Ep73 “The Dangers of Group Think on Decision Making” with Adi Sunderam
TL;DR
This episode explores how flawed decision-making stems not from mathematical errors in Bayesian updating, but from people restricting their 'model set'—the range of explanations they're willing to consider a priori. When groups socially exclude certain hypotheses, members invent increasingly convoluted interpretations to maintain their worldview rather than updating beliefs.
🧠 The Model Set Problem 2 insights
People exclude true explanations rather than updating incorrectly
Instead of failing at Bayesian math, decision-makers exclude the true model from their consideration set, forcing them to assign higher probability to increasingly unlikely alternatives as confirming data arrives.
Dogmatic priors make beliefs immune to evidence
When individuals commit to the position that no data could ever change their view, they exhibit a 'dogmatic prior' that renders rational debate and belief revision impossible.
👥 Group Think and Social Enforcement 2 insights
Communities enforce forbidden hypotheses through social penalties
Groups impose severe costs for considering certain explanations, creating echo chambers where members collaboratively generate convoluted alternative theories rather than facing excluded truths.
Intelligence enables sophisticated rationalization
Smart people are particularly adept at constructing creative explanations that fit data within restricted model sets, making them especially susceptible to this form of collective intellectual waste.
📊 Evidence From Markets and Politics 3 insights
Stock Twits shows persistent belief clustering
Analysis reveals Tesla bulls initially reacting to negative earnings announcements but quickly coalescing on post-hoc explanations like 'Elon Musk is a genius' to preserve their prior worldview.
Identical economic data gets filtered through opposing models
During the 2021-2022 inflation surge, doves and hawks interpreted the same CPI reports through conflicting frameworks, with doves continuously shifting explanations rather than updating beliefs.
Political polls show temporary volatility but long-term stickiness
Scandals cause short-term poll movements that revert to baselines within weeks, consistent with people using flexible interpretations to absorb contradictory data without changing core views.
Bottom Line
When confronting entrenched beliefs, ask 'What specific piece of evidence would change your mind?' before presenting facts to expose dogmatic priors and force consideration of previously excluded models.
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