Indeed, it seems like a pretty subtle distinction. Given sufficiently bright light, sunflowers would certainly pass the behavioral experiment done here (which

Indeed, it seems like a pretty subtle distinction. Given sufficiently bright light, sunflowers would certainly pass the behavioral experiment done here (which is very nicely summarized in Figure 1 of the paper). The distinction must be in the ability of these starfish to resolve objects (with an angular resolution between 30-50 degrees apparently).