Common Knowledge is information that everyone knows, and everyone knows that everyone knows. It sits in the Cognition dimension (COG) of the Human Behavior Taxonomy™ as element HBT-COG-0163, within the Social family. The core principle: information that everyone knows, and everyone knows that everyone knows. In incentive terms, it matters because it changes the payoff people perceive before they choose — which means it can be designed for, or exploited.
Scientific Definition
Information that everyone knows, and everyone knows that everyone knows.
Plain-English Definition
Information that everyone knows, and everyone knows that everyone knows.
Feynman Explanation
The emperor has no clothes, but nobody says it until someone does.
Core Principle
Information that everyone knows, and everyone knows that everyone knows.
Mechanisms
Pending editorial review.
Information that everyone knows, and everyone knows that everyone knows.
Pending editorial review.
Pending editorial review.
Pending editorial review.
Pending editorial review.
Culture change requires making private knowledge common knowledge.
Inputs (Triggers)
Pending editorial review.
Outputs (Behaviors)
Pending editorial review.
Behavioral Signature
The emperor has no clothes, but nobody says it until someone does.
Examples
- A known problem is not fixed until a leader names it publicly.
- Culture change requires making private knowledge common knowledge.
Pending editorial review.
Original analysis from The Incentives Lab — how this element behaves inside real payoff structures.
Why this element matters to incentive design
Most organizations meet this element as a personnel problem. It is not one. The mechanism underneath it is straightforward: information that everyone knows, and everyone knows that everyone knows. You can recognize it in the field by its signature: the emperor has no clothes, but nobody says it until someone does. Every element in the Cognition dimension changes the perceived payoff of an action before the action happens, which is exactly where incentive design has leverage.
How it gets exploited
Left undesigned, culture change requires making private knowledge common knowledge. It is amplified whenever culture change requires making private knowledge common knowledge. Inside organizations that shows up as culture change requires making private knowledge common knowledge. The pattern is the same one Goodhart's Law describes: the measurable proxy attracts the effort, and the purpose behind it quietly loses funding.
How the Lab designs around it
The redesign move is to use all-hands forums to name the unnamed. The leverage is not in explaining the behavior to people. It is in changing what the behavior earns.
Famous Experiments
Pending editorial review.
Design Principles
- Use all-hands forums to name the unnamed.
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.
- Use all-hands forums to name the unnamed.
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.
A group decides on a course of action that nobody actually wants, because everyone assumes others prefer it.
Power tends to corrupt, and absolute power corrupts absolutely.
We attribute our own actions to situations but others' actions to their character.
We favor people who are similar to us or who like us.
Sacrificing for others without expecting a personal reward.
Masking the sponsors of a message to make it appear grassroots.
Disagreement grows more extreme as the parties think more about the issue.
Systematic errors in explaining the causes of behavior — yours or others'.
We accept vague, general statements as personally meaningful.
Adding the word 'because' (with any reason) increases compliance dramatically.
Behaviors spread through groups via observation and imitation.
We come to like people we've done a favor for, more than people who've helped us.
Where Common Knowledge is cited in the corpus
Essays, field guides, and diagnostics from The Incentives Lab that apply this element.
- EssayGoodhart's Law in the Real World
How measurable proxies capture judgment.
- EssayThe Perverse Incentives Hiding in Your KPIs
Cognitive shortcuts turned into scorecards.
- EssayAI Agents Inherit Your Incentives
How this element propagates into automated systems.
- CourseIncentives 101
The free ten-part primer on reading a payoff structure.
- ReferenceThe incentive glossary
Definitions for every mental model, bias, and fallacy in the corpus.
- ReferenceThe Periodic Table of Human Behavior
The full 1,267-element map this page belongs to.
Questions about Common Knowledge
- What is Common Knowledge?
- Common Knowledge is information that everyone knows, and everyone knows that everyone knows. It sits in the Cognition dimension (COG) of the Human Behavior Taxonomy™ as element HBT-COG-0163, within the Social family. The core principle: information that everyone knows, and everyone knows that everyone knows. In incentive terms, it matters because it changes the payoff people perceive before they choose — which means it can be designed for, or exploited.
- What is an example of Common Knowledge?
- Culture change requires making private knowledge common knowledge. The Incentives Lab catalogs everyday, organizational, and historical instances of this element on its Human Behavior Taxonomy™ page (HBT-COG-0163).
- How is Common Knowledge exploited?
- Culture change requires making private knowledge common knowledge.
- How do you design around Common Knowledge?
- Use all-hands forums to name the unnamed.
- Which behavioral dimension does Common Knowledge belong to?
- Common Knowledge is classified in the Cognition dimension (COG) of the Human Behavior Taxonomy™, family "Social", class "Mental Model". Its permanent identifier is HBT-COG-0163 and its evidence grade is B.