Is Intelligence Genetic? What Heritability Really Means
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.
7 min read
Understanding IQ
What IQ is, how IQ tests work, the history and science of intelligence measurement.
28 articles
Do Brain Training Games Work? What the Evidence Shows
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.
6 min read
The WISC-V: How the Children's IQ Test Actually Works
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.
6 min read
Psychometrics: How Psychological Measurement Actually Works
A test is never valid — an interpretation is. Reliability, validity, standard error, norming and latent variables, explained from the governing Standards.
6 min read
Multiple Intelligences: Gardner's Theory Explained (2026)
Howard Gardner's theory of multiple intelligences proposes several distinct intelligences rather than one IQ. The eight intelligences, how it differs from 'g', the criticisms, and why scientists are skeptical.
4 min read
IQ vs EQ — What's the Difference and Which Matters More?
IQ measures reasoning; EQ measures emotional intelligence. How they differ, how each is assessed, and what the research says about which predicts success.
4 min read
The History of IQ Testing — From Binet to Today
From Alfred Binet's 1905 scale to modern adaptive testing: the people, milestones and controversies that shaped how we measure intelligence.
4 min read
Types of IQ Tests — Wechsler, Raven's, Culture-Fair & More
A guide to the major IQ tests — WAIS, Stanford-Binet, Raven's Progressive Matrices, culture-fair tests — what each measures and how they differ.
4 min read
How IQ Tests Work — Norming, Scoring & Reliability
How IQ tests are built and scored: standardization samples, the mean-100/SD-15 scale, item difficulty, reliability and validity — in plain English.
4 min read