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Before receiving her formal diagnosis, Rebecca Sharrock put her ability to recall precise details from nearly every day of her life down to just having an ‘unusual’ memory.
Rebecca, 34, is the only known person in Australia with highly superior autobiographical memory (H-SAM). Worldwide, fewer than 100 people have the condition and like Rebecca, most of them can accurately describe what they were doing on almost any given date.
When she’s asked: ‘What’s it like to live with a super memory?’, her answer is always the same: “I’ve never known life any differently.”
Rebecca was diagnosed with H-SAM at the age of 23 after her parents saw a 60 Minutes episode on those living with the condition in the United States.
She ended up travelling to the University of California, Irvine, where she underwent years of testing and brain scans.
“Anything that I experienced and lived through personally … the vast majority of it, I just can’t get rid of it for some reason,” she told Insight.
“It has its annoyances when I’m having an experience that I’m supposed to be enjoying and I just get an involuntary flashback.”
Like most of us, Rebecca’s highly detailed memory is triggered by different sensory cues.
“When I’m looking at your brightly coloured dress with all the flowers, I remember my favourite shirt as a two-year-old,” she said.
“As soon as I get a sensory trigger like your dress, it just flashes into my mind involuntarily.”
Memories of the womb
When asked if she can stretch her mind back to her earliest memory, Rebecca describes an event that she says can’t be verified but is very real to her.
“If I stretch my mind back as far as it can possibly go, there’s this recollection of me just having my head tucked between my legs,” she said.
“And we’re assuming that’s from when I was a very well-developed foetus in the womb.”
Rebecca Sharrock pictured as a newborn. Source: Supplied
Dr Lila Landowski, a neuroscientist from the University of Tasmania, says the public curiosity and media coverage surrounding H-SAM has led to popular misconceptions.
“The first thing is to separate it from photographic memory. We have this notion of a photographic memory which is often in the media and stories [but] there’s actually no scientific proof that it actually exists,” she said.
“The thing about H-SAM is it basically means you have a fantastic memory when it comes to remembering events, but it’s specifically events that you can relate to.
“They are not necessarily better at remembering other things, or facts or figures — it’s specific to their own lived experiences.”
Professor Penny Van Bergen, who researches memory development at the University of Wollongong, said our memories can help to inform our identity, which she says is a “cyclical process”.
“The things that we remember about ourselves are things that we think, this is me, this is about me,” she told Insight.
“And then as we have that identity, that can help to shape the sorts of things we tend to remember about ourselves.”
What happens when traumatic memories get stuck inside the brain?
“Sweaty palms, dry mouth, elevated heart rate,” is the description Chris Thompson-Lang gave Insight.
Chris was a combat engineer troop commander in the military and served multiple tours in East Timor and Afghanistan.
Chris Thompson-Lang was a combat engineer in the Army for 14 years and spent time deployed to East Timor and Afghanistan. Source: Supplied / Chris Thompson-Lang
In 2011 during one of his many deployments to Afghanistan, he witnessed trauma that would remain stuck inside his brain for years to come.
“There was one particular incident where I was really focused on the protection of Australians because of what was happening and made a decision to not go to a roadside bomb. And it went off and it killed and wounded local villagers, women and children,” Chris said.
“I was involved in treating those casualties, and that had a lasting impact on me and led to sort of a bit of a downward spiral in life.”
When he returned home, he was diagnosed with post-traumatic stress disorder (PTSD).
“It started off with some sleep disturbance, straight away. And then when I returned home to Australia, I had two young children, and when they were crying or upset, that would trigger sort of — I wouldn’t say a true flashback, but intrusive thoughts and remembering what had happened.”
“Alcohol was my refuge. I would use that to sort of dull my senses. But that led to a breakdown in relationship, a loss of career and hospitalisation.”
Associate professor Laura Jobson, a researcher and clinical psychologist at Monash University whose work examines the impact of trauma on memory, said PTSD can bring intrusive memories to the surface.
“The memories actually feel like they’re happening now. You feel like you’re reliving them. You get this very strong feeling in your body,” she said.
As memory is linked to identity, the recall of traumatic events can engulf a person’s sense of self.
“We can ask people, give us five memories that define who you are. And people tend to say graduating, getting married, having a baby.
“For those with PTSD, they’re often centred around that trauma experience.”
Studying the H-SAM brain
Scientists are studying Rebecca Sharrock’s unique brain and memory. She’s optimistic researchers will be able to unlock more about H-SAM, and advance what we understand about human memory.
“I jokingly refer to myself as a human lab rat to my friends and family, and also to a few other people as well, because scientists are researching and studying the way in which my memory works,” Rebecca said.
“I think, if you have any uniqueness in any area, I think it’s very important — much like it is when you have a rare blood type.
“It’s very important to contribute as much of your personal experience as possible to science.”
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