🧮Conjunction Fallacy Test

A vivid, specific story can make an option feel more likely than a plain, general one — even when basic math says the exact opposite must be true. This test recreates one of the most famous demonstrations in judgment research: the conjunction fallacy, sometimes known as the "Linda problem."

How the Conjunction Fallacy Test Works

You'll read 3 short descriptions of fictional people, each written to strongly suggest a particular stereotype. For each one, you'll pick which of two statements about that person seems more likely: a single, general statement, or a more specific statement that combines two conditions. Your result shows how many times you picked the more specific, combined option — the one that's actually mathematically impossible to be more likely than the general one.

The Original Linda Problem

This effect was famously demonstrated by psychologists Amos Tversky and Daniel Kahneman in 1983 using a fictional character named Linda, described as outspoken and deeply concerned with social justice. Participants were asked whether it was more likely that Linda was "a bank teller" or "a bank teller who is active in the feminist movement." The overwhelming majority — including many people trained in statistics — chose the second, more specific option, even though it's a logical impossibility for a more specific claim to be more probable than the general claim it's built on.

Why the Combined Option Can Never Win

The core rule of probability at play here is simple: the chance of two things both being true (a conjunction) can never be higher than the chance of just one of them being true alone. Every additional condition added to a statement can only keep its probability the same or lower it — never raise it. The reason the combined option often feels more likely anyway is the representativeness heuristic: a story that matches a stereotype so well feels intuitively more "realistic" than a plain, generic alternative, even though intuitive plausibility and mathematical probability are two completely different things.

Tips for Spotting This Trap

• ✓Before comparing options emotionally, check whether one option is fully contained within the other — if so, the more specific one can't be more likely.
• ✓Notice when a description feels like it's "building a case" for a stereotype — that's often a signal the conjunction fallacy is being set up.
• ✓Try mentally stripping away the vivid personal details and just comparing the raw logical structure of each option.
• ✓Remember that a compelling story and a probable outcome are not the same thing.

Want to explore a related probability bias? Try our Gambler's Fallacy Test, which looks at how streaks of random events can distort your sense of what's likely to happen next.

Frequently Asked Questions