Hyperthymesia: When you can remember everything

It’s hard to imagine what it would be like to remember every detail of your entire life. People with the rare condition hyperthymesia are able to do just that.

For most of us, our memories are unreliable. Our brains are selective about what we recall. Although our long-term memory stores pivotal moments, the insignificant details of day-to-day life fade away. You might wish for a better memory, but would you want to be one of the people who never forget?

Let’s take a look at the condition known as hyperthymesia or “perfect memory”: what causes it, how it differs from ordinary memory and other types of exceptional memory, and how people who have this condition experience it. Then, we’ll also talk about how you can prevent memory loss and improve your own memory.

What is hyperthymesia?

Hyperthymesia is also known as Highly Superior Autobiographical Memory (HSAM). People with this condition have an almost perfect memory and are able to remember every detail of their lives. For many, the ability begins in childhood or adolescence.

The type of memories they retain are autobiographical, based on personal experiences. They may remember dates of important world events and facts when these events have some relevance to their life.

Dr James McGaugh first discovered HSAM in 2006 after his research into “AJ”, a woman with supreme memory (later named as Jill Price). (1) Since then, just 61 people have been officially diagnosed with the condition.

The vast majority of us will never achieve the superhuman memory of people with hyperthymesia. However, memory can be improved. 

These online memory games from CogniFit can help you train and exercise your brain, to boost your memory and avoid memory loss.

What causes Hyperthymesia?

Hyperthymesia is extremely rare and scientists are still trying to find out what causes it. 

In 2012, scientists investigated whether there were physical differences in the brains of people with hyperthymesia. They noticed that people with HSAM had additional wiring in the frontal lobes and hippocampus, two areas of the brain linked to autobiographical memory. However, they could not conclude that the extra brain matter was the cause of the condition. Equally, it could be that the subjects’ brains had changed as a result of HSAM. (2)

Another theory is that hyperthymesia develops because of thought patterns and behavior. In 2016, researchers found that HSAM individuals were more prone to absorption, fantasizing and obsessing over the past.

Each time an original memory is replayed, it becomes stronger. Many of us do this with important memories, such as a wedding day or special birthday, but HSAM people do it all day, every day. Some scientists believe that this behaviour may be what helps them preserve memories in detail. (3)

Eidetic memory vs hyperthymesia

HSAM vs ordinary memory

A 2016 study sought to compare HSAM individuals and those with ordinary memory. (4) They wanted to find out how both groups retain information over time. Initially, there wasn’t much difference between the two groups, but over time, the control group’s memories began to fade. In contrast, the HSAM group retained a high level of information. In other words, hyperthymesia is not a special ability for making memories, but rather, retaining them. 

Years later, HSAM subjects retained detailed, episodic memories of mundane events. On the other hand, the control group could only recall a vague gist, or had lost the memories altogether. 

Nevertheless, it seems there’s no such thing as a perfect memory. Even people with hyperthymesia can be tricked into having false or distorted memories, according to a study from the University of California. (5)

Eidetic Memory vs Hyperthymesia

Hyperthymesia is distinct from other types of exceptional memory.

Eidetic memory is the ability to recall an image faithfully after only seeing it once. People describe it as a snapshot of a moment that appears as an afterimage in the visual field. This type of memory is more common in young children, and rare in adults. This is very different from the experiences of people with hyperthymesia, who relive events in episodic form.

As another example, memory champions can memorize long strings of complicated information, like sequences of numbers and letters. They use mnemonic rehearsal strategies, which employ rhymes, patterns, and visualization.

Surprisingly, people with hyperthymesia do not have above-average skill for memorizing information this way. (2) Hyperthymesia is done unconsciously. The memories are all autobiographical and a mix of semantic (relating to knowledge and facts) and episodic memories.

Famous people who remember everything

So far, only a small  number of people have been recognised as having HSAM, and they all have unique experiences with the condition.

Jill Price

Jill Price was the first person to ever be recognised as having HSAM. She contacted Dr James McGaugh back in the year 2000 to tell him that she had a problem with her memory. She explained that any time she saw a date she was able to recall exactly what had happened on that day in her life.

McGaugh realized that Jill’s memory was exceptional, so he put a team together to study her ability. Luckily, Jill had kept diaries religiously throughout her life, and researchers were able to use these to put her unique memory power to the test.

She could recall almost every day of her life in minute detail. However, she was only average at learning things by heart, or remembering things that had no relevance to her life. In addition, she could remember the exact date and day of the week of world events, but only in relation to personal experience.

In an article published in The Guardian, Jill describes her memory as a “split screen” where she views present events and replays memories from the past simultaneously. (6)

Jill has appeared many times on television documentaries and interviews, and in 2008 she released her autobiography, The Woman Who Can’t Forget, with Bart Davis.

Nima Veiseh

Some people with hyperthymesia can pinpoint the moment they first started to retain memories at an exceptional level. For Nima Veiseh, it began on the day he met his first girlfriend in December, 2000.

Nima is a scientist, artist, author and public speaker. After spending a lot of time in art galleries, he claims to be able to remember every painting or work of art he has ever seen.

He is the author of a book called “Markets with Memory” and gave a TED talk entitled Memory and Mindfulness, where he teaches the concept of tuning in and being present in the moment even during sensory overload.

He said in a BBC interview that his memory was like “a library of VHS tapes, walk-throughs of every day of my life from waking to sleeping”. (7)

Bob Petrella

“It’s almost like having a time machine, where I can go back to a certain day or a certain period in my life and almost feel like I’m back there. It’s very visceral,” said Bob Petrella in a BBC interview. (8)

Bob Petrella, also known as “The Memory Man”, is a standup comedian who was the fourth person to be diagnosed with HSAM. He can remember what he was doing on any given day over the last 45 years. A big sports fan, he can also remember the dates, scores and details of every game played by his favorite football team, the Pittsburgh Steelers, during his lifetime.

He has appeared on TV to talk about his memory and he gives talks about how his special ability affects his life, career and relationships.

Hyperthymesia: a blessing and a curse

You might think it would be wonderful to have your entire life preserved in memory. However, some describe hyperthymesia as both a blessing and a curse.

Jill Price struggled with depression and at times felt overwhelmed by constantly reliving both good and painful memories from her past. In interview with The Guardian, she explains that she once told Dr James McGaugh: 

“It is non-stop, uncontrollable and totally exhausting … Most have called it a gift but I call it a burden. I run my entire life through my head every day and it drives me crazy!” (6)

On the other hand, most people want to improve their memory and lower their risk of developing bad memory. Here are some simple steps you can take.

How to improve your memory

5 things you can do to improve your memory

1. Take fish oil supplements

Fish oil has many health benefits, and is famously good for memory. A study found that older adults with mild cognitive impairment improved their short-term and working memory scores after taking fish oil supplements for 12 months. (9) When adults with mild symptoms of memory loss took supplements rich in DHA and EPA, like fish oil, they experienced improved episodic memory. (10) 

2. Meditate

While meditation will not get you impeccable memory like people with hyperthymesia, it has been shown to improve short-term memory in people of all ages. (11) A study demonstrated that college students who engaged in meditation practices like mindfulness had significantly better spatial working memory than students who did not practice meditation. (12) 

3. Sleep well

Sleep is crucial to maintaining brain power. Adults need 7-9 hours of sleep per night. (13) Studies show that sleep can improve results on memory tests, while lack of sleep can lead to more errors. (14)

4. Cut down alcohol

Alcohol can have neurotoxic effects on the brain. Binge drinking on a regular basis can damage the hippocampus, which plays a vital role in memory. (15) Conversely, consuming less alcohol can help you protect your memory.

5. Exercise your mind

A study on 42 adults with mild cognitive impairment found that brain-training games improved results in memory tests. (16) 

Another study of 4,715 people showed that when they did 15 minutes of an online brain-training program at least five days a week, their short-term memory, working memory, concentration and problem-solving improved significantly compared to a control group. (17)

Plus, brain-training games can help reduce the risk of dementia in older adults. (18) So, if you’re determined to improve your memory, start playing brain training games today!


(1) Elizabeth S. Parker, Larry Cahill & James L. McGaugh (2006). A Case of Unusual Autobiographical Remembering, Neurocase, 12 (1), 35-49, https://doi.org/10.1080/13554790500473680

(2) Aurora K.R. LePort, Aaron T. Mattfeld, Heather Dickinson-Anson, James H. Fallon, Craig E.L. Stark, Frithjof Kruggel, Larry Cahill, James L. McGaugh. Behavioral and neuroanatomical investigation of Highly Superior Autobiographical Memory (HSAM). Neurobiology of Learning and Memory, 98(1), 78-92, https://dx.doi.org/10.1016/j.nlm.2012.05.002

(3) Lawrence Patihis (2016) Individual differences and correlates of highly superior autobiographical memory, Memory, 24 (7), 961-978, https://doi.org/10.1080/09658211.2015.1061011

(4) LePort, A. K., Stark, S. M., McGaugh, J. L., & Stark, C. E. (2016). Highly Superior Autobiographical Memory: Quality and Quantity of Retention Over Time. Frontiers in psychology, 6, 2017, https://doi.org/10.3389/fpsyg.2015.02017

(5) Lawrence Patihis, Steven J. Frenda, Aurora K. R. LePort, Nicole Petersen, Rebecca M. Nichols, Craig E. L. Stark, James L. McGaugh, Elizabeth F. Loftus (2013). False memories in superior autobiographical memory. Proceedings of the National Academy of Sciences, 110(52), 20947-20952, https://doi.org/10.1073/pnas.1314373110

(6) Linda Rodriguez McRobbie: Total recall: the people who never forget. The Guardian International. Retrieved 1 April 2020 from https://www.theguardian.com/science/2017/feb/08/total-recall-the-people-who-never-forget

(7) David Robson: The blessing and curse of the people who never forget. BBC. Retrieved 1 April 2020 from https://www.bbc.com/future/article/20160125-the-blessing-and-curse-of-the-people-who-never-forget

(8) The man who can remember every day of his life. BBC. Retrieved 1 April 2020 from https://www.bbc.com/future/article/20190802-the-man-who-can-remember-every-day-of-his-life

(9) Lee, L.K., Shahar, S., Chin, A. et al. (2013). Docosahexaenoic acid-concentrated fish oil supplementation in subjects with mild cognitive impairment (MCI): a 12-month randomised, double-blind, placebo-controlled trial. Psychopharmacology, 225(3), 605–612, https://doi.org/10.1007/s00213-012-2848-0

(10) Yurko-Mauro, K., Alexander, D. D., & Van Elswyk, M. E. (2015). Docosahexaenoic acid and adult memory: a systematic review and meta-analysis. PloS one, 10(3), e0120391, https://doi.org/10.1371/journal.pone.0120391

(11) Gard, T., Hölzel, B.K. and Lazar, S.W. (2014), The potential effects of meditation on age‐related cognitive decline: a systematic review. Ann. N.Y. Acad. Sci., 1307(1), 89-103, https://doi.org/10.1111/nyas.12348

(12) Ching, H. H., Koo, M., Tsai, T. H., & Chen, C. Y. (2015). Effects of a Mindfulness Meditation Course on Learning and Cognitive Performance among University Students in Taiwan. Evidence-based complementary and alternative medicine: eCAM, 2015, 254358, https://doi.org/10.1155/2015/254358

(13) Watson, N. F., Badr, M. S., Belenky, G., Bliwise, D. L., Buxton, O. M., Buysse, D., Dinges, D. F., Gangwisch, J., Grandner, M. A., Kushida, C., Malhotra, R. K., Martin, J. L., Patel, S. R., Quan, S. F., & Tasali, E. (2015). Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep, 38(6), 843–844, https://doi.org/10.5665/sleep.4716

(14) Potkin, K. T., & Bunney, W. E., Jr (2012). Sleep improves memory: the effect of sleep on long term memory in early adolescence. PloS one, 7(8), e42191, https://doi.org/10.1371/journal.pone.0042191

(15) Anand, K. S., & Dhikav, V. (2012). Hippocampus in health and disease: An overview. Annals of Indian Academy of Neurology, 15(4), 239–246, https://doi.org/10.4103/0972-2327.104323

(16) Savulich, G., Piercy, T., Fox, C., Suckling, J., Rowe, J. B., O’Brien, J. T., & Sahakian, B. J. (2017). Cognitive Training Using a Novel Memory Game on an iPad in Patients with Amnestic Mild Cognitive Impairment (aMCI). The international journal of neuropsychopharmacology, 20(8), 624–633, https://doi.org/10.1093/ijnp/pyx040 

(17) Joseph L. Hardy, Rolf A. Nelson, Moriah E. Thomason, Daniel A. Sternberg , Kiefer Katovich, Faraz Farzin, Michael Scanlon (2015). Enhancing Cognitive Abilities with Comprehensive Training: A Large, Online, Randomized, Active-Controlled Trial. PLoS One. 10(9), e013446, https://doi.org/10.1371/journal.pone.0134467

(18) Rebok, G. W., Ball, K., Guey, L. T., Jones, R. N., Kim, H. Y., King, J. W., Marsiske, M., Morris, J. N., Tennstedt, S. L., Unverzagt, F. W., Willis, S. L., & ACTIVE Study Group (2014). Ten-year effects of the advanced cognitive training for independent and vital elderly cognitive training trial on cognition and everyday functioning in older adults. Journal of the American Geriatrics Society, 62(1), 16–24, https://doi.org/10.1111/jgs.12607

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