Study
Spectral discrimination in color blind animals via chromatic aberration and pupil shape
Stubbs, Alexander L.; Stubbs, Christopher W.
Proceedings of the National Academy of Sciences, 2016
An optical model asked whether a cephalopod eye could extract colour information despite having only one visual pigment, by exploiting the fact that different wavelengths focus at different depths and that the unusual pupil shape exaggerates that effect.
- Studied in
- Octopus, Sepia, Loligo
The model showed that by changing focus and using an off-axis, U-shaped pupil, an animal with a single photoreceptor type could in principle infer wavelength.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Chromatic aberration combined with pupil shape offers a plausible route to colour vision in otherwise colour-blind cephalopods.
How NatureHQ reads it
A proposed solution to a real puzzle: cephalopods produce astonishing colour displays and match their backgrounds, yet their retinas contain a single visual pigment. This is a model, not an observation — no experiment has yet shown an octopus using this mechanism, and other explanations, including light sensitivity in the skin, are live. It belongs in the "promising idea" column rather than the "how it works" column.
- Purely theoretical; no behavioural or physiological test.
- Requires slow focus adjustments that may not fit fast behavioural colour matching.
- Competing explanations remain untested against it.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Proceedings of the National Academy of SciencesPublished in PNAS.
doi.org/10.1073/pnas.1524578113
This reference was resolved automatically against Crossref and OpenAlex on 2026-08-11.
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