Munger behavioral pick

A fresh round of finance posts is sending readers back to Charlie Munger’s “The Psychology of Human Misjudgment,” a 1995 Harvard talk that catalogs the mental errors investors make. (fs.blog) The speech was delivered at Harvard in 1995 and later revised by Munger in 2005 for *Poor Charlie’s Almanack*, with a checklist of 25 causes of human misjudgment and a warning about “lollapalooza” effects when several biases hit at once. (fs.blog) The latest discussion came from social posts on X in April 2026, including one that called the speech a top primer on behavioral finance and another that contrasted textbook portfolio theory with the way clients actually react during market swings. (x.com 1) (x.com 2) Traditional portfolio theory starts with diversification and risk, not emotion. The Chartered Financial Analyst Institute says portfolio construction has evolved since Harry Markowitz introduced Modern Portfolio Theory in the 1950s, with asset allocation and diversification still at its core. (rpc.cfainstitute.org) Behavioral finance begins from a different premise: people do not always act rationally when money is at stake. The Chartered Financial Analyst Institute’s 2026 curriculum says investors often simplify complex decisions with shortcuts that can lead to suboptimal outcomes, and it groups those errors into cognitive and emotional biases. (cfainstitute.org) That split helps explain why advisors keep returning to Munger’s talk when markets turn volatile. Loss aversion, overconfidence, framing, mental accounting, and regret aversion are all biases the Chartered Financial Analyst Institute flags as forces that can distort financial decisions even when the math of a portfolio has not changed. (cfainstitute.org) The academic backdrop is now mainstream economics, not a niche side debate. Daniel Kahneman won the 2002 Nobel economics prize for integrating psychological research into economic science, especially judgment and decision-making under uncertainty, and his work helped establish prospect theory. (nobelprize.org) Munger approached the same territory from the investor’s side rather than the laboratory. In the revised text, he said his interest was in “standard thinking errors,” and the published version frames the talk as an early statement of what later became a larger field of behavioral finance. (fs.blog) The renewed interest says less about a newly discovered theory than about an old problem that keeps resurfacing in selloffs and rallies alike: a portfolio can be diversified on paper and still be hard to hold in real time. (rpc.cfainstitute.org) (cfainstitute.org)