Charles Spearman
SchoolG Factor Theory
Lived1863 – 1945
FromUnited Kingdom
G Factor Theory

Charles Spearman

One thread running through every ability

The psychologist who proposed that a single general factor underlies our many talents.

A single general ability seems to run through them all.
— Charles Spearman

Who they were

Charles Spearman noticed something simple and strange: people who did well on one mental task tended to do well on others, however unrelated they seemed. To explain it he proposed a general intelligence factor, which he called g, and invented factor analysis — a statistical method for finding the hidden structure beneath scattered scores. His work gave intelligence research a mathematical spine and sparked a century of debate over whether the mind has one engine or many.

Famous books

What they left on the shelf

Their big idea

General Intelligence (g Factor)

Charles Spearman noticed that people who do well on one mental task tend to do well on others, and proposed a single underlying ability, which he called g, running beneath them all. In his account, every specific talent draws on this shared well of general intelligence.

Questions in their spirit

What they’d ask you

Sit with one. Answer online, or in the app.

All questions

Carry the idea forward

Spearman — What they’d ask you

Psipas asks you one small, honest question at a time — and builds the picture from your answers.