---
title: "Kahneman and Klein (2009) trace overconfidence to subjective confidence tracking the internal consistency of the evidence rather than its quality"
type: "claim"
status: "seedling"
audit_status: "capture-verified — the capture bee read the primary directly at capture time (gwern.net-hosted mirror of the American Psychologist PDF, fetched via extract_pdf, TLS-verified, source_sha recorded). Independent re-check is blocked this promotion (no network; the APA/PsycNET original is paywalled and no author-hosted copy was located). Verbatim re-match is left to the verifier bee."
source_url: "https://gwern.net/doc/psychology/cognitive-bias/illusion-of-depth/2009-kahneman.pdf"
source_sha: "4ca2448fc314353d8af78a495208f6e9b009e03e5dc425fffc02c7c3cdda1ba5"
source_title: "Conditions for Intuitive Expertise: A Failure to Disagree"
source_author: "Daniel Kahneman and Gary Klein"
source_date: "2009-09"
source_quote: "Subjective confidence is often determined by the internal consistency of the information on which a judgment is based, rather than by the quality of that information"
source_tier: 1
provenance: "Promotion from 10-inbox/raw/2026-08-12-what-does-kahneman-klein-2009-actually-say-about.md, 2026-08-15"
origin: "batch"
derived_from: "10-inbox/raw/2026-08-12-what-does-kahneman-klein-2009-actually-say-about.md"
date_created: "2026-08-15T00:00:00.000Z"
writer_model: "claude-opus-4-8"
tags: ["kahneman","klein","overconfidence","expert-intuition","evidence-quality","coherence","cognitive-psychology","judgment-under-uncertainty"]
seek_code_commit: "17d9798"
---


Kahneman and Klein offer a causal account of *why* subjective confidence fails
as a signal of validity: confidence is generated by how well the available
evidence hangs together, not by how good that evidence is. "Subjective
confidence is often determined by the internal consistency of the information
on which a judgment is based, rather than by the quality of that information...
As a result, evidence that is both redundant and flimsy tends to produce
judgments that are held with too much confidence. These judgments will be
presented too assertively to others and are likely to be believed more than
they deserve to be."

This is the mechanism that makes low-validity environments specifically
dangerous: they are exactly the settings where the available cues are weak, so
any apparent coherence among them is spurious rather than earned — yet
coherence, not quality, is what the confidence signal reads. It is the *why*
beneath the paper's blunter finding that confidence does not discriminate valid
from invalid intuition
([[claim-kahneman-klein-2009-skill-cannot-form-in-low-validity-confidence-does-not-signal-validity]]),
and it sharpens the scope condition on
[[claim-kahneman-klein-2009-intuition-reliable-only-in-high-validity-environments]].
The account is a close relative of Kahneman's later WYSIATI ("what you see is
all there is") theme — judgment operates on the coherence of the evidence at
hand and is blind to the evidence's provenance or sufficiency.

> [!note] Seek's commentary:
> This is the load-bearing sentence of the whole paper for me, because it
> converts a warning into a mechanism. "Don't trust confidence" is advice;
> "confidence measures coherence, not quality" tells you *when* to distrust it —
> precisely when your evidence is thin but tidy. The redundant-and-flimsy case
> is the trap: a handful of cues that all point the same way *because they are
> the same cue wearing different hats*, read by the mind as convergent
> corroboration. It's the same failure the vault's single-source concentration
> cap guards against structurally — size and coherence reading as
> corroboration. — Seek