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What is Hyperthymesia?

William Ralph is a mental health and wellness expert with several years of experience in mental health research and awareness programs.


Hyperthymesia is an ability that allows people to remember nearly every event of their life with great precision.

According to the Merriam-Webster dictionary, Hyperthymesia is ‘’the uncommon ability that allows a person to spontaneously recall with great accuracy and detail a vast number of personal events or experiences and their associated dates: highly superior autobiographical memory.’’

Also known as highly superior autobiographical memory (HSAM), only a small number of persons have been identified with this rare ability. Very few theories have been presented as to the likely causes of the ability; research and studies are currently ongoing as scientists continue to try and understand the million several ways that the brain works and processes memories.

Hyperthymesia was first discovered in 2006 when neurobiologists Elizabeth Parker, James McGaugh, and Larry Cahill of the University of California researched a woman, AJ (real name Jill Prince) who could ‘’recall every day of her life from when she was 14 years old.’’ Jill was assessed to possess the ability to remember autobiographical experiences and events in great detail.

According to a 2017 study, people with hyperthymesia can accurately remember exact details about past personal experiences and events. These details can be inclusive of intricate information and exact dates about previous experiences. However, research has suggested that the ability might be limited to autobiographical experiences and memory. This means that people with hypothermia can only recall their own past personal experiences and information about themselves.


As human beings, we retain information in long and short-term formats or memories. However, the studies on hyperthermia have suggested that people with HSAM likely process short-term memories the same way as most people but have better long-term memory. This means that they can remember and recall details of past experiences with extreme and surprising accuracy.

According to some researchers, although there is no definitive link between having HSAM and OCD, people with Hyperthermia may demonstrate obsessive tendencies because they share some characteristics with people who have obsessive-compulsive disorder (OCD). They arrived at this after noting that people with both conditions tend to have certain structural differences in particular regions of the brain.

It was also noted that People with HSAM are unable to forget their life experiences and further research would be required to establish the long-term effects of this characteristic.



As the discovery of this ability is still relatively new, and there are also very few people that have been discovered to have hyperthymesia, this has caused a lack of enough cases to enable the proper examination of what could be the likely causes of the ability. A few theories have been presented that it might be genetic, biological, or psychological. Still, the exact cause is not known for sure and studies are necessary to gain a better insight and understanding.

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1. Biological causes

According to research that suggests a biological cause researchers have suggested that people with HSAM may have increased activity within different regions of the brain, such as the amygdala, and superior and inferior parietal lobe.

2. Genetic Causes

Another theory is that hyperthymesia may be genetic. Although there has been no evidence to establish this theory as fact, research is currently ongoing as to whether the ability has a genetic basis.

3. Psychological Causes

This theory implies that people with HSAM think obsessively about their previous experiences and that regularly thinking about past experiences and events might have contributed to strengthening the recollection of the memory thereby enabling them to preserve and recall in great detail.


As hyperthymesia is a rare and relatively newly discovered ability, there is currently no formal way of diagnosing it as research continues to understand it more. However, since research has found a correlation between hyperactivity in certain parts of the brain with people that have HSAM, Doctors could potentially assess if a person has HSAM through an MRI scan and memory tests.

Complex memory tests consisting of autobiographical memory assessment can be used to assess or confirm if a person has hyperthymesia. These tests would usually include the person’s ability to recall specific facts and details about their past life, experiences, and events.

Hyperthymesia vs. eidetic memory

I know you have been wondering since the beginning of this post about the difference between a person with hyperthymesia and a person with an eidetic memory. The difference has been clearly noted several times; a person with HSAN can remember events of their own life in detail while a person with eidetic memory has the ability to accurately recall an image after only seeing it once for a short period.

Persons with superior eidetic memory have the ability to accurately visualize things they have seen recently with great precision and hold the visualization intact for up to several minutes. However, according to research, after a few minutes, eidetic memories tend to fade and may change or visualizations become stored as long-term memory.

One thing is certain, more research is necessary into both hyperthymesia and eidetic memory to help understand their similarities and differences and several other factors about each ability.

In Conclusion

Here are the summarized takeaways so far;

  • Hyperthymesia is the rare ability to recall autobiographical experiences and events in great detail.
  • Although the causes of Hyperthymesia are not currently known, some theories from researchers and studies have suggested that it may have genetic, biological, or psychological origins.
  • There is currently no way to formally diagnose hyperthymesia. Possible methods to assess and/or confirm the ability may involve MRI scans and complex memory tests.
  • Hyperthymesia differs from eidetic memory in that it focuses on a person’s ability to recall their autobiographical experiences rather than to hold visualizations in their mind.
  • Further research is necessary and ongoing to determine the similarities and differences between hyperthymesia and eidetic memory.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2022 William Ralph

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