Humans use virtually all of the brain.

1. Pass Title matches the evidence

   Title 'Humans use virtually all of the brain' matches finding False against the literal 10 percent claim; no invented numbers in the title.

2. Pass No obvious contradictions

   Finding False, answer and conclusion agree; the caveat that percent-used is ill-defined is consistent throughout.

3. Pass Plausible justification

   Conclusion cites energy budget, resting and task imaging, and lesion effects, which support rejecting the literal 10 percent claim.

4. Pass Sources are relevant

   Attwell and Laughlin energy budget, Raichle default-mode paper, Beyerstein myth review and Scientific American explainer are on topic.

5. Pass Common questions answered

   Three objections each receive a response addressing the question.

Coverage: Read the full article payload; sources judged by name/title/description/role only, per First Look's rules; no source snapshots read.

1. Concern (minor) Sourcing is strong and transparent

   Source beyerstein-ten-percent names Beyerstein's 1999 chapter but links Chudler's Neuroscience for Kids page; fix the attribution or link the chapter, and add a primary lesion study.

   Two of four sources are primary peer-reviewed papers with DOIs (good). However, source beyerstein-ten-percent is titled 'Whence Cometh the Myth that We Only Use 10% of our Brains?' and attributed to Barry L. Beyerstein, and e3 says 'Beyerstein's review of the myth notes...' with institutions Simon Fraser University and University of Washington, year 1999. The URL actually resolves to Eric H. Chudler's 'Neuroscience For Kids' page 'Do We Use Only 10% of Our Brains?', which only lists Beyerstein's chapter in its reading list ('This chapter is required reading...'). The text a reader reaches is Chudler's, not Beyerstein's, so it is unclear which work supports e3, and the same URL is also listed separately under resources. The lesion line therefore rests on a children's educational page with no primary lesion study, although the underlying fact is well established and the page does support it ('destruction of even small areas of the human brain can have devastating effects'). The SciAm piece is journalism quoting neurologists; it also contains a dated claim that 90 percent of brain cells are glia, which the article does not repeat. A reader's belief would not change, so Minor. Confidence: High on the misattribution.

   About source:beyerstein-ten-percent, evidence:lesion-deficit-evidence The finding

2. Pass Central claims are accurate

   Main claims: the literal claim 'Humans use only 10 percent of the brain' is False; metabolic, imaging, and lesion evidence converge; 'percent used' is ill-defined. Ratings: (1) Finding False / title 'Humans use virtually all of the brain' - True; SciAm quotes Barry Gordon: 'we use virtually every part of the brain'; the Chudler page: 'functional brain imaging studies show that all parts of the brain function'. (2) e1 energy budget (Attwell & Laughlin 2001) - Unverifiable against source (403), but the description matches the well-known paper and SciAm independently supports the metabolic point ('three percent of the body's weight and uses 20 percent of the body's energy'). (3) e2 default mode (Raichle 2001) - Unverifiable against source (403); description consistent with the well-known PNAS paper. (4) e3 localized damage causes specific deficits - True on content: the cited page says 'destruction of even small areas of the human brain can have devastating effects on behavior' (attribution problem handled under sourcing-quality). (5) e4 SciAm compares imaging, metabolism, damage - Mostly True: it covers imaging and energy, and damage mainly via surgical mapping; it also quotes Henley that people with parts removed can live fairly normal lives through compensation. (6) 'Not every neuron is maximally active simultaneously' - True; SciAm: 'at any given moment all of the brain's regions are not concurrently firing'. No central claim is Mixed or worse. Confidence: Medium-High (two primary papers unread).

3. Pass Claims are supported and labeled

   Each key point maps to an evidence item with a cited source: energy cost (e1), resting and task activity (e2), lesion deficits (e3), synthesis (e4). The article keeps inference apart from fact: the conclusion states the definitional point ('without a definition of "used," that percentage is itself ill-defined') as reasoning, and the objection responses are framed as explanation, not new factual claims. The conclusion rests on cited evidence, not assertion. Confidence: High.

4. Pass Context is complete

   The article includes the key nuance that activity varies by task and time and that 'percent used' has no single definition (conclusion, keyPoints 4-5), addresses task-contrast imaging and plasticity in objections, and notes compensation after damage in limitation e3 ('some damage can be partly compensated'), which aligns with SciAm's Henley quote. Omitting the myth's possible origins (William James, Lashley, glia) is helpful context but does not change the impression. Confidence: High.

5. Pass Framing is fair and neutral

   The claim is stated as it circulates ('Humans use only 10 percent of the brain.'), objections are presented in their strongest popular forms and answered without ridicule. Emphasis is proportionate; the image caption ('contradicting the idea that 90 percent is unused') is mildly promotional but not misleading. Confidence: High.

6. Pass Uncertainty is stated

   Every evidence item has a specific limitation (e.g., e1 'not a direct census of every neuron'; e2 'imaging signals are indirect'), and the conclusion limits High confidence to 'rejecting the literal 10 percent claim' while stating 'the phrase "percent used" has no single scientific definition.' The evidence is not genuinely contested, so High confidence on the literal claim is appropriate. Confidence: High.

Coverage: Read the full article payload (v2). Read live copies of source:beyerstein-ten-percent (faculty.washington.edu/chudler/tenper.html, HTTP 200) and source:scientific-american-ten-percent (HTTP 200). Could NOT read source:attwell-laughlin2001 or source:raichle2001: both publishers returned HTTP 403 to FactHub's server-side fetch and no Wayback capture exists; claims resting on them (evidence e1, e2) were judged against the article's description and general knowledge only and are marked Unverifiable against the source. No live web search.

1. Concern (minor) Strongest objections answered

   Add objections answering hemispherectomy and hydrocephalus cases of near-normal function, and the 'only 10% of brain cells are neurons' glia origin, with evidence.

   The three objections (small task activations, not all neurons fire, latent potential) are the common popular ones and are answered fairly. The article does not address the strongest challenge to its lesion line: whether cases of people living fairly normal lives after hemispherectomy or with severe hydrocephalus show that much tissue is dispensable. Limitation e3 notes 'some damage can be partly compensated' but no objection weighs this with evidence (e.g., that plasticity is largely developmental and does not mean the tissue was idle). It also does not address the glia version of the myth (that only about 10 percent of brain cells are neurons). The main conclusion survives on e1 and e2 regardless, so Minor.

   About conclusion, evidence:lesion-deficit-evidence, limitation:lesion-deficit-evidence The finding

2. Concern (minor) Evidence is independent

   Present evidence e4 (Scientific American) as a secondary synthesis of e1-e3's categories rather than an independent line, or replace it with a primary study.

   e1 (UCL energy-budget model, 2001) and e2 (Washington University imaging, 2001) are independent primary lines. e3 is a secondary review (Beyerstein 1999) rather than a primary lesion study. e4 is titled 'Independent expert explanation compares multiple lines of evidence' and its method is 'Expert scientific synthesis' of 'brain imaging, metabolism, and consequences of damage' - the same three categories as e1-e3, so it re-presents those lines rather than adding an independent one; its own limitation concedes it is 'not a primary experiment'. The context nonetheless counts it toward convergence across 'methods, institutions, countries, and decades'. Independent support from e1-e3 remains, so Minor.

   About evidence:expert-evidence-explainer, evidence:lesion-deficit-evidence The finding

3. Pass Rates the real claim

   Claim 'Humans use only 10 percent of the brain.' is the form in which the myth circulates; method step 1 defines it literally as 'about 90 percent of normal human brain tissue is unused or functionless', which is what a reader repeating it means (with the 'latent potential' variant handled in objection 3). The editorialNote limits scope to the literal claim and excludes learning/plasticity limits; the conclusion stays within it. No strawman. I would rate the same claim.

4. Pass Rating follows from the evidence

   Before reading the verdict: e1 (high metabolic cost of signaling across grey matter), e2 (organized activity at rest and during tasks), and e3 (small lesions cause specific deficits) each contradict a 90-percent-idle brain, from different methods. I would choose False. The article's finding is False, and the answer ('activity and function across the whole brain') agrees with it. The definitional caveat ('percent used' ill-defined) does not move the label toward Mixed, because the literal fixed-10-percent claim fails under any reasonable definition.

5. Pass Confidence matches the evidence

   I would give High confidence for rejecting the literal claim: three method-distinct lines converge and the limitations are stated item by item (e1 'not a direct census of every neuron'; e2 'does not imply uniform or maximal activity'; e3 'some damage can be partly compensated'). The conclusion scopes High to 'rejecting the literal 10 percent claim'. The title 'Humans use virtually all of the brain' is a positive restatement slightly stronger than the evidence strictly measures, but the conclusion and keyPoint 5 explicitly flag that 'percent used' is ill-defined, so a reader is not misled.

Coverage: Read the full article payload (v2): claim, finding, answer, confidence, summary, context, conclusion, four evidence items with limitations, three objections, five method steps, sources list. Per the Skeptic's division of labor, source snapshots were not read; evidence was taken exactly as stated.

1. Concern (minor) Verdict fields agree and stand alone

   Replace "is contradicted" wording in summary, conclusion, and description with the current False label's terms (e.g., "is false").

   Quoted alone: FactHub rates the claim 'Humans use only 10 percent of the brain.' False (High confidence): 'Brain imaging and lesion studies show activity and function across the whole brain.' This reads well and the fields agree in substance. But the changelog records the label changed from 'Contradicted' to False, and stale wording remains: summary 'The literal 10 percent claim is contradicted by...', conclusion 'is contradicted by converging metabolic, neuroimaging, and lesion evidence', description '...contradict the claim'. Rule broken: fields must express the conclusion 'in the current label's terms' (stale wording from an earlier label is Minor).

   About conclusion The finding

2. Concern (minor) Each section does its job

   Cut the hand-written independence note from context ('evidence from different methods, institutions, countries, and decades converges') and make summary one sentence.

   Context reads: 'Fact check — the claim that only one tenth of the human brain is used. No single item is complete proof by itself. The conclusion is strong because evidence from different methods, institutions, countries, and decades converges.' The last sentence is a hand-written independence note repeating what the page generates (rule: the author must not write one; Minor), and the paragraph gives no essential framing beyond restating the claim. Summary is two sentences, while the rule requires one sentence naming the strongest independent lines. Conclusion does synthesize (separates momentary activity from function, states what remains ill-defined), and editorialNote states scope, caveats, and that no external review is recorded, so those pass.

   About conclusion The finding

3. Concern (minor) Readers can verify it

   Re-anchor source beyerstein-ten-percent: it is titled as Beyerstein's 1999 book chapter but links the same UW faculty page listed as a resource; cite the chapter (book, ISBN) separately.

   Sources carry role labels, full titles, and why-chosen descriptions; e1 and e2 have DOI anchors. But source beyerstein-ten-percent is titled 'Whence Cometh the Myth that We Only Use 10% of our Brains?' by Barry L. Beyerstein (e3 lists Simon Fraser University, 1999), while its URL is faculty.washington.edu/chudler/tenper.html - the same URL listed under resources as 'University resource on the 10 percent brain myth' - and its description calls it a 'University-hosted resource'. A reader cannot retrieve the named work from this anchor (rule: identifiable anchors so readers can retrieve the original). The SciAm source also lacks author and date. Method steps cover claim definition (1), independent evidence (2), sources reviewed (3), and limits (5). Minor because the lesion claim still has a retrievable, if mislabeled, anchor.

   About source:beyerstein-ten-percent, evidence:lesion-deficit-evidence The finding

4. Concern (minor) Consistent house style

   Change British "grey matter" to American "gray matter" in evidence e1's summary; keep the paper's published title as is.

   Rule: American English spelling. Evidence e1 summary says 'an energy budget for signaling in brain grey matter'; 'grey' is British (the source title's own spelling may stay). Otherwise consistent: '10 percent'/'90 percent' used uniformly, no leftover drafting text, technical terms such as 'default mode' are described in context.

   About evidence:grey-matter-energy-budget The finding

5. Pass Title states the finding

   Title 'Humans use virtually all of the brain.' states the finding in positive form, names the subject, resolves the claim, and does not repeat the myth (rule: lead with what is true). seoTitle 'Do Humans Use Only 10 Percent of the Brain? No' uses search wording and states the finding ('No'), which the rule permits.

6. Pass Limitations are specific

   Each limitation is specific to its item: e1 'a quantitative model ... not a direct census of every neuron'; e2 'Imaging signals are indirect measures related to blood flow'; e3 'Lesion effects vary with location, extent ... some damage can be partly compensated'; e4 'a secondary expert explanation, not a primary experiment'. None is boilerplate.

7. Pass Tone is measured and respectful

   Language is measured ('inconsistent with', 'does not support a fixed 10 percent-used figure'). Objection responses are short, evidence-based, and concede true premises ('The premise is true but the conclusion does not follow') without ridicule. No unjustified absolutes such as 'proves' or 'impossible'.

Coverage: Examined only the article payload (v2): title, seoTitle, description, claim, finding, answer, confidence, summary, keyPoints, context, conclusion, evidence and limitations, objections, method steps, editorialNote, image caption/alt text, sources, resources, changelog. No sources or web used.