---
title: "Boyer-Kassem et al.'s conjunction-fallacy refutation rejects both the non-degenerate and the general (degenerate) class of quantum-like models"
type: "claim"
status: "seedling"
source_url: "https://arxiv.org/abs/1606.03430"
source_title: "Quantum-like models cannot account for the conjunction fallacy"
source_author: "Thomas Boyer-Kassem, Sébastien Duchêne, Eric Guerci"
source_date: "2016-06-14T00:00:00.000Z"
source_quote: "As we have used very conservative statistical tests, we can safely say this general hypothesis is refuted in at least three tasks out of seven. So the present paper provides the first clear experimental rejection of the quantum-like explanation of the conjunction fallacy."
source_tier: 1
audit_status: "capture-verified. 2026-07-22 opus cross-model audit (scheduled): source_quote verbatim vs arXiv:1606.03430 (pp. lines re-extracted via extract_pdf, tls verified); journal cite Theory and Decision 81(4):479–510 confirmed via RePEc. CORRECTED: commentary read 'five papers' for Hyp #2's shared claim; per source (p.21, 'shared by all papers cited in the beginning of Section 2, except Franco (2009)') the count is four non-Franco papers, matching the note's own body list — changed to 'four papers'."
provenance: "Promotion from 10-inbox/raw/2026-07-19-is-the-conjunction-fallacy-failure-of-quantum-like.md, 2026-07-21"
origin: "batch"
derived_from: ["10-inbox/raw/2026-07-19-is-the-conjunction-fallacy-failure-of-quantum-like.md"]
date_created: "2026-07-21T00:00:00.000Z"
writer_model: "claude-sonnet-5"
tags: ["quantum-cognition","conjunction-fallacy","scope-limit","falsifiability"]
audits: ["2026-07-22 claude-opus-4-8"]
---


[[claim-quantum-like-models-fail-conjunction-fallacy]] records the vault's
existing headline finding from Boyer-Kassem, Duchêne & Guerci (2016,
arXiv:1606.03430; *Theory and Decision* 81:479–510) — that observed behavior
came out "at odds with the predictions of the quantum-like models." Reading
the paper's own hypothesis structure sharpens which models that headline
actually covers.

The paper tests three nested hypotheses across seven experimental tasks
(varying scenario, administration method, and payment). Hypothesis #1 — the
simplest "non-degenerate" model variant, the version defended by Franco
(2009) — is rejected outright. The paper's more consequential result is the
rejection of Hypothesis #2: the broader claim, made across the field's own
leading papers ([[entity-jerome-busemeyer|Busemeyer]] et al. 2011, Busemeyer
& Bruza 2012, Pothos & Busemeyer 2013, Busemeyer et al. 2015), that *either*
degenerate *or* non-degenerate quantum-like models can account for the
[[entity-conjunction-fallacy|conjunction fallacy]]. Using Bonferroni-corrected
(statistically conservative) tests, the authors reject this general
hypothesis in at least three of the seven tasks. So the refutation is not
confined to one narrow model variant that a defender could disown as
unrepresentative — it reaches the general model class the field's central
theorists actually use.

This distinguishes the finding from a typical "we didn't replicate X" null
result: it targets the load-bearing claim of the research program, not a
strawman edge case, and does so with a statistically conservative test
designed to make the rejection hard to explain away.

> [!note] Seek's commentary:
> The detail worth keeping past the headline is *which* hypothesis fell.
> "Quantum-like models fail" reads, on a first pass, like it could be a
> parameter-fitting problem in one paper's toy variant. It isn't — Hypothesis
> #2 is the shared claim of four papers by the field's own central authors.
> That's the difference between a dent and a target hit. — Seek