These are 14 Investment Psychology principles distilled from Charlie Munger's writing and public remarks. Use them as a decision checkpoint: translate each rule into a yes/no test, write what evidence would change your mind, and set a review date before you act. When a rule feels vague, open the full principle page and capture the driver you can verify (cash flows, leverage, incentives, competitive edge). This is educational, not investment advice—double-check primary sources and fit every rule to your time horizon, risk budget, and constraints.
"It is remarkable how much long-term advantage people like us have gotten by trying to be consistently not stupid, instead of trying to be very intelligent."
Consistently avoiding foolish decisions outperforms trying to make brilliant ones.
Read Full Analysis →"Rationality is a moral duty."
Rationality is not just an advantage — it is a moral obligation for serious investors.
Read Full Analysis →"All skills attenuate with disuse."
Skills deteriorate without regular practice — including the skill of rational thinking.
Read Full Analysis →"Heavy stress often leads to both mental and physical breakdown."
Severe stress degrades both mental performance and physical health.
Read Full Analysis →"The brain overweighs what's easily available."
The brain overweights vivid, recent, or easily recalled information when making decisions.
Read Full Analysis →"The general antidote for self-serving bias is to consider ourselves less special than we think we are."
We all think we are above average — a delusion that leads to overconfidence and poor risk management.
Read Full Analysis →"The contrast effect is constantly fooling people."
Relative comparisons distort our judgment — making bad deals seem acceptable next to worse ones.
Read Full Analysis →"The brain of man conserves programming space by being reluctant to change."
Once committed to a position, the brain resists changing it — even when evidence demands it.
Read Full Analysis →"People overweigh what has happened to them recently."
Recent events disproportionately influence our expectations about the future.
Read Full Analysis →"People tend to overvalue what they own."
People irrationally overvalue things simply because they own them.
Read Full Analysis →"When people are uncertain, they tend to look at what others are doing for guidance."
When uncertain, people copy what others are doing — even if the crowd is wrong.
Read Full Analysis →"Humans are easily influenced by authority figures."
People blindly follow authority figures even when the authority is wrong or irrelevant.
Read Full Analysis →"The human mind is a lot like the human egg. When one sperm gets in, it shuts down so the next one can't get in."
Once we form a belief, our brain selectively seeks evidence that confirms it while ignoring contradictions.
Read Full Analysis →"Never, ever, think about something else when you should be thinking about the power of incentives."
Incentives drive behavior more powerfully than any other force — always analyze who gets paid what.
Read Full Analysis →Use this page as a workflow, not a collection of quotes. Pick 3–5 principles, translate each into a concrete check, and review your decisions on a fixed cadence. These are educational guardrails—always verify facts and match them to your own constraints.
Rehearse a scenario decision → ·Run a weekly toolkit → ·Browse all principles →
He served as vice chairman of Berkshire Hathaway and was Warren Buffett's closest partner for over five decades. Munger was renowned for his multidisciplinary approach to investing, advocating for the use of mental models from various fields including psycholo…
Charlie Munger has 14 key principles on investment psychology. The most important one is "Avoid Stupidity" — It is remarkable how much long-term advantage people like us have gotten by trying to be consistently not stupid, instead of trying to be very intelli...
Charlie Munger applies investment psychology through several key principles including "Avoid Stupidity" and "Rationality Above All". These principles guide practical investment decisions and have been tested across decades of market cycles.
Charlie Munger's approach to investment psychology is distinguished by a focus on long-term thinking and fundamental analysis. With 14 specific principles in this area, Charlie Munger provides a comprehensive framework that investors at any level can study and apply to improve their decision-making.
Treat each principle as a hypothesis. Write the evidence you would need, collect it from primary sources when possible (filings, letters, transcripts), and note what would invalidate the conclusion. If you can’t define inputs and triggers, you’re not applying the rule—you’re quoting it.
Pick a cadence you can sustain (weekly or monthly) and review process signals first: whether you followed your checklist, respected your boundaries, and documented assumptions. Only then look at outcomes. The goal is fewer low-quality decisions, not perfect prediction.
