Man-with-a-Hammer Tendency

The man-with-a-hammer tendency is Charlie Munger’s name for the cognitive bias captured by the proverb “to a man with a hammer, every problem looks like a nail” — the disposition to force every situation into the one or few tools you happen to possess. Munger names it directly in his Charlie Munger — Harvard Law School Fiftieth Reunion Address and offers the cure: “If a man has a vast set of skills over multiple disciplines, he, by definition, carries multiple tools and, therefore, will limit bad cognitive effects from man-with-a-hammer tendency.” It is the bias that makes Multidisciplinary Thinking not a luxury but a defense — the whole point of building a latticework of mental models is to stop reaching for the same hammer.

Within the wiki it is the misjudgment that Confirmation Bias most closely approximates: both describe a mind that distorts incoming reality to fit a prior commitment (in confirmation bias, a belief; in the hammer tendency, a tool or discipline). It belongs to Munger’s catalog of the standard causes of human misjudgment.

Context: Man-with-a-hammer tendency appears in Munger’s psychology-of-human-misjudgment framework (collected in Poor Charlie’s Almanack) as a driver of single-discipline over-reach; his prescribed antidote is broad, fluency-level multidisciplinary knowledge.

Where this appears

• Charlie Munger — Harvard Law School Fiftieth Reunion Address — explicitly named as the bias that a “vast set of skills over multiple disciplines” partially cures.
• Confirmation Bias — the wiki concept that most closely approximates this tendency among Munger’s misjudgments.