering.” Jill Price was the first reported modern case of the memory condition.

Price expected few to care about the findings. But news of the report was soon published in the Orange County Register and on National Public Radio. More and more people started reaching out to Dr. McGaugh and his colleagues at UCI, saying they had a similar type of memory as Price.

The second person to reportedly be diagnosed with HSAM was Brad Williams, a now-62-year-old resident of La Crosse, Wisconsin.

Brad Williams

When Brad Williams and his family read about the Neurocase study in a news report, they encouraged him to contact UCI. Within three months, he traveled there, and Dr. McGaugh and his colleagues conducted tests to verify his claims and better understand his memory.

“On a given day, if it’s just something of an ordinary day, I can tell you a little about it,” Williams told via phone. “If we happen to land on a day that’s definitely significant to me, I can probably tell you a great deal more, but we’ll see—or at least I could tell you something that may have happened in history or in the news around that time.”

For Williams, it has always been this way. When he was young, his family recognized something was different about his memory when, in conversations about past vacations or holidays, Williams would instantly link specific events with exact dates, sometimes giving very detailed accounts of what happened. Fast forward to today. Williams is a pro at trivia nights—especially when the questions require knowledge of specific years. Now a radio news reporter, Williams impresses guests at the radio station with his uncanny abilities. His brother produced a documentary about his memory, properly titled “Unforgettable,” in 2010, and he has a blog, Triviazoids, where he explores what happened each day in history.

When presented with a date, what exactly goes on inside the head of someone with HSAM varies. Williams says he visualizes a monthly calendar and snapshots from a given day usually flash through his mind. HSAM has mainly been a positive aspect of Williams’ life, and he doesn’t typically dwell on the bad memories, even though he always knows when the anniversary of a negative event is approaching.

His superior autobiographical memory stretches as far back as when he was four. He knows that in his kindergarten classroom during the afternoon of Tuesday, February 20, 1962, he drew a picture of the rocket ship in John Glenn’s first space flight—which he correctly says took place earlier that day—impressing his teachers so much that they brought him to other classrooms to show off his masterpiece. Fast forward to Monday, August 23, 1982. That day isn’t all too significant to Williams, but he remembers preparing to audition for Hamlet at a local theater in Illinois, which would take place a few days later.

John Glenn entering the Mercury capsule in 1962.

After his initial visit, Williams traveled to UCI several times over the next few years. Yet, aside from his contributions to research, Williams says he’s still trying to find a practical way to use his abilities for something more meaningful. “It’s good to have,” he says. “It’s just frustrating—it’s like, OK, what else is this good for? We’re still trying to figure that out.”

Unanswered Questions and Misconceptions

Contrary to misconceptions, those who have HSAM generally won’t be able to recall all of the minute details of conversations or things they read. “They don’t say, ‘Oh yes, I remember breathing, I remember touching my left foot on the floor,” McGaugh says. “No, it’s: ‘I had dinner with my mother and we went shopping, and then when we got in the car. There was a traffic jam.’ It’s that kind of recall.”

Another important point of clarification, according to McGaugh, is that not everybody with HSAM suffers. “Some of our subjects relish the fact that they have this ability, and it’s very pleasant. Some are on the other side,” McGaugh says, explaining that it largely boils down to what types of life experiences they’ve had.

How exactly HSAM appears is a question that’s been left unanswered. There’s no evidence that it’s genetic or can be developed by training, McGaugh says, and he’s even tested identical twins where just one had HSAM. What McGaugh does know is that those who have HSAM have slightly different brains from the average person—he stresses that the difference is minor, though certain regions of their brains may be more active. One 2013 study also found that those with HSAM are, like anybody else, still susceptible to “false memories,” illustrating that their memories aren’t perfect.

A key turning point in HSAM’s entrance into the public consciousness was on December 19, 2010, when five HSAM subjects appeared on “60 Minutes”—an episode watched by millions. Following its airing, McGaugh received hundreds of emails from viewers saying they either had the ability or knew someone who did. Still, a small percentage ended up passing the test and receiving an HSAM diagnosis.

One person who was told he had HSAM was Joey DeGrandis. When he watched the “60 Minutes” segment, he immediately drew connections to his own life.

Joey DeGrandis

Eight months after the episode aired, DeGrandis was at UCI, where he took (and passed) the HSAM test given by Dr. McGaugh and his colleagues.

The strong memories “started kicking in pretty readily” when DeGrandis was around 10. At that time, he started fascinating his family members in conversations by easily linking memories with their exact dates. His mother, having always kept a detailed record of what the family did and when, was able to confirm that what he said was generally correct.

They decided to put his newfound abilities to the test on Thursday, June 1, 1995, when DeGrandis, then a fourth grader, performed a magic show for his class. Dressed in a magician’s hat and cape, DeGrandis stood in front of the room with his back to month-to-month calendars of 1993 through 1995, visible to his classmates. Someone would yell out a date, and DeGrandis would say what day of the week it fell on.

joey degrandis HSAM

Credit: Joey DeGrandis

DeGrandis, who currently works in human resources for a New York-based tech company, says his friends describe him as an e-list celebrity. He’s participated in multiple news interviews, even appearing on TV on a few occasions. He says he’s received a lot of emails and social media messages from people asking for help determining whether they have HSAM like him. But to DeGrandis, his memory is just a part of daily life, and one that he says has overall been a positive one. Still, there are moments with having HSAM can be overwhelming. DeGrandis also feels that his HSAM is reflected, to an extent, in his personality. “Remembering things the way I do causes me to become really reflective, analytical, nostalgic,” he says—which makes it easier for him to get lost in his thoughts.

Even with HSAM, DeGrandis’ memory isn’t 100 percent flawless. He says he doesn’t have a great short-term memory and, at times, struggles to remember people’s names at social events and parties. “I think that’s just another perhaps part of being human. I can be easily overwhelmed in social scenarios. I’m an extrovert, but there’s a part of me that’s a little overwhelmed by a lot of stimuli.”

“I’m not always thinking about your name when I meet you,” he says, “and that’s also a human thing, I think.”

The Future of Studying HSAM

Today, with the number of people known to have HSAM reaching almost 100, it’s become clear that they span all sorts of personalities, interests, and life experiences. There’s Nima Veiseh, the artist who incorporates the theme of memory into his colorful paintings. There’s Louise Owen, a professional violinist. There’s Marilu Henner, the famous actress who once proclaimed to ABC News, “When somebody gives me a date or a year or something, I see all these little movie montages, basically on a time continuum, and I’m scrolling through them and flashing through them.”

To Jill Price, it’s surreal that an email she sent years ago has attracted such widespread attention. But the fact that she can’t forget continues to present day-to-day challenges—her husband died of a stroke 14 years ago, but she says it might as well have been yesterday. “There is a reason why I went through whatever I went through in my life, suffered because of it, that I wrote a letter to these doctors,” Price says. “I feel that there is some bigger purpose than just what my life has been, so that’s why I felt like I needed to come forward to them and then do whatever they asked me to do.”

alzheimer's mri scans

Price hopes that one day, HSAM can help researchers find a cure for Alzheimer’s. Dr. McGaugh says it’s important to “understand this extraordinary ability so we can learn more about how our brains work. It has a deep significance in terms of neuroscience.” Now retired, McGaugh says the study of HSAM is far from complete. He’s passed on his research at UCI to Dr. Michael Yassa, and one of his former students is also doing neurobiological research related to HSAM in Italy. To this day, people still reach out several times a week saying they think they have this type of superior memory. Typically, they must take a test covering dates and events related to a variety of topics. Only about 1 in 10 of them end up having HSAM, Dr. McGaugh says.

As for Jill Price, she explains, “If you’ve had a great life and have had no tragedies and no disappointments, I’m sure it’s amazing to be able to remember everything. That’s just not how my life has gone. I’ve been down some twists and turns and cobbly roads.”

“My life has not been a straight line,” she adds, “even though I can, in a straight line, tell you where I’ve been.”

By Jordan Friedman, contributor for