Now please read the introduction and Chapter 1 of [Vision]. Make sure you understand Marr's notion of representation, the difference between his three levels of explanation, and the reasons for his moving to representation-based AI. Marr also writes these ideas up in Visual Information Processing from [Psychology of Vision]. You may find this easier to read.
Marr's model illustrates the advantages of having more than one
representation, and how different representations make different kinds
of information explicit. But his model is only a hypothesis about the
brain's workings. The point can be made more forcefully by looking at a
man-made construct (a computer program) whose author has chosen the
representations and documented the reasons for each, and this is why I
started with Evans' program. Note incidentally that Marr, Winston and
Evans were all at MIT (though not perhaps all at the same time).
Since you will be doing tutorials on vision, I'll leave the work of Marr
and his successors here. But representation is not only important to
vision. For a general view of its rôle in AI, see Roger Schank's
article in [Foundations of AI]. Schank's work has been particularly
concerned with the representation of memory, including the case-based
reasoning that I mentioned in connection with planning. I don't know
when the paper was written, but it would be typical of his attitude from
the late 70's onward.