Explicitly distinguish coherence from probability

A story can be internally consistent and still be rare — learn to separate "makes sense" from "likely."

Why it works

The conjunction fallacy happens at the interface between narrative understanding and probability judgment: the brain’s story-comprehension system produces a sense of "that fits" which gets mislabeled as "that’s likely." Practicing the distinction — verbally labeling "this is coherent" separately from "this is frequent" — builds metacognitive separation between the two systems and reduces the substitution error. This is related to Kahneman’s general insight that fast associative reasoning substitutes an easier question (does this fit?) for the harder one (how often does this occur?).

How to do it

1. When evaluating a claim, explicitly state two separate judgments: "Coherence: 9/10 — this story hangs together well. Frequency: unknown — I haven’t checked the base rate."
2. Treat high coherence as a warning sign that you may be about to commit the conjunction error.
3. Look up or estimate the base rate before finalizing any judgment where coherence was the main driver.
4. Practice this labeling habit on news stories before applying it to your own planning.

Evidence

Dual-process theory research (Kahneman, Stanovich & West) supports the existence of fast associative reasoning that is separately calibrated from deliberate probability judgment. The coherence/probability separation is a metacognitive technique grounded in this literature; direct trials on the technique are limited. (mechanistic)

Dual-process framing is influential but also criticized for oversimplification; the practical metacognitive recommendation stands regardless.

Sources

• Kahneman (2011), Thinking, Fast and Slow

Common mistake

Treating "I understand why this would happen" as equivalent to "this is likely to happen" — understanding a mechanism doesn’t tell you how often that mechanism fires.