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Cognitive science, testing standards and the numbers behind them — written for a general reader, with every score carrying the scale it was measured on and the range around it.
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AI & Machine Intelligence →
Human Brain vs Artificial Intelligence: Which Uses More Power?
The brain runs on about 20 watts and has 86.1 billion neurons. One NVIDIA H100 chip is rated at up to 700 watts, about 35 times as much by our arithmetic. Every figure comes from a paper or a spec sheet.
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Math Brain Teasers for Adults: Puzzles With Answers and the Skill Each Trains
Nine original math puzzles for adults, each answer checked by script: a 5-cent pen, a 4% price drop, a 40 km/h trip and a 50.73% chance that two of 23 people share a birthday.
Mechanical Aptitude Test: What It Measures, How Long It Takes, What Scores Mean
The Bennett BMCT-II has 55 items in 25 minutes and the ASVAB's mechanical subtest 15 scored items in 22. None of the publisher pages we read gives a pass mark, and none reports an IQ.
When Is the Human Brain Fully Developed? What 124,000 Brain Scans Show
No single age: grey matter volume peaks at 5.9 years, white matter at 28.7 and network wiring turns near 32. Two large studies, 123,984 scans and 4,216 people, and no study we read shows a switch at 25.
Brain Teasers for Adults: Answers and How Often Adults Solve Them
Eight original brain teasers for adults, each with its answer. Then the numbers nobody prints beside them: 17% of 3,428 people got all three Cognitive Reflection puzzles right, and few solve the famous four-card puzzle.
Do Video Games Rot Your Brain? What a Study of 9,855 US Children Found
In a US study of 9,855 children aged 9 to 10, more gaming went with a gain in intelligence two years later, not a loss. It was observational, covered US children only, and a pooled analysis finds little carry-over to general ability.
IBEW Aptitude Test Score: What the Official Page Says About Passing
The Electrical Training Alliance says applicants are told only whether they qualified and that exact scores are not provided. The battery is 69 items in 97 minutes, about 84 seconds an item.
Types of Artificial Intelligence: Three Ways to Sort AI, and Five Levels
AI can be sorted by breadth (narrow, general, super), by function (four types) or by performance (five DeepMind levels). Those levels are percentiles of skilled adults, not IQ scores.
What Is the Average IQ of a Medical Doctor? What Data Exist
Pages say doctors average 120 to 130, but we found no study that tested a representative group of working doctors. What exists is two UK studies of medical students and doctors, a US survey that ranks doctors high without a number, and MCAT results, which are not IQ.
Koala Brain vs Human Brain: Size, Folds and What It Means
A koala brain is about 79 times lighter than a human brain, at 19.2 g, and its cortex is smooth. The popular claim that it fills only 60% of the skull does not hold for living koalas: MRI found 83% to 90%.
Nine beats, one standard of evidence
Each desk covers a subject we can report on continuously and check against a source. Pick the one you care about — or read everything.
Intelligence Research
New peer-reviewed findings on how reasoning, memory and general ability actually work — reported with the sample size and the error bars.
Brain Health & Aging
Sleep, exercise, diet, illness, medication and environment — what each one measurably does to thinking, and by how much.
AI & Machine Intelligence
How machine reasoning is measured, where it beats people, where it still fails, and what any of it says about human intelligence.
Education & Testing
Admissions exams, gifted programs, national score reports and school testing policy, explained without the spin from either side.
Work & Hiring Tests
The cognitive and aptitude tests employers use, how they are scored, and what a score does and does not predict at work.
Data & Rankings
Chart-led pieces on how scores are distributed across countries, states, ages, jobs and education levels — always with the caveats attached.
Scores & Scales Explained
What a specific number means on a specific scale, why every score needs a confidence range, and how the scales convert.
Myths & Fact Checks
Viral IQ claims checked against the record: where the number came from, who repeated it, and what is actually documented.
Puzzles & Brain Training
A reasoning puzzle every day with the full working shown, plus honest coverage of what brain-training products can and cannot do.
Intelligence Research
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What Is the Smartest Land Animal? What Studies Measured
No test ranks every land animal. On one self-control test, chimpanzees scored 100% and coyotes 95.0%; the elephant that passes a mirror test had the lowest score on another. Here is what each study measured, and what it did not.
What Is the Smartest Fish in the World? What Lab Studies Show
No study ranks fish species on one task. The famous results rest on 4 marked wrasse, 14 groupers and 8 goldfish, and the goldfish study measured a feeding time that came once in 24 hours, not a 3-second memory.
Who Is the Smartest Person Living? Why No One Holds the Title
No one can be named the smartest person living: no test reports scores above about 160, most people have never been tested, and Guinness World Records ended its "Highest IQ" category in 1990 because it judged IQ tests too unreliable to pick one record holder.
Brain Health & Aging
All Brain Health & Aging →When Is the Human Brain Fully Developed? What 124,000 Brain Scans Show
No single age: grey matter volume peaks at 5.9 years, white matter at 28.7 and network wiring turns near 32. Two large studies, 123,984 scans and 4,216 people, and no study we read shows a switch at 25.
Koala Brain vs Human Brain: Size, Folds and What It Means
A koala brain is about 79 times lighter than a human brain, at 19.2 g, and its cortex is smooth. The popular claim that it fills only 60% of the skull does not hold for living koalas: MRI found 83% to 90%.
What Is the Smartest Primate? How Apes and Monkeys Rank
People are the smartest primate on broad measures. Among the rest, chimpanzees and orangutans score near 100% on a self-control task, and so do capuchin monkeys, but each score rests on 5 to 22 animals, and no ape has an IQ.
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Every number carries its scale
An IQ figure is meaningless without the scale it was measured on and the range around it. Every story here reports all three, or says plainly that the source did not.
Sources are listed, not implied
Each story ends with the studies, datasets and documents it draws on, named and attributed, so you can go and read them yourself.
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