New Poll Suggests About 29% of Neuroscientists Doubt the Synaptic Memory Theory

 Although it is often claimed that memories are stored in the brain (specifically in synapses), there is no place in the brain that is a plausible storage site for human memories that can last for 50 years or longer. The proteins that make up both synapses and dendritic spines are quite short-lived, being subject to very high molecular turnover which gives them an average lifetime of only a few weeks or less. The 2018 study here precisely measured the lifetimes of more than 3000 brain proteins from all over the brain, and found not a single one with a lifetime of more than 75 days (figure 2 shows the average protein lifetime was only 11 days).  

Both synapses and dendritic spines are a “shifting sands” substrate absolutely unsuitable for storing memories that last reliably for decades. Synapses are connected to dendritic spines, which have short lifetimes. A 2018 paper has a graph showing a 5-day "survival fraction" of only about 30% for dendritic spines in the cortex.  A 2014 paper found that only 3% of new spines in the cortex persist for more than 22 days. Speaking of dendritic spines, a 2007 paper says, "Most spines that appear in adult animals are transient, and the addition of stable spines and synapses is rare." A 2016 paper found a dendritic spine turnover rate in the neocortex of 4% every 2 days. A 2018 paper found only about 30% of new and existing dendritic spines in the cortex remaining after 16 days (Figure 4 in the paper). 

So it should be doubly-clear that synapses cannot store memories that can last for decades. Similarly there are two reasons why information would not last long if written on maple leaves outdoors: (1) the fact that maple leaves decay after a few months, and (2) the fact that the wind tends to blow away leaves lying outdoors. 

If humans were storing their memories in brains, there would have to be a fantastically complex translation system (almost infinitely more complicated than the ASCII code or the genetic code) by which mental concepts, words, images and episodic memories are translated into neural states. But no trace of any such system has ever been found, no one has given a credible detailed theory of how it could work, and if it existed it would be a “miracle of design” that would be naturally inexplicable.

If human brains actually stored conceptual and experiential memories, the human brain would have to have both a write mechanism by which exact information can be precisely written, and a read mechanism by which exact information can be precisely read. The brain seems to have neither of these things. There is nothing in the brain similar to the “read-write” heads found in computers.  

If memories were to be stored in a brain, it would take you "ages" to retrieve an answer to a question, because brains are totally lacking in any of the things that make fast retrieval possible: sorting, addresses and indexes. The brain has no type of addresses or coordinates or indexes. The brain has a structure in which neurons are rooted in place like trees in a forest, and synapses are rooted in place like the roots of trees in a forest. With such a physical arrangement, sorting is impossible. 

 So if memories were stored in brains, you would have to suffer the most ridiculously long delays every time you wanted to retrieve knowledge or a memory. 

As discussed here, humans can form new memories instantly, at a speed much faster than would be possible if we were using our brains to store such memories. It is typically claimed that memories are stored by “synapse strengthening” and protein synthesis, but such things are relatively sluggish processes that do not work fast enough to explain the formation of memories that can occur instantly.

For decades microscopes have been powerful enough to detect memories in brains, if memories existed in brains. Very much brain tissue has been studied by the most powerful microscopes: both brain tissue extracting from living patients, and brain tissue extracted from someone very soon after he died. Very many thousands of brains preserved soon after death have been microscopically examined.  Microscopes now allow us to see very clearly what is in the tiniest brain structures such as dendritic spines and synapse heads. But microscopic examination of brain tissue has failed to reveal any trace whatsoever of learned information in a brain.  No one has found a single letter of the alphabet stored in a brain; no has found a single number stored in a brain; and no one has ever found even a single pixel of something someone saw a day or more before.  If memories were stored in human brains, microscopes would have revealed decisive evidence of such a thing decades ago.  But no such evidence has appeared. 

There is nothing in the brain that looks like learned information stored according to some systematic format that humans understand or do not understand. Even when scientists cannot figure out a code used to store information, they often can detect hallmarks of encoded information. For example, long before Europeans were able to decipher how hieroglyphics worked, they were able to see a repetition of symbolic tokens that persuaded them that some type of coding system was being used. Nothing like that can be seen in the brain. We see zero signs that synapses or dendritic spines are any such things as encoded information. 

We know that human memory recall can occur massively with complete accuracy. There are numerous cases of people who memorized with complete accuracy the text of books of hundreds of pages. But synapses do not reliably transmit information. Scientists have repeatedly told us that an individual synapse will transmit a nerve signal with a reliability of 50% or less. So every time a nerve signal crosses a synapse, it is a coin flip as to whether that signal will be successfully carried across the synapse gap. So how could memories could ever be reliably retrieved from synapses? That would require a gigantic number of traversals across synaptic gaps, with a 50% chance of failure during each such traversal. You could never get perfect recall of large bodies of text from such a state of affairs, or even recall that was 10% accurate. 

The theory that human memories that can last for 50 years and can be instantly recalled are stored in synapses is a theory that contradicts pretty much everything we know about systems that can permanently store and instantly retrieve information, and contradicts everything we know about synapses, and contradicts everything we observe about the best examples of human memory performance. You could reasonably compare such a theory to the theory that certain clouds in the sky are nuclear missile bases set up by the Swiss to threaten your nation. That would pretty much contradict everything we know about the Swiss, everything we know about clouds, and everything we know about nuclear missile bases. 

But, you may say, "We should trust the theory of synaptic memory because all the neuroscientists believe in it." Do they really? We don't know that at all. To determine what percentage of neuroscientists believe the dogmas typically stated by neuroscientists, you need well-designed secret ballot opinion polls; and such polls are almost never done.  A recent study attempted to poll neuroscientists on their beliefs about memory storage.  The study (which you can read here) is entitled "What are memories made of? A survey of neuroscientists on the structural basis of long-term memory." 

Unfortunately the study fails to follow some of the main principles that should be followed by any study attempting to do an opinion poll of scientists. Specifically:

(1) The survey was not a secret ballot survey. Scientists were sent emails encouraging them to participate in the survey. The survey form promised anonymity, but it seemed like an arrangement where the participants had to trust that those running the survey would not reveal how individual scientists had voted. Anyone responding might have suspected that there might be some way in which his responses could be identified publicly as coming from him, if there were some future  breach in the promised confidentiality. 

Imagine you are a scientist getting an email like this:

Hello, Professor Waterskein. We have here a survey we would like you to fill out, asking you about all kinds of controversial questions. Please send it back to us. Don't worry, we won't ever publicly reveal which answers you gave. We'll only publish the collected results from the entire group of respondents. 

Are you going to feel it is safe to speak your mind? Or, are you going to still fear that somehow your answers might get you into trouble if they are too candid? I think you might tend to "play it safe" by assuming the person who sent you this email (who you know nothing about) cannot be trusted. 

Devising a true secret-ballot opinion poll (as opposed to a "promised anonymity" opinion poll) requires some cleverness and ingenuity, which did not go on in this case. So we can't know how much the responses were affected by scientists thinking "I had better answer as they expect me to answer."

(2) Contrary to all good standards of properly doing opinion polls, the badly fumbling survey organizers wrote a survey form in which the survey questions are preceded by statements strongly tending to bias  respondents towards a particular type of answer.  The survey form is found here. On page 4 of the survey form, before any questions are asked, we have the statement, "Memories are not standalone entities but are embedded within the complex network structure of the brain." Such a statement precedes questions about the nature of memory creation. But the statement "stacks the deck" in favor of a particular type of answer that could be given to one or more of the questions later asked. 

The clumsiness here is very big. It is a cardinal rule of serious polling that you should not precede questions with statements tending to yield particular types of responses to that questions. So, for example, if you are doing an objective poll about Presidential Candidate William Tygersoll, you absolutely should not precede your questions about this person with a statement such as "Here are some questions about that great American hero and patriot William Tygersoll."  Or, to give another example, if you polling people about some scandal involving this candidate, you absolutely should not be preceding your questions by some statement such as "Many are deeply upset about the scandal involving William Tygersoll. We would like to ask you your opinion."

Equally bad is that the survey conductors have stated on page 4 of their survey form this untrue claim: "Some studies have already demonstrated the ability to decode simple information such as visual field from brain maps (e.g. Scholl et. al. 2020." The reference is to the "no real evidence at all" study here involving a way-too-small sample size of only three monkeys. The quoted claim is an untrue one. The paper mentioned did not "demonstrate the ability to decode simple information such as visual field from brain maps."

Once again the scientists conducting the survey have violated the first rule of conducting a survey, which is "do not do anything to pre-sell a particular answer."  Here is Question 11 that appears in the survey form:

"11.Some neuroscientists have suggested that while molecular and subcellular details play a role, the majority of information for long-term memories is likely physically stored in the brain at the level of neuronal connectivity patterns and ensembles of synaptic strengths (e.g. Poo et al., 2016).

To what extent do you agree with the following statement: ' The structural basis of long-term memories primarily consists of lasting changes in neuronal connectivity and ensembles of synaptic strengths, rather than in molecular or subcellular details.'  "

This is a blunder from any standpoint of trying to objectively survey the opinion of scientists. We have a survey question that is preceded by a sentence pre-selling a particular answer to the survey question, as if the survey conductors were interested in pushing a particular response.  

Here are the responses the survey got from the question above asking neuroscientists about agreement with the following statement: "The structural basis of long-term memories primarily consists of lasting changes in neuronal connectivity and ensembles of synaptic strengths, rather than in molecular or subcellular details."

Strongly Agree:  51 respondents

Agree:  111 respondents

Not Sure: 37 respondents

Disagree:  26 respondents

Strongly Disagree: 5 respondents

So 68 out of 230 respondents (or about 29%) refused to endorse the synaptic theory of memory, even though the survey was strongly pre-selling such a theory. 13% flatly said they disagreed or strongly disagreed with such a theory.  We can only wonder how much higher that 29% figure would be if a true secret ballot had been used, and if the survey had followed proper standards of opinion surveying, such as not trying to pre-sell some answer to the questions it was asking. 

Clearly there is no consensus of neuroscientists about the theory that memories are stored in synapses. We are being misinformed when people try to suggest that such a consensus exists. A bad example of that type of misleading statement occurred in the paper "What is memory? The present state of the engram," a paper with many misstatements and many references to junk neuroscience studies failing to qualify as robust research. In that paper Mu-ming Poo stated, "There is now general consensus that persistent modification of the synaptic strength via LTP and LTD of pre-existing connections represents a primary mechanism for the formation of memory engrams." The new poll discussed above shows there is no such consensus. 

When someone tries to make a theory sound more popular than it is, they have done one of the bad deceits of science theory pitchmen. It's a deceit as old as the hills. It works by people trying to make some not-yet-triumphant theory gain more popularity by insinuating that almost everyone already believes in it. For a discussion of the trickery and equivocation and deceit that so often occurs in such cases, see my post "So Much Misleading Talk Occurs in Claims of a Scientific Consensus."

A better-designed poll might have asked a question such as this:

"Which reflects your thinking:

• 'Human memories are stored mainly in synapses.'
• 'Human memories are stored by some other brain mechanism, perhaps something involving neurons or brain chemistry.'
• 'Most memories are not stored in brains, and human memory is mostly a spiritual, psychic or metaphysical phenomenon, or some other subtle reality different from information storage in brains.'
• 'I don't know/no answer.'

Given a question such as this, and also a secret ballot not requiring respondents to trust the confidentiality of those doing a survey,  I doubt whether even 60% of neuroscientists would choose the first answer. 

The poll discussed above also shows us that most of those professing belief in the synaptic theory of memory lack a strong confidence in it. When given a set of poll choices allowing you to choose "agree" or "strongly agree," a mere 22% of the respondents chose to say that they "strongly agree" with the theory of synaptic memory storage. 

I have been generously referring above to a synaptic theory of memory, although it is probably more accurate to say that such a thing is not even a theory, but merely a small group of vague, vacuous jargon phrases repeated by scientists who have yet to develop a real theory on this topic. It's really a "there's no there there" situation. 

Given the huge diversity of the types of things that human can remember, an actual theory of neural memory encoding would require maybe 1,000,000 times more effort than involved in the production of the diagram above. 

Below are some relevant quotes, all statements by scientists:

• "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?" 
• "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). 
• "While a lot of studies have focused on memory processes such as memory consolidation and retrieval, very little is known about memory storage" -- scientific paper (link).
• "While LTP is assumed to be the neural correlate of learning and memory, no conclusive evidence has been produced to substantiate that when an organism learns LTP occurs in that organism’s brain or brain correlate."  -- PhD thesis of a scientist, 2007 (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). 
• "How memory is stored in the brain is unknown." -- Research proposal abstract written by scientists, 2025 (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).
• ""Despite over a hundred years of research, the cellular/molecular mechanisms underlying learning and memory are still not completely understood. Many hypotheses have been proposed, but there is no consensus for any of these."  -- Two scientists in a 2024 paper (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." 
• "Despite recent advancements in identifying engram cells, our understanding of their regulatory and functional mechanisms remains in its infancy." -- Scientists claiming erroneously in 2024 that there have been recent advancements in identifying engram cells, but confessing there is no understanding of how they work (link).
• "Study of the genetics of human memory is in its infancy though many genes have been investigated for their association to memory in humans and non-human animals."  -- Scientists in 2022 (link).
• "The neurobiology of memory is still in its infancy." -- Scientist in 2020 (link). 
• "The investigation of the neuroanatomical bases of semantic memory is in its infancy." -- 3 scientists, 2007 (link). 
• "Currently, our knowledge pertaining to the neural construct of intelligence and memory is in its infancy." -- Scientists, 2011 (link). 
•  "Very little is known about the underlying mechanisms for visual recognition memory."  -- two scientists (link). 
• "Conclusive evidence that specific long-term memory formation relies on dendritic growth and structural synaptic changes has proven elusive. Connectionist models of memory based on this hypothesis are confronted with the so-called plasticity stability dilemma or catastrophic interference. Other fundamental limitations of these models are the feature binding problem, the speed of learning, the capacity of the memory, the localisation in time of an event and the problem of spatio-temporal pattern generation."  -- Two scientists in 2022 (link). 
• "The mechanisms governing successful episodic memory formation, consolidation and retrieval remain elusive,"  - Bogdan Draganski, cogntive neuroscientist (link). 
• " The mechanisms underlying the formation and management of the memory traces are still poorly understood." -- Three scientists in 2023 (link). 
• "The underlying electrophysiological processes underlying memory formation and retrieval in humans remains very poorly understood." --  A scientist in 2021 (link). 
• "As for the explicit types of memory, the biological underpinning of this very long-lasting memory storage is not yet understood." -- Neuroscientist Cristina M. Alberini in a year 2025 paper (link). 

He Had Half a Brain But "Superior Intelligence"

The failure of neuroscientists to adequately study minds is a very severe failure. You can get a PhD in neuroscience while making only a perfunctory study of human minds.  An examination of the courses required to get a Master's Degree in neuroscience will typically show that only one or two courses in psychology are required. Doing a neuroscience PhD dissertation typically involves some highly specialized research on some very narrow topic, research that does not require much in the way of additional study of human minds and the mental capabilities and mental experiences of humans.  The topic of human minds and human mental experiences is a topic of oceanic depth, requiring years of deep study for someone to get a good grasp of the full range of human mental states, human mental capabilities and human mental experiences. Very strangely, a typical neuroscientist is someone who will feel qualified to pontificate about what causes mental experiences, mental states and mental capabilities, even though he typically has done little to very deeply study mental experiences, mental states and mental capabilities.

Ask a neuroscientist to describe the best examples of high capacity and high accuracy in human memory recall, and you will be likely to get a shrug of the shoulders, or an answer that is wrong.  Ask a neuroscientist to describe the best examples of human performance in tests of extrasensory perception (ESP), and you will be likely to get a shrug of the shoulders, or an answer that is wrong. Ask a neuroscientist to describe the best examples of humans learning or memorizing things very quickly, and you will be likely to get an answer showing no study of such a topic. Ask a neuroscientist to describe the fastest examples of human calculation involving no use of any objects such as pencil, paper or blackboards, and you will likely get an answer that fails to describe the most impressive cases. 

Rather amazingly, it is also true that very many neuroscientists are not very deep and broad scholars of the topic of human brains. A typical neuroscientist may be able to tell you in very great detail about some narrow facet of human brains, and may be able to tell you in the greatest detail about how to use some machine that is used to study brains. But the same neuroscientist may have failed to properly study the topic of human brains in a way that involves learning about every relevant thing you could about human brains. Ask that neuroscientist to tell you what happens when you remove half of a human brain, and you may get an answer that is wrong. Ask that neuroscientist to tell you how reliably chemical synapses transmit nerve signals (action potentials), and you may get an answer that is wrong. Ask that neuroscientist to tell you how quickly a brain electrically shuts down when the heart stops (reaching a state called asystole), and you may get an answer that is wrong. 

Part of the job of properly studying brains is to study very thoroughly all of the most impressive cases of high mental performance despite very high brain damage. Relatively few neuroscientists show signs of having studied such a topic. In order to properly study such a topic, you must study unusual medical case histories.  Very many of the most important and relevant medical case histories are recorded in books, newspapers and magazines. But can you ever recall reading of a neuroscientist searching newspapers for unusual case histories in neuroscience? I can never recall reading of such activity by a neuroscientist. 

Luckily there are some web sites that contain very many of the most relevant examples of such medical case histories that are relevant to the question of whether the human mind is the source of the mind and whether the human mind is the storage place of human memories. One of those sites is the very site you are reading.  In my series of posts labeled "High Mental Function Despite Large Brain Damage," which you can read here, I describe many of the most important case histories that are  relevant to the question of whether the human brain is the source of the mind (keep pressing Older Posts at the bottom right to read the whole series). Now let me provide another such case, one I learned about from searching old newspaper articles for a use of the phrase "half a brain." The 1976 case is one that you can read about using the link here. Below are some excerpts from the newspaper article.

We read of a young man named Bruce Lipstadt who had a hemispherectomy operation when he was five years old, an operation that removed the left half of his brain.  Operations of that type are only done when someone is being plagued by very severe seizures, and the seizures cannot be controlled by medication.  The operation was done because as a young boy Bruce was suffering from 10 to 12 seizures a day. 

We are told that despite having the left half of his brain surgically removed, Bruce can ride a bike, swim and play sports. We are told that Bruce got an A grade (the best grade) in a course on statistics at a university. We are told Bruce's speech is normal. We are told that "although not a genius, Bruce has superior intelligence." We are told that Bruce works as a traffic controller, and that next spring he will get a degree in sociology from a university. 

The 1976 newspaper article here gives us some more details on Bruce Lipstadt. We read that his IQ tests showed his verbal IQ to be 126, well above the average IQ of 100. We read this:

A verbal IQ of 126 in a subject who had the left half of his brain removed is a result that would seem to "make mincemeat" out of claims that the brain is the source of the human mind. One of the accounts above mentions an authority named Sugar. The Bruce Lipstadt case seems to be the same one mentioned in the scientific paper here co-authored by Oscar Sugar MD, one entitled "Development of above normal language and intelligence 21 years after left hemispherectomy."

Below is a news account from 1937.

Even more dramatic cases of this type can be found by studying the cases of John Lorber, who reported above-average intelligence in quite a few subjects who had lost almost all of their brains due to disease. A scientific paper states this:

"[Lorber] described a woman with an extreme degree of hydrocephalus showing 'virtually no cerebral mantle' who had an IQ of 118, a girl aged 5 who had an IQ of 123 despite extreme hydrocephalus, a 7-year-old boy with gross hydrocephalus and an IQ of 128, another young adult with gross hydrocephalus and a verbal IQ of 144, and a nurse and an English teacher who both led normal lives despite gross hydrocephalus."

The newspaper account here tells us of a young girl who had the right half of her brain removed, and who can "speak clearly" after having had 80% of the right half of her brain removed.  The newspaper article here tells us more about the same girl. After describing the operation that removed almost all of half of her brain, the article states, "Many of her memory functions, such as her bilingual speech and comprehension skills, have remained intact, Friedman said."

The importance of such an observation can hardly be overemphasized. Bilingual speech (speaking in two languages) requires a massive amount of previous learned information. If the human brain stored memories, we should never expect bilingual speech to survive the removal of half of the brain. 

The article here tells us of Christina Santhouse had the right half of her brain removed in a hemispherectomy operation to stop seizures. We hear no mention of any loss of memory. We get a depiction of a 14-year-old child entering high school, just as a normal 14-year-old would do. 

The writer gives some creative but nonsensical explanations for the lack of any big mental effect from removing half of the brain. We are told the fairy tale story that neurons "haven't decided what they want to do when they grow up."  We are told the groundless claim that one side of the brain takes over the functions of the removed half. A much better explanation is that the functions attributed to brains were never actually produced by brains, so you can lose half a brain with relatively little effect. Your biggest laugh when reading the article is the writer's claim that "memory resides in both hemispheres of the brain, so there is little danger of losing it" when half of the brain is removed. This is as silly as claiming that you wrote your diary by filling up two thick diary books, so you won't be losing information if you burn one of those two thick diary books. 

A similar account can be read in the 1987 story here, where we learn of the preservation of learned knowledge and memories in Beth Usher, despite an operation removing the left half of her brain. 

The newspaper article here notes a case of a man who had the right half of his brain removed with "apparently no mental changes at all after the operation."

The Myths About Patient K. C. and Patient H. M.

A recent National Geographic article has an interview with Harvard scientist Daniel Schacter, who is identified as a "cognitive psychologist," an unfortunate term making an unnecessary use of the word "cognitive," rather like calling someone a specialist in numerical mathematics.  The article is on the topic of memory, and  nothing Schacter says explains any neural basis for memory.  But Schacter does reiterate one of the unfounded myths of neuroscientists and psychologists, the claim that a patient K. C. (Kurt Cochrane) could not recall any of his episodic memories from before a brain injury.  "It's fair to say that he could not remember a single specific episode from any time in his life," Schacter falsely states. The facts do not support such a claim. 

Patient K.C. had three brain injuries. At age 16 a bale of hay fell on his head. He had another brain injury in young adulthood, one not causing a loss of consciousness. These injuries seemed to have caused no cognitive problems. But he then had a motorcycle accident at age 30, which seemed to be followed by memory difficulties. According to the paper here, "His brain lesions include almost complete obliteration to the right and left hippocampi and extensive atrophy of his left and right parahippocampal gyri (more pronounced on the left)."

Even after all this brain damage, his recognition memory seemed preserved, because a paper on patient K.C. says, "Upon his transfer to the rehabilitation hospital, K.C. was noted to be reading and conversing quite well and began to recognize friends."

There seems to have been no big loss of conceptual memories or learned knowledge in patient K.C. A paper on patient K. C. ("The case of K.C.: contributions of a memory-impaired person to memory theory") says this:

"Retention of the many skills and semantic facts learned in pre-accident years enables K.C. to locate without difficulty cereal and eating utensils in the kitchen, to know that the eight-ball is the last to sink in a game of pool, and to explain the difference between a strike and spare in bowling, and between the front crawl and breast stroke. He can describe the layout of his house and summer cottage, and the shortest route between them, without any recollection of a single event that occurred at either of these places. He expects a new ‘trick’ after four cards are placed in the centre of the Bridge table and anticipates Bob Barker on the 'Price is Right' asking contestants to 'spin the wheel,'  though he cannot foresee what he himself will do when the card game or television show is over. Like many individuals suffering from amnesia, he is also able to learn new information or skills normally, such as sorting books according to the Dewey decimal system in his library job, even though he is unable to recall explicitly the circumstances of this anterograde learning, indicating preserved implicit memory."

Note the observation defying neuroscience dogma. Countless times neuroscientists have made the groundless claim that the hippocampus is vital for forming new memories. But this patient K.C. with "almost complete obliteration to the right and left hippocampi" was able to "learn new information or skills normally." 

The same paper claims that other than weaker performance in episodic memory, patient K. C. had pretty normal cognitive skills, and a normal intelligence. We read this:

"As illustrated in Table 2, results from cognitive testing show that K.C.’s intellectual and cognitive function outside the domain of episodic memory are largely, although not completely, preserved. His verbal IQ on the revised version of the Wechsler Adult Intelligence Scale (WAIS-R; Wechsler, 1981), as administered in 1996, was in the normal range, and his performance IQ was in the lower normal range, which is slightly below expected based on a verbal estimate of premorbid intelligence derived from the National Adult Reading Test (Ryan & Paolo, 1992). Nonetheless, on the Wechsler Abbreviated Scale of Intelligence (Wechsler, 1999) administered in 2003, which produces IQ scores that are highly correlated with those from the full WAIS-R battery, he obtained Full-Scale, Performance, and Verbal IQ scores of 99."

What does the paper tell us about K.C.'s episodic memory? The paper gives us some claims on this topic that contradict other things the paper says. On one hand the paper says, "What makes him different, even from many amnesic cases, is his inability to recollect any specific event in which he himself participated or any happening that he himself witnessed." But in other places the paper gives us data contradicting such claims.  

The paper gives us this data for tests of patient K.C.'s retrograde memory (memory of the past):

Retrograde memory 

AMI autobiographical (/9) 

Childhood 2 

Early adult life 3 

Recent life 1 

AMI personal semantics (/21) 

Childhood 16 

Early adult life 13.5 

Recent life 8

The references to AMI are references to the Autobiographical Memory Interview. According to the web site of the American Psychological Association, this AMI is "a semistructured interview designed to assess memory for autobiographical information, impairment of which is often indicative of retrograde amnesia (inability to recall previously learned information or past events) and potentially associated with a variety of neurological and psychiatric disorders."

The paper here tells us more about this AMI test:

"Personal semantic questions. Subjects were asked questions relating to their personal past, including names and locations of schools attended, home addresses, and names of friends. Each time period had a maximum score of 21 points. 

Autobiographical incidents questions. Subjects were asked to relate incidents that occurred during each of the three time periods and to give temporal and spatial contextual information for each incident described. Three such incidents were probed for each time period, and specifications such as “first day at work” were used as probes. Responses were recorded on the scoring sheets as close to verbatim as possible. Each incident was scored out of a possible score of 3, based on the descriptive richness and specificity in time and place of the response. The maximum score per time period was 9."

We should be suspicious about the reliability of scores given using this test, because the underlined line indicates a subjective type of rating, in which someone rating and familiar with a person's brain damage might be more more likely to assign lower scores, even when someone performs as well as control subjects. 

A look at some of the questions asked on the test indicate that they can be pretty hard, such as asking the birthday of relatives or the address of previous schools. 

Now, patient K.C. had no major memory problem until his injury at age 30. So the results listed above very much defy and contradict the paper's claim that patient K.C. had "an inability to recollect any specific event in which he himself participated or any happening that he himself witnessed." And the results listed above very much contradict Schacter's claim that patient K.C. "could not remember a single specific episode from any time in his life." The test scores above indicate very substantial episodic memory of K. C. regarding the recall of events from both the childhood and early adult stages of his life. 

In the paper we have this claim, in which the second claim contradicts the first: 

"During testing, K.C. could not produce a single episode from his past that was distinct in time and place. Performance on the personal semantics subsections was comparable to that reported by Kopelman et al. for other amnesic patients, with the childhood period classified as ‘acceptable’ according to AMI norms."

There are several questions we should ask about the first sentence in this statement:

(1) Was this first sentence a reference to merely a single testing session in which K.C. failed to recall something in his past when asked to do so only once -- or maybe a few such failures in a few such tests? If so, that is not any good evidence of an inability to recall an episodic memory from childhood or early adulthood. You might ask someone during one testing session, "Please recall an incident from your childhood or early adulthood." The person might lazily say, "Nothing comes to mind." But if the test is repeated a few days later, the patient might be able to recall several or many such incidents. 

(2) Did the patient actually recall events that happened in childhood and early adulthood, but were such recollections arbitrarily ignored because they were not regarded as sufficiently "distinct in time and place"?

We do not know the answers to these questions, so we do not know whether the claim that "K.C. could not produce a single episode from his past that was distinct in time and place" is an extremely misleading claim, based on a single testing session, or based on an unreasonable exclusion of recollections because of some arbitrary decision that the memories were not "distinct" enough. Notably, the statement "the childhood period classified as ‘acceptable’ according to AMI norms" dramatically contradicts claims that patient K.C. had no episodic memories from his childhood. 

We then read this, about an episodic memory test given patient K.C. in 1996:

"K.C. showed a similar pattern of deficit on the Galton–Crovitz task for autobiographical information, which was administered in the version developed by Moscovitch and Melo (1997). His performance improved only minimally when he was provided with additional prompts aimed at facilitating recall." 

Very suspiciously, we are not given any details of the exact score on this test. We merely hear of "a pattern of deficit," a phrase which does not at all explicitly mention a very low score. And we are told that the performance improved later. 

This is all extremely suspicious. We must suspect these authors of withholding very relevant information that contradicted their claim that patient K.C. had an "inability to recollect any specific event in which he himself participated or any happening that he himself witnessed." Why are no specific test scores given for this Galton–Crovitz test taken by Patient K.C? Probably because the numbers contradicted the claim that patient K.C.  had an "inability to recollect any specific event in which he himself participated or any happening that he himself witnessed."

Later in the paper the authors make statements that dramatically contradict their earlier claim about patient K.C.   We read this:

"To do so, we used a formal autobiographical interview requiring generation of personal events from different life periods under varying levels of retrieval support (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002). Similar to results from earlier testing of free recall (Tulving et al., 1988; Westmacott et al., 2001), K.C. was unable to produce a single personal story from any time in his life, however remote the episode. Importantly, with supplementary retrieval support in the form of specific cueing, K.C.’s performance continued to remain well below control levels (see Fig. 9), which contrasts with that of patients with frontal lesions who benefit significantly from cueing (e.g., Svoboda et al., 2002). Even those events that K.C. was able to generate with fairly rigorous verbal prompting were without the richness in episodic detail typical of the personal incidents recalled by control participants."

So, aided by a bit of cueing, which might be something like "did you ever miss a day from school from sickness" or "did you ever learn how to swim," patient K.C. was apparently able to remember pretty well events from his childhood and early adulthood.  We have this diagram (Figure 9), which clearly shows that patient K.C. could remember very many details of things that happened to him in his childhood and early adulthood. I have compacted a horizontally larger diagram to make it easier to read. 

The diagram disproves the paper's earlier claim that patient K.C. had an "inability to recollect any specific event in which he himself participated or any happening that he himself witnessed." The diagram shows K.C. recalling many details from before his accident at age 30. Later the very careless paper authors claim that "K.C. has no episodic memory whatsoever for autobiographical details, whether experienced long ago or in more recent times."  Their own graph shows the untruth of this statement, for their Figure 9 is charting that patient K.C. could recall such details. 

A 2006 paper ("Hippocampal Contributions to Recollection in Retrograde and Anterograde Amnesia") gives a diagram on episodic memory tests on patient K.C.  We have the diagram below. The "Ch." stands for childhood; the Ado. stands for adolescence; and the AE stands for "adulthood, early."  These are different periods of his life K.C. was being asked about. We clearly see that patient K.C. could recall details about events that had happened to him before his brain injury at age 30. He simply recalled fewer details than average people (designated below as controls). 

How can we explain these severe discrepancies in the paper on patient K. C. ("The case of K.C.: contributions of a memory-impaired person to memory theory"), the fact that it says things in one place that contradicts the data it gives elsewhere (and data gathered by others on this patient K.C) ? Being charitable, and trying to avoid the idea that the authors were simply lying, we can explain the discrepancy by simply supposing that the authors were guilty in places of very careless language prone to give someone the wrong idea.  Having a mere observation that in one or two tests patient K.C. did not provide an episodic memory when asked to do so, the authors seem to have carelessly stated this as the claim that the patient could not provide such a memory. 

It is all too easy to imagine how something like that could have happened. There could have occurred something like this:

Doctor: Now, could you recall some event from your childhood. 

Lazy or Unmotivated Patient: Uh, let me see...hmm, my mind's a blank.

Doctor: Oh, very interesting! I will write down "Patient could not recall any episodic memories."

But a "did not" never proves a "could not." There are 101 reasons why someone may fail to do something that he is capable of doing, when asked to do it. I once got a perfect score on the CLEP test of American History. But if you ask me to describe the 1880's in the US, I might well say something like, "My mind's a blank." However, given sufficient motivation, such as a $1000 reward, I could probably recall quite a few details about such a decade. 

Below is a a very important rule involving research on memory and amnesia:

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ONE OR TWO CASES OF "DID NOT" NEVER PROVES "COULD NOT"

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What happened, I think, is that the authors of the paper on patient K. C. ("The case of K.C.: contributions of a memory-impaired person to memory theory") were simply guilty of very careless language. All that they had in regard to patient K.C. was a "did not" when he was asked to recall some particular episodic memory. There was never any justification for concluding that he could not recall any memory from before his final accident. Other data mentioned above suggests that he could do such a thing. And there was never any motivation factor that would have justified a "could not" conclusion about an inability to recall any episodic memory. No one ever gave the patient a strong motivation to engage in some memory retrieval exercise that he might have found burdensome. 

What we must always remember is that those promoting "brains make minds" dogma and "brains store memories" dogma tend to be "give me an inch, and I'll take a mile" kind of people when it comes to arguing for their cherished beliefs. Most claims that they make about amnesia should be treated with suspicion. A neuroscientist may use the term "amnesia" for any type of shortfall on memory performance tests, which might sometimes occur for reasons other than memory deficits, as illustrated in the visual below, in which apathy is misidentified as amnesia. 

At the links below you can watch interviews with patient K.C. (Kurt Cochran), which occurred in 1988, when he was 38 years old.  You may not even notice any difficulty in his mental abilities. 

At the first link here, K. C.  is asked about how long he has lived in his house, and he answers since 1960, apparently a correct recall involving personal memory. He is answered some general knowledge questions, and answers most of them correctly. When asked about whether he owned a motorcycle or a car, he says he owned both of them, apparently a correct recall of his experience before his injury in a motorcycle accident. Asked about the make and color of his car, he answers a brown Honda. He correctly describes how to change a flat tire. In the second video here, he shows good short-term memory, repeating series of digits he is asked to repeat. In the third video here, he shows a moderately good ability to define words that are recited to him, and does moderately well on an ability to recall words that were recited to him. The fourth video has him answering two math problems well. 

In the fifth video, K. C. is shown a report he made at a job he had, which he seems to correctly identify. He is asked to describe a place he worked at, and he says it was a big two-story building. He recalls using the back entrance of the building. Asked to recall any of his co-workers who worked with him at the building, he says, "Not offhand." But then a few seconds later, around the 3:40 mark, he does name someone who worked with him in the building, an old person named John, who he says was "almost my boss." Then at the 3:52 mark K. C. is asked to identify a person who shared his office, about his age, who did the same thing he did. Around the 4:00 mark, K. C. identifies the person as Chris, also giving his last name. "Yes, very good," says the interviewer, who apparently knew that this was the correct answer. 

Here is that fifth video:

Assuming a lack of any deliberate lie by him, it is obvious that Harvard scientist Daniel Schacter did not watch these videos or did not watch them carefully. The videos clearly show Schacter's was very badly misinforming us about K. C. when he stated, "It's fair to say that he could not remember a single specific episode from any time in his life."

After watching these videos, showing fair performance on every main  type of memory, we should be suspicious that the low scores in the tests listed above were probably due to biased judgments of score raters, who knew beforehand of K.C.'s brain injuries, and who were biased judges motivated to give him low scores, to help sell a loss-of-memory-by-brain-damage narrative. If there had been judges "blind" as to his brain condition, such scores might have been much higher.  Tests of short-term memory offer little opportunity for distortion by biased judges. There is no subjectivity in rating whether a person did or did not recall a word or number you asked him to recall. Conversely, scientist appraisals of the strength of episodic memory are very subjective things, involving subjective ratings of things such as "level of detail" and "vividness."  With such a thing there is ample opportunity for rating bias in which the reported effects are largely scientists seeing whatever they were hoping to see. 

Another false claim frequently made by neuroscientists and psychologists (and writers about neuroscience) is the false claim that patient H.M. (Henry Gustav Molaison)  "could not form new memories" after having some experimental surgery in 1953.  That is not correct.

A 14-year follow-up study of patient H.M. (whose memory problems started in 1953) actually tells us that H.M. was able to form some new memories. The study says this on page 217:

"In February 1968, when shown the head on a Kennedy half-dollar, he said, correctly, that the person portrayed on the coin was President Kennedy. When asked him whether President Kennedy was dead or alive, and he answered, without hesitation, that Kennedy had been assassinated...In a similar way, he recalled various other public events, such as the death of Pope John (soon after the event), and recognized the name of one of the astronauts, but his performance in these respects was quite variable."

Another paper ("Evidence for Semantic Learning in Profound Amnesia: An Investigation With Patient H.M.") tells us this about patient H.M., clearly providing evidence that patient HM could form many new memories:

"We used cued recall and forced-choice recognition tasks to investigate whether the patient H.M. had acquired knowledge of people who became famous after the onset of his amnesia. Results revealed that, with first names provided as cues, he was able to recall the corresponding famous last name for 12 of 35 postoperatively famous personalities. This number nearly doubled when semantic cues were added, suggesting that his knowledge of the names was not limited to perceptual information, but was incorporated in a semantic network capable of supporting explicit recall. In forced-choice recognition, H.M. discriminated 87% of postmorbid famous names from foils. Critically, he was able to provide uniquely identifying semantic facts for one-third of these recognized names, describing John Glenn, for example, as 'the first rocketeer' and Lee Harvey Oswald as a man who 'assassinated the president.' Although H.M.’s semantic learning was clearly impaired, the results provide robust, unambiguous evidence that some new semantic learning can be supported by structures beyond the hippocampus proper."

Neuroscientists have no understanding of how a brain could store or preserve or retrieve memories, and they lack any credible theory on such things. Microscopic examination of brain tissue has occurred endless times from endless subjects, with the tissue often coming from just-died people or people living. Although involving the most powerful telescopes such as electron microscopes, such examination has never provided the slightest trace of learned information stored in brains, and has never provided the slightest indication that there exists any system for translating episodic memories or learned knowledge into brain states or synapse states. 

So what do you if you are someone trying to convince people that brains store memories? Again and again, such writers will follow the same deceptive pattern. Typically a writer will claim that we know brains store memories because you need a hippocampus for memory. This is despite very much data showing that claim is not true, and that people with a very badly damaged hippocampus often perform very well on memory tests.  The writer will typically offer as his proof the untrue assertion that patient H.M. had a damaged hippocampus, and could not form new memories. The quotes above show that assertion is false; patient H.M. could form new memories and could learn new things. 

Of course, such writers will never mention the fact that patient K.C. had hippocampus damage just as bad or worse than that of patient H.M, and that patient K. C. had no big impairment in his ability to learn new things.  Referring to patient K.C. we read in the paper here, "His brain lesions include almost complete obliteration to the right and left hippocampi and extensive atrophy of his left and right parahippocampal gyri (more pronounced on the left)." The same K.C. according to the paper here  was able to "learn new information or skills normally." 

Never forget that the literature of neuroscience and psychology is abundantly infested with false statements, and that there are extremely many types of false statements about brains, minds, memory and particular patients, false statements that are endlessly repeated. 

Postscript:  The recent article here documents another myth of neuroscience literature involving a particular person: the case of Phineas Gage. In the 19th century Gage suffered an accident in which a thick railroad spike was driven through his skull. He seems to have suffered no permanent damage from this huge brain injury.  But for many years people have passed false tales claiming Gage's judgment was badly damaged. The article states this:

"The available facts about Gage fly in the face of claims made about his transformation and reduced capacities. Macmillan gave a carefully sourced description of the demanding nature of Gage’s job in Chile: the dependability required of him in rising in the small hours, loading passengers’ luggage and possibly handling fares; the high level of dexterity and sustained attention necessary for driving six horses; the foresight and self-control involved in navigating the unwieldy coach along the crowded and sometimes treacherous Valparaíso-Santiago road. He also pointed out that Gage, at first a stranger to Chile, would have had to learn something of its language and customs and ‘deal with political upheavals that frequently spilled into everyday life’. "

 The article makes clear that no statements on Gage should be trusted unless they come from the nineteenth century, and that the statements about Gage's behavior made in that time are so scant that there is no good warrant for the claim that Gage's judgment or intellect was damaged. One of the 19th century sources says that friends of Gage said he "was no longer Gage," but second-hand testimony like that (one person saying that other unnamed persons said something) should not be highly trusted. The article documents cases of claims about Gage having no basis in sources from his time, cases of embellishments (fictional claims) that were then repeated over and over again by different writers. 

The article says this:

"When discussing social disinhibition, most researchers cite cases in addition to Gage, but very few miss out Gage. His was the story that started off the whole idea and has remained by far the most frequently referenced, both in the clinical literature and in wider English language publishing. Given just how weak the evidence of his disinhibition really is, this level of reliance on his case seems astonishing."

Gage's injury (link)