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.

There are difficult questions like the blue eyes logic puzzle, which require strong thinking skills to solve. And then there are TRULY difficult questions, that require an extremely honed thinking process, like:

• How can I make so much money in the next five years that I never have to work again?
• Which job should I choose right now to maximize my average lifetime happiness?
• Which charities help the world the most per thousand dollars donated to them?
• What can I do to change our society into a significantly more ideal place?
• What is the greatest threat to humanity as a species, and what can we do now to reduce this threat?

Notice that these important questions are somewhat ambiguous. They also can’t be addressed without gathering and combining information from many sources, and involve factors that are extremely hard to predict. And they can’t be solved unless you can do a reasonable job of estimating difficult to estimate quantities. They all require truly excellent thinking to tackle. Truth discernment becomes a super power when it leaves the realm of puzzles and enters the realm of extremely valuable real world questions.

At high levels, truth discernment ability is not just IQ, though surely is somewhat correlated with it. It is not just the ability to apply logic, though logic is an important component. It also requires certain habits of mind, like regularly asking yourself what the evidence is for your own beliefs. It requires using techniques, like thinking in terms of probabilities rather than thinking in black and white. It requires caring more about getting the right answer than about seeming right or believing what it is convenient psychologically to believe.

The exciting thing about truth discernment is that it is not just a genetic ability (though genetics is surely a contributing factor). It is an ability that we can improve a great deal if we take the time to hone our thinking. We can familiarize ourselves with the logical fallacies to the point where our brain notices them occurring in real-time. We can learn the cognitive biases so that we know the ways our brains are likely to fail us and can consciously correct for these failures. We can learn to prevent unhelpful emotions from derailing our logic too often. We can practice our reasoning by drilling in LSAT questions. And we can learn the methods of rationality, or at least read about another person using them.

Many comic book writers have realized that intelligence is a legitimate super power. Lex Luthor was superman’s nemesis despite being physically inferior to him in every capacity. He could still compete with superman only because of the power of his thinking. But it is not a very high level of intelligence, per se, that is so powerful. Being able to solve the hardest logic puzzles won’t automatically let you solve problems that matter. Truth discernment is the essential skill, the ability to figure out the likely answer to truth claims regarding important real world questions. Will taking this action bring me more happiness in the long-term than not taking this action? Will this regulation, if it passes, improve poverty? Will this business venture make large quantities of money? Is string theory an accurate description of reality?

Being able to accurately discern the truth can be a super power, and with study and practice, it is an ability that we can very substantially improve.

Influences: Eliezer Yudkowsky