The brain, memory and thought — The World, with the Evidence

Black-and-white anatomical drawing of a human brain, with its folds. — Drawing of the human brain (Henry Vandyke Carter, before 1858). Henry Vandyke Carter, Public domain, source

Three very widespread claims about the brain are false, and were corrected long ago.

Yet they still circulate. What follows sets out what science really says about each of them — and why understanding where they come from is better than laughing at them.

Three received ideas under scrutiny

1. “We only use ten per cent of our brain”

This is probably the most widespread false claim about the human body.

How we know it is false

Through imaging: Activity is observed in all regions of the brain over the course of an ordinary day. There is no silent or unused area.
Through metabolic cost: The brain consumes about 20% of the body’s energy at rest for only 2% of its mass. No organism would spend a fifth of its resources on an organ that is 10% efficient. And during childhood, the same brain demands much more: up to two-thirds of the energy the body spends at rest.
Through clinical evidence: A lesion, even a small one, can have major consequences for behaviour. If 90% of the brain were useless, most injuries would go unnoticed.¹

What was true at the origin

At no moment do all the neurons fire simultaneously. Indeed, an excessive, synchronised discharge of large assemblies of neurons is characteristic of an epileptic seizure. The brain works through the selective activation of targeted networks. This fact is correct, but it does not mean that part of the brain goes unused.²

What is truly remarkable

The brain has no inactive reserve: it reorganises itself. Its synaptic connections are created, strengthened or eliminated according to learning and experience (neuroplasticity).

2. “There are ‘left-brain’ and ‘right-brain’ profiles”

This idea sets a logical, analytical left hemisphere against a creative, intuitive right hemisphere.

How we know it is false

One study measured this in one thousand and eleven people aged seven to twenty-nine, by measuring the lateralisation of the connections between more than seven thousand regions of the brain at rest.³

The result is worth knowing precisely because it does not say that lateralisation does not exist. On the contrary, the study identifies nine hubs on the left and eleven on the right, all very real.⁴

What it establishes is subtler: these hubs do not add up. A person with one strongly left-lateralised network does not, for all that, have all their other networks lateralised on the same side.⁵

The authors’ conclusion is clear: lateralisation is a local property of brain networks, not a global one. Their data show no individual profile of a “left-brained” or “right-brained” person.⁶

Two secondary results are worth mentioning: no difference between the sexes, and a slight increase in lateralisation with age.⁷

What was true at the origin

Functional lateralisation does indeed exist: certain functions, such as language processing, are predominant in one hemisphere.

So the myth does not come from nowhere. It comes from a generalisation — moving from a particular function located on one side to a whole person who would supposedly be “on one side”.

3. “Everyone has their own learning style: visual, auditory, kinaesthetic”

This model (VAK) claims that a pupil learns better if information is presented in their preferred sensory mode.

How we know it is false

Controlled studies in cognitive psychology and education science have not demonstrated any improvement in results when the teaching mode is aligned with the learner’s declared “style”. It is one of the most widespread neuromyths, including among teachers.⁸

What was true at the origin

Individuals have declared preferences and varied aptitudes. However, optimal learning depends on the nature of the content (a diagram for geometry, a sound for pronunciation) and on the level of cognitive engagement, rather than on a fixed sensory profile.

Remembering is reconstructing

A fourth idea deserves to be undone, because it concerns the very tool with which this page is being read. A memory is not a video recording replayed identically. Remembering is a process of reconstruction: at each recall, the brain reassembles elements, and it may incorporate information acquired after the event — what others have said, what one expected, what one has deduced since.⁹

An important consequence: sincere testimony can be factually inaccurate without the slightest intention to deceive. It was a related mechanism — expectation shaping what one believes one sees — that led competent astronomers to map canals on Mars (1.14), and it was against this type of bias that four teams worked in isolation before comparing their images of the black hole M87* (1.10).

This does not mean that memory is faulty: it remains effective in everyday life. It simply works by reconstruction, not by replay.¹⁰

What this field implies

In neuroscience, the spread of preliminary results often runs ahead of rigorous conclusions. To assess a piece of information about the brain:

Distinguish measurement from interpretation: The measurement indicates activity (e.g. local blood flow); the interpretation seeks to give it a psychological meaning.
Put imaging in context: A map of brain activation is not a direct picture of thought, but a statistical model resulting from complex processing.
Date the work: Understanding of brain networks is evolving rapidly with observation tools.

Note 1

In the average adult human, the brain represents about 2% of the body weight. Remarkably, despite its relatively small size, the brain accounts for about 20% of the oxygen and, hence, calories consumed by the body (1). This high rate of metabolism is remarkably constant despite widely varying mental and motoric activity (2).

Raichle, Marcus E. and Gusnard, Debra A., “Appraising the Brain’s Energy Budget”, Proceedings of the National Academy of Sciences, vol. 99, no. 16, 2002, p. 10237-10239

but rather in childhood (66.3% and 65.0% of RMR and 43.3% and 43.8% of DER)

Kuzawa, Christopher W. et al., “Metabolic Costs and Evolutionary Implications of Human Brain Development”, Proceedings of the National Academy of Sciences, vol. 111, no. 36, 2014, p. 13010-13015

We now know that destruction of even small areas of the human brain can have devastating effects on behavior.

Chudler, Eric H., “Do We Use Only 10% of Our Brains?”, Neuroscience For Kids, University of Washington

See the full note ↓

Note 2

the brain never activates all its 86 billion brain cells at the same time […] The uncontrolled mass activation of brain cells is called a seizure […]

Karabanov, Anke Ninija, “Myth: We only use 10 percent of our brain”, ScienceNordic, 26 May 2021

See the full note ↓

Note 3

Data were analyzed from publicly available resting state scans for 1011 individuals between the ages of 7 and 29. For each subject, functional lateralization was measured for each pair of 7266 regions covering the gray matter

Nielsen, Jared A., Zielinski, Brandon A., Ferguson, Michael A., Lainhart, Janet E. and Anderson, Jeffrey S., “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging”, PLOS ONE, vol. 8, no. 8, e71275, 2013

See the full note ↓

Note 4

Nine left- and 11 right-lateralized hubs were identified as peaks in the degree map from the graph of significantly lateralized connections.

See the full note ↓

Note 5

Connections involving only left- or only right-lateralized hubs showed positive correlation across subjects, but only for connections sharing a node.

See the full note ↓

Note 6

Lateralization of brain connections appears to be a local rather than global property of brain networks

our data are not consistent with a whole-brain phenotype of greater "left-brained" or greater "right-brained" network strength across individuals

See the full note ↓

Note 7

Small increases in lateralization with age were seen, but no differences in gender were observed.

See the full note ↓

Note 8

Although the literature on learning styles is enormous, very few studies have even used an experimental methodology capable of testing the validity of learning styles applied to education. Moreover, of those that did use an appropriate method, several found results that flatly contradict the popular meshing hypothesis.

Pashler, Harold, McDaniel, Mark, Rohrer, Doug and Bjork, Robert, “Learning Styles: Concepts and Evidence”, Psychological Science in the Public Interest, vol. 9, no. 3, 2008, p. 105-119

The two most commonly endorsed neuromyths across all groups were related to learning styles and dyslexia.

Macdonald, Kelly, Germine, Laura, Anderson, Alida, Christodoulou, Joanna and McGrath, Lauren M., “Dispelling the Myth: Training in Education or Neuroscience Decreases but Does Not Eliminate Beliefs in Neuromyths”, Frontiers in Psychology, vol. 8, 2017

See the full note ↓

Note 9

The formulation of new memories is sometimes called construction, and the process of bringing up old memories is called reconstruction. Yet as we retrieve our memories, we also tend to alter and modify them. A memory pulled from long-term storage into short-term memory is flexible. New events can be added and we can change what we think we remember about past events, resulting in inaccuracies and distortions.

Spielman, Rose M., Jenkins, William J. and Lovett, Marilyn D., Psychology 2e, OpenStax, 2020, section 8.3 “Problems with Memory”

See the full note ↓

Note 10

Human memory is not a literal reproduction of the past, but instead relies on constructive processes that are sometimes prone to error and distortion.

Schacter, Daniel L., “Constructive Memory: Past and Future”, Dialogues in Clinical Neuroscience, vol. 14, no. 1, 2012, p. 7-18

See the full note ↓

Notes and sources

↑
Passage The brain consumes about 20% of the body’s energy at rest for only 2% of its mass.
In the average adult human, the brain represents about 2% of the body weight. Remarkably, despite its relatively small size, the brain accounts for about 20% of the oxygen and, hence, calories consumed by the body (1). This high rate of metabolism is remarkably constant despite widely varying mental and motoric activity (2).
Source Raichle, Marcus E. and Gusnard, Debra A., “Appraising the Brain’s Energy Budget”, Proceedings of the National Academy of Sciences, vol. 99, no. 16, 2002, p. 10237-10239, p. 10237, 1st paragraph of the article (first 3 sentences).
Open access open the source · checked on 27 October 2026
Passage And during childhood, the same brain demands much more: up to two-thirds of the energy the body spends at rest.
but rather in childhood (66.3% and 65.0% of RMR and 43.3% and 43.8% of DER)
Source Kuzawa, Christopher W. et al., “Metabolic Costs and Evolutionary Implications of Human Brain Development”, Proceedings of the National Academy of Sciences, vol. 111, no. 36, 2014, p. 13010-13015, abstract (peak in the brain’s glucose consumption, as a share of resting metabolic rate, RMR).
Open access open the source · checked on 24 October 2026
Passage A lesion, even a small one, can have major consequences for behaviour.
We now know that destruction of even small areas of the human brain can have devastating effects on behavior.
Source Chudler, Eric H., “Do We Use Only 10% of Our Brains?”, Neuroscience For Kids, University of Washington, “Where Did the 10% Myth Begin?” section, paragraph on Karl Lashley’s experiments.
Open access open the source · checked on 27 October 2026
↑
Passage At no moment do all the neurons fire simultaneously […] is characteristic of an epileptic seizure.
the brain never activates all its 86 billion brain cells at the same time […] The uncontrolled mass activation of brain cells is called a seizure […]
Source Karabanov, Anke Ninija, “Myth: We only use 10 percent of our brain”, ScienceNordic, 26 May 2021, subheading “No secret store of untapped brain power”.
Open access open the source · checked on 27 October 2026
↑
Passage one thousand and eleven people aged seven to twenty-nine, by measuring the lateralisation of the connections between more than seven thousand regions of the brain at rest
Data were analyzed from publicly available resting state scans for 1011 individuals between the ages of 7 and 29. For each subject, functional lateralization was measured for each pair of 7266 regions covering the gray matter
Source Nielsen, Jared A., Zielinski, Brandon A., Ferguson, Michael A., Lainhart, Janet E. and Anderson, Jeffrey S., “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging”, PLOS ONE, vol. 8, no. 8, e71275, 2013, abstract.
Open access open the source · checked on 9 September 2026
↑
Passage the study identifies nine hubs on the left and eleven on the right, all very real
Nine left- and 11 right-lateralized hubs were identified as peaks in the degree map from the graph of significantly lateralized connections.
Source Nielsen, Jared A., Zielinski, Brandon A., Ferguson, Michael A., Lainhart, Janet E. and Anderson, Jeffrey S., “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging”, PLOS ONE, vol. 8, no. 8, e71275, 2013, abstract.
Open access open the source · checked on 9 September 2026
↑
Passage these hubs do not add up. A person with one strongly left-lateralised network does not, for all that, have all their other networks lateralised on the same side.
Connections involving only left- or only right-lateralized hubs showed positive correlation across subjects, but only for connections sharing a node.
Source Nielsen, Jared A., Zielinski, Brandon A., Ferguson, Michael A., Lainhart, Janet E. and Anderson, Jeffrey S., “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging”, PLOS ONE, vol. 8, no. 8, e71275, 2013, abstract.
Open access open the source · checked on 24 October 2026
↑
Passage lateralisation is a local property of brain networks, not a global one
Lateralization of brain connections appears to be a local rather than global property of brain networks
Source Nielsen, Jared A., Zielinski, Brandon A., Ferguson, Michael A., Lainhart, Janet E. and Anderson, Jeffrey S., “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging”, PLOS ONE, vol. 8, no. 8, e71275, 2013, abstract.
Open access open the source · checked on 9 September 2026
Passage Their data show no individual profile of a “left-brained” or “right-brained” person.
our data are not consistent with a whole-brain phenotype of greater "left-brained" or greater "right-brained" network strength across individuals
Source Nielsen, Jared A., Zielinski, Brandon A., Ferguson, Michael A., Lainhart, Janet E. and Anderson, Jeffrey S., “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging”, PLOS ONE, vol. 8, no. 8, e71275, 2013, abstract.
Open access open the source · checked on 9 September 2026
↑
Passage no difference between the sexes, and a slight increase in lateralisation with age
Small increases in lateralization with age were seen, but no differences in gender were observed.
Source Nielsen, Jared A., Zielinski, Brandon A., Ferguson, Michael A., Lainhart, Janet E. and Anderson, Jeffrey S., “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging”, PLOS ONE, vol. 8, no. 8, e71275, 2013, abstract.
Open access open the source · checked on 9 September 2026
↑
Passage Controlled studies […] have not demonstrated any improvement in results when the teaching mode is aligned with the learner’s declared “style”.
Although the literature on learning styles is enormous, very few studies have even used an experimental methodology capable of testing the validity of learning styles applied to education. Moreover, of those that did use an appropriate method, several found results that flatly contradict the popular meshing hypothesis.
Source Pashler, Harold, McDaniel, Mark, Rohrer, Doug and Bjork, Robert, “Learning Styles: Concepts and Evidence”, Psychological Science in the Public Interest, vol. 9, no. 3, 2008, p. 105-119, abstract.
Open access open the source · checked on 27 October 2026
Passage It is one of the most widespread neuromyths, including among teachers.
The two most commonly endorsed neuromyths across all groups were related to learning styles and dyslexia.
Source Macdonald, Kelly, Germine, Laura, Anderson, Alida, Christodoulou, Joanna and McGrath, Lauren M., “Dispelling the Myth: Training in Education or Neuroscience Decreases but Does Not Eliminate Beliefs in Neuromyths”, Frontiers in Psychology, vol. 8, 2017, abstract (groups compared: teachers, general public, people trained in neuroscience).
Open access open the source · checked on 24 October 2026
↑
Passage at each recall, the brain reassembles elements, and it may incorporate information acquired after the event
The formulation of new memories is sometimes called construction, and the process of bringing up old memories is called reconstruction. Yet as we retrieve our memories, we also tend to alter and modify them. A memory pulled from long-term storage into short-term memory is flexible. New events can be added and we can change what we think we remember about past events, resulting in inaccuracies and distortions.
Source Spielman, Rose M., Jenkins, William J. and Lovett, Marilyn D., Psychology 2e, OpenStax, 2020, section 8.3 “Problems with Memory”, section 8.3, subheading “Memory Construction and Reconstruction”, 1st paragraph.
Open access open the source · checked on 27 October 2026
↑
Passage It simply works by reconstruction, not by replay.
Human memory is not a literal reproduction of the past, but instead relies on constructive processes that are sometimes prone to error and distortion.
Source Schacter, Daniel L., “Constructive Memory: Past and Future”, Dialogues in Clinical Neuroscience, vol. 14, no. 1, 2012, p. 7-18, abstract, 1st sentence.
Open access open the source · checked on 27 October 2026

Bibliography

Beyerstein, Barry L., “Whence Cometh the Myth That We Only Use 10 % of Our Brains?”, dans Della Sala, Sergio (dir.), Mind Myths: Exploring Popular Assumptions about the Mind and Brain, Wiley, 1999, p. 3-24, in libraries (the uncertain origin of the 10% myth and the arguments that refute it).
Chudler, Eric H., “Do We Use Only 10% of Our Brains?”, Neuroscience For Kids, University of Washington, open access (the serious effects on behaviour of even small brain lesions). https://faculty.washington.edu/chudler/tenper.html
Karabanov, Anke Ninija, “Myth: We only use 10 percent of our brain”, ScienceNordic, 26 May 2021, open access (the brain never activates all its cells at once; uncontrolled mass activation, the mark of a seizure). https://sciencenordic.com/article/id/1856351
Kuzawa, Christopher W. et al., “Metabolic Costs and Evolutionary Implications of Human Brain Development”, Proceedings of the National Academy of Sciences, vol. 111, no. 36, 2014, p. 13010-13015, open access (the peak in the brain’s consumption during childhood, about two-thirds of resting energy expenditure). https://doi.org/10.1073/pnas.1323099111
Loftus, Elizabeth F. and Palmer, John C., “Reconstruction of Automobile Destruction: An Example of the Interaction between Language and Memory”, Journal of Verbal Learning and Verbal Behavior, vol. 13, 1974, p. 585-589, paywalled (the founding experiment on the reconstruction of memories).
Macdonald, Kelly, Germine, Laura, Anderson, Alida, Christodoulou, Joanna and McGrath, Lauren M., “Dispelling the Myth: Training in Education or Neuroscience Decreases but Does Not Eliminate Beliefs in Neuromyths”, Frontiers in Psychology, vol. 8, 2017, open access (learning styles among the most widely shared neuromyths, among teachers as well as the general public). https://doi.org/10.3389/fpsyg.2017.01314
Nielsen, Jared A., Zielinski, Brandon A., Ferguson, Michael A., Lainhart, Janet E. and Anderson, Jeffrey S., “An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging”, PLOS ONE, vol. 8, no. 8, e71275, 2013, open access (1,011 people and 7,266 regions; nine left-lateralised hubs and eleven right-lateralised ones; lateralisation as a local rather than global property; the absence of an individual profile; the absence of any difference between the sexes and the slight increase with age). https://doi.org/10.1371/journal.pone.0071275
Pashler, Harold, McDaniel, Mark, Rohrer, Doug and Bjork, Robert, “Learning Styles: Concepts and Evidence”, Psychological Science in the Public Interest, vol. 9, no. 3, 2008, p. 105-119, open access (the absence of any measured effect of alignment with the declared style).
Raichle, Marcus E. and Gusnard, Debra A., “Appraising the Brain’s Energy Budget”, Proceedings of the National Academy of Sciences, vol. 99, no. 16, 2002, p. 10237-10239, open access (about 20% of the energy for 2% of the mass).
Schacter, Daniel L., The Seven Sins of Memory: How the Mind Forgets and Remembers, Houghton Mifflin, 2001, in libraries (memory as reconstruction and its typical failings).
Schacter, Daniel L., “Constructive Memory: Past and Future”, Dialogues in Clinical Neuroscience, vol. 14, no. 1, 2012, p. 7-18, open access (memory not as a literal reproduction of the past but as a constructive process prone to error). https://doi.org/10.31887/DCNS.2012.14.1/dschacter
Spielman, Rose M., Jenkins, William J. and Lovett, Marilyn D., Psychology 2e, OpenStax, 2020, section 8.3 “Problems with Memory”, open access. https://openstax.org/books/psychology-2e/pages/8-3-problems-with-memory

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