MENTAL MODEL · M3706

System 1 and System 2

DecideHigh supportDecision Science

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Updated 2026-08-05

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INTRODUCTION

English translation pending.

CORE DEFINITION

A dual-process theory popularized by Daniel Kahneman in Thinking, Fast and Slow, describing two modes of cognition. System 1 is fast, automatic, associative, and always running; System 2 is slow, serial, effortful, and lazy, endorsing System 1's output unless it detects a problem. The core proposition is that most judgments originate in System 1, so systematic errors come from heuristics rather than from failures of reasoning ability.

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

- Mode check: ask which system is currently producing the judgment in front of you. - Deliberate switch: force slow thinking on decisions that are rare and consequential. - Guardrail design: build checklists so review fires without relying on willpower.

anchor

Anchor fast decisions

System 1 runs continuously and generates impressions cheaply, while System 2 consumes attention and energy and therefore engages only when triggered. Because System 2 usually accepts whatever System 1 supplies, heuristics such as anchoring and availability pass into decisions unchallenged. Errors appear precisely where intuition is miscalibrated and no trigger forces a deliberate review.

MINIMUM ACTION

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Practice this model in one real situation:

Label the decision as routine or as genuinely high-stakes. 2. For high-stakes calls, slow down and write the reasoning out. 3. Check the first answer against base rates or an outside view. 4. Invite a dissenting view from someone before committing to the call. 5. Use a checklist to trigger deliberate review every time.

Check to track your progress (stored locally)

Learning progress0%

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Source support: Explicit

link
en.wikipedia.orghttps://en.wikipedia.org/wiki/Thinking,_Fast_and_SlowZH · Explicit
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