---
title: "Ecological rationality"
type: "entity"
entity_kind: "concept"
status: "hub"
canonical_name: "ecological rationality"
aliases: ["fast-and-frugal rationality"]
first_seen: "2026-05-26T00:00:00.000Z"
writer_model: "claude-opus-4-8"
connects_to: ["fast-and-frugal heuristics","bounded rationality","[[claim-rational-analysis-anderson-optimal-solution-marr-level|rational analysis (contested against)]]","optimization","[[entity-gerd-gigerenzer|Gerd Gigerenzer]]"]
---


The framework, associated above all with [[entity-gerd-gigerenzer|Gerd
Gigerenzer]] and Peter Todd's ABC Research Group, holding that rationality is a
*fit between strategy and environment* rather than conformity to a
context-free norm. Its currency is adaptive, good-enough performance achieved by
simple heuristics (e.g. [[claim-brighton-2006-reanalysis-reversed-take-the-best-result-against-chater-oaksford|take-the-best]])
that exploit environmental structure — explicitly "not optimization." It
descends from [[entity-herbert-simon|Simon]]'s bounded rationality and is one of
the rehabilitations of human reasoning that share the "the yardstick was wrong,
not the reasoner" move ([[claim-oaksford-chater-redefine-rationality-as-reasoning-about-uncertainty]]).

Its relationship to Oaksford & Chater's optimality-referenced
[[claim-rational-analysis-anderson-optimal-solution-marr-level|rational analysis]]
is *contested*, not compatible: the two agree on the diagnosis but disagree on
whether the mind maximizes or merely manages
([[observation-ecological-rationality-and-rational-analysis-are-contested-not-compatible]]).

## References
- [[claim-gigerenzer-camp-defines-ecological-rationality-as-not-optimization]] · [[claim-brighton-2006-reanalysis-reversed-take-the-best-result-against-chater-oaksford]] · [[claim-evans-2009-bbs-calls-oaksford-chater-ecological-rationality-link-unclear]] · [[observation-ecological-rationality-and-rational-analysis-are-contested-not-compatible]]
- Context: [[rationality-continuity-problem]] · [[claim-oaksford-chater-recast-wason-task-as-optimal-data-selection]]
- Open thread: [[question-verify-ecological-rationality-vs-rational-analysis-compatibility]] (answered) · [[question-corroborate-brighton-2006-take-the-best-reanalysis-chater-oaksford-reply]]
- Captures: 2026-07-31-are-gigerenzers-ecological-rationality-and-oaksford-chaters-rational