Psychology of Human Misjudgment

Munger's magnum opus: a taxonomy of 25 standard causes of human misjudgment, developed over decades of self-taught psychology and revised in 2005 at age 81. The framework was built by inversion — collecting instances of bad judgment rather than theorizing about good judgment.


The 25 Tendencies

#TendencyCore Mechanism
1Reward/Punishment SuperpowerIncentives change cognition, not just behavior
2Liking/LovingIgnore faults of the loved; distort facts to serve affection
3Disliking/HatingIgnore virtues of the hated; distort facts to serve hatred
4Doubt-AvoidanceRush to conclusions under puzzlement + stress
5Inconsistency-AvoidanceResist changing conclusions, habits, identities once formed
6CuriosityInnate drive to learn; strongest in humans among primates
7Kantian FairnessExpect and provide reciprocal courtesy; hostile when violated
8Envy/JealousyDeeply wired; taboo to discuss; drives more behavior than greed
9ReciprocationSubconsciously return favors and disfavors; exploitable
10Mere-AssociationPast associations distort judgment of new situations
11Pain-Avoiding DenialDistort reality to make it bearable
12Excessive Self-RegardOverrate yourself, your possessions, your conclusions
13OveroptimismBelieve what you wish; Demosthenes knew this 300 BC
14Deprival-SuperreactionLoss hurts more than equivalent gain helps; near-misses trigger it
15Social ProofThink/do what others think/do; strongest under stress
16Contrast-MisreactionJudge by contrast, not absolutes; small steps mask disaster
17Stress-InfluenceHeavy stress causes depression or Pavlovian breakdown
18Availability-MisweighingOverweight vivid/recent/available information
19Use-It-or-Lose-ItSkills atrophy without practice; maintain via simulator equivalents
20Drug-MisinfluenceChemical dependency destroys cognition and morals
21Senescence-MisinfluenceCognitive decay with age; continuous learning delays it
22Authority-MisinfluenceFollow leaders too far, even into obvious error
23TwaddlePrattle crowds out serious work; keep twaddlers away
24Reason-RespectingCompliance increases when reasons are given — even bad reasons
25LollapaloozaMultiple tendencies in confluence → extreme outcomes

Meta-Insights

  1. Tendencies combine — the lollapalooza-effect is more important than any single tendency
  2. Use a checklist — run through all 25 when analyzing any high-stakes situation
  3. Antidotes exist — for most tendencies (checklists, delay, disconfirming evidence, system design, rules like Sam Walton's no-gifts policy)
  4. Psychology professors missed the synthesis — they studied tendencies in isolation, like collecting butterflies, without asking how they interact

Connection to Other Concepts

Sources