The main theory of a brain storage of memories is that people acquire new memories through a strengthening of synapses. There are many reasons for disbelieving this claim. One is that information is generally stored through a writing process, not a strengthening process. It seems that there has never been a verified case of any information being stored through a mere process of strengthening. Another reason for rejecting the claim is that human memories can last 1000 times longer than the average lifetime of proteins in the brain. A scientific paper states, "Recent studies have revealed that most proteins, including synaptic proteins, have half-lives that range between 5 and 7 days (Cohen et al., 2013, Dörrbaum et al., 2018)." The average lifetime of a protein is about twice its half-life.
The 2018 paper here is entitled "Brain tissue plasticity: protein synthesis rates of the human brain." It tells us the astonishing fact that proteins in the human brain are replaced at a rate of 3% to 4% per day. We read this:
"Where skeletal muscle tissue has been shown to turnover at a rate of 1–2% per day, here we show that brain tissue turns over much faster at a rate of 3–4% per day. This would imply complete renewal of brain tissue proteins well within 4–5 weeks. From a physiological viewpoint this is astounding, as it provides us with a much greater framework for the capacity of brain tissue to recondition. Moreover, from a philosophical perspective these observations are even more surprising. If rapid protein turnover of brain tissue implies that all organic material is renewed, then all data internalized in that tissue are also prone to renewal. These findings spark (even) more debate on the interpretation and (long-term) storage of data in neural matter, the capacity of humans to consciously or unconsciously process data, and the (organic) basis of our own personality and ego. All of this becomes quite remarkable in light of such rapid protein turnover rates of the human brain."
Such rapid replacement of brain proteins is utterly inconsistent with claims that brains store old memories of what someone learned decades ago. A person like me remembers many things he learned 50 years ago, but if my brain was storing my memories, I would not be able to remember back more than a few months, given a 3% per day replacement of brain proteins. A 2022 scientific paper confesses this:
"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."
If it were true that memories were stored by a strengthening of synapses, this would be a slow process. The only way in which a synapse can be strengthened is if proteins are added to it. We know that the synthesis of new proteins is a rather slow effect, requiring many minutes of time. In addition, there would have to be some very complicated encoding going on if a memory was to be stored in synapses. The reality of newly-learned knowledge and new experience would somehow have to be encoded or translated into some brain state that would store this information. When we add up the time needed for this protein synthesis and the time needed for this encoding, we find that the theory of memory storage in brain synapses predicts that the acquisition of new memories should be a very slow affair, which can occur at only a tiny bandwidth, a speed which is like a mere trickle. Do a Google image search for "speed of protein synthesis" and you will see charts that look like this (with data point dots scattered across the lines):
Don't make the mistake of thinking that a brain storage of new memories would occur as quickly as the speed of protein synthesis. Such a storage would rely on three things that would be slow:
(1) Protein synthesis itself, which would require an average of multiple minutes.
(2) Much additional time required for some act by which sensory information was encoded in some never-discovered storage format allowing sensory information to be translated into brain states or synapse states.
(3) The time needed for signal transmission to occur across various parts of the brain, which would be quite an additional slowing factor, because of the relatively slow speed of transmission across synapses and dendrites, illustrated by the diagram below:
The synaptic gaps of chemical synapses and relatively slow dendrites (speed bumps for the brain) vastly outnumber myelinated axons, meaning for the brain the slowing parts vastly outnumber the fast parts.
Memory contests show that some humans can actually acquire new memories at a speed very many times greater than the slow speed that would occur if brains were storing memories by protein synthesis. For example, according to a page on the site of the Guinness Book of World Records, "The fastest time to memorize and recall a deck of playing cards is 13.96 seconds, achieved by Zou Lujian (China) at the 2017 World Memory Championships held in Shenzhen, Guangdong Province, China, on 6-8 December 2017." Memorization speeds this fast utterly discredit claims that learning occurs by synapse strengthening, which would require the synthesis of new proteins, something which would require multiple minutes.
The page here on www.wikipedia.org describes a competition called the World Memory Championships, which has the website here. There are various different competitions, which are described in Chapter 7 (page 57) of the handbook you can read here:
Discipline 1: a competition to memorize as many abstract images as possible, given 15 minutes to memorize, and 30 minutes to recall. (Page 58.)
Discipline 2: a competition to memorize as many binary numbers as possible given 5 minutes to memorize, and 15 minutes to recall (national level), or 30 minutes to memorize, and 60 minutes to recall (international level). (Page 62.)
Discipline 3: a competition to memorize as many random decimal digits ( such as 8, 9, and 2) as possible, given 15 minutes to memorize, and 30 minutes to recall (national level), or 30 minutes to memorize, and 60 minutes to recall (international level), or 60 minutes to memorize, and 120 minutes to recall (world level). (Page 67.)
Discipline 4: a competition to memorize as many name and face combinations as possible, given 5 minutes to memorize, and 15 minutes to recall (national level), or 15 minutes to memorize, and 30 minutes to recall (international level or world level). (Page 70.) Competitors are asked to provide names when shown a face.
Discipline 5: a "Speed Numbers" competition to memorize as many random decimal digits ( such as 8, 9, and 2) as possible, given 5 minutes to memorize, and 15 minutes to recall. (Page 75.)
Discipline 6: a competition to memorize as many pairs of dates and fictional events as possible, given 5 minutes to memorize, and 15 minutes to recall. (Page 80.)
Discipline 7: a competition to memorize as many separate packs of shuffled playing cards as possible, given 10 minutes to memorize, and 30 minutes to recall (national level), or 30 minutes to memorize, and 60 minutes to recall (international level), or 60 minutes to memorize, and 120 minutes to recall (world level). (Page 82.)
Discipline 8: a competition to memorize as many random words as possible, given 5 minutes to memorize, and 15 minutes to recall (national level), or 15 minutes to memorize, and 30 minutes to recall (international level or world level). (Page 87.)
Discipline 9: a 'Spoken Numbers" competition to memorize as many spoken numbers as possible, with the numbers being read at a rate of one number per second. (Page 92, complicated rules.)
Discipline 10: a "Speed Cards" competition to commit to memory as many cards as possible, given 5 minutes or less for memorization, and only 5 minutes for recall. (Page 98.)
Discipline 1, abstract images: Two competitors in 2021 (Huang Jinyao and Xu Yangran) were able to memorize more than 1000 abstract images in only 15 minutes (or score more than 1000 points on such a competition, indicating similar ability). Discipline 4, face and name combinations: Katie Kermode was able to recall the names of 224 previously unseen people from their images, having had only 15 minutes to memorize their names (IAM World Championship 2018). Similarly, the scientific paper here says someone identified as SM1 "memorized 215 German names to the corresponding faces within 15 minutes at the Memoriad in 2015 in Istanbul." (The paper stated that the super-memorizers it studied did not have increased hippocampal volumes.) Several Mongolian or Chinese contestants were able to recall the names of more than 600 previously unseen people from their images, having had only 15 minutes to memorize their names (2021 World Memory Championships). Discipline 5, Speed Numbers: Wei Quinru was able to recall 642 digits memorized in a 5-minute period (Korea Open Memory Championship 2024). Four people were able to each recall more than 800 digits memorized in a 5-minute period (2021 World Memory Championships). Discipline 6, Dates and Fictional Events: Prateek Yadav memorized in 5 minutes dates corresponding to 154 fictional events (2019). Several other contestants memorized in 5 minutes dates corresponding to 700+ fictional events (2021 World Memory Championships).
Below from the World Memory Championships site is a table showing some of the best performers (link).
What we have in the performance records above is what can be roughly describing as lightning-fast memorization ability. Such an ability has been demonstrated by many subjects, doing many different types of memorization. The performances listed above are many times faster than any conceivable result that could be produced if memories are stored in brains. There does not exist any detailed credible theory that can explain fast memorization by neural or synaptic processes. When neuroscientists say something about how memories form, they typically engage in hand-waving that vaguely refers to processes that are known to be very slow, such as synaptic strengthening.
Routinely displaying instant recall abilities utterly unaccountable by the activity of brains completely lacking in addresses, sorting or indexes (the things that make fast retrieval possible in computers), humans do not recall at the speed of brains. Humans recall at the speed of souls. And the fastest memorizers do not memorize at the speed of brains. Such memorizers memorize at the speed of souls.
For other posts documenting the ability of some humans to memorize at a blazing fast speed, see my posts with a tag of "photographic memory" or "eidetic memory." On page 29 of the nineteenth century book here, we have an interesting account of photographic memory obtained under hypnosis (with it apparently progressing to become photographic memorization that could occur outside of hypnosis). The author states that eventually outside of hypnosis "the duration of a single second or a mere
glimpse at the page was sufficient for the pupils to retain in their memory the whole contents of it."
