Cause of misjudgment № 21
Senescence-Misinfluence Tendency
Cognitive decline comes with age — but continuous learning and practice slow it, so the response is to keep the mind working.
Munger, who kept thinking sharply into his late nineties, was honest that aging brings real cognitive decline. Older brains lose some capacity, particularly for acquiring genuinely new skills, and — because of the related tendencies of self-regard and denial — the people declining are often the last to recognize it. He did not pretend otherwise, and he counted this among the standard causes of human misjudgment for good reason.
The hopeful half is that the decline is not uniform and can be substantially slowed. Munger connected this directly to the Use-It-or-Lose-It Tendency: skills that are continuously practiced hold up far better than skills left to rust, and a mind kept in vigorous, varied use ages more gracefully than one allowed to coast. Some very old people, by dint of lifelong mental exercise, retain abilities that much younger people lack.
His practical conclusion was to keep learning and keep thinking, deliberately and without let-up, as the best available defense against the erosion that age otherwise brings. The same continuous, multidisciplinary engagement that makes a person wiser in midlife is what keeps the machinery running longer in old age. It is, again, the “learning machine” ideal — and Munger’s own long, productive life was offered as evidence that the strategy works.
