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 correlated 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?

The Big Five personality traits.

In our data, openness, conscientiousness, extraversion, agreeableness, and neuroticism (when all 5 are used together) outperformed IQ at predicting most outcomes.

IQ clearly matters—it unavoidably jumps out from the data when testing people on a diverse range of cognitive tasks.

And yet…

IQ is far from being all that matters and is definitely not destiny.

We used the data from our study to create a new cognitive assessment, which analyzes ability across 7 dimensions and aims to provide you with useful insights about your mind.

If you’d like to take it, you can do so here:

https://programs.clearerthinking.org/cognitive-test-intro.html

(Proceeds support our mission.)

This piece was first written on March 25, 2025, and first appeared on my website on May 15, 2025.