Richard Marshall interviews Susanna Schellenberg in 3:AM Magazine:
3:AM: One of the questions about perception is whether we can only be conscious of conceptually structured content. Perhaps before going into your response to the issue you might lay out the issue for newcomers and say why non-conceptually structured perception is thought to be such a difficulty?
SS: This debate is in part terminological. Depending on how concepts are understood it is more or less plausible to think of experience as conceptually structured. Concepts have been understood in terms of mental representations, stereotypes, functional roles, and in terms, and inferential roles to name just a few standard candidates. Nonconceptual structures have been understood in terms of image-like or map-like representations, or simply in terms of the idea that we represent naked properties and objects without representing them in terms of employing concepts.
Reasons to think that perceptual content is nonconceptually structured are to account for the fineness of grain of perceptual experience and the richness of perceptual experience. The idea is that perceptual experience is much richer and finely grained than our concepts. For example, our color concepts are much more course grained than the color shades we are able to discriminate between in perception. If that’s right (and on certain notions of concepts it is), then that’s a reason to think experience is nonconceptually structured. Another reason is that non-rational animals have perceptions, but don’t have concepts, so perceptual content cannot be conceptually structured. Whether this is a good reason depends again on what notion of concept one is operating with. After all, on certain notions of concepts it’s unproblematic to attribute concepts to non-rational animals.
One standard reasons for thinking that perceptual content is conceptually structured is that on a Fregean understanding of content it’s not clear that content could not be conceptually structured. I don’t think this is a good reason for accepting the thesis that perceptual content is conceptually structured. In a number of papers, I’ve developed a Fregean notion of perceptual content in terms of employing perceptual capacities that are not conceptual capacities.
More here.