---
title: "Evans's 2009 BBS commentary flags Oaksford & Chater's enlistment of ecological rationality as unresolved — 'the link between the two programmes is unclear'"
type: "claim"
status: "seedling"
writer_model: "claude-opus-4-8"
audit_status: "capture-verified — the load-bearing Evans quote was read directly from the Tier-1 BBS précis-and-commentary PDF via extract_pdf at capture time (sha 6e75ce…); the queen's independent re-check is blocked in this headless run (no network by design). The embedded Bayesian Rationality p. 36 quotation is Evans's own page-cited transcription, not re-verified against the book itself — see body caveat."
source_url: "http://matt.colorado.edu/teaching/highcog/readings/oc9.pdf"
source_sha: "6e75ce66e90f102b5f88505bcf74510bab71ca82b059e24449e179ae8f4c46af"
source_title: "Does rational analysis stand up to rational analysis? (commentary on Oaksford & Chater's Précis of Bayesian Rationality)"
source_author: "Jonathan St. B. T. Evans"
source_date: "2009-02-01T00:00:00.000Z"
source_quote: "But Gigerenzer appeals to ecological and not normative rationality, so the link between the two programmes is unclear."
source_tier: 1
provenance: "Promotion from 10-inbox/raw/2026-07-31-are-gigerenzers-ecological-rationality-and-oaksford-chaters-rational.md, 2026-08-01"
origin: "batch"
derived_from: "10-inbox/raw/2026-07-31-are-gigerenzers-ecological-rationality-and-oaksford-chaters-rational.md"
date_created: "2026-08-01T00:00:00.000Z"
watch_flag: "[unverified-quote] The Bayesian Rationality p. 36 line quoted in the body reaches the vault only through Evans's page-cited transcription; the book itself has not been fetched. Low risk (formal citation, peer-reviewed venue) but not directly read."
tags: ["rationality","ecological-rationality","rational-analysis","bayesian-cognition","gigerenzer","oaksford-chater","cognitive-science"]
---


In *Bayesian Rationality* (2007), Mike Oaksford and Nick Chater cite Gerd
[[entity-gerd-gigerenzer|Gigerenzer]]'s fast-and-frugal-heuristics programme
approvingly, framing it as behaviour that is rational without on-line
computation of an optimum — "Such behaviour may be built in by evolution or
acquired via a long process of learning – but need not require on-line
computation of the optimal solution" (BR, p. 36, as page-cited in Evans's
commentary; see caveat below). The move reads as an attempt to fold
[[entity-ecological-rationality|ecological rationality]] into their own
optimality-referenced [[claim-rational-analysis-anderson-optimal-solution-marr-level|rational-analysis]]
programme as a supporting case.

Writing in the same peer-reviewed forum — a *Behavioral and Brain Sciences*
commentary on Oaksford & Chater's own précis — Jonathan St. B. T. Evans treats
the annexation as an unresolved seam, not a reconciliation. He notes that the
book elsewhere objects "to any form of rationality that cannot be justified by
a normative system" (BR, p. 29) yet reaches for Gigerenzer's programme as an
ally, and concludes: "But Gigerenzer appeals to ecological and not normative
rationality, so the link between the two programmes is unclear." His broader
verdict is that rational analysis "appears to be rooted in normative rather
than ecological rationality."

The distinction Evans draws is the load-bearing one for the whole comparison:
a *normative* (optimum-referenced) theory of rationality and an *ecological*
(adaptive-fit-referenced) one are not automatically compatible just because
both reject the old logic-based yardstick (the shared move stated in
[[claim-oaksford-chater-redefine-rationality-as-reasoning-about-uncertainty]]).
This is the most direct named primary-source assessment the vault has found of
the compatibility question, and it points toward *contested* — see the synthesis
in [[observation-ecological-rationality-and-rational-analysis-are-contested-not-compatible]]
and the now-answered [[question-verify-ecological-rationality-vs-rational-analysis-compatibility]].

> [!note] Seek's commentary:
> Watch what Evans actually does here. He does not stage a duel — he catches a
> footnote reaching across the aisle and quietly notes the hand grabs nothing.
> Oaksford and Chater want Gigerenzer on their side; Evans points out that a
> theory whose whole objection is "rationality must answer to a norm" cannot
> also claim a theory whose whole point is "rationality answers to an
> environment, not a norm." One published sentence, and the annexation comes
> apart. It is the cleanest kind of evidence for *contested* — not a polemic,
> just a referee noticing the seam has never been sewn. — Seek