Is the idea of IQ legit or total B.S.? With the replication crisis in social science, it's worth asking this since a number of major psychology findings didn't hold up under scrutiny.

To find out, at Clearer Thinking, we ran a massive study.

We tested thousands of people performing random subsets of 62 diverse cognitive tasks (vocab, math, logic, pattern recognition, reaction time, games, memorization, mental rotation, language learning, etc.)

We successfully replicated a classic finding: performance on nearly all cognitive tasks correlates positively with performance on the other tasks—a phenomenon known as the "positive manifold," foundational to IQ.

IQ scores explained ~45% of variation across our diverse cognitive tasks, aligning with previous research. That's very substantial for a single number (IQ score) but also far from capturing everything.

Some of the remaining 55% variance is pure noise; the rest likely comes from task skill (developed through practice) and task-specific aptitudes (likely influenced by both genetics and childhood experiences).

It's also worth noting that while IQ is predictive of a diverse range of intelligence tasks, it doesn't necessarily capture ALL that's meant by intelligence. It's unclear if it includes "street smarts," social skills, or deep nature skills (like hunter-gatherers have).

We confirmed IQ predicts interesting outcomes:

• Actively open-minded thinking (r=0.43)

• Household income (weakly, r=0.15)

• Self-reported job performance (for lower IQ ranges only, r=0.48)

• Celebrity worship (substantially negatively correlation with IQ, r=-0.42)

• No link to happiness or life satisfaction.

IQ captures something—but WHAT? There's no consensus. Theories include that IQ is...

• A single cognitive resource
• Working memory + executive control
• A measure of brain integration
• The result of overlapping cognitive processes
• The top of a hierarchy of abilities

Guess what's a BETTER predictor of major life outcomes than IQ?