📌 Key takeaways
- g is a proposed general intelligence factor that influences performance across all kinds of mental tasks.
- It is the empirical finding that virtually all cognitive tests correlate positively — people good at one tend to be good at others.
- No.
- g predicts academic and job performance reasonably well and anchors most modern IQ tests, even as researchers debate what it fundamentally is.
What is g?
g is a proposed general intelligence factor that influences performance across all kinds of mental tasks. Spearman introduced it after noticing that scores on different tests tend to correlate.
What is the positive manifold?
It is the empirical finding that virtually all cognitive tests correlate positively — people good at one tend to be good at others. This pattern is the main evidence for g.
Does g explain everything?
No. Spearman’s model also includes specific factors (s) for each task, and later theorists added group factors. But g remains a robust statistical regularity.
Why does g still matter?
g predicts academic and job performance reasonably well and anchors most modern IQ tests, even as researchers debate what it fundamentally is.
🧭 Explore Intelligence
📅 Last updated: 2026-06-18 · ✔ Reviewed by the All-Lifes editorial team · About · Methodology