Concept · Cognitive Bias: Decision-making and judgment biases
Planning fallacy
Origin: Kahneman & Tversky, 1979
The Biological Bridge
This business construct is human-invented, but the outcome it's trying to achieve has deep biological roots.
Surface Construct
Underestimating time/cost/risk for future tasks
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Underlying Outcome
Optimism bias that enables action under uncertainty
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Biological Mechanism
Motivational optimism. Animals that accurately forecast the difficulty of migration, mating competition, or territory establishment might never attempt them. Slight overconfidence is necessary to initiate costly, uncertain ventures. The bias toward action exists because inaction is often more costly than failed attempts.
Key Insight: Planning fallacy may be a feature that prevents analysis paralysis. Accurate forecasting can be demotivating when action is required despite uncertainty.
The Full Picture
Embryonic development follows a genetic blueprint, yet consistently runs longer than the minimum theoretical timeline because each stage encounters stochastic delays: protein folding errors, resource fluctuations, checkpoint corrections. The planning fallacy isn't cognitive bias—it's the inevitable collision between idealized models and noisy reality. Biology plans in expected time but executes in probabilistic time, where variance always extends timelines.