She Has the Most Astounding Memory Skills But a Smaller-Than-Average Hippocampus

The explanations of neuroscientists lack very many things. For example, they lack:

• Any coherent or credible theory of how a brain could convert experience into brain states or synapse states when a memory is created;
• any coherent or credible theory of how a brain could convert brain states or synapse states into thoughts or recollections when a memory is recalled;
• any coherent or credible theory of how a brain could instantly create new memories, something that humans routinely do; 
• any coherent or credible theory of how a brain could instantly retrieve a memory, such as instantly getting just the right answer when someone is asked to identify some person or object or technical term or historical event;
• any coherent or credible theory of how a brain could create an abstract idea such as the idea of a child or the idea of a dog or the idea of a nation;  
• any coherent or credible theory of how a brain could imagine something such as some invention no one ever built yet. 

A standard approach of the writers about the brain is to use the trick that can be described as: when you don't have a how, try using a where. For the typical writer about brains, this involves making claims of localization of brain activity.  For example:

• When they don't have a "how" in regard to the brain and abstract thought, they try using a "where" by claiming that abstract thought comes from the frontal cortex. This claim is very dubious because of evidence I discuss in my post "Reasons for Doubting Thought Comes from the Frontal Lobes or Prefrontal Cortex" you can read here.
• When they don't have a "how" in regard to the brain and memory, they try using a "where" by claiming that the hippocampus drives the wonders of memory. This claim is very dubious because of evidence I discuss in my post here. A key element of false claims about the hippocampus and memory is the claim that patient HM could not form new memories after his hippocampus was surgically ravaged. The claim that this patient could not form new memories after  such damage is untrue, as I show in my post here. 

People have been so conditioned to think that the hippocampus is crucial for memory that you can predict exactly what a typical reader of brain-related articles might say after reading this quote from a paper on the astonishing case of subject RS: "RS’s recall of past events appears profoundly rich in episodic detail, including associated tastes, smells, emotions, interactions with others, as well as more trivial details that others would likely forget (e.g., weather conditions). As mentioned above RS... apparently remembers the entire text from all seven Harry Potter novels." Hearing of  such amazing memory abilities far beyond the memory performance of almost everyone, a typical person might say something like: "Wow, she must have a really big hippocampus!"

But the astonishing subject RS actually has a hippocampus well-below average in size. 

The case of subject RS is described in the paper "Enhanced semantic memory in a case of highly superior autobiographical memory" which you can read here. The title refers to Highly Superior Autobiographical Memory or HSAM, a very rare ability in some people to recall  very well with extraordinary accuracy events and detail events in their lives. Such subjects are discussed in my posts here:

HSAM Memory Whiz Subjects Scored 25 Times Higher on a Random Dates Test

HSAM Wonder Daniel McCartney Was a Math and Memory Marvel

The Rare "Total Recall" Effect That Conflicts with Brain Dogmas

The paper describes the young subject RS in this way: 

"RS has vivid autobiographical memories that apparently arise automatically. At the same time, she describes her memories as being organised sequentially, so that to retrieve an event she mentally 'scans'  an ordered structure starting from the earliest memory and continuing to more recent memories until the correct entry is found, akin to scanning a mental timeline (Price & Mattingley, 2013)."

This is a striking description that seems to describe memory working different from the way memory works with the average person.  The paper says this about subject RS:

"The first source of her superior memory involved being able to name days of the week for any given calendar date since the year 2000 (e.g., 'What day was it on 2 March 2002?' Answer: Saturday). The second involved her seeming ability to remember the entire text, practically word for word, of the seven books of the Harry Potter series by J.K. Rowling."

Those who have studied the most impressive examples of human memory performance will recognize the calendar ability described, which is typically called "calendar calculating" (although it can occur so quickly that it seems beyond any explanation of calculation, as confessed in the scientific article here).  It has long been known that some humans have an extraordinary ability to accurately name the day of the week given a very old random date from years ago. Such people may be called "human calendars" or "calendar calculators."  One of the most famous examples is Kim Peek, the autistic savant who inspired the Tom Cruise movie Rain Man. At the 2:31 mark of the extremely interesting video here, we see an example of Kim Peek's calendar ability. At that part he is asked by the adult Daniel Tammet what day of the week was Daniel's birthday of January 31, 1979. Within five seconds Kim correctly answers that the date was a Wednesday.  The same ability was proven to exist as early as the 19th century. My post here on the case of Daniel McCartney quotes an interview in which a reporter repeatedly asked Daniel what day of the week corresponded to some random date the reporter selected, with the dates spanning many decades.  Daniel would give the correct date of the week very quickly when asked such questions, just as if no calculation was involved. 

To test the calendar calculation abilities of subject RS, the paper authors devised a test in which a computer screen would ask 60 times a question like this (with the dates varying in each of the 60 trials): "Which date is earlier in the week:  25 September 2005 or 2 March 2005?"  Answering a question like this at levels above chance requires two different successes in the mysterious "calendar calculating" ability, one that might yield the day of the week for the first date, and another that might yield the day of the week for the first date. The performance of subject RS on this task was compared to that of 10 controls, ordinary people with no special memory ability. 

This was the result of the experiment, verifying that subject RS did really have the ability of being able able to tell the day of the week corresponding to randomly selected dates:

"Overall mean accuracy for determining the earlier date within a week was 90% for RS (SD = 0.30) and 50% for controls (ranging from 43% to 55%; SD = 0.50). Overall median reaction time was 17.12 s for RS (SD = 7.01) and 1.24 s for controls (ranging from 0.51 to 18.85 s; SD = 10.64). Controls responded quickly because they were only able to guess on this task, unlike RS who deliberated carefully and was correct on 9 out of 10 trials."

So in 62 trials subject RS answered 90% correctly when asked questions such as "Which date is earlier in the week:  25 September 2005 or 2 March 2005?" -- a type of question that requires "day of the week" remembering or "day of the week" calculation for two random dates. The control subjects scored only at the chance level of 50%.

To test how well subject RS could recall text from the Harry Potter series of books, scientists had RS and some control subjects attempt to answer 30 questions such as the one shown below, which has quotes from a particular book in the Harry Potter series of books. 

The control subjects presumably all had knowledge of the Harry Potter series of books much better than the average person, because they are described in the paper as "aficionados of the Harry Potter series." The results were that subject RS got 97% of the 30 questions correct (29 out of 30), while the control subjects got 71% correct (better than the by-chance expected value of 50%, because the control subjects were aficionados of the Harry Potter series). The almost-perfect result of patient RS in this experiment tends to back up the author's claim that she had a "seeming ability to remember the entire text, practically word for word, of the seven books of the Harry Potter series by J.K. Rowling."

So we have in this subject RS several types of astounding memory ability, with RS having memory abilities of breathtaking power.  The same subject had an MRI scan of her brain. Did it reveal some anatomical anomaly that can explain the supernormal memory ability? Not at all.

Referring to regions of interest (ROIs0), which in this case means parts of the brain, the paper says, "High-resolution structural MRI scans revealed no volumetric or cortical thickness differences between RS and controls within any of the expected ROIs (i.e., hippocampus, amygdala, insula, temporal gyri and pole, subiculum, putamen)." In other words, she did not have some unusual brain anatomy that can explain her memory skills. 

In fact, the measured volume of the hippocampus of subject RS was below-average. The scientific paper tells us the total volume of her hippocampus (the sum of the volume on her hippocampus on the left side of her brain and the  hippocampus on the right side of her brain) was 4.731 cubic centimeters.  The scientific paper "HIPPOCAMPAL VOLUME AND SHAPE ANALYSIS IN AN OLDER ADULT POPULATION" attempted to judge the size of the hippocampus in 40 elderly adults.  Using "cc" to mean "cubic centimeters," the paper tells us this:  "Total ICV-adjusted volumes were 3.48 cc [cubic centimeters]  (±0.43) for the left hippocampus and 3.68 (±0.42) for the right hippocampus." That gives an average total hippocampus volume of 7.16 cubic centimeters for these 40 people.  According to Table 1 of the paper about her, subject RS had a "whole hippocampus" volume of 4.731 cubic centimeters; so her hippocampus was quite smaller than average. The same scientific paper on the 40 people tells us this: "There were no significant correlations between ICV-adjusted hippocampal volumes and age or memory performance (p>.05)."

So it seems we should not be surprised at all that this woman with the miracle memory had a hippocampus of below-average size, simply because there is no basis for any claim that hippocampus size has any major relation to memory performance, contrary to the misleading insinuations of people writing about the hippocampus.  

The term "hyperthymesia" is another term used for HSAM or Highly Superior Autobiographical Memory. A recent paper is entitled "Autobiographical hypermnesia as a particular form of mental time travel." In the abstract we read this:

"Here, we describe a case of hyperthymesia with an objective as well as a subjective assessment of mental time travel abilities in different temporal distances. This is the first observation of hyperthymesia with a full evaluation of mental time travel capacities in different temporal distances, encompassing the individual capacity to retrieve personal events from the personal past as well as to foresee personal events in the future."

Unfortunately the paper is behind a paywall. But an article on the story summarizes some of its details:

"The study focused on a 17-year-old girl, referred to as TL, who organizes her memories with unusual precision. She separates her memories into two types: ‘black memory,’ which is factual information learned in school without emotional significance, and her autobiographical memories, which she stores in a detailed mental framework.

TL describes her autobiographical memories as being stored in a ‘white room,’ where binders are organized by theme and date. In this mental space, she can review episodes from family life, vacations, friendships, or childhood experiences. Some memories are recalled as images or text messages."

Newspaper Accounts of Memory Marvels (Part 2)

 The credibility of claims that memory recollections come from brains is inversely proportional to the speed and capacity and reliability at which things can be memorized and things can be recalled. There are numerous signal slowing factors in the brain, such as the relatively slow speed of dendrites, and the cumulative effect of synaptic delays in which signals have to travel over relatively slow chemical synapses (by far the most common type of synapse in the brain). As explained in my post here, such physical factors should cause brain signals to move at a typical speed very many times slower than the often cited figure of 100 meters per second: a sluggish "snail's pace" speed of only about a centimeter per second (about half an inch per second).  Ordinary everyday evidence of very fast thinking and instant recall is therefore evidence against claims that memory recall occurs because of brain activity, particularly because the brain is totally lacking in the things humans add to constructed objects to allow fast recall (things such as sorting and addressing and indexes). Chemical synapses in the brain do not even reliably transmit signals. Scientific papers say that each time a signal is transmitted across a chemical synapse, it is transmitted with a reliability of 50% or less.  (A paper states, "Several recent studies have documented the unreliability of central nervous system synapses: typically, a postsynaptic response is produced less than half of the time when a presynaptic nerve impulse arrives at a synapse." Another scientific paper says, "In the cortex, individual synapses seem to be extremely unreliable: the probability of transmitter release in response to a single action potential can be as low as 0.1 or lower.")  The more evidence we have of very fast and very accurate and very capacious recall (what a computer expert might call high-speed high-throughput retrieval), the stronger is the evidence against the claim that memory recall occurs from brain activity. 

It is therefore very important to collect and study all cases of exceptional human memory performance. The more such cases we find, and the more dramatic such cases are, the stronger is the case against the claim that memory is a neural phenomenon. Or to put it another way, the credibility of claims that memory is a brain phenomenon is inversely proportional to the speed and reliability and capacity of the best cases of human mental performance.  The more cases that can be found of humans that seem to recall too quickly for a noisy address-free brain to ever do, or humans that seem to recall too well for a noisy, index-free, signal-mangling brain to ever do,  the stronger is the case that memory is not a neural phenomenon but instead a spiritual or psychic or metaphysical phenomenon.  In part 1 of this post, I gave many newspaper clips giving examples of such exceptional human memory performance. Let us now look at some more of such newspaper clips. 

Below is part of an 1886 newspaper that describes what seems like what is now called Highly Superior Autobiographical Memory (HSAM), also called hyperthymesia. 

The account can be read below:

https://chroniclingamerica.loc.gov/lccn/sn85032490/1886-09-02/ed-1/seq-7/

The source of the account below is the W. D. Henkle January, 1871 article here, "Remarkable Cases of Memory," which documents the abilities of Daniel McCartney in very great detail, giving transcripts of interviews with him. I will have a post on this case in the next few months. 

On the same 1886 page shown above we can read the account below, which tells of a man with an extraordinary ability to remember architectural details. The case reminds you of the modern case of Stephen Wiltshire:

Later on the same page, we read of these memory marvels. The reference to "almost the whole of Horace, Virgil, Homer, Cicero and Livy" refers to a set of books with a totality of many thousands of pages. The Aeneid referred to is a book of 9883 lines. 

 

The reference to Porson is a reference to Richard Porson (1759 -1808). A web page says this about him:

"Their author [Porson] gives the impression of knowing every page of the Christian fathers [e.g. Augustine, Aquinas] as if they were indexed and capable of flashing up before him on a computer screen whenever needed. And in a manner of speaking they were. Anecdotes from several different sources attest to what we should nowadays call his photographic memory, and to that memory was committed not only classical and post-classical Greek and Latin literature but a wealth of English and some French literature as well, to which his own writings contain a host of often fleeting allusions."

Another web page says this about Richard Porson:

"It was here that his uncanny powers of memory came into full voice: one person heard him declaim an ode of Pindar in Greek, and then a whole act of Samuel Foote’s farce The Mayor of Garratt (1763), each without error. ...Porson could be presented briefly with a book, read a couple of pages from memory, and then do so backwards – almost without error."

We read in one of the pages cited above a reference to Giuseppe Gasparo Mezzofanti (17 September 1774 – 15 March 1849), who was famed for his ability to speak more than 30 different languages.  Of course, any such ability would require the most prodigious memory very far beyond that of the average person. 

A 1905 news article tells of a man who only developed amazing powers of memory after a severe brain injury (the man was named J. A. Bottle, or W. J. M. Bottle, but used a stage name of Datas):

You can read the full story here:

https://chroniclingamerica.loc.gov/lccn/sn85058130/1905-11-27/ed-1/seq-1/

The newspaper account here describes the same person. We read that this man widely called a "human encyclopedia" actually suffered a head injury before his stage career began:

This type of acquisition of previously absent mental powers after a traumatic injury (inexplicable under the idea that brains make minds) is sometimes called acquired savant syndrome. At the link here is an article giving another example: " At age ten, Orlando Serrell was struck on the left side of his head with a baseball; he is able to clearly remember the weather and details about his personal activities for every day since that accident (Hughes 2010, 149)." 

A 1913 newspaper article tells us of a case of a man with photographic memory:

You can read the account here:

https://chroniclingamerica.loc.gov/lccn/sn87078082/1913-08-19/ed-1/seq-3/

The same article makes the statements below. We have a reference to "the whole of Tacitus," which means The Annals consisting of more than 500 pages each having about 400 words each, and also additional works consisting of hundreds of other pages. The reference to the Metaphysics of Aristotle refers to a book of more than 300 pages, each with about 400 words.  The Aeneid referred to has 9883 lines. The Iliad referred to has 15,693 lines. 

The account below appeared in 1905:

You can read the account here:

https://chroniclingamerica.loc.gov/lccn/sn94056446/1905-06-02/ed-1/seq-4/

Below is an obituary of the prodigy called Blind Tom. The reported ability to replay any composition after having heard it only once is an ability known to exist in today's world, having been demonstrated repeatedly by Derek Paravicini. 

You can read the full account below:

https://chroniclingamerica.loc.gov/lccn/sn86090233/1908-07-09/ed-1/seq-8/

HSAM Memory Whiz Subjects Scored 25 Times Higher on a Random Dates Test

 In my previous post on this blog "The Rare 'Total Recall' Effect That Conflicts With Brain Dogmas," I discussed some fascinating cases of what is called hyperthymesia or Highly Superior Autobiographical Memory (HSAM). People with this rare ability have an extraordinary ability to recall things that happened in their lives -- an ability seemingly many times greater than that of the average person.  Some have suggested that HSAM cases can be explained as being merely the result of superior mnemonic techniques. Others have suggested that press reports about this topic are just exaggeration or sensationalism. But a scientific paper documents the dramatic reality of  Highly Superior Autobiographical Memory (HSAM). The paper documents that certain people have memory about past events that is literally dozens of times better than the average person has. 

The paper (which can be read here) is a 2022 paper entitled "Individuals with highly superior autobiographical memory do not show enhanced creative thinking." The paper gives us this description of the memory tests given to 14 subjects with  Highly Superior Autobiographical Memory (HSAM), and also twenty-eight normal control subjects:

"We assessed participants’ ability to recollect public and personal past events using the Public Event Quiz and the Random Dates Quiz (LePort et al., 2012). The Public Events Quiz consisted of thirty questions, based on public events selected from five categories: sporting events, political events, notable negative events, events concerning famous people and holidays. For fifteen of these questions, participants were asked to retrieve the date of a given significant public (national or international) event (e.g., 'Please give the day of the week and precise date with day, month and year of when Federica Pellegrini, the famous Italian swimmer, won the gold medal at the Olympic game in Beijing'); the remaining fifteen questions requested participants to associate a given date with a highly significant public event (e.g., 'What happened on the 25th of June 2009?'). All questions concerned events that took place when the participants were at least 8 years old. For each question, individuals were asked to name the day of the week on which the date fell. One point was awarded for each correct response (i.e., the event, the day of the week, the month, the date and the year); the maximum total score was 88 points. The Random Dates Quiz consisted of ten computer-generated random dates, ranging from the individuals’ age of fifteen to five years before the testing. Individuals were asked to provide three details for each date: (1) the day of the week; (2) a description of a verifiable event (i.e., any event that could be confirmed via a search engine) that occurred within a few days before and after the generated date; (3) a description of a personal autobiographical event. One point each was awarded for the correct day of the week, a correct public event, and unverified personal autobiographical memory. A maximum of three points per date could be achieved (30 points total)." 

The results were spectacular.  The 14 subjects with Highly Superior Autobiographical Memory (HSAM) scored more than 25 times higher on the Random Dates test, scoring an average of 68.57% of the maximum possible.  The control subjects scored an average of merely 2.62% of the maximum possible on the Random Dates test. On the Public Events test, the 14 subjects with Highly Superior Autobiographical Memory (HSAM) scored more than 5 times higher, scoring an average of 58.20% of the maximum possible. The control subjects scored an average of merely 10.39% of the maximum possible on the Public Events test. The best-performing of the 14 subjects with Highly Superior Autobiographical Memory (HSAM) scored 96.67% of the maximum possible, an almost perfect score. 

The diagram below (from the paper) shows the differences, with the HSAM subjects being the two tall bars, and the control subjects being the two short bars. The squares are the results for individual subjects. 

Conversely, tests on other abilities not related to memory (such as creativity) showed no big differences in performance between the two groups. 

We have in this paper proof of the claim that certain rare individuals have a dramatically superior ability to recall the past, an ability vastly better than the average person has.  Cases such as these are evidence against claims that memory is mostly a neural phenomenon.  If memory was mostly a neural phenomenon, we would expect that only vast differences in brains could produce vast differences in memory performance. But those with Highly Superior Autobiographical Memory have brains that do not substantially differ from those with ordinary memories.  Read my post here for a discussion of two studies that attempted to show differences in the brains of those with Highly Superior Autobiographical Memory, but actually failed to show any major differences. The same post has a very interesting discussion of numerous memory marvels with recollection abilities as impressive as those with Highly Superior Autobiographical Memory. 

The normal facts of human memory performance are sufficient to discredit claims that memory formation and memory recall are brain activities. There is not a neuroscientist who can credibly explain how a brain can store a detailed memory.  Nothing known to neuroscientists can explain how learned information or experiences could be translated into brain states or synapse states. Neuroscientists claim that memories are stored in synapses, but we know that the proteins in synapses have average lifetimes of only a few weeks, 1000 times shorter than the maximum length of time that humans can remember things (more than 50 years).  We know the kind of things  (in products that humans manufacture) that make possible an instant retrieval of stored information: things such as sorting, addressing, indexing, and read/write heads.  The human brain has no such things.  Humans such as actors playing the role of Hamlet can recall large bodies of text with 100% accuracy, but such recall should be impossible using a brain in which each chemical synapse can only transmit a signal with 50% accuracy or less.  Brains are too slow, too noisy and too unstable to be the source of human memory recall which can occur at blazing fast speeds with 100% accuracy. 

Here are some relevant quotes:

• "Direct evidence that synaptic plasticity is the actual cellular mechanism for human learning and memory is lacking." -- 3 scientists, "Synaptic plasticity in human cortical circuits: cellular mechanisms of learning and memory in the human brain?" 
• "The fundamental problem is that we don't really know where or how thoughts are stored in the brain. We can't read thoughts if we don't understand the neuroscience behind them." -- Juan Alvaro Gallego, neuroscientist. 
• "The search for the neuroanatomical locus of semantic memory has simultaneously led us nowhere and everywhere. There is no compelling evidence that any one brain region plays a dedicated and privileged role in the representation or retrieval of all sorts of semantic knowledge."  Psychologist Sharon L. Thompson-Schill, "Neuroimaging studies of semantic memory: inferring 'how' from 'where' ".
• "How the brain stores and retrieves memories is an important unsolved problem in neuroscience." --Achint Kumar, "A Model For Hierarchical Memory Storage in Piriform Cortex." 
• "We are still far from identifying the 'double helix' of memory—if one even exists. We do not have a clear idea of how long-term, specific information may be stored in the brain, into separate engrams that can be reactivated when relevant."  -- Two scientists, "Understanding the physical basis of memory: Molecular mechanisms of the engram."
• "There is no chain of reasonable inferences by means of which our present, albeit highly imperfect, view of the functional organization of the brain can be reconciled with the possibility of its acquiring, storing and retrieving nervous information by encoding such information in molecules of nucleic acid or protein." -- Molecular geneticist G. S. Stent, quoted in the paper here. 
• "Up to this point, we still don’t understand how we maintain memories in our brains for up to our entire lifetimes.”  --neuroscientist Sakina Palida.
• "The available evidence makes it extremely unlikely that synapses are the site of long-term memory storage for representational content (i.e., memory for 'facts'’ about quantities like space, time, and number)." --Samuel J. Gershman,  "The molecular memory code and synaptic plasticity: A synthesis."
• "Synapses are signal conductors, not symbols. They do not stand for anything. They convey information bearing signals between neurons, but they do not themselves convey information forward in time, as does, for example, a gene or a register in computer memory. No specifiable fact about the animal’s experience can be read off from the synapses that have been altered by that experience.” -- Two scientists, "Locating the engram: Should we look for plastic synapses or information- storing molecules?
• " If I wanted to transfer my memories into a machine, I would need to know what my memories are made of. But nobody knows." -- neuroscientist Guillaume Thierry (link). 
• "Memory retrieval is even more mysterious than storage. When I ask if you know Alex Ritchie, the answer is immediately obvious to you, and there is no good theory to explain how memory retrieval can happen so quickly." -- Neuroscientist David Eagleman.
• "How could that encoded information be retrieved and transcribed from the enduring structure into the transient signals that carry that same information to the computational machinery that acts on the information?....In the voluminous contemporary literature on the neurobiology of memory, there is no discussion of these questions."  ---  Neuroscientists C. R. Gallistel and Adam Philip King, "Memory and the Computational Brain: Why Cognitive Science Will Transform Neuroscience,"  preface. 
• "The very first thing that any computer scientist would want to know about a computer is how it writes to memory and reads from memory....Yet we do not really know how this most foundational element of computation is implemented in the brain."  -- Noam Chomsky and Robert C. Berwick, "Why Only Us? Language and Evolution," page 50. 
• "When we are looking for a mechanism that implements a read/write memory in the nervous system, looking at synaptic strength and connectivity patterns might be misleading for many reasons...Tentative evidence for the (classical) cognitive scientists' reservations toward the synapse as the locus of memory in the brain has accumulated....Changes in synaptic strength are not directly related to storage of new information in memory....The rate of synaptic turnover in absence of learning is actually so high that the newly formed connections (which supposedly encode the new memory) will have vanished in due time. It is worth noticing that these findings actually are to be expected when considering that synapses are made of proteins which are generally known to have a short lifetime...Synapses have been found to be constantly turning over in all parts of cortex that have been examined using two-photon microscopy so far...The synapse is probably an ill fit when looking for a basic memory mechanism in the nervous system." -- Scientist Patrick C. Trettenbrein, "The Demise of the Synapse As the Locus of Memory: A Looming Paradigm Shift? (link).
• "Most neuroscientists believe that memories are encoded by changing the strength of synaptic connections between neurons....Nevertheless, the question of whether memories are stored locally at synapses remains a point of contention. Some cognitive neuroscientists have argued that for the brain to work as a computational device, it must have the equivalent of a read/write memory and the synapse is far too complex to serve this purpose (Gaallistel and King, 2009; Trettenbrein, 2016). While it is conceptually simple for computers to store synaptic weights digitally using their read/write capabilities during deep learning, for biological systems no realistic biological mechanism has yet been proposed, or in my opinion could be envisioned, that would decode symbolic information in a series of molecular switches (Gaallistel and King, 2009) and then transform this information into specific synaptic weights." -- Neuroscientist Wayne S. Sossin (link).
• "We take up the question that will have been pressing on the minds of many readers ever since it became clear that we are profoundly skeptical about the hypothesis that the physical basis of memory is some form of synaptic plasticity, the only hypothesis that has ever been seriously considered by the neuroscience community. The obvious question is: Well, if it’s not synaptic plasticity, what is it? Here, we refuse to be drawn. We do not think we know what the mechanism of an addressable read/write memory is, and we have no faith in our ability to conjecture a correct answer."  -- Neuroscientists C. R. Gallistel and Adam Philip King, "Memory and the Computational Brain Why Cognitive Science Will Transform Neuroscience."  page Xvi (preface). 
• "Current theories of synaptic plasticity and network activity cannot explain learning, memory, and cognition."  -- Neuroscientist Hessameddin Akhlaghpourƚ (link). 
• "We don’t know how the brain stores anything, let alone words." -- Scientists David Poeppel and, William Idsardi, 2022 (link).
• "If we believe that memories are made of patterns of synaptic connections sculpted by experience, and if we know, behaviorally, that motor memories last a lifetime, then how can we explain the fact that individual synaptic spines are constantly turning over and that aggregate synaptic strengths are constantly fluctuating? How can the memories outlast their putative constitutive components?" --Neuroscientists Emilio Bizzi and Robert Ajemian (link).
• "After more than 70 years of research efforts by cognitive psychologists and neuroscientists, the question of where memory information is stored in the brain remains unresolved." -- Psychologist James Tee and engineering expert Desmond P. Taylor, "Where Is Memory Information Stored in the Brain?"
• "There is no such thing as encoding a perception...There is no such thing as a neural code...Nothing that one might find in the brain could possibly be a representation of the fact that one was told that Hastings was fought in 1066." -- M. R.  Bennett, Professor of Physiology at the University of Sydney (link).
• "No sense has been given to the idea of encoding or representing factual information in the neurons and synapses of the brain." -- M. R. Bennett, Professor of Physiology at the University of Sydney (link).
• "We have still not discovered the physical basis of memory, despite more than a century of efforts by many leading figures. Researchers searching for the physical basis of memory are looking for the wrong thing (the associative bond) in the wrong place (the synaptic junction), guided by an erroneous conception of what memory is and the role it plays in computation." --Neuroscientist C.R. Gallistel, "The Physical Basis of Memory," 2021.
• "To name but a few examples, the formation of memories and the basis of conscious  perception, crossing  the threshold  of  awareness, the  interplay  of  electrical  and  molecular-biochemical mechanisms of signal transduction at synapses, the role of glial cells in signal transduction and metabolism, the role of different brain states in the life-long reorganization of the synaptic structure or  the mechanism of how  cell  assemblies  generate a  concrete  cognitive  function are  all important processes that remain to be characterized." -- "The coming decade of digital brain research, a 2023 paper co-authored by more than 100 neuroscientists, one confessing scientists don't understand how a brain could store memories. 
• "The human brain isn’t really empty, of course. But it does not contain most of the things people think it does – not even simple things such as ‘memories’....We don’t create representations of visual stimuli, store them in a short-term memory buffer, and then transfer the representation into a long-term memory device. We don’t retrieve information or images or words from memory registers. Computers do all of these things, but organisms do not." -- Robert Epstein,  senior research psychologist, "The Empty Brain." 

Every additional piece of evidence establishing extraordinary human memory abilities is an additional nail in the coffin of the doctrine that brains store memories. Given a brain lacking any of the characteristics that would be required to allow the best examples of human memory performance, the credibility of the claim that brains store memories is inversely proportional to the highest observed speed, accuracy, duration and depth of human memory performance.  The longer humans can remember things and the more they can remember and the more quickly they can remember and the more quickly they can form new memories, the less credible are claims of brain memory creation and storage. 

Below is an account of the memory of Antonio Magliabechi, from page 8 of the periodical here:

 "Magliabechi was born at Florence in 1633. His parents were of mean rank and estate. Being taken into the service of a bookseller, a passion for reading took possession of him, and a prodigious memory ensued. He read every book that came into his hands with surprising quickness, and yet retained not only the sense, but often all the words. His extraordinary talent soon obtained for him an appointment under the great Duke’s librarian. A trial of his surprising powers was once made. A gentleman in Florence had written a piece which was to be played. He lent it to Magliabechi, and some time after it had been returned he came with a long face to Magliabechi, and, seeming almost inconsolable, asked if he would try to recollect as much as he could, and write it down. Magliabechi assured him he would, and on setting about it wrote out the entire play without missing a word. By treasuring up everything he read, his head at last became an universal index both of titles and matter. When a priest was going to compose anything about a favourite saint, Magliabechi could at once tell him what everybody had written about that saint, and refer to the authors. The Grand Duke Cosmo III made him his librarian. Here he had immense facilities for reading, but ultimately he was dissatisfied, for he had read almost everything ever written or printed, it being a custom for most authors to send him a copy. He not only knew the contents of books, but the very place on the very shelf where they stood in the great libraries of Europe. The grand duke asked if he could get a certain book that was particularly scarce : ' No, sir,'  answered Magliabechi, ' it is impossible, for there is but one in the world, and that is in the Grand Signor’s library at Constantinople, and is the seventh book on the second shelf, on the right hand as you go in.' " 

Another source says this of Magliabechi: "He not only knew all the volumes in the library, as well as every other possible work, but could also tell the page and paragraph in which any passage occurred."

According to a book, "The great thinker, Pascal, is said never to have forgotten anything he had ever known or read, and the same is told of Hugo, Grotius, Liebnitz, and Euler. All knew the whole of Virgil's 'Aeneid' by heart." The famous conductor Toscanini was able to keep conducting despite bad eyesight, because he had memorized the musical scores of a very large number of symphonies and operas. 

A book tells us this: 

"The geographer Maretus, narrates an instance of memory probably  unequalled. He actually witnessed the feat, and had it attested by four Venetian nobles. He met in Padua, a young Corsican who had so powerful a memory that he could repeat as many as 36,000 words read over to him only once. Maretus, desiring to test this extraordinary youth, in the presence of his friends, read over to him an almost interminable list of words strung together anyhow in every language, and some mere gibberish. The audience was exhausted before the list, which had been written down for the sake of accuracy, and at the end of it the young Corsican smilingly began and repeated the entire list without a break and without a mistake. Then to show his remarkable power, he went over it backward, then every alternate word, first and fifth, and so on until his hearers were thoroughly exhausted, and had no hesitation in certifying that the memory of this individual was without a rival in the world, ancient or modern." 

The scientific paper "Extremely long-term memory and familiarity after 12 years" documents an ability of some people to remember trivial sensory experiences after many years, experiences they should have forgotten under common ideas of human memory. In 2016 the study authors rounded up 25 subjects who had been briefly exposed to some very forgettable images in a scientific experiment done between eight and fourteen years earlier: thumbnail-sized images such as a little drawing of a coffee cup and a little drawing of a hen.  The subjects were tested with a set of images, half of which were the original images, and half of which were decoy images designed to be similar to the original images. The subjects were asked to guess whether or not they had seen the images before, when they were tested many years earlier. The authors expected the subjects to make guesses no more accurate than chance. But they found that the subjects were able to guess with about 55% accuracy.  We read this:

"In this study we found that our group of test participants was able to recognize simple colored pictures seen for a few seconds between eight and 14 years earlier. Our best performer, who had been exposed to the pictures at most three times, was able to identify 15 pictures more than the 84 pictures expected by chance. Note that no instruction to learn the stimuli was ever given to the subjects, even at initial encoding, which makes this performance even more remarkable." 

Exceptional Memories Strengthen the Case Against Neural Memory Storage

Materialist thinkers often act as if their motto was "make humans seem like something much less than humans."  There are various different ways in which they do this:

• They sometimes make the utterly preposterous claim made by Darwin that there is no fundamental difference between the mental abilities of humans and the mental abilities of higher mammals, a claim contrary to all human experience.
• They senselessly classify humans as animals, and arbitrarily put the human species in an animal kingdom (given the abundant mental and behavioral differences between humans and animals, a sensible classification of organisms would be to have four kingdoms: a microbe kingdom, a plant kingdom, an animal kingdom and a human kingdom).
• They refuse to acknowledge hundreds of years of written testimony from reliable witnesses such as doctors and scientists (and many decades of compelling experimental evidence) that humans have faculties such as clairvoyance and ESP that are beyond any biological explanation.
• When describing human mental faculties, they tend to describe them as being far weaker than they are. 

It is interesting to read the writings of neuroscientists who try to portray human memory as something weak and unreliable.  Again and again they will try to suggest that learning something requires multiple exposures to some source material, a claim that is contrary to the facts of actual human experience, which is that humans can very often reliably learn things after a single exposure, that people can recognize faces they have seen briefly only one time, that people can remember stories they have heard only one time, and that people can remember events they have seen only one time. 

Neuroscienitsts often try to make us think that humans can't remember very well things they experienced years ago, or that each time we remember something there will be a high chance of error.  Such claims are contrary to abundant human experience. It is rather obvious why neuroscientists tend to speak in such a way. The more you believe that human memory is not very reliable, and something that requires multiple exposures, the more likely you may be to believe that human memories are stored in the brain. 

A neuroscientist's portrayal of weak and unreliable human memory can be refuted by citing a host of ordinary human experiences. Such a portrayal can also be refuted by citing cases of exceptional human memories.  Below are some examples:

• Steven Wiltshire has repeatedly shown the ability to accurately draw an entire skyline after seeing it only one time. 
• Mathematician and computer scientist Herman Goldstine wrote this about the legendary mathematician John von Neumann: "One of his remarkable abilities was his power of absolute recall. As far as I could tell, von Neumann was able on once reading a book or article to quote it back verbatim; moreover, he could do it years later without hesitation."
• According to an article in the LA Times, Kim Peek could recall the contents of 12,000 books he had read, even though his brain was severely damaged, and he lacked most or all of the corpus callosum fibers that connect the two hemispheres of the brain. 
• According to one book, "John Fuller, a land agent, of the county of Norfolk, could correctly write out a sermon or lecture after hearing it once; and one, Robert Dillon, could, in the morning, repeat six columns of a newspaper which he had read the preceding evening. More wonderful still was George Watson, who... could tell the date of every day since his childhood and how he had occupied himself on that day."
• The mathematician Leonhard Euler could recite the entire Aeneid from beginning to end, a work of 9896 lines.  Another mathematician (Alexander Aitken) also memorized the whole Aeneid, and could recite the first 1000 digits of pi.  George Vogan de Arrezo also memorized the entire text of Virgil's Aeneid (consisting of 9,896 lines). 
• Young Leste May Williams memorized 12,000+ biblical verses including the whole New Testament. The New Testament has about 180,000 words, so the feat of Leste May Williams would seem to be far more impressive than the memorization of Virgil's Aeneid, which has only 63,719 words.
• Between age 59 and age 67 a person memorized all 10,565 lines of Milton's Paradise Lost, recalling the entire work over a three-day period.
• A scientific paper says, "Rajan S. Mahadevan ...was listed in the Guinness Book of World Records (McWhirter, 1983) for reciting pi to 31,811 places."  The same paper says that after about three minutes of study Rajan can perfectly recall all numbers in a grid of 50 random numbers, recalling not just the numbers but also their positions in the grid. 
• Solomon Shereshevsky was called "S" in the book The Mind of a Mnemonist by Alexander Romanovitch Luria. A scientific paper says this about Shereshevsky: "According to Luria, Shereshevsky could' 'easily remember any number of words and digits' and 'equally easily he memorizes whole pages from books on any subject and in any language.'  He could accurately quote information from a decade earlier, including tables of numbers and strings of nonsense words....What Luria learned was that Shereshevsky’s memory differed from that of the vast majority of individuals; time did not erode his memories. Neither did a new stimulus affect his memory of an earlier one."
• Mezzofanti could speak very well thirty different languages. 
• A four-year-old girl demonstrated on TV her ability to speak seven different languages. 
• Numerous Muslim scholars have memorized all 6000+ lines of their holy book, and some did this as early as age 10. 
• According to a book, "The great thinker, Pascal, is said never to have forgotten anything he had ever known or read, and the same is told of Hugo, Grotius, Liebnitz, and Euler. All knew the whole of Virgil's 'Aeneid' by heart." 
• The famous conductor Toscanini was able to keep conducting despite bad eyesight, because he had memorized the musical scores of a very large number of symphonies and operas.  According to the 1920 newspaper article here, he had so well-memorized 150 opera scores that he "never even glances at a score when conducting."
• A 1902 newspaper story said that Professor Asa Gray claimed to be able to name 25,000 types of plants. It also says that thousands of Hindu Brahmins have memorized 10,000 verses of the Rig Veda. 
• Zafrullah Khan recited to a newspaper reporter 28 different roads he had taken and all the places they had passed through, while describing a long auto trip he took in 1954, just as if he had a photographic memory of a map of the complex route. 
• It has been estimated that the Babylonian Talmud contains roughly 1,860,131 words. According to page 4 of the document here, "Stromeyer mentions Luria’s famous mnemonist and the case of the 'Shass Pollaks,' who memorized all 12 volumes of the Babylonian Talmud, and Oliver Sacks has reported a similar case of a person who among other things knew by heart all 9 volumes and 6000 pages of Grove’s Dictionary of Music and Musicians."
• According to a book, a waiter in San Francisco could recall exactly what any customer had previously ordered, even if the customer had not visited the restaurant in years. 
• The artist Franco Magnani (famed as "the Memory Artist") was able to draw "photographically accurate" drawings of his hometown that he had not seen in more than 30 years. 
• G. C. Leland says: " It is recorded of a Slavonian Oriental Sect called the Bogomiles, which spread over Europe during the middle ages, that its members were required to memorize the Bible verbatim. Their latest historian, Dragomanoff, declares that there were none of them who did not memorize the New Testament at least; one of their bishops publicly proclaimed that, in his own diocese of four thousand communicants, there was not one unable to repeat the entire scriptures without an error."
• Akira Haraguchi was able to recite correctly from memory 100,000 digits of pi in 16 hours, in a filmed public exhibition.
• The scholar and librarian Antonio Magliabechi of Florence, Italy was legendary for his memory.  According to the source here, " He not only knew all the volumes in the library, as well as every other possible work, but could also tell the page and paragraph in which any passage occurred."  The wikipedia.org article on him says, "Many stories are told of his marvellous memory that was 'like wax to receive and marble to retain.' "
• The fascinating 47-minute video here "The Boy Who Can't Forget" documents cases of Highly Superior Autobiographical Memory (HSAM), also called hyperthymesia.  According to the article here a scientist named McGaugh "is adamant that the super memory demonstrated by the small number of people he and others have identified represents a genuine phenomenon." People with such a Highly Superior Autobiographical Memory (including Jill Price and Aureilien Hayman) can recall what happened to them every day in the past ten years. 
• A book tells us this: "The geographer Maretus, narrates an instance of memory probably  unequalled. He actually witnessed the feat, and had it attested by four Venetian nobles. He met in Padua, a young Corsican who had so powerful a memory that he could repeat as many as 36,000 words read over to him only once. Maretus, desiring to test this extraordinary youth, in the presence of his friends, read over to him an almost interminable list of words strung together anyhow in every language, and some mere gibberish. The audience was exhausted before the list, which had been written down for the sake of accuracy, and at the end of it the young Corsican smilingly began and repeated the entire list without a break and without a mistake. Then to show his remarkable power, he went over it backward, then every alternate word, first and fifth, and so on until his hearers were thoroughly exhausted, and had no hesitation in certifying that the memory of this individual was without a rival in the world, ancient or modern."
• Encyclopedia.com refers to the "miraculous photographic memory" of Thomas Babington Macaulay.
• A newspaper account states, "That Italian prodigy of learning, Ignatius de Rosal, made the boast that if any one could repeat a line from any of the four great poets of Italy he would follow it by reciting 100 lines following in due order of succession, and on a trial being made be actually accomplished the feat."
• Describing both high recall capacity and very quick speed of recall, a 1914 newspaper account tells us that the boy Cleo Smith of Denver, Colorado "has accomplished the unbelievable task of being able to give from memory—'right off the reel'—the population of all the cities in the world having more than 90,000. the names of all the capital cities of the world, giving their altitudes; the population of every county seat in the United States; the altitude of every city in the United States, and of every mountain peak in the world; the number of miles of railroad in each state in the United States and in every country in the world; the number of farms in every state; the population of every city of more than 100,000, both in the United States and Canada; the length of every principal river in the world; the population of every country in the world; the foreign population in every city and in every state, telling the number of Indians, Chinese, Japanese, etc.; the total number of foreigners in every state; the number of counties in each state; the date of admission to the Union of every state; the number of manufactories in every state and in Canada, and in every principal city in the United States."
• According to an article on bbc.com, "Ask Nima Veiseh what he was doing for any day in the past 15 years, however, and he will give you the minutiae of the weather, what he was wearing, or even what side of the train he was sitting on his journey to work."
• Derek Paravicini was born 25 weeks early, with severe brain damage, but he has reliably demonstrated countless times the ability to very accurately play back on a keyboard any song that is played to him, note for note, even if he has never heard the song before. 
• A child (identified only as "Prodigy 1" in the paper here) was born seven weeks early, but still has a working memory in the 99.9 percentile, and "reproduced complicated musical pieces such as The Entertainer after only one or two hearings at age four," eventually scoring 149 on a test of nonverbal IQ. 
• A nineteenth century work describes a similar ability in a prodigy known as Blind Tom: "The doctor then called for some one of the audience to come and play a piece of music for the first  time in Tom's hearing, promising a very faithful imitation ; Miss Jones was persuaded to play a piece of her own composition, and hence unknown to Tom and the audience....When the lady was through and escorted from the stage, Tom sat down and played it through perfectly. " The next page states, "Tom executes some of the most difficult pieces of Beethoven, Mendelssohn, Bach, Gottschalk, Thalberg and others, and these he learnt by hearing them played."

Thomas Babington Macaulay

A scientific paper tells us this about the autistic savant Daniel Tammet:

"DT [Daniel Tammet] speaks 10 languages, including Estonian and Finnish, has invented his own language (Manti) and learnt Spanish in one weekend. He performs mathematical calculations at lightning speed, including multiplying six-digit numbers together. He commented that 31, 19, 79 and 1979 are all prime numbers, an indication of how he sees patterns in numbers very rapidly. As mentioned earlier, as part of a formal competition he recited Pi to 22,514 decimal paces, earning the title of European champion."

If normal human memory abilities are inexplicable as being produced by brains with very rapid protein turnover, very high levels of signal noise of several different types, and nothing like an indexing system, a position notation system or any known mechanism for reading or writing memories, brains that replace about 3% of their proteins every day, which is certainly the case, then cases of exceptional memory such as these are all the more inexplicable as being neural effects. 

Brain studies of people with exceptional memories have failed to present  any robust evidence for any brain difference that could explain such memories. The paper here  claims to have studied the brains of 11 people with Highly Superior Autobiographical Memory (HSAM).  The abstract makes no specific claim of having found any specific difference in the brains of such people.  The abstract does vaguely claim to have identified "nine structures as being morphologically different from those of control participants," but the text of the paper does not justify any claim of any significant morphological difference in the 11 people with Highly Superior Autobiographical Memory (HSAM).  We read in the paper nothing different from what you would get by randomly picking 11 people and comparing their brains to 11 other random people. 

It is interesting that Table 1 of this paper shows us the nine regions that were supposedly "morphologically different" from controls.  There are nine up arrows to indicate little regions of neural superiority in the HSAM subjects with amazing autobiographical memory, and down nine down arrows to indicate little regions of neural inferiority in such subjects.  "That's a wash," as they say: the negatives cancel out the positives. Overall there is no indication of neural superiority in these HSAM subjects with amazing memories. 

A more recent paper on this topic can be read here.  The paper fails to show any robust evidence of any significant brain activity difference between those with astonishing HSAM memories and normal controls. The very marginal differences discussed are merely the type of differences we would expect from comparing about 10 randomly selected people with 10 other randomly selected people. 

The fact that people with vastly superior recall ability have brains that are not structurally superior (and are sometimes very structurally inferior) to those with normal recall abilities, and the fact that brain scans of such people show nothing very noteworthy are both facts that strengthen the case against the claim that memories are stored in the brain. 

Postscript: Below is a quote from page 53 of the book The Mind and Beyond published by Time-Life Books:

"As reported in the 1990 edition of the Guinness Book of World Records, in 1967, one Mehmed Ali Halici of Turkey recited from memory 6,666 verses of the Koran in six hours. And in 1989, Englishman Tony Power memorized in correct order a random sequence of thirteen packs of shuffled playing cards – 676 cards in all – after looking at them only once. But the world record for a single eidetic memory feat may be held by Bhandanta Vicitasara of Rangoon, Burma who in 1974 correctly recited from memory 16,000 pages of Buddhist canonical texts."

On page 266 of the June 4, 1875 edition of The Spiritualist, Cox describes a state of extraordinary memory, what sounds like a case of photographic or eidetic memory. Cox describes himself as having a similar memory. Cox states this:

"The Rev. Henry Christmas, formerly of Sion College, possessed an extraordinary memory. I have seen him read a page of Greek or Latin opened at random, close the book and repeat the whole of the page verbatim, beginning with the broken sentence in the first line. He knew by heart the entire of many volumes of poems. He could repeat the whole of Horace from memory : one perusal usually sufficed. He informed me that this marvellous memory of his was a memory not of sound but of sight. He did not recall the words, but the page on which they had been printed when he learned them, and in his mind’s eye he saw that page and read from it. I suspect such a form of memory to be not uncommon. It is possessed by myself. When I desire to repeat anything learned by rote I am compelled to recall to my mind the book and the page of the book from which I learned it. I see in my mental vision the very misprints, creases, and spots upon the paper, and I mentally read it from the ideal representation of the book. This is plainly memory for objects of sight, not for language."