What IQ is, how IQ tests work, the history and science of intelligence measurement.
25 articles
The Wechsler Adult Intelligence Scale is the world's most used adult IQ test. Its editions, index scores, the General Ability Index — and why independent researchers reject the WAIS-5's five-factor structure.
The Cognitive Reflection Test answers are 5 cents, 5 minutes and 47 days. Why the intuitive answers fail, what your score means, and whether knowing the answers really invalidates it.
Cognitive tests fall into three unrelated categories. How clinical screens like the MoCA and MMSE differ from IQ tests, what the scores mean, and why the 26/30 cutoff misleads.
Ability tests, trait questionnaires and mixed models measure different things. How the MSCEIT is scored, why self-report EI is mostly personality, and why there is no EQ score.
There are no left-brained or right-brained people — 1,011 brains and 14 million connections found none. What is genuinely lateralised, and what Sperry warned about.
The SB5's five factors, its adaptive routing, and the standard-deviation change from 16 to 15 that makes old Stanford–Binet scores incomparable with new ones.
Heritability rises from 20% in infancy to 80% in later adulthood — and means almost nothing people think it means. Why it depends on the society doing the measuring.
11,430 people trained for six weeks and transferred nothing. Near vs far transfer, the n-back replication failure, and why the FTC fined Lumosity $2 million.
The WISC-V Full Scale IQ comes from seven subtests, not ten — and independent factor analysis of 16 models does not support its five-factor structure.
