Jason Zweig

In The Psychology of Money, Morgan Housel uses Jason Zweig — the Wall Street Journal investment columnist — as a recurring witness on the human side of investing. Zweig annotated a later edition of Benjamin Graham’s The Intelligent Investor and observed that Graham “was constantly experimenting and retesting his assumptions,” discarding old formulas in each revised edition in favor of “the formulas that seem to work better now.” Zweig also conducted the interview in which Harry Markowitz admitted that the pioneer of modern portfolio theory built his initial portfolio with little regard for his own research — leading Zweig to reflect that “people are neither rational nor irrational. We are human.” Most memorably, Zweig worked with psychologist Daniel Kahneman on Thinking, Fast and Slow and recorded Kahneman’s habit of “detonating” finished drafts and rewriting them wholesale; when asked how, Kahneman gave the line Zweig never forgot: “I have no sunk costs.”

Context: Jason Zweig is an American financial journalist who has written the “Intelligent Investor” column for The Wall Street Journal, edited the revised edition of Benjamin Graham’s The Intelligent Investor, and authored Your Money and Your Brain.

Where this appears

• The Psychology of Money — cited for the Graham “constant retesting” insight, the Markowitz interview, and Kahneman’s “I have no sunk costs” anecdote