Mental Models a field guide

An open field guide · 1,104 entries · 150 written so far

Ideas for thinking clearly, and the traps that get in the way.

Mental models, biases and fallacies explained from the outside in. Each entry starts with the moment you'd recognize, then the idea, then what to do about it, and ends with an honest note on the evidence.

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one idea orbits another

What kind of idea is it?

  • Traps

    Is my mind doing this to me?

    Something your mind does to you. Biases, fallacies and effects worth noticing.

    e.g. Ad Hominem

  • Tools

    How could I think this through?

    A lens you choose to apply. Techniques for thinking a problem through.

    e.g. A/B Testing

  • Patterns

    What will the world do next?

    How the world tends to behave. Laws and dynamics that keep showing up.

    e.g. Adverse Selection

  • Concepts

    What's the word for this?

    The vocabulary the others are built from.

    e.g. Asymmetric Information

Places to start

All 150 in the index →
Trap · No. 0705Overconfidence EffectYou promise the client Friday, leave no buffer, and are surprised when one ordinary snag pushes delivery into next week. Tool · No. 0199Consider-the-Opposite StrategyBefore sending a furious reply, you jot down three reasons your coworker’s message might not be an insult. Pattern · No. 0437Goodhart’s LawWhen a number becomes the goal, people find ways to move the number that don’t move the goal. Concept · No. 0694Opportunity CostYou accept a Saturday overtime shift, then realize it costs you the only afternoon you could spend with your visiting sister. Trap · No. 0191Confirmation BiasYou decide a job offer is right, then spend the evening reading only the reviews that make it sound good. Tool · No. 0087Bayesian UpdatingThe fraud alert looks damning, until you learn how often it flags perfectly ordinary purchases. Pattern · No. 0444GroupthinkIn the budget meeting, you leave your warning unspoken as everyone nods along with the director. Concept · No. 0343Expected ValueThe repair shop offers a $180 protection plan, and you weigh that price against repairs you might never need. Trap · No. 0895Selection BiasYou read glowing reviews of a difficult course, then notice that every reviewer made it to the final lesson. Tool · No. 0754Pre-MortemImagine the plan has already failed, then explain why. You’ll find problems you couldn’t see while hoping it would work. Pattern · No. 0630Moral HazardYour insurance pays the whole repair bill, so you accept the first quote instead of shopping around. Concept · No. 0591Marginal AnalysisThe hotel offers a room upgrade for $40, and you pause before clicking.

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