Scientific Definition
Underestimating the probability of bad outcomes — especially to us.
Plain-English Definition
Underestimating the probability of bad outcomes — especially to us.
Feynman Explanation
Every project plan was written by an optimist who has never met the project.
Core Principle
Underestimating the probability of bad outcomes — especially to us.
Mechanisms
Underestimating the probability of bad outcomes — especially to us.
Pending editorial review.
Pending editorial review.
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Pending editorial review.
Inputs (Triggers)
Pending editorial review.
Outputs (Behaviors)
Pending editorial review.
Behavioral Signature
Every project plan was written by an optimist who has never met the project.
Examples
- Roadmaps that assume zero unknowns and infinite engineering capacity.
- Strategic plans systematically beat their own forecasts to death.
Pending editorial review.
Famous Experiments
Pending editorial review.
Design Principles
- Reference-class forecasting. Compare to the last five similar projects.
Measurement Approaches
Pending editorial review.
Evidence
Pending editorial review.
Pending editorial review.
The Perverse Incentive Lens™
How this behavior is exploited — and how to redesign around it.
- Reference-class forecasting. Compare to the last five similar projects.
Pending editorial review.
Pending editorial review.
Interactive Mini Network
Click any neighbor to re-center the graph and follow the threads of connection.
Knowledge Graph Neighbors
Auto-linked to the rest of the Human Behavior Taxonomy by family, domain, dimension, and shared keywords.
We prefer known risks to unknown ones, even when the unknown is better.
We ignore underlying probabilities in favor of vivid specifics.
Believing a specific scenario is more likely than its more general one.
Believing past random events influence future independent ones.
Believing streaks predict future streaks.
Overestimating the probability of bad outcomes.
Worst-cases assumed as base-cases because they 'feel responsible.'
We underestimate time and cost; we overestimate benefit.
We prefer eliminating a small risk completely over reducing a larger one partially.
Systematic deviations from rationality in judgment.
Doing something feels safer than doing nothing — even when nothing wins.
The brain evolved to reason adaptively, not always truthfully, to reduce the cost of errors.