Russian psychologist Alexander Luria documented the famous case of mnemonist Solomon Shereshevsky, who was quite different from the first documented hyperthymestic known as AJ (real name Jill Price) in that Shereshevsky could memorize virtually unlimited amounts of information deliberately, while AJ could not – she could only remember autobiographical information (and events she had personally seen on the news or read about). In fact, she was not very good at memorizing anything at all, according to the study published in Neurocase. Hyperthymestic individuals appear to have poorer than average memory for arbitrary information. Another striking parallel drawn between the two cases was that Shereshevsky exemplified an interesting case of synesthesia and it has been suggested that superior autobiographical memory is intimately tied to time-space synaesthesia.
Hyperthymestic abilities can have a detrimental effect. The constant, irrepressible stream of memories has caused significant disruption to AJ's life. She described her recollection as "non-stop, uncontrollable and totally exhausting" and as "a burden". AJ is prone to getting lost in remembering. This can make it difficult to attend to the present or future, as she is permanently living in the past. Others who have hyperthymesia do not display any of these traits, however.
AJ displays considerable difficulty in memorizing allocentric information. "Her autobiographical memory, while incredible, is also selective and even ordinary in some respects," – McGaugh. This was demonstrated by AJ's poor performance on standardised memory tests. At school, AJ was an average student, unable to apply her exceptional memory to her studies.
Deficits in executive functioning and anomalous lateralisation were also identified in AJ. These cognitive deficiencies are characteristic of frontostriatal disorders.
Even those with a high level of hyperthymesia do not remember exactly everything in their lives or have "perfect memory". Studies have shown that it is a selective ability, as shown by AJ's case, and they can have comparative difficulty with rote memorization and therefore cannot apply their ability to school and work…
It has been proposed that the initial encoding of events by such people includes semantic processing, and therefore semantic cues are used in retrieval. Once cued, the memory is retrieved as episodic and follows a pattern similar to that of a spreading activation model. This is particularly evident in AJ's case. She describes how one memory triggers another, which in turn triggers another and how she is powerless to stop it: "It's like a split screen; I'll be talking to someone and seeing something else." This theory serves to explain why hyperthymestics have both a sense of 'knowing' (semantic memory) and 'remembering' (episodic memory) during recollection.
One writer claimed hyperthymesia may be a result of reviewing memories constantly to an obsessive-compulsive degree. However AJ has completely dismissed this article as "a load of crap" and others with hyperthymesia claim to never revisit uneventful memories. Other findings have shown that the tendencies to absorb new information and fantasize are personality traits that are higher in hyperthymestics than the rest of the population. These traits: absorption and fantasizing also correlated with one of the tests that measures superior autobiographical memory within the hyperthymestic sample.
An MRI study conducted on AJ provides a plausible argument as to the neurological foundation of her superior memory. Both the temporal lobe and the caudate nucleus were found to be enlarged. The hippocampus, located in the medial temporal lobe, is involved in the encoding of declarative memory (memory for facts and events), while the temporal cortex is involved in the storage of such memory. The caudate nucleus is primarily associated with procedural memory, in particular habit formation, and is, therefore, intrinsically linked to obsessive-compulsive disorder. Parker and colleagues speculated that a defective frontostriatal circuit could be responsible for the observed executive function deficits in hyperthymesia. This circuit plays a crucial role in neurodevelopmental disorders. Given the parallels in some aspects of behavior, AJ's hyperthymestic abilities possibly stem from atypical neurodevelopment. Scientists now need to ascertain if and how these brain areas are connected to establish a coherent neurological model for superior autobiographical memory.
As of April 2016, six cases of hyperthymesia have been confirmed in peer-reviewed articles, first being that of "AJ" (real name Jill Price) in 2006. More cases have been identified that are yet to be published. AJ's case was originally reported by researchers from the University of California, Irvine, Elizabeth Parker, Larry Cahill, and James McGaugh, and is credited as being the first case of hyperthymesia. AJ can apparently recall every day of her life from when she was 14 years old: "Starting on February 5th, 1980, I remember everything. That was a Tuesday."
In March 2009, AJ was interviewed for an article in Wired magazine by Gary Marcus, a cognitive psychologist at New York University. Price's brain had been subject to a brain scan and the hippocampus and prefrontal cortex had been reportedly normal. Marcus claimed, however, that her brain resembled "those of people with obsessive-compulsive disorder" and suggested that her remarkable memory might be "the byproduct of obsession", claiming also that "the memory woman clings tightly to her past". Price has since reacted angrily to such claims and McGaugh has also expressed skepticism about this explanation. Price gave her first interview in over a year for the UK's Channel 4 documentary The Boy Who Can't Forget, and provided an insight into just how difficult life can be for people who have this ability.
Parker ES, Cahill L, McGaugh JL. A case of unusual autobiographical remembering. Neurocase. 2006 Feb;12(1):35-49.
This report describes AJ, a woman whose remembering dominates her life. Her memory is "nonstop, uncontrollable, and automatic." AJ spends an excessive amount of time recalling her personal past with considerable accuracy and reliability. If given a date, she can tell you what she was doing and what day of the week it fell on. She differs from other cases of superior memory who use practiced mnemonics to remember vast amounts of personally irrelevant information. We propose the name hyperthymestic syndrome, from the Greek word thymesis meaning remembering, and that AJ is the first reported case.