Ask Warren Buffett what separates a smart investor from a foolish one, and he will not mention a score on a page. He talks about rationality instead.
Buffett has watched brilliant people wreck their investment portfolios and financial futures through nothing more than bad habits. He has also watched ordinary people build wealth through patience and discipline alone.
The pattern shows up in behavior, not in test results. Here are ten odd behaviors that Buffett says point to a lack of real-world intellect.
1. Mindless Imitation of the Crowd
“It’s ego, greed, envy, fear. It’s a mindless imitation of other people. I mean, there are a variety of factors that cause that horsepower of the mind to get diminished dramatically before the output turns out.” – Warren Buffett.
Buffett views blind conformity as one of the clearest signs of poor judgment. Doing something simply because everyone else is doing it removes thought from the equation. A person can have enormous raw intelligence and still fail when ego, fear, or envy take over the decision.
Buffett has spent his career avoiding trends for this reason. He buys when others panic. He stays cautious when others celebrate, even when that means sitting out a rally that everyone around him is chasing prices higher.
2. Making Easy Things Unnecessarily Complex
“There seems to be some perverse human characteristic that likes to make easy things difficult.” – Warren Buffett.
Some people overcomplicate simple situations because complexity feels impressive. Buffett sees this as backward thinking. Understanding a subject tends to simplify it. Confusion is usually what gets dressed up in jargon.
His entire investing philosophy rests on this idea. Buy good businesses at fair prices, then hold them. The advice sounds almost too plain to be valuable, and that plainness is exactly the point. People who chase complexity are often hiding the fact that they don’t fully understand what they are doing in the first place.
3. Chronically Failing to Control Your Urges
“Once you have ordinary intelligence, what you need is the temperament to control the urges that get other people into trouble.” – Warren Buffett.
A high IQ offers little protection against poor impulse control. Temperament matters more than raw brainpower once a person clears a basic intelligence threshold, and Buffett has said this in one form or another for decades. Emotional discipline is the real dividing line between success and failure.
People who can’t manage their urges buy at the top. They sell at the bottom. They chase excitement rather than following a plan, and Buffett considers this pattern a far greater threat to wealth than any gap in technical knowledge.
4. An Inability to Sit Still and Do Nothing
“The stock market is a device for transferring money from the impatient to the patient.” – Warren Buffett.
“Inactivity strikes us as intelligent behavior.” – Warren Buffett.
Restlessness, in Buffett’s eyes, is a form of irrational behavior. Many people feel a constant urge to act, tinker, or trade even when the smartest move is to wait. That need for motion often comes from anxiety, not analysis.
Patience has defined Buffett’s career at Berkshire Hathaway. He is known for holding cash for years while waiting for the right opportunity. Sitting still is often the hardest decision a person can make, and it is usually the correct one.
5. Overestimating Your Circle of Competence
“What counts for most people in investing is not how much they know, but how realistically they define what they don’t know.” – Warren Buffett.
Pretending to understand something you don’t is a common and expensive habit. Knowing the edges of your own knowledge is worth more than knowing a great deal about everything, at least by Buffett’s math. People who overestimate their expertise wander into situations they can’t properly evaluate.
Buffett has avoided industries he doesn’t understand for this exact reason, even ones that were popular and profitable for a stretch. Staying inside a defined circle of competence has spared him from countless bad decisions.
6. Flaunting Intellect but Lacking Integrity
“Somebody once said that in looking for people to hire, you look for three qualities: integrity, intelligence, and energy. And if you don’t have the first, the other two will k*ll you.” – Warren Buffett.
Being intellectually sharp while lacking basic ethics is a dangerous combination. Intelligence and energy without integrity tend to speed up a person’s downfall rather than their success. A clever plan built on dishonesty usually collapses. It just takes time to show.
Buffett has structured his hiring and partnership decisions around this idea for his entire career. He would rather work with an honest person of average ability than a brilliant person he can’t trust. The math almost always favors honesty over the long run.
7. Having Too Much IQ and Not Enough Wisdom
“If you’ve got 160 IQ, sell 30 points to somebody else because you won’t need it in investing.” – Warren Buffett.
Excess intellectual horsepower can turn into a liability when it feeds an oversized ego. Very intelligent people sometimes talk themselves into complicated and risky positions simply because they trust their own cleverness too much. Wisdom keeps decisions grounded in a way that raw IQ can’t.
Ordinary intelligence paired with discipline beats extraordinary intelligence paired with overconfidence, and Buffett has pointed this out more than once. Humility about your own limits is not something any test can measure.
8. Relying on Debt to Look Wealthy
“I’ve seen more people fail because of liquor and leverage. Leverage is borrowed money. You really don’t need much leverage in this world. If you’re smart, you’re going to make a lot of money without borrowing.” – Warren Buffett.
Using heavy debt to speed up wealth building is a form of financial impatience. Borrowed money can turn a survivable setback into a total wipeout, and Buffett has warned about this for decades because it removes the margin of safety a person needs to get through a downturn.
Wealth, in Buffett’s view, gets built through patience and compounding, not shortcuts. People who lean on debt to appear successful are often trying to skip the slow, effective process.
9. Failing to Build Arks Before the Rain
“Predicting rain doesn’t count. Building arks does.” – Warren Buffett.
“It’s only when the tide goes out that you learn who’s been swimming naked.” – Warren Buffett.
Assuming good times will last forever is a classic blunder, even among otherwise sharp people. Preparation matters more than prediction. Anyone can guess that trouble is coming. Far fewer people actually get ready for it.
Berkshire Hathaway keeps large cash reserves for this exact reason. Buffett wants to be ready for opportunity or hardship rather than caught off guard by either one, and he treats a lack of preparation as a failure of judgment rather than a failure of luck.
10. Acting on the Predictions of Gurus and Forecasters
“Forecasts may tell you a great deal about the forecaster. They tell you nothing about the future.” – Warren Buffett.
Blind trust in market forecasters is one of the more irrational habits investors fall into, according to Buffett. Predictions reveal more about the personality and incentives of the forecaster than about what will actually happen. Facts and analysis matter far more than confident-sounding prophecy.
This skepticism has shaped Buffett’s entire approach to research. He reads financial statements and studies businesses directly, rather than outsourcing his thinking to television pundits. Relying on someone else’s guesswork is a poor substitute for independent judgment, and he has said as much in interview after interview.
Conclusion
Warren Buffett’s view of intelligence has little to do with test scores or vocabulary. It has everything to do with rationality, patience, integrity, and self-awareness. None of the behaviors on this list describes a low IQ in the traditional sense. They describe poor judgment, and even naturally gifted people fall into that trap.
Temperament can be trained even when raw intelligence can’t be changed. That is the encouraging part of Buffett’s philosophy. Anyone willing to slow down, stay honest, and think independently can avoid the traps that have derailed far smarter people than themselves.