Table S2.

Prior behavioral cephalopod experiments testing for color vision

Experiment	Experiment description	Consistent with model?
1950: Kühn (21)	(A) Test of camouflage response on textured colored backgrounds vs. greyscale; (B) training experiment on Octopus vulgaris using stationary targets	Yes for both. Kühn (21) concludes a wavelength sensing capability; both of his experimental designs (A and B) allow for the determination of chromatically induced defocus
1973: Messenger et al. (9)	(C) Training experiments on octopus under fluorescent lighting using colored rods vibrated at 3 Hz; (D) nystagmus response in octopus to alternating colored stripes	Yes, rapidly vibrating color cues would make color assessment by chromatic defocus impossible. Yes, under our model, they are unable to judge coloration absent fine-scale structure; adjacent colors are not resolvable
1975: Roffe (10)	(E) Training experiment on octopus with unfocused monochromatic light projected onto a white screen without focusing cues	Yes, light projected onto uniform disk would not allow for determination of chromatic defocus
1977: Messenger (8)	(F) Training experiments on octopus with rectangles of colored cues vibrated at 3 Hz	Yes, rapid vibration makes color assessment by chromatic defocus impossible
1996: Marshall and Messenger (11)	(G) Camouflage assay using two adjacent colors of artificial fine gravel	Yes, under our model, adjacent colors are not resolvable
2006: Mäthger et al. (7)	(H) Nystagmus tracking response in Sepia using alternating adjacent colored bars rotated around the head of the animal; (i) camouflage assay using two adjacent colors in a uniform checkerboard	Yes for both. Both lines of evidence (H and I) use adjacent colors without fine-scale structure; this degeneracy defeats a spectral discrimination model using chromatically dependent defocus as seen in Fig. 3

This table provides a summary of how prior laboratory cephalopod behavior and vision experiments compare with the chromatic aberration model proposed here.