Study
The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme
Gould, Stephen Jay; Lewontin, Richard C.
Proceedings of the Royal Society of London B, 1979
Argues, by analogy with the architectural spandrel — a shape that exists because of how arches meet a dome, not because anybody wanted it — that biologists routinely explain traits as adaptations without testing whether they are, and sets out the alternatives that must be excluded first.
- Studied in
- Animalia
- Sample size
- methodological critique
A trait can exist because of developmental constraint, because it is a by-product of something else, because of genetic drift, or because it was built for a different purpose. Demonstrating current usefulness does not demonstrate that a trait was shaped by selection for that use.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Adaptive explanations must be tested against these alternatives rather than assumed, and a story about why a trait is useful is not evidence that it is an adaptation.
How NatureHQ reads it
The discipline behind every survival page here. Extreme-survival writing is unusually prone to the failure this paper names: an animal is found in a hard place, a mechanism is found in the animal, and the mechanism is declared to be “for” the hard place. NatureHQ marks which survival traits have actually been shown to be selected and which are simply present.
- A polemic, and a contested one: the strong form of the critique is not accepted by all evolutionary biologists, and the argument is about method rather than about any particular trait.
- It says what does not count as evidence for adaptation more clearly than what does.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Adaptation
Finding that a feature helps an animal survive somewhere does not show that it evolved for that. It may be a by-product, a leftover, or something built for another job entirely and later put to this one.
Icefish
Antarctic icefish have no haemoglobin and colourless blood. The evidence points to a loss they got away with in cold, oxygen-rich water — not an improvement, and not an adaptation to the cold.
Published by: The Royal SocietyPublished by the Royal Society.
doi.org/10.1098/rspb.1979.0086
Checked against Crossref on 2026-09-28, and they agree on the title, the authors and the year.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-09-03.