Mental Models

Mental models and decision frameworks.
One page each.

Each page covers one mental model, cognitive bias, or decision tool from the Decisions Matter book. Structured to answer your question directly. Designed for real decisions, not academic study.

Field Note 01 Mental Model
Regret Minimization Framework
Project yourself to 80 and ask which choice you would regret not making. Jeff Bezos used this to start Amazon.
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Field Note 02 Decision Tool
The Pre-Mortem
Imagine the decision has already failed. Work backwards to find out why. The tool that bypasses groupthink.
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Field Note 03 Cognitive Bias
Confirmation Bias
By the time you are researching a choice, you have often already decided. Confirmation bias finds the evidence you need.
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Field Note 04 Cognitive Bias
Sunk Cost Fallacy
The money is gone. The years are spent. Staying because you invested is not loyalty — it is a thinking error.
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Field Note 05 Mental Model
Inversion Thinking
Charlie Munger's signature move: ask what would guarantee failure, then avoid it.
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Field Note 06 Decision Tool
The 10/10/10 Rule
How will you feel in 10 minutes, 10 months, and 10 years? Suzy Welch's framework for breaking out of short-term thinking.
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Field Note 07 Cognitive Bias
Loss Aversion
Losing hurts twice as much as gaining feels good. Kahneman's finding that drives most risk avoidance — and most financial mistakes.
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Field Note 08 Mental Model
First Principles Thinking
Break the problem to its fundamental truths and reason up. Elon Musk's most applied mental model.
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Field Note 09 Decision Guide
Should I Take This Job Offer?
A structured framework for the career decision most people make with their gut and regret with their head.
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Field Note 10 Decision Guide
How to Decide on a Co-Founder Equity Split
50/50 feels fair. It usually is not. How to have the conversation and structure the split.
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Field Note 11 Mental Model
The Two-Door Framework
Bezos's framework for classifying decisions: reversible vs. irreversible. Most organisations slow down the wrong ones.
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Field Note 12 Decision Tool
Hell Yes or No
Derek Sivers' rule for eliminating low-conviction commitments before they consume your time and attention.
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Field Note 13 Cognitive Bias
Overconfidence Bias
We overestimate our accuracy, our ability, and our probability of success. The most replicated finding in behavioural economics.
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Field Note 14 Cognitive Bias
Anchoring Bias
The first number you hear becomes the reference point for everything that follows — even when it is irrelevant.
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Field Note 15 Cognitive Bias
Status Quo Bias
We prefer the current state by default. The test: would you choose this if starting from zero today?
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Field Note 16 Mental Model
Expected Value Thinking
Probability multiplied by outcome, summed across scenarios. The framework used by poker players, investors, and military planners.
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Field Note 17 Decision Tool
The 5-Step Decision System
The core framework from Decisions Matter: capture, frame, scan for bias, pre-mortem, decide and record.
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Field Note 18 Decision Tool
How to Write a Decision Journal
Record what you decided, why, and what you expected. Review later. The feedback loop that improves decision-making over time.
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Field Note 19 Mental Model
Asymmetric Risk/Reward
The best decisions have capped downside and large upside. How to identify and seek out asymmetric opportunities.
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Field Note 20 Mental Model
Second-Order Thinking
First-order asks what happens next. Second-order asks what happens after that. Howard Marks applied it to investing. It works everywhere.
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Field Note 21 Cognitive Bias
The Planning Fallacy
We consistently underestimate time, cost, and risk. The fix is reference class forecasting — not optimism management.
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Field Note 22 Mental Model
Margin of Safety
Benjamin Graham's principle: the gap between what you think will happen and what you need if you are wrong.
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Field Note 23 Decision Tool
How to Detect Your Personal Bias Fingerprint
Not all biases affect everyone equally. How to audit your last five decisions and find the pattern.
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Field Note 24 Decision Guide
Teaching Kids to Make Better Decisions
Decision-making is a teachable skill. The frameworks, the age-appropriate approach, and the conversations that build judgment early.
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