Originally published 2017-07-21.
Rebecca Sharrock, from Brisbane, Australia, has highly superior autobiographical memory (HSAM), also called hyperthymesia: a very rare condition in which a person can recall the events of almost every day of their life in vivid detail. She was diagnosed at 23 and is the only known case in Australia. Fewer than 100 people worldwide have been confirmed with HSAM, but contrary to many viral headlines, none of them remembers "everything".
Her story is fascinating both for what her memory can do and for what it costs her. Below we explain what HSAM is, share Rebecca's own account of her earliest years, and look at what scientists can and cannot confirm about memories from infancy.
Who is Rebecca Sharrock?
Rebecca grew up in Brisbane. For most of her life she assumed everyone remembered the way she did. According to an SBS Insight report, it was only when her parents watched a 60 Minutes segment about HSAM that the family realised her memory might be unusual. She then spent years travelling to the University of California, Irvine, the main research centre for the condition, for testing and brain scans, and was formally diagnosed at 23.
She describes her memories as arriving on their own, often triggered by a sight, smell or sound. A bright dress or a song can carry her straight back to a particular day. She has said she has never known life any other way. She jokes about being a "human lab rat" because she has taken part in several research projects.
What HSAM is, and what it is not
The condition was first described in 2006 by Elizabeth Parker, Larry Cahill and James McGaugh at UC Irvine, in a paper about a woman they called "AJ", later identified as Jill Price. Since then a small number of people have been verified, including the actress Marilu Henner, who discussed her memory on 60 Minutes in 2010.
What sets them apart:
- The memory is personal. People with HSAM can recall what they did, where they were and how they felt on a given date, often along with what day of the week it was and what was in the news.
- It is automatic. They do not use memory tricks; the recollections surface whether they want them or not.
- It is not a photographic memory. Many do no better than average at memorising lists, numbers or other arbitrary information. Jill Price scored poorly on some standard memory tests. Neuroscientist Lila Landowski told SBS there is no scientific proof that photographic memory exists at all.
- It is not perfect. Recall is selective, and research suggests people with HSAM can form false memories much like everyone else.
So the popular claim that a few dozen people on Earth "cannot forget anything" is an exaggeration. A more accurate line is that they forget far less of their own lives than the rest of us.
Rebecca's earliest memories, in her words
What makes Rebecca's case especially striking is how far back she says her memories go. In a blog post and interviews, she has described memories from her first weeks of life, and she shared family photos to illustrate them.
Her earliest datable memory, she says, is from when she was about 12 days old: her parents laid her on the driver's seat of the family car to take a photo, and she remembers being curious about the seat cover and the steering wheel above her.
She also describes long stretches in her cot, gazing at the soft toys around her and the standing fan beside it.
A birthday from Rebecca's early childhood. Her first birthday, as she tells it, was not a happy one at first. She was put in an itchy satin dress and cried, and a Minnie Mouse plush given to her that day frightened her so much that she pushed it away whenever she saw it.
Around 18 months, she says, she began dreaming and believed she really left home every night, so she wanted her mother close while she slept. Her sister Jessica was born just after Rebecca's second birthday; at the time, Rebecca recalls, a new sibling interested her much less than her toy train, though sharing clothes and toys later led to some mischief.
Rebecca as a girl at Christmas. She says she can also replay ordinary days from her school years in detail.
Can anyone really remember being a baby?
This is where science urges caution. Most adults' earliest memories date from around the age of three to four, a pattern known as childhood or infantile amnesia. Rebecca has questioned this, saying that a newspaper article claiming no one remembers events before four struck her as nonsense, and that many people she has met remember a sibling's arrival or early birthdays.
Researchers respond that very early memories cannot be checked against independent records. Landowski made this point about Rebecca's account to SBS, and SBS also reported that she describes a memory from before birth, which no one can verify. Childhood photos and family stories can also shape what we later "remember", even with no bad intent. A 2013 study in PNAS found that people with HSAM were about as susceptible to some kinds of false memory as other people.
None of this means Rebecca is inventing anything. Her later memories have been tested by researchers, and her confidence is sincere. It simply means that the earliest ones, like everyone's, belong in a different category from memories that can be confirmed.
The hard side of never forgetting
A memory like this sounds like a gift, but Rebecca and others with HSAM describe a heavy downside. Painful memories do not fade the way they do for most people. Rebecca has written that the condition leaves her "constantly reliving my past (emotionally) in clear-cut detail." An embarrassment from years ago can feel as raw as if it happened this morning.
Reading is a big part of Rebecca's life; she has reportedly said she can recite the Harry Potter books from memory, a claim that has been widely repeated in coverage of her story.
Others with the condition report similar struggles. Jill Price has described her memory as exhausting. Some researchers have also noticed traits such as a strong tendency to become absorbed in experiences and, in some people, obsessive habits, though the link is debated. Brain scans have produced mixed findings, including differences in regions and connections involved in recalling personal events, and no single "memory centre" explains the condition.
If constant recall of painful events is affecting your sleep, mood or daily life, whatever your memory is like, it is worth talking to a doctor.
Why she takes part in research
Rebecca has volunteered for memory studies, including research connected to Alzheimer's disease and dementia. Her motivation is personal: her step-father's father, whom she loved like a grandfather, had Alzheimer's. She has noted that people in the early stages of dementia often recall distant memories more easily than recent ones, and she hopes studying unusual memories like hers might help explain how memories are stored and lost. Scans reported in that research showed heightened connectivity between brain areas involved in conscious and unconscious processing.
Rebecca on a theme park ride as an adult. She has written about her life in a memoir project titled My Life is a Puzzle.
Watch Rebecca describe her condition in her own words:
Her case is a reminder that memory is not a recording but a living process, one that can be extraordinary in some people without being flawless in anyone.
Sources: SBS Insight: Rebecca remembers her entire life in detail; Wikipedia: Hyperthymesia; Rebecca Sharrock's account on Omni; reporting by the Daily Mail and Bored Panda; story first covered by True Activist. Photos: Rebecca Sharrock.
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