Conjunction Fallacy
Believing a specific scenario is more likely than its more general one.
"'Linda is a feminist bank teller' feels more likely than just 'Linda is a bank teller.' It can't be."
What is Conjunction Fallacy? Believing a specific scenario is more likely than its more general one. Forecasts that gain credibility by gaining unnecessary detail.
Strategies sold as detailed scenarios that are necessarily less likely than the general bet.
Forecasts that gain credibility by gaining unnecessary detail.
AI predictions trusted more when narratively rich; that's the wrong signal.
Decompose claims into base probabilities.
Linda is 31, single, outspoken, a philosophy major, active in social-justice causes. Which is more probable?
Pick the more likely statement about Linda today.
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The full taxonomy entry
Every concept in the Atlas uses the same structure — so Conjunction Fallacy can be compared, recombined, and cited like an element on a periodic table.
- Business
- Leadership
- Government
- Healthcare
- Education
- Sales
- Marketing
- AI
- Negotiation
- Media
- Public Policy
- Relationships
- Where in our org would Conjunction Fallacy most often show up unnoticed?
- Which metric, ritual, or contract clause quietly rewards Conjunction Fallacy?
- If we removed every payoff for Conjunction Fallacy, what behavior would replace it?
- Who benefits when Conjunction Fallacy persists — and who pays the cost?
- People defend the status quo using the language of conjunction fallacy.
- Decisions cluster around the easiest narrative rather than the strongest evidence.
- New data changes the slide deck but not the decision.
- Anyone naming the pattern is treated as the problem.
Every Atlas entry is a node in a knowledge graph. See the related rail below to follow the connections.
See Conjunction Fallacy through 5 lenses
Each layer of the Incentives OS reframes this concept with its own thinkers, vocabulary, and diagnostic question.
- Layer 2Behavioral Economics
Which biases are most likely operating right now?
- Layer 8Organizational Psychology
What is the org actually rewarding — versus claiming to reward?
- Layer 13Leadership
What kind of leadership move does this situation actually require?
- Layer 15AI & Alignment
What proxy reward is the AI optimizing — and what is it ignoring?
- Layer 17Information Theory
What is signal here — and what is noise being treated as signal?
Do you actually know Conjunction Fallacy?
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Which best describes Conjunction Fallacy?
Worked example, counter-example & concept map
On-demand AI analysis grounded in the Lab's research. Cached on your device after first run.
When you encounter Conjunction Fallacy, your prefrontal cortex has to do extra work to override the automatic response — and that override budget is finite.
Executive control, planning, impulse override, working memory, System 2. First thing to go offline under stress, fatigue, or low blood sugar. Why your 4pm decisions are worse than your 9am ones.
See Prefrontal in the Brain Atlas →Picked for you, from the Atlas
Ranked by shared learning paths, overlapping chips, and what you've saved.
We prefer known risks to unknown ones, even when the unknown is better.
We ignore underlying probabilities in favor of vivid specifics.
Believing past random events influence future independent ones.
Believing streaks predict future streaks.
Underestimating the probability of bad outcomes — especially to us.
Overestimating the probability of bad outcomes.
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More definitions to follow
Every term in the Atlas connects to a dozen others. Pick any of these and see where it takes you.
Each additional unit of a good provides less satisfaction than the previous one.
Neurochemistry of trust, bonding, and in-group loyalty.
Introducing an irrelevant topic to distract from the issue.
Demand for a good drops as more people own it.
Real cost includes data, ops, monitoring, governance, training.
Cuts that lift margin this quarter erode product quality and brand equity over years.
Posterior = (likelihood × prior) / evidence.
Police agencies that keep seized assets gain a direct fiscal interest in seizures.
Judging phenomena by the standards of one's own culture.
CEO pay tied to size rewards deal-making even when acquisitions destroy value.
IQ scores have risen substantially over generations.
Confidence in predictions outruns their actual accuracy.