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." 

Astray Authorities #8

 Here is the latest in a series of videos I am making. 

Pareidolia Helps Neuroscientists Getting Nowhere Trying to Show a Brain Basis for Memory

Our neuroscientists are getting nowhere in trying to show that there is a neural basis for human memory. But they have something they can rely on to help hide their lack of progress:  pareidolia. Pareidolia is when you see patterns that aren't really there, like some guy examining his toast every day for years, and then one day saying, "I finally see the face of Jesus in my toast."  A scientist conjuring up some pareidolia can make a nice-sounding progress report when no real progress has been made. I describe some examples of this in my post "Scientists Have a Hundred Ways to Conjure Up Phantasms That Don't Exist." Recently on a single screen of my I-Pad I saw three examples of neuroscientist pareidolia (which I identify here by using yellow text):

The first example was an article in Scientific American (copied from the journal Nature) entitled "Memories Are Made by Breaking DNA -- And Fixing It, Study in Mice Finds." The nonsense story is behind a paywall, but the Singularity Hub article here tells basically the same nonsense story.  We read this silly narrative, not grounded in any solid research:

"DNA damage isn’t always detrimental. It’s been associated with memory formation since 2021. One study found breakage of our genetic material is widespread in the brain and was surprisingly linked to better memory in mice. After learning a task, mice had more DNA breaks in multiple types of brain cells, hinting that the temporary damage may be part of the brain’s learning and memory process."

As evidence for such claims, we have a link to the  poor quality science paper "Formation of memory assemblies through the DNA-sensing TLR9 pathway."  The paper is guilty of several bad examples of Questionable Research Practices (as are most experimental papers in cognitive neuroscience these days).  One big sin of the paper is to use way-too-small study sizes such as only 5 mice, 6 mice and 7 mice.  I once pointed out that the average number of authors in a typical neuroscience paper is about equal to the number of mice used in the resulting research; and I sardonically pointed out that it was as if scientists were following the ridiculous rule of "use only 1 mouse per neuroscientist." But in this case it seems even worse.  We have 16 authors for a study that uses measly study group sizes of only about six mice per study group. 

The study fails to mention any rigorous blinding protocol, and merely mentions that behavioral tests were performed blindly. For a study like this to be taken seriously, you would need to have much more of a blinding protocol, one also involving data analysis.  Then there is the ridiculous use of "freezing behavior" judgments to try to judge whether memory recall has occurred in mice. For a full explanation of why all neuroscience papers that use this technique are unreliable, see my post "All Papers Relying on Rodent 'Freezing Behavior' Estimations Are Junk Science." 

The title of the paper refers to "memory assemblies," but nothing has been done to show that any such thing was found. Here are all of the paper's references to "assemblies":

"Memories of individuals’ experiences are represented across assemblies of neurons in hippocampal and cortical circuits.  Several mechanisms of formation and maintenance of these assemblies have been proposed...Recent focus has also been on the role of the interneuronal perineuronal nets (PNNs) in the stabilization of memory circuits through tightened control of inhibitory inputs to dedicated neuronal assemblies. Here we explored whether an overarching process could integrate stimulus-dependent and pre-existing mechanisms that underlie the commitment of neurons to memory-specific assemblies...The recruitment of individual neurons to assemblies is essential not only for encoding individual memories, but also for protecting them from streams of incoming information over time, ensuring stability and persistence of memory representations....Given the association of dsDNA damage with neurodegeneration, neurons undergoing learning-induced dsDNA breaks might be expected to be excluded from memory assemblies."

It is rather clear from these sparse and not-very-substantial uses of the word "assemblies" that nothing has been done to establish the existence of "memory assemblies" in the brain. Our authors are merely seeing some sort of something happening somewhere in the brain, and calling that a "memory assembly," without any justification of such a claim.  The claim in the headline of the Scientific American article ("Memories Are Made by Breaking DNA -- And Fixing It") is a nonsensical-sounding claim that does not match any robust research. DNA does not store memories, and does not have any structure that could support the storage of human learned knowledge or human episodic memories.  If scientists thought that DNA stored memories, they would try very hard to preserve the brains of dead people, and try and scan them to extract what the dead people had learned or experienced.  Instead (except for rare cases) the brains of dead people are left for burial or cremation, just as if scientists thought that a dead brain was worthless. Thousands of human brains have been stored after death and studied, but no evidence has been found from such activity that memories are stored in brains, not in brain DNA  nor anywhere else. For details, see my post "They Stored and Studied Thousands of Brains, But Still Failed to Show Brains Store Memories." 

The next bunk story shown on the visual above is an NBC News story entitled "How the brain chooses which memories are important enough to save and which to let fade away."  The story gives us this  nonsensical claim: "Experiments in mice revealed that during waking hours, cells in the brain’s hippocampus spark in a specific pattern called 'sharp-wave ripples,' which tag important experiences for movement into long-term memory storage during sleep."   We read this:

"As part of the research, Buzsáki and his colleagues put mice through a maze that had a sugary reward at the end for those that successfully reached it. Meanwhile, the researchers were monitoring the activity of nerve cells through electrodes implanted in the rodent brains that fed data into computer programs.  They observed that as the mice paused to eat their treats, their brains sparked sharp-wave ripples that were repeated as many as 20 times. The daytime pattern of sharp-wave ripples was replayed during the night, a process that moved the experience into long-term memory."

Many people familiar with the drawbacks of EEG analysis will chuckle at the claims made above. The EEG is a device that can detect electrical activity from parts of the brain. When an EEG device is used, electrodes are placed next to different parts of the skull. The device will pick up a dozen or more different lines that show electrical activity in different parts of the brain. 

Brains have a great deal of signal noise, and the abundance of such noise is one of several major reasons for disbelieving that the brain is the source of human thinking and recall which can occur with incredible accuracy, such as when people perfectly recall very large bodies of text and perfectly perform extremely difficult math calculations without using tools such as computers, pencils or paper. The analysis of brain waves obtained by EEG devices is an area of science where bad methods, pareidolia and junk analysis is very abundant.  There is an abundance of people trying to use fancy statistical methods to try to extract identifiable "signals" or "signs" from data that is very noisy and polluted. Muscle movements abundantly contaminate EEG readings. 

What seems to be going on in the research mentioned by NBC News is mainly pareidolia. Having lots of EEG data that appear as an abundance of squiggly lines, anyone can find as many "ripples" as he wants.  EEG ripples or squiggles are not any mechanism for storing memories.  The people who have done this research are like someone wishing to believe that the ghosts of dead animals live in the clouds, and who (after examining thousands of photos of clouds) says that he sees something that looks like the shape of an animal.  Anyone eagerly hoping to find some kind of pattern in a stream of noisy random data will be able to find a few cases that he can believe are instances of some pattern that he was hoping to find. This is pareidolia, not robust science. 

The NBC News story has no link to a paper, but it is almost certainly referring to this 2024 paper co-authored by György Buzsáki (mentioned in the story), the paper "Selection of experience for memory by hippocampal sharp wave ripples." That's a poorly designed Questionable Research Practices study using a study group size of only six mice.  A study like this should be taken seriously by no one unless it used a  rigorous blinding protocol. But the text of the paper fails to use the word "blind" or "blinding." Because the study is not a pre-registered study, all of its analytics are just arbitrary post-hoc stuff meaning little. Anyone analyzing the constantly varying squiggles of brain wave data can pretty much see anything he  wants to see. Studies of this type have little value unless they are pre-registered studies that follow a rigorous blinding protocol and have large study group sizes, and this study fails to be any of these things.  The paper has a nonsensical title.  Brain waves (sharp wave ripples or any other type) do not select anything. Brain waves are an epiphenomenon of brain activity, like cooking smells are an epiphenomenon of cooking activity. Claiming that brains waves select memories is as nonsensical as claiming that the scent from your cooking soup selects something. 

The last of the three bunk stories is a Popular Science story entitled "How these feathery ‘memory geniuses’ remember where they stashed their food."  The subtitle of the story has the groundless claim that "Chickadee brains make neural ‘barcodes’ to help recall thousands of hiding spots." We have a repetition of the false claim that "Scientists have long known that the brain's hippocampus is necessary for storing episodic memories like where a car is parked or food is kept."  Read my post "Studies Debunk Hippocampus Memory Myths" for why that claim is untrue. We then have a reference to a mistitled paper "Barcoding of episodic memories in the hippocampus of a food-caching bird." It's one of endless scientific papers with a title that is not justified by anything reported in the paper. We have a misleading visual showing barcodes next to some chickadee birds, but this is just suggestive artwork not matching any data collected. 

No discovery was actually made of anything like barcodes in the brain of these birds, and we can tell that funny business is going on by the paper's use of the word "barcodes" in quotation marks, as if to suggest "they're not really barcodes."  In the caption to Figure 3 (which looks nothing like a barcode) we have this statement:

"Activity of neurons across caches after subtraction of the place code and the average cache response. We refer to this activity as the 'barcode.' ” 

No robust research has occurred here. We have some arbitrary statistical invention (as arbitrary as calculating someone's weight in kilograms divided by his height in centimeters multiplied by his shoe size), and this is misleadingly referred to as a "barcode." The authors haven't found any evidence of anything like a barcode used by an animal brain.  What is going on here is pareidolia, in which people see some pattern that isn't really there. 

No study like this should be taken seriously unless a rigorous blinding protocol was followed, but no such thing was done. We merely hear that someone was blind to the sex of the birds, which is not the type of blinding that needed to be done. 

Here (in Figure 4) is the best the authors can do to try and get some evidence of what they call "barcode reactivation." They claim that the two visuals on the left are similar, and that the two visuals on the right are similar. Probably the data was carefully filtered, massaged and selected to try and give the best match that could be found. But it's no good match at all. There's not even a repetition of a distinctive detailed pattern. 

We should take this about as seriously as someone photographing thousands of clouds hoping to find the reappearance of an animal ghost, and showing us two clouds that both look like a tiny bit like a cat, and saying that this is evidence of an animal ghost reappearance.  The visuals above aren't barcodes, and they don't look anything like barcodes. Here is what a barcode looks like:

Also without any merit is a recent press release with the headline "Researchers discover dynamic DNA structures that regulate the formation of memory."  The press release is referring to the  low quality paper "DNA G-quadruplex is a transcriptional control device that regulates memory."  It's another mouse study, one using only a way-too-small study group of eight mice. Besides failing to use any blinding protocol (an essential for a paper like this to be taken seriously), the paper is another paper that hinges on subjective judgments of "freezing behavior" to try to measure fear in mice. Read here for why all such papers are junk science.  In general, biology papers that refer to something chemical and use the word "regulate" are using unjustified and misleading language. Biochemical processes are incredibly complex, and individual chemicals are not regulators. The paper uses the word "control" rather than "controls," seemingly indicating that only one control animal was used.  A well-designed  experimental study would have used a minimum of 15 subjects per study group, and 15 subjects in the control group. The fact that major publications such as Newsweek did stories based on this low-quality research tells you something about the appalling lack of standards these days in science journalism. 

We have only 8 mice in a study that has 19 authors. We should laugh whenever we encounter "One Mouse Per Scientist" researchers, and suspect any research they produce is poor research. 

Our scientists are getting nowhere trying to back up the erroneous claim that memories are stored in the brain. No such memories can be found by microscopic examination of brain tissue, although we would have found them about 70 years ago if memories were stored in the brain, at about the same time DNA and the genetic code were discovered. To prevent us from noticing the dismal lack of progress in backing up claims that memories are stored in brains, we have a flow of poorly designed neuroscience studies on memory, studies failing to follow high standards of experimental science and honesty. That flow of studies is like a sewer pipe. 

A kind of "anything is allowed" lying goes on these days in neuroscience press releases.  A recent news story was entitled "Neuroscience Breakthrough Unveils How We Learn and Remember."  The story was about some analysis of low-level changes in dendrites,  and was promoting a paper that made no serious effort to link such changes to learning or memory.  Previously scientists have usually claimed that learning occurs by changes in synapses, not dendrites. Chemical changes in both dendrites and synapses are slow, and cannot explain human learning, which can occur instantly.

When reading stories about neuroscience research, always assume that any uses of the word "breakthrough" or the phrases "unveils how" or "reveals how" or "shows how" are totally unjustified. 99% of the time such an assumption will be correct.  A 2022 paper says this about neuroscience research: "The current landscape is characterized both by a lack of robust, validated standards and a plethora of overlapping, underdeveloped, untested and underutilized standards and best practices." The truth is: bad practices and poorly designed studies are more the rule than the exception in experimental neuroscience. 

We should also remember that these days science-related clickbait is big business. Science-related stories with untrue but interesting-sounding claims lead to web pages with ads, and such ads make much revenue for the people funding the websites.  So it's more than just pareidolia and paper-count-building  and citation-count-building that explains all these junk stories: greed also plays a large part in it. What I call the scitainment industry (a mixture of science and entertainment) is very big business. 

Surprising Studies on Memory Loss or IQ Changes After Brain Surgery or Brain Damage

Neuroscientists typically claim that memories are stored in the brain. There are some very complex ways and very simple ways in which such a hypothesis can be tested. A very complex way would be to use dissection to see whether any sign of human memories can be found. You could do this in two different ways: (1) by dissecting the brains of people who had recently died, looking for learned information such as facts learned in school; (2) by analyzing tissue removed from the brains of living people, to look for  learned information such as facts learned in school. There are plenty of opportunities for the second of these methods, because brain tissue is often removed to treat diseases such as epilepsy. Sometimes an entire half of the brain is removed in an operation called a hemispherectomy, to treat very severe and frequent seizures. Epilepsy is also treated by less severe operations that involve removing much less than half of the brain. 

Examining removed brain tissue has never produced any support for the claim that memories are stored in brains. No one has ever seen any words or letters by looking at brain tissue through a microscope. No one has ever used a microscope to look at brain tissue of some particular person, and seen images corresponding to sights that person  previously saw. No one has ever seen any sign of encoded information by looking at brain tissue through a microscope,  other than genetic information which is not information that anyone learns through school or experience.  

The method described above is a very complex method that might require the use of very sophisticated equipment such as electron microscopes. But there is a very simple way of testing the hypothesis that memories are stored in brains. You can simply do what may be called a  "loss of learned information" test, testing someone both before and after the person had surgery to remove some of their brain tissue. You can look for loss of memories and learned information that had been acquired before the operation. 

Such a test would be different from a typical memory test. A typical memory test might measure how well someone can remember some new information he was asked to memorize. But a "loss of learned information" test would only test whether something learned or remembered before some brain surgery had been lost by the act of surgery itself. 

You would think that scientists eager to prove their claims that memories are stored in brains would often do such a "loss of learned information" test.  But it seems very hard to find examples of such tests in the scientific literature. 

Let us look at some papers that may be relevant to discussions of whether human brains store memories.  We must carefully distinguish between two types of tests:

(1) A "performance on new learning" memory test will test how well some person can still acquire different types of new memories after having lost some brain tissue.

(2) A "loss of old memory" test will test whether a person lost some memory he had acquired, because of some loss of brain tissue.  

The second type of test is more relevant to whether the brain stores memories.  Removal of some brain tissue might damage your senses or perception in a way that might decrease your ability to learn new things and acquire new memories. But that would not show that your previous memories acquired before such a removal were stored in your brain. Similarly, if you make a person blind, that will reduce his ability to learn, but that does nothing to show that brains store memories. 

We must also carefully distinguish between a random pool of brain tissue loss subjects, and a pool of subjects who have been selected because they showed symptoms of memory loss. I have looked at quite a few papers in which we are told that some pool of subjects was selected for both brain tissue loss and also memory problems. Tests of the extent of memory loss in such persons may be giving a very misleading impression, because only subjects having memory loss were selected for the tests. Such studies may merely show that "people with memory problems have memory problems." 

It seems that our medical professionals are usually bad about testing preservation of memories after doing operations that remove half of a brain or a large fraction of the brain. I think this may be because they do not want to do a test that will produce results that contradict their dogma that memories are stored in brains. But here and there in the scientific literature you will be able to find some tests that serve as tests of how well memories were preserved after half of the brain was removed. In some other cases, we will be able to infer that there was  little or no loss of memories acquired before the operation, either because of a lack of mention of any such thing (which would be noteworthy and worthy of mention if it occurred), or because of some general assurance that the operation usually produced "no serious complications," a claim that should only be made if previously acquired memories were well-preserved.  

Let us look at some of the papers that might be relevant. 

• The paper here ("Unexpected amnesia: are there lessons to be learned from cases of amnesia following unilateral temporal lobe surgery?") tells us that "Cases of amnesia following unilateral temporal lobe surgery are rare." It tells us that "Davies and Weeks (1993) did report one case of postoperative amnesia in a series of 58 cases of unilateral temporal lobectomy, whereas Walczak et al. (1990) found one case of marked deterioration in memory from a preoperative normal state in their series of 100 patients who underwent such surgery." The authors state, "We were able to locate nine definite cases of amnesia following unilateral temporal lobe surgery in the English language literature." But the paper gives us no interesting accounts describing amnesia in any of these cases. We do have a Table 3 that has "before" and "after" columns for seven of the nine cases. The table fails to mention much of anything backing up claims that the patients had amnesia in the sense of loss of memories or learning they had acquired before the surgery. We have "before and after" IQ scores for the first five subjects, which show no significant difference (there sometimes being an increase).  For patient 6 there is no data, and for patient 7 we read "postoperative scores on executive and language function similar to preoperative scores." In the column labeled "Post-surgery memory functioning" we hear of some declines in memory performance tests for some of the subjects, but we hear nothing about a loss of memories that they had acquired before the operation.  And some of the results in that column involve tests taken years after the surgery, so we don't know whether any declines reported were the result of the surgery. In short, the paper fails to provide any good evidence that memories or learned information can be lost by temporal lobe surgery for epilepsy. 
• The paper "Memory outcome after temporal lobe epilepsy surgery: corticoamygdalohippocampectomy versus selective amygdalohippocampectomy" fails to discuss any measurements or observations about how acquired memories or learned knowledge declined after brain surgery that removed substantial tissue. It does tell us that for 63 patients IQ went up by about five points after such surgery, and that for another 60 patients IQ increased by nearly five points. The paper tells us that "General intelligence increases after epilepsy surgery." 
• Almost the same claim is made by the paper here ("Psychiatric and Neuropsychological Problems in Epilepsy Surgery: Analysis of 100 Cases That Underwent Surgery"), which tells us, "The full IQ score of the Wechsler Adult Intelligence Scale–Revised (WAIS-R) was increased after temporal lobectomy in 75% of the cases (p < 0.01; n 4 44)." 
• The paper "Retrograde amnesia in patients with diencephalic temporal lobe or frontal lesions" has some interesting graphs showing memory tests in a group of subjects that included "15 patients with dicephalic lesions, 15 patients with temporal lobe lesions, 15 with frontal lobe lesions and 20 healthy control subjects." We have graphs showing performance on tests that include tests of autobiographical incidents, news recall and famous faces. All of the patients with lesions are able to produce scores ranging from about 70% to 30% of the scores produced by control subjects.  This is not a very impressive result, considering that the paper says, "The patients were selected in all cases on the basis of their having significant anterograde memory impairment in association with clinical and CT scan evidence of pre- dominantly focal lesions in either the temporal or frontal lobes or the diencephalon."  Since both having brains lesions and being not good at remembering the past was a requirement for being chosen in the study, the paper fails to show a link between the lesions and the memory performance. Similarly, if you did a study that only accepted subjects who were both gay and alcoholic, that would do nothing to show that being alcoholic tends to make people gay. 
• The paper "Retrograde amnesia in patients with hippocampal, medial temporal, temporal lobe, or frontal pathology" suffers from the same shortcoming.  We have some graphs showing inferior memory performance on five patients, on tasks of autobiographical recall, recalling famous news events, and recalling famous faces. But the paper eventually tells us that these patients "were selected on the basis of significant anterograde memory loss and MRI evidence that regional brain atrophy was restricted to the medial temporal lobe structures."  So the result merely tells us that people who have trouble remembering what they learned have trouble remembering what they learned. A random sample of five subjects with the same brain tissue loss might tell a very different tale. 
• The paper "Clinical outcomes of hemispherectomy for epilepsy in childhood and adolescence" (about surgeries removing half of a brain) tells us that "the overall developmental/cognitive category was unchanged following surgery in 23 out of 27 children," and that "two children showed a >15 point improvement in DQ/IQ following surgery,"  referring to a substantial increase in intelligence as measured by IQ tests. 
• The paper here "Seizure control and developmental trajectories after hemispherotomy for refractory epilepsy in childhood and adolescence" (in Figure 4) describes IQ outcomes for 41 children who had half of their brains removed in hemispherectomy operations in Freiburg, Germany. For the vast majority of children, the IQ was about the same after the operation. The number of children who had increased IQs after the operation was greater than the number who had decreased IQs. 
• The paper "With childhood hemispherectomy, one hemisphere can support—but is suboptimal for—word and face recognition" involved tests on 15 left hemispherectomy patients, 24 right hemispherectomy patients, and 58 age-matched control subjects. A hemispherectomy typically involves removal of one-half of the brain to stop very frequent epileptic seizures. According to Figure 5, most of the patients who had a hemispherectomy were only "mildly impaired" in their ability to recognize words and faces, with a few being "moderately impaired," a few others having "average" performance, and one having "above average" performance.  The tests performed seemed to have been purely "performance on new learning" tests. We read that "Childhood hemispherectomy patients showed above 80% accuracy on tasks of face and word recognition," and the paper calls this "surprisingly good performance."
• A 2015 scientific paper ("Brain abscess: surgical experiences of 162 cases") looked at 162 cases of surgery to treat brain abscess, in which parts of the brain undergo the cell death known as necrosis, often being replaced with a yellowish pus. The article contains quite a few photos of people with holes in their brains caused by the abscesses, holes in their brains of various sizes. The paper says that “complete resolution of abscess with complete recovery of preoperative neuro-deficit was seen in 80.86%” of the patients, and that only about 6% of the patients suffered a major functional deficit, even though 22% of the patients had multiple brain abscesses, and 30% of the abscesses occurred in the frontal lobe (claimed to be the center of higher thought). Interestingly, the long review article on 162 brain abscesses treated by brain surgery make no mention at all of amnesia or any memory effects, other than to tell us that “there was short-term memory loss in 5 cases.” If our memories really are stored in our brain, how come none of these 162 cases of brain abscesses seem to have shown an effect at all on permanent memories?
• Similarly, a scientific paper ("Brain abscess: clinical aspects of 100 patients") about 100 brain abscess cases (in which one fourth of the patients had multiple brain abscesses) makes no mention of any specific memory effect or thinking effect. It tells us that most of the patients had “neurological focal deficits,” but that's a vague term that doesn't tell us whether intellect or memory was affected. (A wikiepdia.org article says that such a term refers to "impairments of nerve, spinal cord, or brain function that affects a specific region of the body, e.g. weakness in the left arm, the right leg, paresis, or plegia.")   The paper tells us that after treatment “80 (83.3%) were cured, eight (8.3%) died (five of them were in coma at admission), seven had a relapse of the abscess,” without mentioning any permanent loss of memory or mental function in anyone.
• Another paper ("Epidemiology of brain abscess in Taiwan: A 14-year population-based cohort study") discusses thousands of cases of brain abscesses, without mentioning any specific thinking effects or memory effects. 
•  Another paper ("Retrospective analysis of 49 cases of brain abscess and review of the literature") refers to 49 brain abscess patients, and tells us that "the frontal lobe was the most common site," referring to the place that is claimed to be a "seat of thought" in the brain. But rather than mentioning any great intellectual damage caused by these brain holes, the paper says that 39 of the patients “recovered fully or had minimal incapacity,” and that five died.
• A paper tested the ability to recognize faces and words in a group of control subjects and about 39 subjects who had undergone hemispherectomy, typically to remove half of their brains. Most of those who had the hemispherectomy operation performed almost as well as the normal controls.  We read, "This performance level is perhaps surprisingly high, relative to the brain volume resected  [removed] (often close to 50%), hinting at a nonlinear degradation of function with resection. Second, the patients' accuracy was not dependent on the hemisphere removed. That is, the single LH or RH of patients showed comparable performance on face and word recognition."
• The paper "Memory outcomes following hemispherectomy in children" fails to mention in its abstract any loss of episodic or conceptual memories after hemispherectomy operations typically involving removal of half a brain. It says, "Undergoing hemispherectomy was not necessarily associated with declined memory performance, with the majority of patients showing stable scores."
• The paper "The Cognitive Outcome of Hemispherectomy in 71 Children" describes outcomes of operations typically removing half of a brain to stop very frequent seizures. The paper gives us in Table 7 the pre-operation and post-operation IQ scores for 31 different children. The decline in IQ is only small. The children went from an average IQ of  80.5 to an average IQ of 75.7. 26 of these children were given a test called the Peabody Picture Vocabulary Test. For these 26 children the average score increased from 79.0 to 82.1. This test is very important because it is effectively a test of previously acquired knowledge. In the test a person is shown a series of four pictures, and is asked a question such as "Which picture shows laughing?" The test therefore measures previously acquired knowledge. The increase in the score on this test is most remarkable. It is not at all what we would expect if the human brain stores memories. Under the hypothesis that the brain stores memories, removal of half of a brain should cause a sharp decline in performance on this test. Similar results are shown in Table 9. We have pre-operation and post-operation IQ scores for 15 different children (not the ones described in Table 7). The decline in measured IQ is less than a single point. Scores on the Peabody Picture Vocabulary Test rose from an average of 43.0 to an average of 51.7. Another paper summarizes these results by saying, " Pulsifer et al. ... reported cognitive outcomes in 71 children who underwent hemispherectomies and found little changes in cognitive performance pre- and post-surgery."
• The paper "Long-term functional outcomes and their predictors after hemispherectomy in 115 children" did not test for IQ or memory, but reports on things such as speech ability, walking ability and reading ability. We read this: "In this cohort of 115 children, at a mean follow-up of 6.05 years after hemispherectomy, 83% patients walked independently, 73% had minimal or no behavioral problems, 69.5% had satisfactory spoken language skills, and 42% had good reading skills."
• The paper "Hemispherectomy in adults patients with severe unilateral epilepsy and hemiplegia" discusses "25 adults who presented severe unilateral epilepsy and hemiplegia and underwent anatomic or functional hemispherectomy in between 2006 and 2011."  16 of these were "anatomic hemispherectomies" apparently involving removal of half of the brain, and the other nine were "functional hemispherectomies."  Very remarkably, we are told "All of the patients’ postoperative scores of overall QOL, full IQ, verbal IQ and performance IQ improved compared with pretreatment scores."  We don't read anything about before-and-after tests of memory retention, but we read that "Hemispherectomy is a safe operation for epileptic adults with hemiplegia and serious seizures and seldom leads to severe complications."  We may presume that the people having these operations still preserve almost all their memories, seeing that the loss of much of your memories would certainly be a "severe complication." 
• The paper here ("Retrograde amnesia after traumatic injury of the fronto-temporal cortex") tells us of a man who suffered severe brain damage after falling from a horse. He was in a coma for 6 weeks, and his MRI showed very extensive brain damage in multiple areas. The man was given various tests of how good his acquired memories were preserved. He scored 33 out of 60 on the Famous Faces Test, and 70 out of 100 on the Semantic Knowledge Test.  He was able to remember 8 of 16 objects from his past. He scored 100 on an IQ test. Since the test was done four years after the fall, we don't know how much of this decline was caused by the fall. 
• The paper "The Effect of Early and Late Brain Injury upon Test Scores, and the Nature of Normal Adult Intelligence" is behind a paywall. But from the freely available first page we get the interesting information that after searching for IQ scores recorded about brain surgery, the author found 15 subjects, and found that they had an average post-operative IQ of 108.   The author also found another group of 23 brain surgery patients who had an average post-operative IQ of 107. We are told "in none was there postoperative loss" of IQ.
• The paper "When only the right hemisphere is left: Studies in language and communication" reports on the case of a patient BL of "above normal intelligence" who underwent a left hemispherectomy at age five. Despite lacking the left half of his brain, BL "attended regular elementary and high school and graduated from college with a Bachelor's degree with a double major in business and sociology," he "played the baritone horn in a band," and worked "several years as an accountant in international business." The paper reports BL scoring normally on most of the cognitive tests he took.
• The paper "Functional consequences of hemispherectomy" gives us in Table 1 before-and-after IQ scores for 12 children who had half of their brains surgically removed. The worst result was a decline in IQ of 11 points, occurring for only one of the subjects. The best result was an increase in IQ of 8 points, which occurred for three different subjects. Overall, there was more of an increase in IQs than a decrease.  
• The paper "Long-term outcome of hemispheric surgery at different ages in 61 epilepsy patients" examines the IQ effects of removing half of a brain.  Near the bottom of Table 2 we are told that out of 55 patients, only 5 experienced post-surgical "intellectual deterioration," with 50 categorized as "not worse" in regard to "intellectual deterioration." 21 of these 55 patients are called "better" in regard to "intellectual improvement," and 34 are called "not better."  We read, "More than 80% appeared improved or unchanged in intelligence following surgery." We don't hear much specifics on memory, but we get the claim that these "remove half the brain" operations have "low risk of adverse cognitive effects." 
• In 1994 Simon Lewis was in his car when it was struck by a van driving at 75 miles per hour. The crash killed Lewis' wife, and “destroyed a third of his right hemisphere” according to this press account. Lewis remained in coma for 31 days, and then awoke. Now, many years later, according to the press account, “he actually has an IQ as high as the one he had before the crash.” In 1997, according to the press account, Lewis had an IQ of 151, which is 50% higher than the average IQ of 100. How could someone be so smart with such heavy brain damage, if our brains are really the source of our minds?  
• In a scientific paper "Why Would You Remove Half a Brain? The Outcome of 58 Children After Hemispherectomy −−The Johns Hopkins Experience: 1968 to 1996" by Vining and others, we read about how surgeons at Johns Hopkins Medical School performed fifty-eight hemispherectomy operations on children over a thirty-year period. Eleven of these children had the left hemisphere of their brains removed; most of the rest had the right hemisphere of their brains removed.  The paper states this: "Despite removal of one hemisphere  [i.e. one half of the brain], the intellect of all but one of the children seems either unchanged or improved. " We are told "language recovers after removal of the dysfunctional left hemisphere," and the authors speculate about why it is they saw "intellectual improvement in these children after removal of half of the cortex." The authors state, "We are awed by the apparent retention of memory after removal of half of the brain, either half, and by the retention of the child’s personality and sense of humor." The final statement is very important. Although the authors do not give us the results of exact tests documenting a preservation of memory, the statement I just quoted suggests they observed a preservation of episodic and factual/conceptual memory after half of the brain was removed. 
• The paper "Cognitive Impairment 3 Months After Moderate and Severe Traumatic Brain Injury: A Prospective Follow-Up Study" gives us the result of cognitive tests on people who had brain injuries as the result of events such as falls and traffic accidents.  We have some tables that are hard to read. In the Discussion section we read that after moderate Traumatic Brain Injury (TBI), "most patients had a normal neuropsychological assessment," with no more than 1 score much below normal (or, to put it more technically, no more than 1 score below 1.5 standard deviates below the norm).  We read that "even after severe [brain] injury, normal performances were found in one third of patients." The authors say, "This was unexpected." We are told that the average total IQ score of 35 subjects with moderate traumatic brain injury was an above-average score of 109, and the average total IQ score of 26 subjects with severe traumatic brain injury was an above-average score of 103. There is a reason to suspect that some subjects may deliberately perform poorly in such tests. Some of the subjects (such as those injured in a crash) may have pending law suits, and may think that good performance in cognitive tests may reduce their chance of being rewarded lots of money in a law suit. 
• At the page here, we read an account of a girl who had the left half of the brain removed in a hemispherectomy operation, to try to stop severe seizures. We hear of a successful operation. We are told, "In addition to the seizures, Rehab also struggled with being able to remember things before her surgery." In the next sentence we hear one of the girl's parents saying, "Her memory was so poor, but now she remembers everything."  This is the opposite of what you would expect under the "brains make minds" hypothesis. 
• The paper "Neuropsychological functioning during the year following severe traumatic brain injury" studied cognitive functioning in 65 subjects who had severe brain damage, mostly after road traffic crashes. The patients were rated with a level of impairment of "mild" or "severe" on various measures, based on tests 6 months after the injury and 1 year after. Fewer than half of the subjects were rated as having "severe" impairment in memory performance tests taken at the 1-year mark. Only 9% of the subjects were rated as having "severe" impairment in one test of executive function at the 1-year mark, with a minority rated as having "severe" impairment in another test executive function at the 1-year mark. One test of attention at the 1-year mark result showed only 8% with a severe impairment, and another test of attention at the 1-year mark result showed only 28% with a severe impairment. There is a reason to suspect that some subjects may deliberately perform poorly in such tests. Some of the subjects (such as those injured in a traffic accident) may have pending law suits, and may think that good performance in cognitive tests may reduce their chance of being rewarded lots of money in a law suit. Moreover, we must also wonder whether the scientists selecting the subjects had a bias in looking for subjects with particularly bad memory problems. The average IQ of the brain-damaged subjects was 93, and we don't know whether this below-average result was caused by brain injury.  There is reason to suspect that the set of average people suffering from traffic accident brain damage may be slightly below average in IQ, given that higher IQ might tend to avoid such accidents. 
• The paper "Association of Traumatic Brain Injury With Dementia and Memory Decline in Older Adults in the United States" used a very large sample of 9,794 patients who had an assessment of traumatic brain injury.  The study says, "There was no significant relation between history of TBI [traumatic brain injury] with LOC [loss of consciousness] and memory score or memory decline." We read this: "In a nationally representative prospective cohort of older adults free of dementia at baseline, we did not find evidence for any long-term associations between history of TBI [traumatic brain injury] with LOC [loss of consciousness]  (of unknown frequency and severity) and risk of dementia over 14 years of follow-up. " We read that "similarly, decline in memory performance did not differ between participants with or without history of TBI with LOC." The authors state, "our findings showing no association between TBI history with LOC and dementia are consistent with the results of several other recent studies looking at dementia, AD [Alzheimer's Disease], or AD biomarkers or neuropathology." 
• The paper "Working Memory after Traumatic Brain
  Injury in Children" tested working memory in eighty children with mild or severe traumatic brain injury (TBI). The paper has nice easy-to-read graphs comparing the performance of the brain-injured with controls, and the first two of the graphs show no appreciable difference in performance in two working memory tests, even when comparing the severe cases with control (uninjured cases).  
• The paper "Central executive system impairment in traumatic brain injury" is one that does not give us a random sample of patients with traumatic brain injury, because the paper tells us this about its 64 patients: "Patients were selected for participating in the study if they complained of lack of attention, poor
  memory or loss of efficiency in everyday life." Despite such a selection bias, Table III of the paper tells us that the majority of the subjects had "normal performance" in long-term memory acquisition, long-term memory storage, long-term memory delayed recall, sustained attention and short-term memory, with an average of about 60% of the subjects being normal in such areas.  
• At the University of Chicago page here, we read, "Nordli recalled a patient whose IQ rose to 100, a normal intellect, from 80 before hemispherectomy." The patient seemed to get much smarter after they took out half of the brain. 
• The very interesting paper "Preserved Cognition After Right Hemispherectomy" gives us extensive performance tests for a woman who had almost all of her right brain removed after a severe stroke at age 29. We have a very good visual showing that her performance on a wide variety of cognitive tests is average or slightly below average. 

A 2020 paper gives us an indication of the appalling failure of neuroscientists and doctors to properly test for losses of pre-surgical episodic memories and pre-surgical learning in people who had hemispherectomy operations. We read this:

"Only four studies have investigated memory functioning prior to and following hemispherectomy surgery. It is worth noting that all used short-term memory tasks, typically involving immediate repetition or recognition and did not test for more challenging aspects of memory involving recall or recognition over longer delays."

The authors of a 2017 paper tell us something similar. Referring to hemispherectomy operations in which half of the brain is removed, it says this:

" Physicians have long wondered about the surprising finding that one can lead a normal life with only one hemisphere....

The discrepancy between cerebral and cognitive functioning in these cases is strikingly highlighted by the fact that most patients, even adults, do not seem to lose their long-term memory such as episodic (autobiographic) memories. Even so, this puzzle, and possible explanatory models for this retention of long-term memory, is only rarely

discussed in the medical literature dealing with hemispherectomy. Although memory features are sometimes assessed by using the Wechsler Memory Scale (e.g., Loddenkemper et al., 2004), we were unable to find a single peer-reviewed publication in which the peculiar retention of the patient's autobiographic memory was explicitly addressed. That said, this remarkable phenomenon was at least casually mentioned by authors such as Dandy (1933) and Bell and Karnosh (1949), who stated that their patient's memory seemed unimpaired after hemispherectomy. Similarly, Vining et al. (1997) were surprised by the apparent retention of memory after the removal of the left or the right hemisphere of their patients. Dorman (1991) described the extraordinary case of a subject who was able to perform brilliant calendar calculations, although his left hemisphere had been removed several years before."

Despite this appalling failure to properly test whether episodic memories and learned information are preserved after removing half of a brain, several of the studies quoted above make statements strongly suggesting that such memories are preserved after removal of half a brain, contrary to the dogma that memories are stored in brains. And when studies such as the ones above tell us that there are usually no major cognitive effects of removing half of a brain, we can regard this as being a rather clear indication that episodic memories and learned information are well-preserved after removal of half of a brain, as any major loss of such  episodic memories and learned information would be a severe cognitive effect that should be reported. 

The quote above refers to Dandy. Here is the basis of the reference. The case of Dandy's patients are reported in the American Journal of Psychology, Vol. 46, No. 3 (Jul., 1934), pages 500-503. We read this: 

"Dandy has completely removed the right cerebral hemisphere from eight patients. He has performed total extirpations of one or more lobes much oftener... There are tabulated below certain generalizations on the effects of removing the right hemisphere.... The operation was the complete extirpation of the right frontal, temporal, parietal, and occipital lobes peripheral to the corpus striatum. The weight of the tissue removed varies, with the pathological conditions involved, from 250 to 584 grm [grams].Coherent conversation began within twenty-four hours after operation, and in one case on the afternoon of the same day. Later examinations showed no observable mental changes. The patients were perfectly oriented in respect of time, place, and person; their memory was unimpaired for immediate and remote events; conversation was always coherent; ability to read, write, compute, and learn new material was unaltered. Current events were followed with normal interest. There were no personality changes apparent; the patients were emotionally stable, without fears, delusions, hallucinations, expansive ideas or obsessions, and with a good sense of humor; they joked frequently. They showed a natural interest in their condition and future. They cooperated intelligently at all times throughout post-operative care and subsequent testing of function." How could the memory of patients be "unimpaired for immediate and remote events" if memories are stored in brains?

The quote above also refers to the Vining paper I quote from above. The quote also refers to Bell and Karnosh, who in 1949 referred to 4 operations they had done, stating, "In all cases the relative freedom from severe physical handicap and gross mental defect after removal of almost half the cerebrum was striking" (pages 285-286). That is not a quote anyone would make if patients had lost their episodic or learned memories. 

All in all, the results discussed above are consistent with the idea that the human brain is not the storage place of human memories and is not the source of the human mind.  The results are not the results we would get if brains stored human memories and brains produced minds.